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9ae8ffe7 | 1 | /* Alias analysis for GNU C |
9cd9e512 | 2 | Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 |
1afdf91c | 3 | Free Software Foundation, Inc. |
9ae8ffe7 JL |
4 | Contributed by John Carr (jfc@mit.edu). |
5 | ||
1322177d | 6 | This file is part of GCC. |
9ae8ffe7 | 7 | |
1322177d LB |
8 | GCC is free software; you can redistribute it and/or modify it under |
9 | the terms of the GNU General Public License as published by the Free | |
10 | Software Foundation; either version 2, or (at your option) any later | |
11 | version. | |
9ae8ffe7 | 12 | |
1322177d LB |
13 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
9ae8ffe7 JL |
17 | |
18 | You should have received a copy of the GNU General Public License | |
1322177d | 19 | along with GCC; see the file COPYING. If not, write to the Free |
366ccddb KC |
20 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA |
21 | 02110-1301, 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" |
78528714 JQ |
31 | #include "alias.h" |
32 | #include "emit-rtl.h" | |
9ae8ffe7 JL |
33 | #include "regs.h" |
34 | #include "hard-reg-set.h" | |
e004f2f7 | 35 | #include "basic-block.h" |
9ae8ffe7 | 36 | #include "flags.h" |
264fac34 | 37 | #include "output.h" |
2e107e9e | 38 | #include "toplev.h" |
eab5c70a | 39 | #include "cselib.h" |
3932261a | 40 | #include "splay-tree.h" |
ac606739 | 41 | #include "ggc.h" |
d23c55c2 | 42 | #include "langhooks.h" |
0d446150 | 43 | #include "timevar.h" |
ab780373 | 44 | #include "target.h" |
b255a036 | 45 | #include "cgraph.h" |
9ddb66ca | 46 | #include "varray.h" |
ef330312 | 47 | #include "tree-pass.h" |
ea900239 DB |
48 | #include "ipa-type-escape.h" |
49 | ||
50 | /* The aliasing API provided here solves related but different problems: | |
51 | ||
52 | Say there exists (in c) | |
53 | ||
54 | struct X { | |
55 | struct Y y1; | |
56 | struct Z z2; | |
57 | } x1, *px1, *px2; | |
58 | ||
59 | struct Y y2, *py; | |
60 | struct Z z2, *pz; | |
61 | ||
62 | ||
63 | py = &px1.y1; | |
64 | px2 = &x1; | |
65 | ||
66 | Consider the four questions: | |
67 | ||
68 | Can a store to x1 interfere with px2->y1? | |
69 | Can a store to x1 interfere with px2->z2? | |
70 | (*px2).z2 | |
71 | Can a store to x1 change the value pointed to by with py? | |
72 | Can a store to x1 change the value pointed to by with pz? | |
73 | ||
74 | The answer to these questions can be yes, yes, yes, and maybe. | |
75 | ||
76 | The first two questions can be answered with a simple examination | |
77 | of the type system. If structure X contains a field of type Y then | |
78 | a store thru a pointer to an X can overwrite any field that is | |
79 | contained (recursively) in an X (unless we know that px1 != px2). | |
80 | ||
81 | The last two of the questions can be solved in the same way as the | |
82 | first two questions but this is too conservative. The observation | |
83 | is that in some cases analysis we can know if which (if any) fields | |
84 | are addressed and if those addresses are used in bad ways. This | |
85 | analysis may be language specific. In C, arbitrary operations may | |
86 | be applied to pointers. However, there is some indication that | |
87 | this may be too conservative for some C++ types. | |
88 | ||
89 | The pass ipa-type-escape does this analysis for the types whose | |
90 | instances do not escape across the compilation boundary. | |
91 | ||
92 | Historically in GCC, these two problems were combined and a single | |
93 | data structure was used to represent the solution to these | |
94 | problems. We now have two similar but different data structures, | |
95 | The data structure to solve the last two question is similar to the | |
96 | first, but does not contain have the fields in it whose address are | |
97 | never taken. For types that do escape the compilation unit, the | |
98 | data structures will have identical information. | |
99 | */ | |
3932261a MM |
100 | |
101 | /* The alias sets assigned to MEMs assist the back-end in determining | |
102 | which MEMs can alias which other MEMs. In general, two MEMs in | |
ac3d9668 RK |
103 | different alias sets cannot alias each other, with one important |
104 | exception. Consider something like: | |
3932261a | 105 | |
01d28c3f | 106 | struct S { int i; double d; }; |
3932261a MM |
107 | |
108 | a store to an `S' can alias something of either type `int' or type | |
109 | `double'. (However, a store to an `int' cannot alias a `double' | |
110 | and vice versa.) We indicate this via a tree structure that looks | |
111 | like: | |
112 | struct S | |
113 | / \ | |
114 | / \ | |
115 | |/_ _\| | |
116 | int double | |
117 | ||
ac3d9668 RK |
118 | (The arrows are directed and point downwards.) |
119 | In this situation we say the alias set for `struct S' is the | |
120 | `superset' and that those for `int' and `double' are `subsets'. | |
121 | ||
3bdf5ad1 RK |
122 | To see whether two alias sets can point to the same memory, we must |
123 | see if either alias set is a subset of the other. We need not trace | |
95bd1dd7 | 124 | past immediate descendants, however, since we propagate all |
3bdf5ad1 | 125 | grandchildren up one level. |
3932261a MM |
126 | |
127 | Alias set zero is implicitly a superset of all other alias sets. | |
128 | However, this is no actual entry for alias set zero. It is an | |
129 | error to attempt to explicitly construct a subset of zero. */ | |
130 | ||
b604074c | 131 | struct alias_set_entry GTY(()) |
d4b60170 | 132 | { |
3932261a | 133 | /* The alias set number, as stored in MEM_ALIAS_SET. */ |
3bdf5ad1 | 134 | HOST_WIDE_INT alias_set; |
3932261a MM |
135 | |
136 | /* The children of the alias set. These are not just the immediate | |
95bd1dd7 | 137 | children, but, in fact, all descendants. So, if we have: |
3932261a | 138 | |
ca7fd9cd | 139 | struct T { struct S s; float f; } |
3932261a MM |
140 | |
141 | continuing our example above, the children here will be all of | |
142 | `int', `double', `float', and `struct S'. */ | |
b604074c | 143 | splay_tree GTY((param1_is (int), param2_is (int))) children; |
2bf105ab RK |
144 | |
145 | /* Nonzero if would have a child of zero: this effectively makes this | |
146 | alias set the same as alias set zero. */ | |
147 | int has_zero_child; | |
b604074c GK |
148 | }; |
149 | typedef struct alias_set_entry *alias_set_entry; | |
9ae8ffe7 | 150 | |
4682ae04 AJ |
151 | static int rtx_equal_for_memref_p (rtx, rtx); |
152 | static rtx find_symbolic_term (rtx); | |
4682ae04 AJ |
153 | static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT); |
154 | static void record_set (rtx, rtx, void *); | |
155 | static int base_alias_check (rtx, rtx, enum machine_mode, | |
156 | enum machine_mode); | |
157 | static rtx find_base_value (rtx); | |
158 | static int mems_in_disjoint_alias_sets_p (rtx, rtx); | |
159 | static int insert_subset_children (splay_tree_node, void*); | |
160 | static tree find_base_decl (tree); | |
161 | static alias_set_entry get_alias_set_entry (HOST_WIDE_INT); | |
162 | static rtx fixed_scalar_and_varying_struct_p (rtx, rtx, rtx, rtx, | |
163 | int (*) (rtx, int)); | |
164 | static int aliases_everything_p (rtx); | |
165 | static bool nonoverlapping_component_refs_p (tree, tree); | |
166 | static tree decl_for_component_ref (tree); | |
167 | static rtx adjust_offset_for_component_ref (tree, rtx); | |
168 | static int nonoverlapping_memrefs_p (rtx, rtx); | |
389fdba0 | 169 | static int write_dependence_p (rtx, rtx, int); |
4682ae04 | 170 | |
4682ae04 | 171 | static void memory_modified_1 (rtx, rtx, void *); |
04e2b4d3 | 172 | static void record_alias_subset (HOST_WIDE_INT, HOST_WIDE_INT); |
9ae8ffe7 JL |
173 | |
174 | /* Set up all info needed to perform alias analysis on memory references. */ | |
175 | ||
d4b60170 | 176 | /* Returns the size in bytes of the mode of X. */ |
9ae8ffe7 JL |
177 | #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) |
178 | ||
41472af8 | 179 | /* Returns nonzero if MEM1 and MEM2 do not alias because they are in |
264fac34 MM |
180 | different alias sets. We ignore alias sets in functions making use |
181 | of variable arguments because the va_arg macros on some systems are | |
182 | not legal ANSI C. */ | |
183 | #define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2) \ | |
3932261a | 184 | mems_in_disjoint_alias_sets_p (MEM1, MEM2) |
41472af8 | 185 | |
ea64ef27 | 186 | /* Cap the number of passes we make over the insns propagating alias |
ac3d9668 | 187 | information through set chains. 10 is a completely arbitrary choice. */ |
ea64ef27 | 188 | #define MAX_ALIAS_LOOP_PASSES 10 |
ca7fd9cd | 189 | |
9ae8ffe7 JL |
190 | /* reg_base_value[N] gives an address to which register N is related. |
191 | If all sets after the first add or subtract to the current value | |
192 | or otherwise modify it so it does not point to a different top level | |
193 | object, reg_base_value[N] is equal to the address part of the source | |
2a2c8203 JC |
194 | of the first set. |
195 | ||
196 | A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
197 | expressions represent certain special values: function arguments and | |
ca7fd9cd | 198 | the stack, frame, and argument pointers. |
b3b5ad95 JL |
199 | |
200 | The contents of an ADDRESS is not normally used, the mode of the | |
201 | ADDRESS determines whether the ADDRESS is a function argument or some | |
202 | other special value. Pointer equality, not rtx_equal_p, determines whether | |
203 | two ADDRESS expressions refer to the same base address. | |
204 | ||
205 | The only use of the contents of an ADDRESS is for determining if the | |
206 | current function performs nonlocal memory memory references for the | |
207 | purposes of marking the function as a constant function. */ | |
2a2c8203 | 208 | |
c582d54a | 209 | static GTY(()) varray_type reg_base_value; |
ac606739 | 210 | static rtx *new_reg_base_value; |
c582d54a JH |
211 | |
212 | /* We preserve the copy of old array around to avoid amount of garbage | |
213 | produced. About 8% of garbage produced were attributed to this | |
214 | array. */ | |
1431042e | 215 | static GTY((deletable)) varray_type old_reg_base_value; |
d4b60170 | 216 | |
bf1660a6 JL |
217 | /* Static hunks of RTL used by the aliasing code; these are initialized |
218 | once per function to avoid unnecessary RTL allocations. */ | |
219 | static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER]; | |
220 | ||
9ae8ffe7 | 221 | #define REG_BASE_VALUE(X) \ |
c582d54a JH |
222 | (reg_base_value && REGNO (X) < VARRAY_SIZE (reg_base_value) \ |
223 | ? VARRAY_RTX (reg_base_value, REGNO (X)) : 0) | |
9ae8ffe7 | 224 | |
c13e8210 | 225 | /* Vector indexed by N giving the initial (unchanging) value known for |
bb1acb3e RH |
226 | pseudo-register N. This array is initialized in init_alias_analysis, |
227 | and does not change until end_alias_analysis is called. */ | |
228 | static GTY((length("reg_known_value_size"))) rtx *reg_known_value; | |
9ae8ffe7 JL |
229 | |
230 | /* Indicates number of valid entries in reg_known_value. */ | |
bb1acb3e | 231 | static GTY(()) unsigned int reg_known_value_size; |
9ae8ffe7 JL |
232 | |
233 | /* Vector recording for each reg_known_value whether it is due to a | |
234 | REG_EQUIV note. Future passes (viz., reload) may replace the | |
235 | pseudo with the equivalent expression and so we account for the | |
ac3d9668 RK |
236 | dependences that would be introduced if that happens. |
237 | ||
238 | The REG_EQUIV notes created in assign_parms may mention the arg | |
239 | pointer, and there are explicit insns in the RTL that modify the | |
240 | arg pointer. Thus we must ensure that such insns don't get | |
241 | scheduled across each other because that would invalidate the | |
242 | REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
243 | wrong, but solving the problem in the scheduler will likely give | |
244 | better code, so we do it here. */ | |
bb1acb3e | 245 | static bool *reg_known_equiv_p; |
9ae8ffe7 | 246 | |
2a2c8203 JC |
247 | /* True when scanning insns from the start of the rtl to the |
248 | NOTE_INSN_FUNCTION_BEG note. */ | |
83bbd9b6 | 249 | static bool copying_arguments; |
9ae8ffe7 | 250 | |
3932261a | 251 | /* The splay-tree used to store the various alias set entries. */ |
b604074c | 252 | static GTY ((param_is (struct alias_set_entry))) varray_type alias_sets; |
ac3d9668 | 253 | \f |
3932261a MM |
254 | /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
255 | such an entry, or NULL otherwise. */ | |
256 | ||
9ddb66ca | 257 | static inline alias_set_entry |
4682ae04 | 258 | get_alias_set_entry (HOST_WIDE_INT alias_set) |
3932261a | 259 | { |
9ddb66ca | 260 | return (alias_set_entry)VARRAY_GENERIC_PTR (alias_sets, alias_set); |
3932261a MM |
261 | } |
262 | ||
ac3d9668 RK |
263 | /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that |
264 | the two MEMs cannot alias each other. */ | |
3932261a | 265 | |
9ddb66ca | 266 | static inline int |
4682ae04 | 267 | mems_in_disjoint_alias_sets_p (rtx mem1, rtx mem2) |
3932261a | 268 | { |
3932261a MM |
269 | /* Perform a basic sanity check. Namely, that there are no alias sets |
270 | if we're not using strict aliasing. This helps to catch bugs | |
271 | whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
272 | where a MEM is allocated in some way other than by the use of | |
273 | gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
274 | use alias sets to indicate that spilled registers cannot alias each | |
275 | other, we might need to remove this check. */ | |
298e6adc NS |
276 | gcc_assert (flag_strict_aliasing |
277 | || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2))); | |
3932261a | 278 | |
1da68f56 RK |
279 | return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); |
280 | } | |
3932261a | 281 | |
1da68f56 RK |
282 | /* Insert the NODE into the splay tree given by DATA. Used by |
283 | record_alias_subset via splay_tree_foreach. */ | |
284 | ||
285 | static int | |
4682ae04 | 286 | insert_subset_children (splay_tree_node node, void *data) |
1da68f56 RK |
287 | { |
288 | splay_tree_insert ((splay_tree) data, node->key, node->value); | |
289 | ||
290 | return 0; | |
291 | } | |
292 | ||
293 | /* Return 1 if the two specified alias sets may conflict. */ | |
294 | ||
295 | int | |
4682ae04 | 296 | alias_sets_conflict_p (HOST_WIDE_INT set1, HOST_WIDE_INT set2) |
1da68f56 RK |
297 | { |
298 | alias_set_entry ase; | |
299 | ||
300 | /* If have no alias set information for one of the operands, we have | |
301 | to assume it can alias anything. */ | |
302 | if (set1 == 0 || set2 == 0 | |
303 | /* If the two alias sets are the same, they may alias. */ | |
304 | || set1 == set2) | |
305 | return 1; | |
3932261a | 306 | |
3bdf5ad1 | 307 | /* See if the first alias set is a subset of the second. */ |
1da68f56 | 308 | ase = get_alias_set_entry (set1); |
2bf105ab RK |
309 | if (ase != 0 |
310 | && (ase->has_zero_child | |
311 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
312 | (splay_tree_key) set2))) |
313 | return 1; | |
3932261a MM |
314 | |
315 | /* Now do the same, but with the alias sets reversed. */ | |
1da68f56 | 316 | ase = get_alias_set_entry (set2); |
2bf105ab RK |
317 | if (ase != 0 |
318 | && (ase->has_zero_child | |
319 | || splay_tree_lookup (ase->children, | |
1da68f56 RK |
320 | (splay_tree_key) set1))) |
321 | return 1; | |
3932261a | 322 | |
1da68f56 | 323 | /* The two alias sets are distinct and neither one is the |
3932261a | 324 | child of the other. Therefore, they cannot alias. */ |
1da68f56 | 325 | return 0; |
3932261a | 326 | } |
5399d643 JW |
327 | |
328 | /* Return 1 if the two specified alias sets might conflict, or if any subtype | |
329 | of these alias sets might conflict. */ | |
330 | ||
331 | int | |
332 | alias_sets_might_conflict_p (HOST_WIDE_INT set1, HOST_WIDE_INT set2) | |
333 | { | |
334 | if (set1 == 0 || set2 == 0 || set1 == set2) | |
335 | return 1; | |
336 | ||
337 | return 0; | |
338 | } | |
339 | ||
3bdf5ad1 | 340 | \f |
1da68f56 RK |
341 | /* Return 1 if any MEM object of type T1 will always conflict (using the |
342 | dependency routines in this file) with any MEM object of type T2. | |
343 | This is used when allocating temporary storage. If T1 and/or T2 are | |
344 | NULL_TREE, it means we know nothing about the storage. */ | |
345 | ||
346 | int | |
4682ae04 | 347 | objects_must_conflict_p (tree t1, tree t2) |
1da68f56 | 348 | { |
82d610ec RK |
349 | HOST_WIDE_INT set1, set2; |
350 | ||
e8ea2809 RK |
351 | /* If neither has a type specified, we don't know if they'll conflict |
352 | because we may be using them to store objects of various types, for | |
353 | example the argument and local variables areas of inlined functions. */ | |
981a4c34 | 354 | if (t1 == 0 && t2 == 0) |
e8ea2809 RK |
355 | return 0; |
356 | ||
1da68f56 RK |
357 | /* If they are the same type, they must conflict. */ |
358 | if (t1 == t2 | |
359 | /* Likewise if both are volatile. */ | |
360 | || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
361 | return 1; | |
362 | ||
82d610ec RK |
363 | set1 = t1 ? get_alias_set (t1) : 0; |
364 | set2 = t2 ? get_alias_set (t2) : 0; | |
1da68f56 | 365 | |
82d610ec RK |
366 | /* Otherwise they conflict if they have no alias set or the same. We |
367 | can't simply use alias_sets_conflict_p here, because we must make | |
368 | sure that every subtype of t1 will conflict with every subtype of | |
369 | t2 for which a pair of subobjects of these respective subtypes | |
370 | overlaps on the stack. */ | |
371 | return set1 == 0 || set2 == 0 || set1 == set2; | |
1da68f56 RK |
372 | } |
373 | \f | |
3bdf5ad1 RK |
374 | /* T is an expression with pointer type. Find the DECL on which this |
375 | expression is based. (For example, in `a[i]' this would be `a'.) | |
376 | If there is no such DECL, or a unique decl cannot be determined, | |
f5143c46 | 377 | NULL_TREE is returned. */ |
3bdf5ad1 RK |
378 | |
379 | static tree | |
4682ae04 | 380 | find_base_decl (tree t) |
3bdf5ad1 | 381 | { |
6615c446 | 382 | tree d0, d1; |
3bdf5ad1 RK |
383 | |
384 | if (t == 0 || t == error_mark_node || ! POINTER_TYPE_P (TREE_TYPE (t))) | |
385 | return 0; | |
386 | ||
0b494699 ILT |
387 | /* If this is a declaration, return it. If T is based on a restrict |
388 | qualified decl, return that decl. */ | |
6615c446 | 389 | if (DECL_P (t)) |
0b494699 ILT |
390 | { |
391 | if (TREE_CODE (t) == VAR_DECL && DECL_BASED_ON_RESTRICT_P (t)) | |
392 | t = DECL_GET_RESTRICT_BASE (t); | |
393 | return t; | |
394 | } | |
3bdf5ad1 RK |
395 | |
396 | /* Handle general expressions. It would be nice to deal with | |
397 | COMPONENT_REFs here. If we could tell that `a' and `b' were the | |
398 | same, then `a->f' and `b->f' are also the same. */ | |
399 | switch (TREE_CODE_CLASS (TREE_CODE (t))) | |
400 | { | |
6615c446 | 401 | case tcc_unary: |
3bdf5ad1 RK |
402 | return find_base_decl (TREE_OPERAND (t, 0)); |
403 | ||
6615c446 | 404 | case tcc_binary: |
3bdf5ad1 RK |
405 | /* Return 0 if found in neither or both are the same. */ |
406 | d0 = find_base_decl (TREE_OPERAND (t, 0)); | |
407 | d1 = find_base_decl (TREE_OPERAND (t, 1)); | |
408 | if (d0 == d1) | |
409 | return d0; | |
410 | else if (d0 == 0) | |
411 | return d1; | |
412 | else if (d1 == 0) | |
413 | return d0; | |
414 | else | |
415 | return 0; | |
416 | ||
3bdf5ad1 RK |
417 | default: |
418 | return 0; | |
419 | } | |
420 | } | |
421 | ||
2039d7aa RH |
422 | /* Return true if all nested component references handled by |
423 | get_inner_reference in T are such that we should use the alias set | |
424 | provided by the object at the heart of T. | |
425 | ||
426 | This is true for non-addressable components (which don't have their | |
427 | own alias set), as well as components of objects in alias set zero. | |
428 | This later point is a special case wherein we wish to override the | |
429 | alias set used by the component, but we don't have per-FIELD_DECL | |
430 | assignable alias sets. */ | |
431 | ||
432 | bool | |
433 | component_uses_parent_alias_set (tree t) | |
6e24b709 | 434 | { |
afe84921 RH |
435 | while (1) |
436 | { | |
2039d7aa | 437 | /* If we're at the end, it vacuously uses its own alias set. */ |
afe84921 | 438 | if (!handled_component_p (t)) |
2039d7aa | 439 | return false; |
afe84921 RH |
440 | |
441 | switch (TREE_CODE (t)) | |
442 | { | |
443 | case COMPONENT_REF: | |
444 | if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))) | |
2039d7aa | 445 | return true; |
afe84921 RH |
446 | break; |
447 | ||
448 | case ARRAY_REF: | |
449 | case ARRAY_RANGE_REF: | |
450 | if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))) | |
2039d7aa | 451 | return true; |
afe84921 RH |
452 | break; |
453 | ||
454 | case REALPART_EXPR: | |
455 | case IMAGPART_EXPR: | |
456 | break; | |
457 | ||
458 | default: | |
459 | /* Bitfields and casts are never addressable. */ | |
2039d7aa | 460 | return true; |
afe84921 RH |
461 | } |
462 | ||
463 | t = TREE_OPERAND (t, 0); | |
2039d7aa RH |
464 | if (get_alias_set (TREE_TYPE (t)) == 0) |
465 | return true; | |
afe84921 | 466 | } |
6e24b709 RK |
467 | } |
468 | ||
3bdf5ad1 RK |
469 | /* Return the alias set for T, which may be either a type or an |
470 | expression. Call language-specific routine for help, if needed. */ | |
471 | ||
472 | HOST_WIDE_INT | |
4682ae04 | 473 | get_alias_set (tree t) |
3bdf5ad1 RK |
474 | { |
475 | HOST_WIDE_INT set; | |
3bdf5ad1 RK |
476 | |
477 | /* If we're not doing any alias analysis, just assume everything | |
478 | aliases everything else. Also return 0 if this or its type is | |
479 | an error. */ | |
480 | if (! flag_strict_aliasing || t == error_mark_node | |
481 | || (! TYPE_P (t) | |
482 | && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
483 | return 0; | |
484 | ||
485 | /* We can be passed either an expression or a type. This and the | |
f47e9b4e RK |
486 | language-specific routine may make mutually-recursive calls to each other |
487 | to figure out what to do. At each juncture, we see if this is a tree | |
488 | that the language may need to handle specially. First handle things that | |
738cc472 | 489 | aren't types. */ |
f824e5c3 | 490 | if (! TYPE_P (t)) |
3bdf5ad1 | 491 | { |
738cc472 | 492 | tree inner = t; |
738cc472 | 493 | |
8ac61af7 RK |
494 | /* Remove any nops, then give the language a chance to do |
495 | something with this tree before we look at it. */ | |
496 | STRIP_NOPS (t); | |
ae2bcd98 | 497 | set = lang_hooks.get_alias_set (t); |
8ac61af7 RK |
498 | if (set != -1) |
499 | return set; | |
500 | ||
738cc472 | 501 | /* First see if the actual object referenced is an INDIRECT_REF from a |
6fce44af RK |
502 | restrict-qualified pointer or a "void *". */ |
503 | while (handled_component_p (inner)) | |
738cc472 | 504 | { |
6fce44af | 505 | inner = TREE_OPERAND (inner, 0); |
8ac61af7 | 506 | STRIP_NOPS (inner); |
738cc472 RK |
507 | } |
508 | ||
509 | /* Check for accesses through restrict-qualified pointers. */ | |
1b096a0a | 510 | if (INDIRECT_REF_P (inner)) |
738cc472 RK |
511 | { |
512 | tree decl = find_base_decl (TREE_OPERAND (inner, 0)); | |
513 | ||
514 | if (decl && DECL_POINTER_ALIAS_SET_KNOWN_P (decl)) | |
515 | { | |
e5837c07 | 516 | /* If we haven't computed the actual alias set, do it now. */ |
738cc472 RK |
517 | if (DECL_POINTER_ALIAS_SET (decl) == -2) |
518 | { | |
4f430fb9 MM |
519 | tree pointed_to_type = TREE_TYPE (TREE_TYPE (decl)); |
520 | ||
738cc472 RK |
521 | /* No two restricted pointers can point at the same thing. |
522 | However, a restricted pointer can point at the same thing | |
523 | as an unrestricted pointer, if that unrestricted pointer | |
524 | is based on the restricted pointer. So, we make the | |
525 | alias set for the restricted pointer a subset of the | |
526 | alias set for the type pointed to by the type of the | |
527 | decl. */ | |
528 | HOST_WIDE_INT pointed_to_alias_set | |
4f430fb9 | 529 | = get_alias_set (pointed_to_type); |
738cc472 RK |
530 | |
531 | if (pointed_to_alias_set == 0) | |
532 | /* It's not legal to make a subset of alias set zero. */ | |
e7844ffb | 533 | DECL_POINTER_ALIAS_SET (decl) = 0; |
4f430fb9 MM |
534 | else if (AGGREGATE_TYPE_P (pointed_to_type)) |
535 | /* For an aggregate, we must treat the restricted | |
536 | pointer the same as an ordinary pointer. If we | |
537 | were to make the type pointed to by the | |
538 | restricted pointer a subset of the pointed-to | |
539 | type, then we would believe that other subsets | |
540 | of the pointed-to type (such as fields of that | |
541 | type) do not conflict with the type pointed to | |
471854f8 | 542 | by the restricted pointer. */ |
4f430fb9 MM |
543 | DECL_POINTER_ALIAS_SET (decl) |
544 | = pointed_to_alias_set; | |
738cc472 RK |
545 | else |
546 | { | |
547 | DECL_POINTER_ALIAS_SET (decl) = new_alias_set (); | |
ca7fd9cd KH |
548 | record_alias_subset (pointed_to_alias_set, |
549 | DECL_POINTER_ALIAS_SET (decl)); | |
738cc472 RK |
550 | } |
551 | } | |
552 | ||
553 | /* We use the alias set indicated in the declaration. */ | |
554 | return DECL_POINTER_ALIAS_SET (decl); | |
555 | } | |
556 | ||
557 | /* If we have an INDIRECT_REF via a void pointer, we don't | |
22421b79 RK |
558 | know anything about what that might alias. Likewise if the |
559 | pointer is marked that way. */ | |
560 | else if (TREE_CODE (TREE_TYPE (inner)) == VOID_TYPE | |
561 | || (TYPE_REF_CAN_ALIAS_ALL | |
562 | (TREE_TYPE (TREE_OPERAND (inner, 0))))) | |
738cc472 RK |
563 | return 0; |
564 | } | |
565 | ||
566 | /* Otherwise, pick up the outermost object that we could have a pointer | |
6fce44af | 567 | to, processing conversions as above. */ |
2039d7aa | 568 | while (component_uses_parent_alias_set (t)) |
f47e9b4e | 569 | { |
6fce44af | 570 | t = TREE_OPERAND (t, 0); |
8ac61af7 RK |
571 | STRIP_NOPS (t); |
572 | } | |
f824e5c3 | 573 | |
738cc472 RK |
574 | /* If we've already determined the alias set for a decl, just return |
575 | it. This is necessary for C++ anonymous unions, whose component | |
576 | variables don't look like union members (boo!). */ | |
5755cd38 | 577 | if (TREE_CODE (t) == VAR_DECL |
3c0cb5de | 578 | && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t))) |
5755cd38 JM |
579 | return MEM_ALIAS_SET (DECL_RTL (t)); |
580 | ||
f824e5c3 RK |
581 | /* Now all we care about is the type. */ |
582 | t = TREE_TYPE (t); | |
3bdf5ad1 RK |
583 | } |
584 | ||
3bdf5ad1 RK |
585 | /* Variant qualifiers don't affect the alias set, so get the main |
586 | variant. If this is a type with a known alias set, return it. */ | |
587 | t = TYPE_MAIN_VARIANT (t); | |
738cc472 | 588 | if (TYPE_ALIAS_SET_KNOWN_P (t)) |
3bdf5ad1 RK |
589 | return TYPE_ALIAS_SET (t); |
590 | ||
591 | /* See if the language has special handling for this type. */ | |
ae2bcd98 | 592 | set = lang_hooks.get_alias_set (t); |
8ac61af7 | 593 | if (set != -1) |
738cc472 | 594 | return set; |
2bf105ab | 595 | |
3bdf5ad1 RK |
596 | /* There are no objects of FUNCTION_TYPE, so there's no point in |
597 | using up an alias set for them. (There are, of course, pointers | |
598 | and references to functions, but that's different.) */ | |
599 | else if (TREE_CODE (t) == FUNCTION_TYPE) | |
600 | set = 0; | |
74d86f4f RH |
601 | |
602 | /* Unless the language specifies otherwise, let vector types alias | |
603 | their components. This avoids some nasty type punning issues in | |
604 | normal usage. And indeed lets vectors be treated more like an | |
605 | array slice. */ | |
606 | else if (TREE_CODE (t) == VECTOR_TYPE) | |
607 | set = get_alias_set (TREE_TYPE (t)); | |
608 | ||
3bdf5ad1 RK |
609 | else |
610 | /* Otherwise make a new alias set for this type. */ | |
611 | set = new_alias_set (); | |
612 | ||
613 | TYPE_ALIAS_SET (t) = set; | |
2bf105ab RK |
614 | |
615 | /* If this is an aggregate type, we must record any component aliasing | |
616 | information. */ | |
1d79fd2c | 617 | if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) |
2bf105ab RK |
618 | record_component_aliases (t); |
619 | ||
3bdf5ad1 RK |
620 | return set; |
621 | } | |
622 | ||
623 | /* Return a brand-new alias set. */ | |
624 | ||
f103e34d GK |
625 | static GTY(()) HOST_WIDE_INT last_alias_set; |
626 | ||
3bdf5ad1 | 627 | HOST_WIDE_INT |
4682ae04 | 628 | new_alias_set (void) |
3bdf5ad1 | 629 | { |
3bdf5ad1 | 630 | if (flag_strict_aliasing) |
9ddb66ca | 631 | { |
3416f5c2 JH |
632 | if (!alias_sets) |
633 | VARRAY_GENERIC_PTR_INIT (alias_sets, 10, "alias sets"); | |
634 | else | |
635 | VARRAY_GROW (alias_sets, last_alias_set + 2); | |
9ddb66ca JH |
636 | return ++last_alias_set; |
637 | } | |
3bdf5ad1 RK |
638 | else |
639 | return 0; | |
640 | } | |
3932261a | 641 | |
01d28c3f JM |
642 | /* Indicate that things in SUBSET can alias things in SUPERSET, but that |
643 | not everything that aliases SUPERSET also aliases SUBSET. For example, | |
644 | in C, a store to an `int' can alias a load of a structure containing an | |
645 | `int', and vice versa. But it can't alias a load of a 'double' member | |
646 | of the same structure. Here, the structure would be the SUPERSET and | |
647 | `int' the SUBSET. This relationship is also described in the comment at | |
648 | the beginning of this file. | |
649 | ||
650 | This function should be called only once per SUPERSET/SUBSET pair. | |
3932261a MM |
651 | |
652 | It is illegal for SUPERSET to be zero; everything is implicitly a | |
653 | subset of alias set zero. */ | |
654 | ||
04e2b4d3 | 655 | static void |
4682ae04 | 656 | record_alias_subset (HOST_WIDE_INT superset, HOST_WIDE_INT subset) |
3932261a MM |
657 | { |
658 | alias_set_entry superset_entry; | |
659 | alias_set_entry subset_entry; | |
660 | ||
f47e9b4e RK |
661 | /* It is possible in complex type situations for both sets to be the same, |
662 | in which case we can ignore this operation. */ | |
663 | if (superset == subset) | |
664 | return; | |
665 | ||
298e6adc | 666 | gcc_assert (superset); |
3932261a MM |
667 | |
668 | superset_entry = get_alias_set_entry (superset); | |
ca7fd9cd | 669 | if (superset_entry == 0) |
3932261a MM |
670 | { |
671 | /* Create an entry for the SUPERSET, so that we have a place to | |
672 | attach the SUBSET. */ | |
b604074c | 673 | superset_entry = ggc_alloc (sizeof (struct alias_set_entry)); |
3932261a | 674 | superset_entry->alias_set = superset; |
ca7fd9cd | 675 | superset_entry->children |
b604074c | 676 | = splay_tree_new_ggc (splay_tree_compare_ints); |
570eb5c8 | 677 | superset_entry->has_zero_child = 0; |
9ddb66ca | 678 | VARRAY_GENERIC_PTR (alias_sets, superset) = superset_entry; |
3932261a MM |
679 | } |
680 | ||
2bf105ab RK |
681 | if (subset == 0) |
682 | superset_entry->has_zero_child = 1; | |
683 | else | |
684 | { | |
685 | subset_entry = get_alias_set_entry (subset); | |
686 | /* If there is an entry for the subset, enter all of its children | |
687 | (if they are not already present) as children of the SUPERSET. */ | |
ca7fd9cd | 688 | if (subset_entry) |
2bf105ab RK |
689 | { |
690 | if (subset_entry->has_zero_child) | |
691 | superset_entry->has_zero_child = 1; | |
d4b60170 | 692 | |
2bf105ab RK |
693 | splay_tree_foreach (subset_entry->children, insert_subset_children, |
694 | superset_entry->children); | |
695 | } | |
3932261a | 696 | |
2bf105ab | 697 | /* Enter the SUBSET itself as a child of the SUPERSET. */ |
ca7fd9cd | 698 | splay_tree_insert (superset_entry->children, |
2bf105ab RK |
699 | (splay_tree_key) subset, 0); |
700 | } | |
3932261a MM |
701 | } |
702 | ||
a0c33338 RK |
703 | /* Record that component types of TYPE, if any, are part of that type for |
704 | aliasing purposes. For record types, we only record component types | |
705 | for fields that are marked addressable. For array types, we always | |
706 | record the component types, so the front end should not call this | |
707 | function if the individual component aren't addressable. */ | |
708 | ||
709 | void | |
4682ae04 | 710 | record_component_aliases (tree type) |
a0c33338 | 711 | { |
3bdf5ad1 | 712 | HOST_WIDE_INT superset = get_alias_set (type); |
a0c33338 RK |
713 | tree field; |
714 | ||
715 | if (superset == 0) | |
716 | return; | |
717 | ||
718 | switch (TREE_CODE (type)) | |
719 | { | |
720 | case ARRAY_TYPE: | |
2bf105ab RK |
721 | if (! TYPE_NONALIASED_COMPONENT (type)) |
722 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
a0c33338 RK |
723 | break; |
724 | ||
725 | case RECORD_TYPE: | |
726 | case UNION_TYPE: | |
727 | case QUAL_UNION_TYPE: | |
6614fd40 | 728 | /* Recursively record aliases for the base classes, if there are any. */ |
fa743e8c | 729 | if (TYPE_BINFO (type)) |
ca7fd9cd KH |
730 | { |
731 | int i; | |
fa743e8c NS |
732 | tree binfo, base_binfo; |
733 | ||
734 | for (binfo = TYPE_BINFO (type), i = 0; | |
735 | BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
736 | record_alias_subset (superset, | |
737 | get_alias_set (BINFO_TYPE (base_binfo))); | |
ca7fd9cd | 738 | } |
a0c33338 | 739 | for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) |
b16a49a1 | 740 | if (TREE_CODE (field) == FIELD_DECL && ! DECL_NONADDRESSABLE_P (field)) |
2bf105ab | 741 | record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); |
a0c33338 RK |
742 | break; |
743 | ||
1d79fd2c JW |
744 | case COMPLEX_TYPE: |
745 | record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
746 | break; | |
747 | ||
a0c33338 RK |
748 | default: |
749 | break; | |
750 | } | |
751 | } | |
752 | ||
3bdf5ad1 RK |
753 | /* Allocate an alias set for use in storing and reading from the varargs |
754 | spill area. */ | |
755 | ||
f103e34d GK |
756 | static GTY(()) HOST_WIDE_INT varargs_set = -1; |
757 | ||
3bdf5ad1 | 758 | HOST_WIDE_INT |
4682ae04 | 759 | get_varargs_alias_set (void) |
3bdf5ad1 | 760 | { |
cd3ce9b4 JM |
761 | #if 1 |
762 | /* We now lower VA_ARG_EXPR, and there's currently no way to attach the | |
763 | varargs alias set to an INDIRECT_REF (FIXME!), so we can't | |
764 | consistently use the varargs alias set for loads from the varargs | |
765 | area. So don't use it anywhere. */ | |
766 | return 0; | |
767 | #else | |
f103e34d GK |
768 | if (varargs_set == -1) |
769 | varargs_set = new_alias_set (); | |
3bdf5ad1 | 770 | |
f103e34d | 771 | return varargs_set; |
cd3ce9b4 | 772 | #endif |
3bdf5ad1 RK |
773 | } |
774 | ||
775 | /* Likewise, but used for the fixed portions of the frame, e.g., register | |
776 | save areas. */ | |
777 | ||
f103e34d GK |
778 | static GTY(()) HOST_WIDE_INT frame_set = -1; |
779 | ||
3bdf5ad1 | 780 | HOST_WIDE_INT |
4682ae04 | 781 | get_frame_alias_set (void) |
3bdf5ad1 | 782 | { |
f103e34d GK |
783 | if (frame_set == -1) |
784 | frame_set = new_alias_set (); | |
3bdf5ad1 | 785 | |
f103e34d | 786 | return frame_set; |
3bdf5ad1 RK |
787 | } |
788 | ||
2a2c8203 JC |
789 | /* Inside SRC, the source of a SET, find a base address. */ |
790 | ||
9ae8ffe7 | 791 | static rtx |
4682ae04 | 792 | find_base_value (rtx src) |
9ae8ffe7 | 793 | { |
713f41f9 | 794 | unsigned int regno; |
0aacc8ed | 795 | |
9ae8ffe7 JL |
796 | switch (GET_CODE (src)) |
797 | { | |
798 | case SYMBOL_REF: | |
799 | case LABEL_REF: | |
800 | return src; | |
801 | ||
802 | case REG: | |
fb6754f0 | 803 | regno = REGNO (src); |
d4b60170 | 804 | /* At the start of a function, argument registers have known base |
2a2c8203 JC |
805 | values which may be lost later. Returning an ADDRESS |
806 | expression here allows optimization based on argument values | |
807 | even when the argument registers are used for other purposes. */ | |
713f41f9 BS |
808 | if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) |
809 | return new_reg_base_value[regno]; | |
73774bc7 | 810 | |
eaf407a5 | 811 | /* If a pseudo has a known base value, return it. Do not do this |
9b462c42 RH |
812 | for non-fixed hard regs since it can result in a circular |
813 | dependency chain for registers which have values at function entry. | |
eaf407a5 JL |
814 | |
815 | The test above is not sufficient because the scheduler may move | |
816 | a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
9b462c42 | 817 | if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) |
c582d54a | 818 | && regno < VARRAY_SIZE (reg_base_value)) |
83bbd9b6 RH |
819 | { |
820 | /* If we're inside init_alias_analysis, use new_reg_base_value | |
821 | to reduce the number of relaxation iterations. */ | |
1afdf91c RH |
822 | if (new_reg_base_value && new_reg_base_value[regno] |
823 | && REG_N_SETS (regno) == 1) | |
83bbd9b6 RH |
824 | return new_reg_base_value[regno]; |
825 | ||
c582d54a JH |
826 | if (VARRAY_RTX (reg_base_value, regno)) |
827 | return VARRAY_RTX (reg_base_value, regno); | |
83bbd9b6 | 828 | } |
73774bc7 | 829 | |
e3f049a8 | 830 | return 0; |
9ae8ffe7 JL |
831 | |
832 | case MEM: | |
833 | /* Check for an argument passed in memory. Only record in the | |
834 | copying-arguments block; it is too hard to track changes | |
835 | otherwise. */ | |
836 | if (copying_arguments | |
837 | && (XEXP (src, 0) == arg_pointer_rtx | |
838 | || (GET_CODE (XEXP (src, 0)) == PLUS | |
839 | && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
38a448ca | 840 | return gen_rtx_ADDRESS (VOIDmode, src); |
9ae8ffe7 JL |
841 | return 0; |
842 | ||
843 | case CONST: | |
844 | src = XEXP (src, 0); | |
845 | if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
846 | break; | |
d4b60170 | 847 | |
ec5c56db | 848 | /* ... fall through ... */ |
2a2c8203 | 849 | |
9ae8ffe7 JL |
850 | case PLUS: |
851 | case MINUS: | |
2a2c8203 | 852 | { |
ec907dd8 JL |
853 | rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); |
854 | ||
0134bf2d DE |
855 | /* If either operand is a REG that is a known pointer, then it |
856 | is the base. */ | |
857 | if (REG_P (src_0) && REG_POINTER (src_0)) | |
858 | return find_base_value (src_0); | |
859 | if (REG_P (src_1) && REG_POINTER (src_1)) | |
860 | return find_base_value (src_1); | |
861 | ||
ec907dd8 JL |
862 | /* If either operand is a REG, then see if we already have |
863 | a known value for it. */ | |
0134bf2d | 864 | if (REG_P (src_0)) |
ec907dd8 JL |
865 | { |
866 | temp = find_base_value (src_0); | |
d4b60170 | 867 | if (temp != 0) |
ec907dd8 JL |
868 | src_0 = temp; |
869 | } | |
870 | ||
0134bf2d | 871 | if (REG_P (src_1)) |
ec907dd8 JL |
872 | { |
873 | temp = find_base_value (src_1); | |
d4b60170 | 874 | if (temp!= 0) |
ec907dd8 JL |
875 | src_1 = temp; |
876 | } | |
2a2c8203 | 877 | |
0134bf2d DE |
878 | /* If either base is named object or a special address |
879 | (like an argument or stack reference), then use it for the | |
880 | base term. */ | |
881 | if (src_0 != 0 | |
882 | && (GET_CODE (src_0) == SYMBOL_REF | |
883 | || GET_CODE (src_0) == LABEL_REF | |
884 | || (GET_CODE (src_0) == ADDRESS | |
885 | && GET_MODE (src_0) != VOIDmode))) | |
886 | return src_0; | |
887 | ||
888 | if (src_1 != 0 | |
889 | && (GET_CODE (src_1) == SYMBOL_REF | |
890 | || GET_CODE (src_1) == LABEL_REF | |
891 | || (GET_CODE (src_1) == ADDRESS | |
892 | && GET_MODE (src_1) != VOIDmode))) | |
893 | return src_1; | |
894 | ||
d4b60170 | 895 | /* Guess which operand is the base address: |
ec907dd8 JL |
896 | If either operand is a symbol, then it is the base. If |
897 | either operand is a CONST_INT, then the other is the base. */ | |
d4b60170 | 898 | if (GET_CODE (src_1) == CONST_INT || CONSTANT_P (src_0)) |
2a2c8203 | 899 | return find_base_value (src_0); |
d4b60170 | 900 | else if (GET_CODE (src_0) == CONST_INT || CONSTANT_P (src_1)) |
ec907dd8 JL |
901 | return find_base_value (src_1); |
902 | ||
9ae8ffe7 | 903 | return 0; |
2a2c8203 JC |
904 | } |
905 | ||
906 | case LO_SUM: | |
907 | /* The standard form is (lo_sum reg sym) so look only at the | |
908 | second operand. */ | |
909 | return find_base_value (XEXP (src, 1)); | |
9ae8ffe7 JL |
910 | |
911 | case AND: | |
912 | /* If the second operand is constant set the base | |
ec5c56db | 913 | address to the first operand. */ |
2a2c8203 JC |
914 | if (GET_CODE (XEXP (src, 1)) == CONST_INT && INTVAL (XEXP (src, 1)) != 0) |
915 | return find_base_value (XEXP (src, 0)); | |
9ae8ffe7 JL |
916 | return 0; |
917 | ||
61f0131c R |
918 | case TRUNCATE: |
919 | if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) | |
920 | break; | |
921 | /* Fall through. */ | |
9ae8ffe7 | 922 | case HIGH: |
d288e53d DE |
923 | case PRE_INC: |
924 | case PRE_DEC: | |
925 | case POST_INC: | |
926 | case POST_DEC: | |
927 | case PRE_MODIFY: | |
928 | case POST_MODIFY: | |
2a2c8203 | 929 | return find_base_value (XEXP (src, 0)); |
1d300e19 | 930 | |
0aacc8ed RK |
931 | case ZERO_EXTEND: |
932 | case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
933 | { | |
934 | rtx temp = find_base_value (XEXP (src, 0)); | |
935 | ||
5ae6cd0d | 936 | if (temp != 0 && CONSTANT_P (temp)) |
0aacc8ed | 937 | temp = convert_memory_address (Pmode, temp); |
0aacc8ed RK |
938 | |
939 | return temp; | |
940 | } | |
941 | ||
1d300e19 KG |
942 | default: |
943 | break; | |
9ae8ffe7 JL |
944 | } |
945 | ||
946 | return 0; | |
947 | } | |
948 | ||
949 | /* Called from init_alias_analysis indirectly through note_stores. */ | |
950 | ||
d4b60170 | 951 | /* While scanning insns to find base values, reg_seen[N] is nonzero if |
9ae8ffe7 JL |
952 | register N has been set in this function. */ |
953 | static char *reg_seen; | |
954 | ||
13309a5f JC |
955 | /* Addresses which are known not to alias anything else are identified |
956 | by a unique integer. */ | |
ec907dd8 JL |
957 | static int unique_id; |
958 | ||
2a2c8203 | 959 | static void |
4682ae04 | 960 | record_set (rtx dest, rtx set, void *data ATTRIBUTE_UNUSED) |
9ae8ffe7 | 961 | { |
b3694847 | 962 | unsigned regno; |
9ae8ffe7 | 963 | rtx src; |
c28b4e40 | 964 | int n; |
9ae8ffe7 | 965 | |
f8cfc6aa | 966 | if (!REG_P (dest)) |
9ae8ffe7 JL |
967 | return; |
968 | ||
fb6754f0 | 969 | regno = REGNO (dest); |
9ae8ffe7 | 970 | |
298e6adc | 971 | gcc_assert (regno < VARRAY_SIZE (reg_base_value)); |
ac606739 | 972 | |
c28b4e40 JW |
973 | /* If this spans multiple hard registers, then we must indicate that every |
974 | register has an unusable value. */ | |
975 | if (regno < FIRST_PSEUDO_REGISTER) | |
66fd46b6 | 976 | n = hard_regno_nregs[regno][GET_MODE (dest)]; |
c28b4e40 JW |
977 | else |
978 | n = 1; | |
979 | if (n != 1) | |
980 | { | |
981 | while (--n >= 0) | |
982 | { | |
983 | reg_seen[regno + n] = 1; | |
984 | new_reg_base_value[regno + n] = 0; | |
985 | } | |
986 | return; | |
987 | } | |
988 | ||
9ae8ffe7 JL |
989 | if (set) |
990 | { | |
991 | /* A CLOBBER wipes out any old value but does not prevent a previously | |
992 | unset register from acquiring a base address (i.e. reg_seen is not | |
993 | set). */ | |
994 | if (GET_CODE (set) == CLOBBER) | |
995 | { | |
ec907dd8 | 996 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
997 | return; |
998 | } | |
999 | src = SET_SRC (set); | |
1000 | } | |
1001 | else | |
1002 | { | |
9ae8ffe7 JL |
1003 | if (reg_seen[regno]) |
1004 | { | |
ec907dd8 | 1005 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1006 | return; |
1007 | } | |
1008 | reg_seen[regno] = 1; | |
38a448ca RH |
1009 | new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, |
1010 | GEN_INT (unique_id++)); | |
9ae8ffe7 JL |
1011 | return; |
1012 | } | |
1013 | ||
5da6f168 RS |
1014 | /* If this is not the first set of REGNO, see whether the new value |
1015 | is related to the old one. There are two cases of interest: | |
1016 | ||
1017 | (1) The register might be assigned an entirely new value | |
1018 | that has the same base term as the original set. | |
1019 | ||
1020 | (2) The set might be a simple self-modification that | |
1021 | cannot change REGNO's base value. | |
1022 | ||
1023 | If neither case holds, reject the original base value as invalid. | |
1024 | Note that the following situation is not detected: | |
1025 | ||
1026 | extern int x, y; int *p = &x; p += (&y-&x); | |
1027 | ||
9ae8ffe7 JL |
1028 | ANSI C does not allow computing the difference of addresses |
1029 | of distinct top level objects. */ | |
5da6f168 RS |
1030 | if (new_reg_base_value[regno] != 0 |
1031 | && find_base_value (src) != new_reg_base_value[regno]) | |
9ae8ffe7 JL |
1032 | switch (GET_CODE (src)) |
1033 | { | |
2a2c8203 | 1034 | case LO_SUM: |
9ae8ffe7 JL |
1035 | case MINUS: |
1036 | if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
ec907dd8 | 1037 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1038 | break; |
61f0131c R |
1039 | case PLUS: |
1040 | /* If the value we add in the PLUS is also a valid base value, | |
1041 | this might be the actual base value, and the original value | |
1042 | an index. */ | |
1043 | { | |
1044 | rtx other = NULL_RTX; | |
1045 | ||
1046 | if (XEXP (src, 0) == dest) | |
1047 | other = XEXP (src, 1); | |
1048 | else if (XEXP (src, 1) == dest) | |
1049 | other = XEXP (src, 0); | |
1050 | ||
1051 | if (! other || find_base_value (other)) | |
1052 | new_reg_base_value[regno] = 0; | |
1053 | break; | |
1054 | } | |
9ae8ffe7 JL |
1055 | case AND: |
1056 | if (XEXP (src, 0) != dest || GET_CODE (XEXP (src, 1)) != CONST_INT) | |
ec907dd8 | 1057 | new_reg_base_value[regno] = 0; |
9ae8ffe7 | 1058 | break; |
9ae8ffe7 | 1059 | default: |
ec907dd8 | 1060 | new_reg_base_value[regno] = 0; |
9ae8ffe7 JL |
1061 | break; |
1062 | } | |
1063 | /* If this is the first set of a register, record the value. */ | |
1064 | else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
ec907dd8 JL |
1065 | && ! reg_seen[regno] && new_reg_base_value[regno] == 0) |
1066 | new_reg_base_value[regno] = find_base_value (src); | |
9ae8ffe7 JL |
1067 | |
1068 | reg_seen[regno] = 1; | |
1069 | } | |
1070 | ||
43fe47ca JW |
1071 | /* Clear alias info for a register. This is used if an RTL transformation |
1072 | changes the value of a register. This is used in flow by AUTO_INC_DEC | |
1073 | optimizations. We don't need to clear reg_base_value, since flow only | |
1074 | changes the offset. */ | |
1075 | ||
1076 | void | |
4682ae04 | 1077 | clear_reg_alias_info (rtx reg) |
43fe47ca | 1078 | { |
4e1a4144 JW |
1079 | unsigned int regno = REGNO (reg); |
1080 | ||
bb1acb3e RH |
1081 | if (regno >= FIRST_PSEUDO_REGISTER) |
1082 | { | |
1083 | regno -= FIRST_PSEUDO_REGISTER; | |
1084 | if (regno < reg_known_value_size) | |
1085 | { | |
1086 | reg_known_value[regno] = reg; | |
1087 | reg_known_equiv_p[regno] = false; | |
1088 | } | |
1089 | } | |
1090 | } | |
1091 | ||
1092 | /* If a value is known for REGNO, return it. */ | |
1093 | ||
1094 | rtx | |
1095 | get_reg_known_value (unsigned int regno) | |
1096 | { | |
1097 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1098 | { | |
1099 | regno -= FIRST_PSEUDO_REGISTER; | |
1100 | if (regno < reg_known_value_size) | |
1101 | return reg_known_value[regno]; | |
1102 | } | |
1103 | return NULL; | |
43fe47ca JW |
1104 | } |
1105 | ||
bb1acb3e RH |
1106 | /* Set it. */ |
1107 | ||
1108 | static void | |
1109 | set_reg_known_value (unsigned int regno, rtx val) | |
1110 | { | |
1111 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1112 | { | |
1113 | regno -= FIRST_PSEUDO_REGISTER; | |
1114 | if (regno < reg_known_value_size) | |
1115 | reg_known_value[regno] = val; | |
1116 | } | |
1117 | } | |
1118 | ||
1119 | /* Similarly for reg_known_equiv_p. */ | |
1120 | ||
1121 | bool | |
1122 | get_reg_known_equiv_p (unsigned int regno) | |
1123 | { | |
1124 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1125 | { | |
1126 | regno -= FIRST_PSEUDO_REGISTER; | |
1127 | if (regno < reg_known_value_size) | |
1128 | return reg_known_equiv_p[regno]; | |
1129 | } | |
1130 | return false; | |
1131 | } | |
1132 | ||
1133 | static void | |
1134 | set_reg_known_equiv_p (unsigned int regno, bool val) | |
1135 | { | |
1136 | if (regno >= FIRST_PSEUDO_REGISTER) | |
1137 | { | |
1138 | regno -= FIRST_PSEUDO_REGISTER; | |
1139 | if (regno < reg_known_value_size) | |
1140 | reg_known_equiv_p[regno] = val; | |
1141 | } | |
1142 | } | |
1143 | ||
1144 | ||
db048faf MM |
1145 | /* Returns a canonical version of X, from the point of view alias |
1146 | analysis. (For example, if X is a MEM whose address is a register, | |
1147 | and the register has a known value (say a SYMBOL_REF), then a MEM | |
1148 | whose address is the SYMBOL_REF is returned.) */ | |
1149 | ||
1150 | rtx | |
4682ae04 | 1151 | canon_rtx (rtx x) |
9ae8ffe7 JL |
1152 | { |
1153 | /* Recursively look for equivalences. */ | |
f8cfc6aa | 1154 | if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) |
bb1acb3e RH |
1155 | { |
1156 | rtx t = get_reg_known_value (REGNO (x)); | |
1157 | if (t == x) | |
1158 | return x; | |
1159 | if (t) | |
1160 | return canon_rtx (t); | |
1161 | } | |
1162 | ||
1163 | if (GET_CODE (x) == PLUS) | |
9ae8ffe7 JL |
1164 | { |
1165 | rtx x0 = canon_rtx (XEXP (x, 0)); | |
1166 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1167 | ||
1168 | if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
1169 | { | |
9ae8ffe7 | 1170 | if (GET_CODE (x0) == CONST_INT) |
ed8908e7 | 1171 | return plus_constant (x1, INTVAL (x0)); |
9ae8ffe7 | 1172 | else if (GET_CODE (x1) == CONST_INT) |
ed8908e7 | 1173 | return plus_constant (x0, INTVAL (x1)); |
38a448ca | 1174 | return gen_rtx_PLUS (GET_MODE (x), x0, x1); |
9ae8ffe7 JL |
1175 | } |
1176 | } | |
d4b60170 | 1177 | |
9ae8ffe7 JL |
1178 | /* This gives us much better alias analysis when called from |
1179 | the loop optimizer. Note we want to leave the original | |
1180 | MEM alone, but need to return the canonicalized MEM with | |
1181 | all the flags with their original values. */ | |
3c0cb5de | 1182 | else if (MEM_P (x)) |
f1ec5147 | 1183 | x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); |
d4b60170 | 1184 | |
9ae8ffe7 JL |
1185 | return x; |
1186 | } | |
1187 | ||
1188 | /* Return 1 if X and Y are identical-looking rtx's. | |
45183e03 | 1189 | Expect that X and Y has been already canonicalized. |
9ae8ffe7 JL |
1190 | |
1191 | We use the data in reg_known_value above to see if two registers with | |
1192 | different numbers are, in fact, equivalent. */ | |
1193 | ||
1194 | static int | |
4682ae04 | 1195 | rtx_equal_for_memref_p (rtx x, rtx y) |
9ae8ffe7 | 1196 | { |
b3694847 SS |
1197 | int i; |
1198 | int j; | |
1199 | enum rtx_code code; | |
1200 | const char *fmt; | |
9ae8ffe7 JL |
1201 | |
1202 | if (x == 0 && y == 0) | |
1203 | return 1; | |
1204 | if (x == 0 || y == 0) | |
1205 | return 0; | |
d4b60170 | 1206 | |
9ae8ffe7 JL |
1207 | if (x == y) |
1208 | return 1; | |
1209 | ||
1210 | code = GET_CODE (x); | |
1211 | /* Rtx's of different codes cannot be equal. */ | |
1212 | if (code != GET_CODE (y)) | |
1213 | return 0; | |
1214 | ||
1215 | /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
1216 | (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
1217 | ||
1218 | if (GET_MODE (x) != GET_MODE (y)) | |
1219 | return 0; | |
1220 | ||
db048faf MM |
1221 | /* Some RTL can be compared without a recursive examination. */ |
1222 | switch (code) | |
1223 | { | |
1224 | case REG: | |
1225 | return REGNO (x) == REGNO (y); | |
1226 | ||
1227 | case LABEL_REF: | |
1228 | return XEXP (x, 0) == XEXP (y, 0); | |
ca7fd9cd | 1229 | |
db048faf MM |
1230 | case SYMBOL_REF: |
1231 | return XSTR (x, 0) == XSTR (y, 0); | |
1232 | ||
40e02b4a | 1233 | case VALUE: |
db048faf MM |
1234 | case CONST_INT: |
1235 | case CONST_DOUBLE: | |
1236 | /* There's no need to compare the contents of CONST_DOUBLEs or | |
1237 | CONST_INTs because pointer equality is a good enough | |
1238 | comparison for these nodes. */ | |
1239 | return 0; | |
1240 | ||
db048faf MM |
1241 | default: |
1242 | break; | |
1243 | } | |
9ae8ffe7 | 1244 | |
45183e03 JH |
1245 | /* canon_rtx knows how to handle plus. No need to canonicalize. */ |
1246 | if (code == PLUS) | |
9ae8ffe7 JL |
1247 | return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) |
1248 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
1249 | || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
1250 | && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
45183e03 JH |
1251 | /* For commutative operations, the RTX match if the operand match in any |
1252 | order. Also handle the simple binary and unary cases without a loop. */ | |
ec8e098d | 1253 | if (COMMUTATIVE_P (x)) |
45183e03 JH |
1254 | { |
1255 | rtx xop0 = canon_rtx (XEXP (x, 0)); | |
1256 | rtx yop0 = canon_rtx (XEXP (y, 0)); | |
1257 | rtx yop1 = canon_rtx (XEXP (y, 1)); | |
1258 | ||
1259 | return ((rtx_equal_for_memref_p (xop0, yop0) | |
1260 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
1261 | || (rtx_equal_for_memref_p (xop0, yop1) | |
1262 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
1263 | } | |
ec8e098d | 1264 | else if (NON_COMMUTATIVE_P (x)) |
45183e03 JH |
1265 | { |
1266 | return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
4682ae04 | 1267 | canon_rtx (XEXP (y, 0))) |
45183e03 JH |
1268 | && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), |
1269 | canon_rtx (XEXP (y, 1)))); | |
1270 | } | |
ec8e098d | 1271 | else if (UNARY_P (x)) |
45183e03 | 1272 | return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), |
4682ae04 | 1273 | canon_rtx (XEXP (y, 0))); |
9ae8ffe7 JL |
1274 | |
1275 | /* Compare the elements. If any pair of corresponding elements | |
de12be17 JC |
1276 | fail to match, return 0 for the whole things. |
1277 | ||
1278 | Limit cases to types which actually appear in addresses. */ | |
9ae8ffe7 JL |
1279 | |
1280 | fmt = GET_RTX_FORMAT (code); | |
1281 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1282 | { | |
1283 | switch (fmt[i]) | |
1284 | { | |
9ae8ffe7 JL |
1285 | case 'i': |
1286 | if (XINT (x, i) != XINT (y, i)) | |
1287 | return 0; | |
1288 | break; | |
1289 | ||
9ae8ffe7 JL |
1290 | case 'E': |
1291 | /* Two vectors must have the same length. */ | |
1292 | if (XVECLEN (x, i) != XVECLEN (y, i)) | |
1293 | return 0; | |
1294 | ||
1295 | /* And the corresponding elements must match. */ | |
1296 | for (j = 0; j < XVECLEN (x, i); j++) | |
45183e03 JH |
1297 | if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), |
1298 | canon_rtx (XVECEXP (y, i, j))) == 0) | |
9ae8ffe7 JL |
1299 | return 0; |
1300 | break; | |
1301 | ||
1302 | case 'e': | |
45183e03 JH |
1303 | if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), |
1304 | canon_rtx (XEXP (y, i))) == 0) | |
9ae8ffe7 JL |
1305 | return 0; |
1306 | break; | |
1307 | ||
3237ac18 AH |
1308 | /* This can happen for asm operands. */ |
1309 | case 's': | |
1310 | if (strcmp (XSTR (x, i), XSTR (y, i))) | |
1311 | return 0; | |
1312 | break; | |
1313 | ||
aee21ba9 JL |
1314 | /* This can happen for an asm which clobbers memory. */ |
1315 | case '0': | |
1316 | break; | |
1317 | ||
9ae8ffe7 JL |
1318 | /* It is believed that rtx's at this level will never |
1319 | contain anything but integers and other rtx's, | |
1320 | except for within LABEL_REFs and SYMBOL_REFs. */ | |
1321 | default: | |
298e6adc | 1322 | gcc_unreachable (); |
9ae8ffe7 JL |
1323 | } |
1324 | } | |
1325 | return 1; | |
1326 | } | |
1327 | ||
1328 | /* Given an rtx X, find a SYMBOL_REF or LABEL_REF within | |
1329 | X and return it, or return 0 if none found. */ | |
1330 | ||
1331 | static rtx | |
4682ae04 | 1332 | find_symbolic_term (rtx x) |
9ae8ffe7 | 1333 | { |
b3694847 SS |
1334 | int i; |
1335 | enum rtx_code code; | |
1336 | const char *fmt; | |
9ae8ffe7 JL |
1337 | |
1338 | code = GET_CODE (x); | |
1339 | if (code == SYMBOL_REF || code == LABEL_REF) | |
1340 | return x; | |
ec8e098d | 1341 | if (OBJECT_P (x)) |
9ae8ffe7 JL |
1342 | return 0; |
1343 | ||
1344 | fmt = GET_RTX_FORMAT (code); | |
1345 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
1346 | { | |
1347 | rtx t; | |
1348 | ||
1349 | if (fmt[i] == 'e') | |
1350 | { | |
1351 | t = find_symbolic_term (XEXP (x, i)); | |
1352 | if (t != 0) | |
1353 | return t; | |
1354 | } | |
1355 | else if (fmt[i] == 'E') | |
1356 | break; | |
1357 | } | |
1358 | return 0; | |
1359 | } | |
1360 | ||
94f24ddc | 1361 | rtx |
4682ae04 | 1362 | find_base_term (rtx x) |
9ae8ffe7 | 1363 | { |
eab5c70a BS |
1364 | cselib_val *val; |
1365 | struct elt_loc_list *l; | |
1366 | ||
b949ea8b JW |
1367 | #if defined (FIND_BASE_TERM) |
1368 | /* Try machine-dependent ways to find the base term. */ | |
1369 | x = FIND_BASE_TERM (x); | |
1370 | #endif | |
1371 | ||
9ae8ffe7 JL |
1372 | switch (GET_CODE (x)) |
1373 | { | |
1374 | case REG: | |
1375 | return REG_BASE_VALUE (x); | |
1376 | ||
d288e53d DE |
1377 | case TRUNCATE: |
1378 | if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) | |
ca7fd9cd | 1379 | return 0; |
d288e53d | 1380 | /* Fall through. */ |
9ae8ffe7 | 1381 | case HIGH: |
6d849a2a JL |
1382 | case PRE_INC: |
1383 | case PRE_DEC: | |
1384 | case POST_INC: | |
1385 | case POST_DEC: | |
d288e53d DE |
1386 | case PRE_MODIFY: |
1387 | case POST_MODIFY: | |
6d849a2a JL |
1388 | return find_base_term (XEXP (x, 0)); |
1389 | ||
1abade85 RK |
1390 | case ZERO_EXTEND: |
1391 | case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
1392 | { | |
1393 | rtx temp = find_base_term (XEXP (x, 0)); | |
1394 | ||
5ae6cd0d | 1395 | if (temp != 0 && CONSTANT_P (temp)) |
1abade85 | 1396 | temp = convert_memory_address (Pmode, temp); |
1abade85 RK |
1397 | |
1398 | return temp; | |
1399 | } | |
1400 | ||
eab5c70a BS |
1401 | case VALUE: |
1402 | val = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1403 | if (!val) |
1404 | return 0; | |
eab5c70a BS |
1405 | for (l = val->locs; l; l = l->next) |
1406 | if ((x = find_base_term (l->loc)) != 0) | |
1407 | return x; | |
1408 | return 0; | |
1409 | ||
9ae8ffe7 JL |
1410 | case CONST: |
1411 | x = XEXP (x, 0); | |
1412 | if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
1413 | return 0; | |
938d968e | 1414 | /* Fall through. */ |
9ae8ffe7 JL |
1415 | case LO_SUM: |
1416 | case PLUS: | |
1417 | case MINUS: | |
1418 | { | |
3c567fae JL |
1419 | rtx tmp1 = XEXP (x, 0); |
1420 | rtx tmp2 = XEXP (x, 1); | |
1421 | ||
f5143c46 | 1422 | /* This is a little bit tricky since we have to determine which of |
3c567fae JL |
1423 | the two operands represents the real base address. Otherwise this |
1424 | routine may return the index register instead of the base register. | |
1425 | ||
1426 | That may cause us to believe no aliasing was possible, when in | |
1427 | fact aliasing is possible. | |
1428 | ||
1429 | We use a few simple tests to guess the base register. Additional | |
1430 | tests can certainly be added. For example, if one of the operands | |
1431 | is a shift or multiply, then it must be the index register and the | |
1432 | other operand is the base register. */ | |
ca7fd9cd | 1433 | |
b949ea8b JW |
1434 | if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) |
1435 | return find_base_term (tmp2); | |
1436 | ||
3c567fae JL |
1437 | /* If either operand is known to be a pointer, then use it |
1438 | to determine the base term. */ | |
3502dc9c | 1439 | if (REG_P (tmp1) && REG_POINTER (tmp1)) |
3c567fae JL |
1440 | return find_base_term (tmp1); |
1441 | ||
3502dc9c | 1442 | if (REG_P (tmp2) && REG_POINTER (tmp2)) |
3c567fae JL |
1443 | return find_base_term (tmp2); |
1444 | ||
1445 | /* Neither operand was known to be a pointer. Go ahead and find the | |
1446 | base term for both operands. */ | |
1447 | tmp1 = find_base_term (tmp1); | |
1448 | tmp2 = find_base_term (tmp2); | |
1449 | ||
1450 | /* If either base term is named object or a special address | |
1451 | (like an argument or stack reference), then use it for the | |
1452 | base term. */ | |
d4b60170 | 1453 | if (tmp1 != 0 |
3c567fae JL |
1454 | && (GET_CODE (tmp1) == SYMBOL_REF |
1455 | || GET_CODE (tmp1) == LABEL_REF | |
1456 | || (GET_CODE (tmp1) == ADDRESS | |
1457 | && GET_MODE (tmp1) != VOIDmode))) | |
1458 | return tmp1; | |
1459 | ||
d4b60170 | 1460 | if (tmp2 != 0 |
3c567fae JL |
1461 | && (GET_CODE (tmp2) == SYMBOL_REF |
1462 | || GET_CODE (tmp2) == LABEL_REF | |
1463 | || (GET_CODE (tmp2) == ADDRESS | |
1464 | && GET_MODE (tmp2) != VOIDmode))) | |
1465 | return tmp2; | |
1466 | ||
1467 | /* We could not determine which of the two operands was the | |
1468 | base register and which was the index. So we can determine | |
1469 | nothing from the base alias check. */ | |
1470 | return 0; | |
9ae8ffe7 JL |
1471 | } |
1472 | ||
1473 | case AND: | |
d288e53d DE |
1474 | if (GET_CODE (XEXP (x, 1)) == CONST_INT && INTVAL (XEXP (x, 1)) != 0) |
1475 | return find_base_term (XEXP (x, 0)); | |
9ae8ffe7 JL |
1476 | return 0; |
1477 | ||
1478 | case SYMBOL_REF: | |
1479 | case LABEL_REF: | |
1480 | return x; | |
1481 | ||
1482 | default: | |
1483 | return 0; | |
1484 | } | |
1485 | } | |
1486 | ||
1487 | /* Return 0 if the addresses X and Y are known to point to different | |
1488 | objects, 1 if they might be pointers to the same object. */ | |
1489 | ||
1490 | static int | |
4682ae04 AJ |
1491 | base_alias_check (rtx x, rtx y, enum machine_mode x_mode, |
1492 | enum machine_mode y_mode) | |
9ae8ffe7 JL |
1493 | { |
1494 | rtx x_base = find_base_term (x); | |
1495 | rtx y_base = find_base_term (y); | |
1496 | ||
1c72c7f6 JC |
1497 | /* If the address itself has no known base see if a known equivalent |
1498 | value has one. If either address still has no known base, nothing | |
1499 | is known about aliasing. */ | |
1500 | if (x_base == 0) | |
1501 | { | |
1502 | rtx x_c; | |
d4b60170 | 1503 | |
1c72c7f6 JC |
1504 | if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) |
1505 | return 1; | |
d4b60170 | 1506 | |
1c72c7f6 JC |
1507 | x_base = find_base_term (x_c); |
1508 | if (x_base == 0) | |
1509 | return 1; | |
1510 | } | |
9ae8ffe7 | 1511 | |
1c72c7f6 JC |
1512 | if (y_base == 0) |
1513 | { | |
1514 | rtx y_c; | |
1515 | if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
1516 | return 1; | |
d4b60170 | 1517 | |
1c72c7f6 JC |
1518 | y_base = find_base_term (y_c); |
1519 | if (y_base == 0) | |
1520 | return 1; | |
1521 | } | |
1522 | ||
1523 | /* If the base addresses are equal nothing is known about aliasing. */ | |
1524 | if (rtx_equal_p (x_base, y_base)) | |
9ae8ffe7 JL |
1525 | return 1; |
1526 | ||
ca7fd9cd | 1527 | /* The base addresses of the read and write are different expressions. |
56ee9281 RH |
1528 | If they are both symbols and they are not accessed via AND, there is |
1529 | no conflict. We can bring knowledge of object alignment into play | |
1530 | here. For example, on alpha, "char a, b;" can alias one another, | |
1531 | though "char a; long b;" cannot. */ | |
9ae8ffe7 | 1532 | if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) |
c02f035f | 1533 | { |
56ee9281 RH |
1534 | if (GET_CODE (x) == AND && GET_CODE (y) == AND) |
1535 | return 1; | |
1536 | if (GET_CODE (x) == AND | |
1537 | && (GET_CODE (XEXP (x, 1)) != CONST_INT | |
8fa2140d | 1538 | || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
56ee9281 RH |
1539 | return 1; |
1540 | if (GET_CODE (y) == AND | |
1541 | && (GET_CODE (XEXP (y, 1)) != CONST_INT | |
8fa2140d | 1542 | || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
56ee9281 | 1543 | return 1; |
b2972551 JL |
1544 | /* Differing symbols never alias. */ |
1545 | return 0; | |
c02f035f | 1546 | } |
9ae8ffe7 JL |
1547 | |
1548 | /* If one address is a stack reference there can be no alias: | |
1549 | stack references using different base registers do not alias, | |
1550 | a stack reference can not alias a parameter, and a stack reference | |
1551 | can not alias a global. */ | |
1552 | if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
1553 | || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
1554 | return 0; | |
1555 | ||
1556 | if (! flag_argument_noalias) | |
1557 | return 1; | |
1558 | ||
1559 | if (flag_argument_noalias > 1) | |
1560 | return 0; | |
1561 | ||
ec5c56db | 1562 | /* Weak noalias assertion (arguments are distinct, but may match globals). */ |
9ae8ffe7 JL |
1563 | return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); |
1564 | } | |
1565 | ||
eab5c70a BS |
1566 | /* Convert the address X into something we can use. This is done by returning |
1567 | it unchanged unless it is a value; in the latter case we call cselib to get | |
1568 | a more useful rtx. */ | |
3bdf5ad1 | 1569 | |
a13d4ebf | 1570 | rtx |
4682ae04 | 1571 | get_addr (rtx x) |
eab5c70a BS |
1572 | { |
1573 | cselib_val *v; | |
1574 | struct elt_loc_list *l; | |
1575 | ||
1576 | if (GET_CODE (x) != VALUE) | |
1577 | return x; | |
1578 | v = CSELIB_VAL_PTR (x); | |
40e02b4a JH |
1579 | if (v) |
1580 | { | |
1581 | for (l = v->locs; l; l = l->next) | |
1582 | if (CONSTANT_P (l->loc)) | |
1583 | return l->loc; | |
1584 | for (l = v->locs; l; l = l->next) | |
3c0cb5de | 1585 | if (!REG_P (l->loc) && !MEM_P (l->loc)) |
40e02b4a JH |
1586 | return l->loc; |
1587 | if (v->locs) | |
1588 | return v->locs->loc; | |
1589 | } | |
eab5c70a BS |
1590 | return x; |
1591 | } | |
1592 | ||
39cec1ac MH |
1593 | /* Return the address of the (N_REFS + 1)th memory reference to ADDR |
1594 | where SIZE is the size in bytes of the memory reference. If ADDR | |
1595 | is not modified by the memory reference then ADDR is returned. */ | |
1596 | ||
04e2b4d3 | 1597 | static rtx |
4682ae04 | 1598 | addr_side_effect_eval (rtx addr, int size, int n_refs) |
39cec1ac MH |
1599 | { |
1600 | int offset = 0; | |
ca7fd9cd | 1601 | |
39cec1ac MH |
1602 | switch (GET_CODE (addr)) |
1603 | { | |
1604 | case PRE_INC: | |
1605 | offset = (n_refs + 1) * size; | |
1606 | break; | |
1607 | case PRE_DEC: | |
1608 | offset = -(n_refs + 1) * size; | |
1609 | break; | |
1610 | case POST_INC: | |
1611 | offset = n_refs * size; | |
1612 | break; | |
1613 | case POST_DEC: | |
1614 | offset = -n_refs * size; | |
1615 | break; | |
1616 | ||
1617 | default: | |
1618 | return addr; | |
1619 | } | |
ca7fd9cd | 1620 | |
39cec1ac | 1621 | if (offset) |
45183e03 JH |
1622 | addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), |
1623 | GEN_INT (offset)); | |
39cec1ac MH |
1624 | else |
1625 | addr = XEXP (addr, 0); | |
45183e03 | 1626 | addr = canon_rtx (addr); |
39cec1ac MH |
1627 | |
1628 | return addr; | |
1629 | } | |
1630 | ||
9ae8ffe7 JL |
1631 | /* Return nonzero if X and Y (memory addresses) could reference the |
1632 | same location in memory. C is an offset accumulator. When | |
1633 | C is nonzero, we are testing aliases between X and Y + C. | |
1634 | XSIZE is the size in bytes of the X reference, | |
1635 | similarly YSIZE is the size in bytes for Y. | |
45183e03 | 1636 | Expect that canon_rtx has been already called for X and Y. |
9ae8ffe7 JL |
1637 | |
1638 | If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
1639 | referenced (the reference was BLKmode), so make the most pessimistic | |
1640 | assumptions. | |
1641 | ||
c02f035f RH |
1642 | If XSIZE or YSIZE is negative, we may access memory outside the object |
1643 | being referenced as a side effect. This can happen when using AND to | |
1644 | align memory references, as is done on the Alpha. | |
1645 | ||
9ae8ffe7 | 1646 | Nice to notice that varying addresses cannot conflict with fp if no |
0211b6ab | 1647 | local variables had their addresses taken, but that's too hard now. */ |
9ae8ffe7 | 1648 | |
9ae8ffe7 | 1649 | static int |
4682ae04 | 1650 | memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) |
9ae8ffe7 | 1651 | { |
eab5c70a BS |
1652 | if (GET_CODE (x) == VALUE) |
1653 | x = get_addr (x); | |
1654 | if (GET_CODE (y) == VALUE) | |
1655 | y = get_addr (y); | |
9ae8ffe7 JL |
1656 | if (GET_CODE (x) == HIGH) |
1657 | x = XEXP (x, 0); | |
1658 | else if (GET_CODE (x) == LO_SUM) | |
1659 | x = XEXP (x, 1); | |
1660 | else | |
45183e03 | 1661 | x = addr_side_effect_eval (x, xsize, 0); |
9ae8ffe7 JL |
1662 | if (GET_CODE (y) == HIGH) |
1663 | y = XEXP (y, 0); | |
1664 | else if (GET_CODE (y) == LO_SUM) | |
1665 | y = XEXP (y, 1); | |
1666 | else | |
45183e03 | 1667 | y = addr_side_effect_eval (y, ysize, 0); |
9ae8ffe7 JL |
1668 | |
1669 | if (rtx_equal_for_memref_p (x, y)) | |
1670 | { | |
c02f035f | 1671 | if (xsize <= 0 || ysize <= 0) |
9ae8ffe7 JL |
1672 | return 1; |
1673 | if (c >= 0 && xsize > c) | |
1674 | return 1; | |
1675 | if (c < 0 && ysize+c > 0) | |
1676 | return 1; | |
1677 | return 0; | |
1678 | } | |
1679 | ||
6e73e666 JC |
1680 | /* This code used to check for conflicts involving stack references and |
1681 | globals but the base address alias code now handles these cases. */ | |
9ae8ffe7 JL |
1682 | |
1683 | if (GET_CODE (x) == PLUS) | |
1684 | { | |
1685 | /* The fact that X is canonicalized means that this | |
1686 | PLUS rtx is canonicalized. */ | |
1687 | rtx x0 = XEXP (x, 0); | |
1688 | rtx x1 = XEXP (x, 1); | |
1689 | ||
1690 | if (GET_CODE (y) == PLUS) | |
1691 | { | |
1692 | /* The fact that Y is canonicalized means that this | |
1693 | PLUS rtx is canonicalized. */ | |
1694 | rtx y0 = XEXP (y, 0); | |
1695 | rtx y1 = XEXP (y, 1); | |
1696 | ||
1697 | if (rtx_equal_for_memref_p (x1, y1)) | |
1698 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1699 | if (rtx_equal_for_memref_p (x0, y0)) | |
1700 | return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
1701 | if (GET_CODE (x1) == CONST_INT) | |
63be02db JM |
1702 | { |
1703 | if (GET_CODE (y1) == CONST_INT) | |
1704 | return memrefs_conflict_p (xsize, x0, ysize, y0, | |
1705 | c - INTVAL (x1) + INTVAL (y1)); | |
1706 | else | |
1707 | return memrefs_conflict_p (xsize, x0, ysize, y, | |
1708 | c - INTVAL (x1)); | |
1709 | } | |
9ae8ffe7 JL |
1710 | else if (GET_CODE (y1) == CONST_INT) |
1711 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1712 | ||
6e73e666 | 1713 | return 1; |
9ae8ffe7 JL |
1714 | } |
1715 | else if (GET_CODE (x1) == CONST_INT) | |
1716 | return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); | |
1717 | } | |
1718 | else if (GET_CODE (y) == PLUS) | |
1719 | { | |
1720 | /* The fact that Y is canonicalized means that this | |
1721 | PLUS rtx is canonicalized. */ | |
1722 | rtx y0 = XEXP (y, 0); | |
1723 | rtx y1 = XEXP (y, 1); | |
1724 | ||
1725 | if (GET_CODE (y1) == CONST_INT) | |
1726 | return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); | |
1727 | else | |
1728 | return 1; | |
1729 | } | |
1730 | ||
1731 | if (GET_CODE (x) == GET_CODE (y)) | |
1732 | switch (GET_CODE (x)) | |
1733 | { | |
1734 | case MULT: | |
1735 | { | |
1736 | /* Handle cases where we expect the second operands to be the | |
1737 | same, and check only whether the first operand would conflict | |
1738 | or not. */ | |
1739 | rtx x0, y0; | |
1740 | rtx x1 = canon_rtx (XEXP (x, 1)); | |
1741 | rtx y1 = canon_rtx (XEXP (y, 1)); | |
1742 | if (! rtx_equal_for_memref_p (x1, y1)) | |
1743 | return 1; | |
1744 | x0 = canon_rtx (XEXP (x, 0)); | |
1745 | y0 = canon_rtx (XEXP (y, 0)); | |
1746 | if (rtx_equal_for_memref_p (x0, y0)) | |
1747 | return (xsize == 0 || ysize == 0 | |
1748 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
1749 | ||
1750 | /* Can't properly adjust our sizes. */ | |
1751 | if (GET_CODE (x1) != CONST_INT) | |
1752 | return 1; | |
1753 | xsize /= INTVAL (x1); | |
1754 | ysize /= INTVAL (x1); | |
1755 | c /= INTVAL (x1); | |
1756 | return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
1757 | } | |
1d300e19 KG |
1758 | |
1759 | default: | |
1760 | break; | |
9ae8ffe7 JL |
1761 | } |
1762 | ||
1763 | /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
ca7fd9cd | 1764 | as an access with indeterminate size. Assume that references |
56ee9281 RH |
1765 | besides AND are aligned, so if the size of the other reference is |
1766 | at least as large as the alignment, assume no other overlap. */ | |
9ae8ffe7 | 1767 | if (GET_CODE (x) == AND && GET_CODE (XEXP (x, 1)) == CONST_INT) |
56ee9281 | 1768 | { |
02e3377d | 1769 | if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) |
56ee9281 | 1770 | xsize = -1; |
45183e03 | 1771 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c); |
56ee9281 | 1772 | } |
9ae8ffe7 | 1773 | if (GET_CODE (y) == AND && GET_CODE (XEXP (y, 1)) == CONST_INT) |
c02f035f | 1774 | { |
56ee9281 | 1775 | /* ??? If we are indexing far enough into the array/structure, we |
ca7fd9cd | 1776 | may yet be able to determine that we can not overlap. But we |
c02f035f | 1777 | also need to that we are far enough from the end not to overlap |
56ee9281 | 1778 | a following reference, so we do nothing with that for now. */ |
02e3377d | 1779 | if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) |
56ee9281 | 1780 | ysize = -1; |
45183e03 | 1781 | return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c); |
c02f035f | 1782 | } |
9ae8ffe7 JL |
1783 | |
1784 | if (CONSTANT_P (x)) | |
1785 | { | |
1786 | if (GET_CODE (x) == CONST_INT && GET_CODE (y) == CONST_INT) | |
1787 | { | |
1788 | c += (INTVAL (y) - INTVAL (x)); | |
c02f035f | 1789 | return (xsize <= 0 || ysize <= 0 |
9ae8ffe7 JL |
1790 | || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); |
1791 | } | |
1792 | ||
1793 | if (GET_CODE (x) == CONST) | |
1794 | { | |
1795 | if (GET_CODE (y) == CONST) | |
1796 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1797 | ysize, canon_rtx (XEXP (y, 0)), c); | |
1798 | else | |
1799 | return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
1800 | ysize, y, c); | |
1801 | } | |
1802 | if (GET_CODE (y) == CONST) | |
1803 | return memrefs_conflict_p (xsize, x, ysize, | |
1804 | canon_rtx (XEXP (y, 0)), c); | |
1805 | ||
1806 | if (CONSTANT_P (y)) | |
b949ea8b | 1807 | return (xsize <= 0 || ysize <= 0 |
c02f035f | 1808 | || (rtx_equal_for_memref_p (x, y) |
b949ea8b | 1809 | && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); |
9ae8ffe7 JL |
1810 | |
1811 | return 1; | |
1812 | } | |
1813 | return 1; | |
1814 | } | |
1815 | ||
1816 | /* Functions to compute memory dependencies. | |
1817 | ||
1818 | Since we process the insns in execution order, we can build tables | |
1819 | to keep track of what registers are fixed (and not aliased), what registers | |
1820 | are varying in known ways, and what registers are varying in unknown | |
1821 | ways. | |
1822 | ||
1823 | If both memory references are volatile, then there must always be a | |
1824 | dependence between the two references, since their order can not be | |
1825 | changed. A volatile and non-volatile reference can be interchanged | |
ca7fd9cd | 1826 | though. |
9ae8ffe7 | 1827 | |
dc1618bc RK |
1828 | A MEM_IN_STRUCT reference at a non-AND varying address can never |
1829 | conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
1830 | also must allow AND addresses, because they may generate accesses | |
1831 | outside the object being referenced. This is used to generate | |
1832 | aligned addresses from unaligned addresses, for instance, the alpha | |
1833 | storeqi_unaligned pattern. */ | |
9ae8ffe7 JL |
1834 | |
1835 | /* Read dependence: X is read after read in MEM takes place. There can | |
1836 | only be a dependence here if both reads are volatile. */ | |
1837 | ||
1838 | int | |
4682ae04 | 1839 | read_dependence (rtx mem, rtx x) |
9ae8ffe7 JL |
1840 | { |
1841 | return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
1842 | } | |
1843 | ||
c6df88cb MM |
1844 | /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and |
1845 | MEM2 is a reference to a structure at a varying address, or returns | |
1846 | MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
1847 | value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
1848 | to decide whether or not an address may vary; it should return | |
eab5c70a BS |
1849 | nonzero whenever variation is possible. |
1850 | MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
ca7fd9cd | 1851 | |
2c72b78f | 1852 | static rtx |
4682ae04 AJ |
1853 | fixed_scalar_and_varying_struct_p (rtx mem1, rtx mem2, rtx mem1_addr, |
1854 | rtx mem2_addr, | |
1855 | int (*varies_p) (rtx, int)) | |
ca7fd9cd | 1856 | { |
3e0abe15 GK |
1857 | if (! flag_strict_aliasing) |
1858 | return NULL_RTX; | |
1859 | ||
ca7fd9cd | 1860 | if (MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) |
e38fe8e0 | 1861 | && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) |
c6df88cb MM |
1862 | /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a |
1863 | varying address. */ | |
1864 | return mem1; | |
1865 | ||
ca7fd9cd | 1866 | if (MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) |
e38fe8e0 | 1867 | && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) |
c6df88cb MM |
1868 | /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a |
1869 | varying address. */ | |
1870 | return mem2; | |
1871 | ||
1872 | return NULL_RTX; | |
1873 | } | |
1874 | ||
1875 | /* Returns nonzero if something about the mode or address format MEM1 | |
1876 | indicates that it might well alias *anything*. */ | |
1877 | ||
2c72b78f | 1878 | static int |
4682ae04 | 1879 | aliases_everything_p (rtx mem) |
c6df88cb | 1880 | { |
c6df88cb | 1881 | if (GET_CODE (XEXP (mem, 0)) == AND) |
35fd3193 | 1882 | /* If the address is an AND, it's very hard to know at what it is |
c6df88cb MM |
1883 | actually pointing. */ |
1884 | return 1; | |
ca7fd9cd | 1885 | |
c6df88cb MM |
1886 | return 0; |
1887 | } | |
1888 | ||
998d7deb RH |
1889 | /* Return true if we can determine that the fields referenced cannot |
1890 | overlap for any pair of objects. */ | |
1891 | ||
1892 | static bool | |
4682ae04 | 1893 | nonoverlapping_component_refs_p (tree x, tree y) |
998d7deb RH |
1894 | { |
1895 | tree fieldx, fieldy, typex, typey, orig_y; | |
1896 | ||
1897 | do | |
1898 | { | |
1899 | /* The comparison has to be done at a common type, since we don't | |
d6a7951f | 1900 | know how the inheritance hierarchy works. */ |
998d7deb RH |
1901 | orig_y = y; |
1902 | do | |
1903 | { | |
1904 | fieldx = TREE_OPERAND (x, 1); | |
c05a0766 | 1905 | typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx)); |
998d7deb RH |
1906 | |
1907 | y = orig_y; | |
1908 | do | |
1909 | { | |
1910 | fieldy = TREE_OPERAND (y, 1); | |
c05a0766 | 1911 | typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy)); |
998d7deb RH |
1912 | |
1913 | if (typex == typey) | |
1914 | goto found; | |
1915 | ||
1916 | y = TREE_OPERAND (y, 0); | |
1917 | } | |
1918 | while (y && TREE_CODE (y) == COMPONENT_REF); | |
1919 | ||
1920 | x = TREE_OPERAND (x, 0); | |
1921 | } | |
1922 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
998d7deb | 1923 | /* Never found a common type. */ |
c05a0766 | 1924 | return false; |
998d7deb RH |
1925 | |
1926 | found: | |
1927 | /* If we're left with accessing different fields of a structure, | |
1928 | then no overlap. */ | |
1929 | if (TREE_CODE (typex) == RECORD_TYPE | |
1930 | && fieldx != fieldy) | |
1931 | return true; | |
1932 | ||
1933 | /* The comparison on the current field failed. If we're accessing | |
1934 | a very nested structure, look at the next outer level. */ | |
1935 | x = TREE_OPERAND (x, 0); | |
1936 | y = TREE_OPERAND (y, 0); | |
1937 | } | |
1938 | while (x && y | |
1939 | && TREE_CODE (x) == COMPONENT_REF | |
1940 | && TREE_CODE (y) == COMPONENT_REF); | |
ca7fd9cd | 1941 | |
998d7deb RH |
1942 | return false; |
1943 | } | |
1944 | ||
1945 | /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
1946 | ||
1947 | static tree | |
4682ae04 | 1948 | decl_for_component_ref (tree x) |
998d7deb RH |
1949 | { |
1950 | do | |
1951 | { | |
1952 | x = TREE_OPERAND (x, 0); | |
1953 | } | |
1954 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1955 | ||
1956 | return x && DECL_P (x) ? x : NULL_TREE; | |
1957 | } | |
1958 | ||
1959 | /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
1960 | offset of the field reference. */ | |
1961 | ||
1962 | static rtx | |
4682ae04 | 1963 | adjust_offset_for_component_ref (tree x, rtx offset) |
998d7deb RH |
1964 | { |
1965 | HOST_WIDE_INT ioffset; | |
1966 | ||
1967 | if (! offset) | |
1968 | return NULL_RTX; | |
1969 | ||
1970 | ioffset = INTVAL (offset); | |
ca7fd9cd | 1971 | do |
998d7deb | 1972 | { |
44de5aeb | 1973 | tree offset = component_ref_field_offset (x); |
998d7deb RH |
1974 | tree field = TREE_OPERAND (x, 1); |
1975 | ||
44de5aeb | 1976 | if (! host_integerp (offset, 1)) |
998d7deb | 1977 | return NULL_RTX; |
44de5aeb | 1978 | ioffset += (tree_low_cst (offset, 1) |
998d7deb RH |
1979 | + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) |
1980 | / BITS_PER_UNIT)); | |
1981 | ||
1982 | x = TREE_OPERAND (x, 0); | |
1983 | } | |
1984 | while (x && TREE_CODE (x) == COMPONENT_REF); | |
1985 | ||
1986 | return GEN_INT (ioffset); | |
1987 | } | |
1988 | ||
95bd1dd7 | 1989 | /* Return nonzero if we can determine the exprs corresponding to memrefs |
a4311dfe RK |
1990 | X and Y and they do not overlap. */ |
1991 | ||
1992 | static int | |
4682ae04 | 1993 | nonoverlapping_memrefs_p (rtx x, rtx y) |
a4311dfe | 1994 | { |
998d7deb | 1995 | tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); |
a4311dfe RK |
1996 | rtx rtlx, rtly; |
1997 | rtx basex, basey; | |
998d7deb | 1998 | rtx moffsetx, moffsety; |
a4311dfe RK |
1999 | HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; |
2000 | ||
998d7deb RH |
2001 | /* Unless both have exprs, we can't tell anything. */ |
2002 | if (exprx == 0 || expry == 0) | |
2003 | return 0; | |
ea900239 | 2004 | |
998d7deb RH |
2005 | /* If both are field references, we may be able to determine something. */ |
2006 | if (TREE_CODE (exprx) == COMPONENT_REF | |
2007 | && TREE_CODE (expry) == COMPONENT_REF | |
2008 | && nonoverlapping_component_refs_p (exprx, expry)) | |
2009 | return 1; | |
2010 | ||
ea900239 | 2011 | |
998d7deb RH |
2012 | /* If the field reference test failed, look at the DECLs involved. */ |
2013 | moffsetx = MEM_OFFSET (x); | |
2014 | if (TREE_CODE (exprx) == COMPONENT_REF) | |
2015 | { | |
ea900239 DB |
2016 | if (TREE_CODE (expry) == VAR_DECL |
2017 | && POINTER_TYPE_P (TREE_TYPE (expry))) | |
2018 | { | |
2019 | tree field = TREE_OPERAND (exprx, 1); | |
2020 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2021 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2022 | TREE_TYPE (field))) | |
2023 | return 1; | |
2024 | } | |
2025 | { | |
2026 | tree t = decl_for_component_ref (exprx); | |
2027 | if (! t) | |
2028 | return 0; | |
2029 | moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
2030 | exprx = t; | |
2031 | } | |
998d7deb | 2032 | } |
1b096a0a | 2033 | else if (INDIRECT_REF_P (exprx)) |
c67a1cf6 RH |
2034 | { |
2035 | exprx = TREE_OPERAND (exprx, 0); | |
2036 | if (flag_argument_noalias < 2 | |
2037 | || TREE_CODE (exprx) != PARM_DECL) | |
2038 | return 0; | |
2039 | } | |
2040 | ||
998d7deb RH |
2041 | moffsety = MEM_OFFSET (y); |
2042 | if (TREE_CODE (expry) == COMPONENT_REF) | |
2043 | { | |
ea900239 DB |
2044 | if (TREE_CODE (exprx) == VAR_DECL |
2045 | && POINTER_TYPE_P (TREE_TYPE (exprx))) | |
2046 | { | |
2047 | tree field = TREE_OPERAND (expry, 1); | |
2048 | tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
2049 | if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
2050 | TREE_TYPE (field))) | |
2051 | return 1; | |
2052 | } | |
2053 | { | |
2054 | tree t = decl_for_component_ref (expry); | |
2055 | if (! t) | |
2056 | return 0; | |
2057 | moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
2058 | expry = t; | |
2059 | } | |
998d7deb | 2060 | } |
1b096a0a | 2061 | else if (INDIRECT_REF_P (expry)) |
c67a1cf6 RH |
2062 | { |
2063 | expry = TREE_OPERAND (expry, 0); | |
2064 | if (flag_argument_noalias < 2 | |
2065 | || TREE_CODE (expry) != PARM_DECL) | |
2066 | return 0; | |
2067 | } | |
998d7deb RH |
2068 | |
2069 | if (! DECL_P (exprx) || ! DECL_P (expry)) | |
a4311dfe RK |
2070 | return 0; |
2071 | ||
998d7deb RH |
2072 | rtlx = DECL_RTL (exprx); |
2073 | rtly = DECL_RTL (expry); | |
a4311dfe | 2074 | |
1edcd60b RK |
2075 | /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they |
2076 | can't overlap unless they are the same because we never reuse that part | |
2077 | of the stack frame used for locals for spilled pseudos. */ | |
3c0cb5de | 2078 | if ((!MEM_P (rtlx) || !MEM_P (rtly)) |
1edcd60b | 2079 | && ! rtx_equal_p (rtlx, rtly)) |
a4311dfe RK |
2080 | return 1; |
2081 | ||
2082 | /* Get the base and offsets of both decls. If either is a register, we | |
2083 | know both are and are the same, so use that as the base. The only | |
2084 | we can avoid overlap is if we can deduce that they are nonoverlapping | |
2085 | pieces of that decl, which is very rare. */ | |
3c0cb5de | 2086 | basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx; |
a4311dfe RK |
2087 | if (GET_CODE (basex) == PLUS && GET_CODE (XEXP (basex, 1)) == CONST_INT) |
2088 | offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); | |
2089 | ||
3c0cb5de | 2090 | basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly; |
a4311dfe RK |
2091 | if (GET_CODE (basey) == PLUS && GET_CODE (XEXP (basey, 1)) == CONST_INT) |
2092 | offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); | |
2093 | ||
d746694a | 2094 | /* If the bases are different, we know they do not overlap if both |
ca7fd9cd | 2095 | are constants or if one is a constant and the other a pointer into the |
d746694a RK |
2096 | stack frame. Otherwise a different base means we can't tell if they |
2097 | overlap or not. */ | |
2098 | if (! rtx_equal_p (basex, basey)) | |
ca7fd9cd KH |
2099 | return ((CONSTANT_P (basex) && CONSTANT_P (basey)) |
2100 | || (CONSTANT_P (basex) && REG_P (basey) | |
2101 | && REGNO_PTR_FRAME_P (REGNO (basey))) | |
2102 | || (CONSTANT_P (basey) && REG_P (basex) | |
2103 | && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
a4311dfe | 2104 | |
3c0cb5de | 2105 | sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) |
a4311dfe RK |
2106 | : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) |
2107 | : -1); | |
3c0cb5de | 2108 | sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly)) |
a4311dfe RK |
2109 | : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : |
2110 | -1); | |
2111 | ||
0af5bc3e RK |
2112 | /* If we have an offset for either memref, it can update the values computed |
2113 | above. */ | |
998d7deb RH |
2114 | if (moffsetx) |
2115 | offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
2116 | if (moffsety) | |
2117 | offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
a4311dfe | 2118 | |
0af5bc3e | 2119 | /* If a memref has both a size and an offset, we can use the smaller size. |
efc981bb | 2120 | We can't do this if the offset isn't known because we must view this |
0af5bc3e | 2121 | memref as being anywhere inside the DECL's MEM. */ |
998d7deb | 2122 | if (MEM_SIZE (x) && moffsetx) |
a4311dfe | 2123 | sizex = INTVAL (MEM_SIZE (x)); |
998d7deb | 2124 | if (MEM_SIZE (y) && moffsety) |
a4311dfe RK |
2125 | sizey = INTVAL (MEM_SIZE (y)); |
2126 | ||
2127 | /* Put the values of the memref with the lower offset in X's values. */ | |
2128 | if (offsetx > offsety) | |
2129 | { | |
2130 | tem = offsetx, offsetx = offsety, offsety = tem; | |
2131 | tem = sizex, sizex = sizey, sizey = tem; | |
2132 | } | |
2133 | ||
2134 | /* If we don't know the size of the lower-offset value, we can't tell | |
2135 | if they conflict. Otherwise, we do the test. */ | |
a6f7c915 | 2136 | return sizex >= 0 && offsety >= offsetx + sizex; |
a4311dfe RK |
2137 | } |
2138 | ||
9ae8ffe7 JL |
2139 | /* True dependence: X is read after store in MEM takes place. */ |
2140 | ||
2141 | int | |
4682ae04 AJ |
2142 | true_dependence (rtx mem, enum machine_mode mem_mode, rtx x, |
2143 | int (*varies) (rtx, int)) | |
9ae8ffe7 | 2144 | { |
b3694847 | 2145 | rtx x_addr, mem_addr; |
49982682 | 2146 | rtx base; |
9ae8ffe7 JL |
2147 | |
2148 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2149 | return 1; | |
2150 | ||
c4484b8f RH |
2151 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2152 | This is used in epilogue deallocation functions. */ | |
2153 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2154 | return 1; | |
2155 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2156 | return 1; | |
9cd9e512 RH |
2157 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2158 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2159 | return 1; | |
c4484b8f | 2160 | |
41472af8 MM |
2161 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2162 | return 0; | |
2163 | ||
389fdba0 RH |
2164 | /* Read-only memory is by definition never modified, and therefore can't |
2165 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2166 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2167 | if (MEM_READONLY_P (x)) |
9ae8ffe7 JL |
2168 | return 0; |
2169 | ||
a4311dfe RK |
2170 | if (nonoverlapping_memrefs_p (mem, x)) |
2171 | return 0; | |
2172 | ||
56ee9281 RH |
2173 | if (mem_mode == VOIDmode) |
2174 | mem_mode = GET_MODE (mem); | |
2175 | ||
eab5c70a BS |
2176 | x_addr = get_addr (XEXP (x, 0)); |
2177 | mem_addr = get_addr (XEXP (mem, 0)); | |
2178 | ||
55efb413 JW |
2179 | base = find_base_term (x_addr); |
2180 | if (base && (GET_CODE (base) == LABEL_REF | |
2181 | || (GET_CODE (base) == SYMBOL_REF | |
2182 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2183 | return 0; | |
2184 | ||
eab5c70a | 2185 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) |
1c72c7f6 JC |
2186 | return 0; |
2187 | ||
eab5c70a BS |
2188 | x_addr = canon_rtx (x_addr); |
2189 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2190 | |
0211b6ab JW |
2191 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, |
2192 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2193 | return 0; | |
2194 | ||
c6df88cb | 2195 | if (aliases_everything_p (x)) |
0211b6ab JW |
2196 | return 1; |
2197 | ||
f5143c46 | 2198 | /* We cannot use aliases_everything_p to test MEM, since we must look |
c6df88cb MM |
2199 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2200 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
a13d4ebf AM |
2201 | return 1; |
2202 | ||
2203 | /* In true_dependence we also allow BLKmode to alias anything. Why | |
2204 | don't we do this in anti_dependence and output_dependence? */ | |
2205 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2206 | return 1; | |
2207 | ||
2208 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, | |
2209 | varies); | |
2210 | } | |
2211 | ||
2212 | /* Canonical true dependence: X is read after store in MEM takes place. | |
ca7fd9cd KH |
2213 | Variant of true_dependence which assumes MEM has already been |
2214 | canonicalized (hence we no longer do that here). | |
2215 | The mem_addr argument has been added, since true_dependence computed | |
a13d4ebf AM |
2216 | this value prior to canonicalizing. */ |
2217 | ||
2218 | int | |
4682ae04 AJ |
2219 | canon_true_dependence (rtx mem, enum machine_mode mem_mode, rtx mem_addr, |
2220 | rtx x, int (*varies) (rtx, int)) | |
a13d4ebf | 2221 | { |
b3694847 | 2222 | rtx x_addr; |
a13d4ebf AM |
2223 | |
2224 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
2225 | return 1; | |
2226 | ||
0fe854a7 RH |
2227 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2228 | This is used in epilogue deallocation functions. */ | |
2229 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2230 | return 1; | |
2231 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2232 | return 1; | |
9cd9e512 RH |
2233 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2234 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2235 | return 1; | |
0fe854a7 | 2236 | |
a13d4ebf AM |
2237 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2238 | return 0; | |
2239 | ||
389fdba0 RH |
2240 | /* Read-only memory is by definition never modified, and therefore can't |
2241 | conflict with anything. We don't expect to find read-only set on MEM, | |
41806d92 | 2242 | but stupid user tricks can produce them, so don't die. */ |
389fdba0 | 2243 | if (MEM_READONLY_P (x)) |
a13d4ebf AM |
2244 | return 0; |
2245 | ||
a4311dfe RK |
2246 | if (nonoverlapping_memrefs_p (x, mem)) |
2247 | return 0; | |
2248 | ||
a13d4ebf AM |
2249 | x_addr = get_addr (XEXP (x, 0)); |
2250 | ||
2251 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
2252 | return 0; | |
2253 | ||
2254 | x_addr = canon_rtx (x_addr); | |
2255 | if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
2256 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2257 | return 0; | |
2258 | ||
2259 | if (aliases_everything_p (x)) | |
2260 | return 1; | |
2261 | ||
f5143c46 | 2262 | /* We cannot use aliases_everything_p to test MEM, since we must look |
a13d4ebf AM |
2263 | at MEM_MODE, rather than GET_MODE (MEM). */ |
2264 | if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
c6df88cb | 2265 | return 1; |
0211b6ab | 2266 | |
c6df88cb MM |
2267 | /* In true_dependence we also allow BLKmode to alias anything. Why |
2268 | don't we do this in anti_dependence and output_dependence? */ | |
2269 | if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
2270 | return 1; | |
0211b6ab | 2271 | |
eab5c70a BS |
2272 | return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2273 | varies); | |
9ae8ffe7 JL |
2274 | } |
2275 | ||
da7d8304 | 2276 | /* Returns nonzero if a write to X might alias a previous read from |
389fdba0 | 2277 | (or, if WRITEP is nonzero, a write to) MEM. */ |
9ae8ffe7 | 2278 | |
2c72b78f | 2279 | static int |
389fdba0 | 2280 | write_dependence_p (rtx mem, rtx x, int writep) |
9ae8ffe7 | 2281 | { |
6e73e666 | 2282 | rtx x_addr, mem_addr; |
c6df88cb | 2283 | rtx fixed_scalar; |
49982682 | 2284 | rtx base; |
6e73e666 | 2285 | |
9ae8ffe7 JL |
2286 | if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) |
2287 | return 1; | |
2288 | ||
c4484b8f RH |
2289 | /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. |
2290 | This is used in epilogue deallocation functions. */ | |
2291 | if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
2292 | return 1; | |
2293 | if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
2294 | return 1; | |
9cd9e512 RH |
2295 | if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER |
2296 | || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
2297 | return 1; | |
c4484b8f | 2298 | |
eab5c70a BS |
2299 | if (DIFFERENT_ALIAS_SETS_P (x, mem)) |
2300 | return 0; | |
2301 | ||
389fdba0 RH |
2302 | /* A read from read-only memory can't conflict with read-write memory. */ |
2303 | if (!writep && MEM_READONLY_P (mem)) | |
2304 | return 0; | |
55efb413 | 2305 | |
a4311dfe RK |
2306 | if (nonoverlapping_memrefs_p (x, mem)) |
2307 | return 0; | |
2308 | ||
55efb413 JW |
2309 | x_addr = get_addr (XEXP (x, 0)); |
2310 | mem_addr = get_addr (XEXP (mem, 0)); | |
2311 | ||
49982682 JW |
2312 | if (! writep) |
2313 | { | |
55efb413 | 2314 | base = find_base_term (mem_addr); |
49982682 JW |
2315 | if (base && (GET_CODE (base) == LABEL_REF |
2316 | || (GET_CODE (base) == SYMBOL_REF | |
2317 | && CONSTANT_POOL_ADDRESS_P (base)))) | |
2318 | return 0; | |
2319 | } | |
2320 | ||
eab5c70a BS |
2321 | if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), |
2322 | GET_MODE (mem))) | |
41472af8 MM |
2323 | return 0; |
2324 | ||
eab5c70a BS |
2325 | x_addr = canon_rtx (x_addr); |
2326 | mem_addr = canon_rtx (mem_addr); | |
6e73e666 | 2327 | |
c6df88cb MM |
2328 | if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, |
2329 | SIZE_FOR_MODE (x), x_addr, 0)) | |
2330 | return 0; | |
2331 | ||
ca7fd9cd | 2332 | fixed_scalar |
eab5c70a BS |
2333 | = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, |
2334 | rtx_addr_varies_p); | |
2335 | ||
c6df88cb MM |
2336 | return (!(fixed_scalar == mem && !aliases_everything_p (x)) |
2337 | && !(fixed_scalar == x && !aliases_everything_p (mem))); | |
2338 | } | |
2339 | ||
2340 | /* Anti dependence: X is written after read in MEM takes place. */ | |
2341 | ||
2342 | int | |
4682ae04 | 2343 | anti_dependence (rtx mem, rtx x) |
c6df88cb | 2344 | { |
389fdba0 | 2345 | return write_dependence_p (mem, x, /*writep=*/0); |
9ae8ffe7 JL |
2346 | } |
2347 | ||
2348 | /* Output dependence: X is written after store in MEM takes place. */ | |
2349 | ||
2350 | int | |
4682ae04 | 2351 | output_dependence (rtx mem, rtx x) |
9ae8ffe7 | 2352 | { |
389fdba0 | 2353 | return write_dependence_p (mem, x, /*writep=*/1); |
9ae8ffe7 | 2354 | } |
c14b9960 | 2355 | \f |
6e73e666 | 2356 | |
6e73e666 | 2357 | void |
4682ae04 | 2358 | init_alias_once (void) |
6e73e666 | 2359 | { |
b3694847 | 2360 | int i; |
6e73e666 | 2361 | |
6e73e666 JC |
2362 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
2363 | /* Check whether this register can hold an incoming pointer | |
2364 | argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
ec5c56db | 2365 | numbers, so translate if necessary due to register windows. */ |
6e73e666 JC |
2366 | if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) |
2367 | && HARD_REGNO_MODE_OK (i, Pmode)) | |
bf1660a6 JL |
2368 | static_reg_base_value[i] |
2369 | = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i)); | |
2370 | ||
bf1660a6 JL |
2371 | static_reg_base_value[STACK_POINTER_REGNUM] |
2372 | = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); | |
2373 | static_reg_base_value[ARG_POINTER_REGNUM] | |
2374 | = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); | |
2375 | static_reg_base_value[FRAME_POINTER_REGNUM] | |
2376 | = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); | |
2377 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
2378 | static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
2379 | = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); | |
2380 | #endif | |
2381 | } | |
2382 | ||
7b52eede JH |
2383 | /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed |
2384 | to be memory reference. */ | |
2385 | static bool memory_modified; | |
2386 | static void | |
4682ae04 | 2387 | memory_modified_1 (rtx x, rtx pat ATTRIBUTE_UNUSED, void *data) |
7b52eede | 2388 | { |
3c0cb5de | 2389 | if (MEM_P (x)) |
7b52eede JH |
2390 | { |
2391 | if (anti_dependence (x, (rtx)data) || output_dependence (x, (rtx)data)) | |
2392 | memory_modified = true; | |
2393 | } | |
2394 | } | |
2395 | ||
2396 | ||
2397 | /* Return true when INSN possibly modify memory contents of MEM | |
454ff5cb | 2398 | (i.e. address can be modified). */ |
7b52eede | 2399 | bool |
4682ae04 | 2400 | memory_modified_in_insn_p (rtx mem, rtx insn) |
7b52eede JH |
2401 | { |
2402 | if (!INSN_P (insn)) | |
2403 | return false; | |
2404 | memory_modified = false; | |
2405 | note_stores (PATTERN (insn), memory_modified_1, mem); | |
2406 | return memory_modified; | |
2407 | } | |
2408 | ||
c13e8210 MM |
2409 | /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE |
2410 | array. */ | |
2411 | ||
9ae8ffe7 | 2412 | void |
4682ae04 | 2413 | init_alias_analysis (void) |
9ae8ffe7 | 2414 | { |
c582d54a | 2415 | unsigned int maxreg = max_reg_num (); |
ea64ef27 | 2416 | int changed, pass; |
b3694847 SS |
2417 | int i; |
2418 | unsigned int ui; | |
2419 | rtx insn; | |
9ae8ffe7 | 2420 | |
0d446150 JH |
2421 | timevar_push (TV_ALIAS_ANALYSIS); |
2422 | ||
bb1acb3e RH |
2423 | reg_known_value_size = maxreg - FIRST_PSEUDO_REGISTER; |
2424 | reg_known_value = ggc_calloc (reg_known_value_size, sizeof (rtx)); | |
2425 | reg_known_equiv_p = xcalloc (reg_known_value_size, sizeof (bool)); | |
9ae8ffe7 | 2426 | |
6e73e666 JC |
2427 | /* Overallocate reg_base_value to allow some growth during loop |
2428 | optimization. Loop unrolling can create a large number of | |
2429 | registers. */ | |
c582d54a JH |
2430 | if (old_reg_base_value) |
2431 | { | |
2432 | reg_base_value = old_reg_base_value; | |
2433 | /* If varray gets large zeroing cost may get important. */ | |
2434 | if (VARRAY_SIZE (reg_base_value) > 256 | |
2435 | && VARRAY_SIZE (reg_base_value) > 4 * maxreg) | |
2436 | VARRAY_GROW (reg_base_value, maxreg); | |
2437 | VARRAY_CLEAR (reg_base_value); | |
2438 | if (VARRAY_SIZE (reg_base_value) < maxreg) | |
2439 | VARRAY_GROW (reg_base_value, maxreg); | |
2440 | } | |
2441 | else | |
2442 | { | |
2443 | VARRAY_RTX_INIT (reg_base_value, maxreg, "reg_base_value"); | |
2444 | } | |
ac606739 | 2445 | |
5ed6ace5 MD |
2446 | new_reg_base_value = XNEWVEC (rtx, maxreg); |
2447 | reg_seen = XNEWVEC (char, maxreg); | |
ec907dd8 JL |
2448 | |
2449 | /* The basic idea is that each pass through this loop will use the | |
2450 | "constant" information from the previous pass to propagate alias | |
2451 | information through another level of assignments. | |
2452 | ||
2453 | This could get expensive if the assignment chains are long. Maybe | |
2454 | we should throttle the number of iterations, possibly based on | |
6e73e666 | 2455 | the optimization level or flag_expensive_optimizations. |
ec907dd8 JL |
2456 | |
2457 | We could propagate more information in the first pass by making use | |
2458 | of REG_N_SETS to determine immediately that the alias information | |
ea64ef27 JL |
2459 | for a pseudo is "constant". |
2460 | ||
2461 | A program with an uninitialized variable can cause an infinite loop | |
2462 | here. Instead of doing a full dataflow analysis to detect such problems | |
2463 | we just cap the number of iterations for the loop. | |
2464 | ||
2465 | The state of the arrays for the set chain in question does not matter | |
2466 | since the program has undefined behavior. */ | |
6e73e666 | 2467 | |
ea64ef27 | 2468 | pass = 0; |
6e73e666 | 2469 | do |
ec907dd8 JL |
2470 | { |
2471 | /* Assume nothing will change this iteration of the loop. */ | |
2472 | changed = 0; | |
2473 | ||
ec907dd8 JL |
2474 | /* We want to assign the same IDs each iteration of this loop, so |
2475 | start counting from zero each iteration of the loop. */ | |
2476 | unique_id = 0; | |
2477 | ||
f5143c46 | 2478 | /* We're at the start of the function each iteration through the |
ec907dd8 | 2479 | loop, so we're copying arguments. */ |
83bbd9b6 | 2480 | copying_arguments = true; |
9ae8ffe7 | 2481 | |
6e73e666 | 2482 | /* Wipe the potential alias information clean for this pass. */ |
c582d54a | 2483 | memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); |
8072f69c | 2484 | |
6e73e666 | 2485 | /* Wipe the reg_seen array clean. */ |
c582d54a | 2486 | memset (reg_seen, 0, maxreg); |
9ae8ffe7 | 2487 | |
6e73e666 JC |
2488 | /* Mark all hard registers which may contain an address. |
2489 | The stack, frame and argument pointers may contain an address. | |
2490 | An argument register which can hold a Pmode value may contain | |
2491 | an address even if it is not in BASE_REGS. | |
8072f69c | 2492 | |
6e73e666 JC |
2493 | The address expression is VOIDmode for an argument and |
2494 | Pmode for other registers. */ | |
2495 | ||
7f243674 JL |
2496 | memcpy (new_reg_base_value, static_reg_base_value, |
2497 | FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
6e73e666 | 2498 | |
ec907dd8 JL |
2499 | /* Walk the insns adding values to the new_reg_base_value array. */ |
2500 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
9ae8ffe7 | 2501 | { |
2c3c49de | 2502 | if (INSN_P (insn)) |
ec907dd8 | 2503 | { |
6e73e666 | 2504 | rtx note, set; |
efc9bd41 RK |
2505 | |
2506 | #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
f5143c46 | 2507 | /* The prologue/epilogue insns are not threaded onto the |
657959ca JL |
2508 | insn chain until after reload has completed. Thus, |
2509 | there is no sense wasting time checking if INSN is in | |
2510 | the prologue/epilogue until after reload has completed. */ | |
2511 | if (reload_completed | |
2512 | && prologue_epilogue_contains (insn)) | |
efc9bd41 RK |
2513 | continue; |
2514 | #endif | |
2515 | ||
ec907dd8 JL |
2516 | /* If this insn has a noalias note, process it, Otherwise, |
2517 | scan for sets. A simple set will have no side effects | |
ec5c56db | 2518 | which could change the base value of any other register. */ |
6e73e666 | 2519 | |
ec907dd8 | 2520 | if (GET_CODE (PATTERN (insn)) == SET |
efc9bd41 RK |
2521 | && REG_NOTES (insn) != 0 |
2522 | && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
84832317 | 2523 | record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); |
ec907dd8 | 2524 | else |
84832317 | 2525 | note_stores (PATTERN (insn), record_set, NULL); |
6e73e666 JC |
2526 | |
2527 | set = single_set (insn); | |
2528 | ||
2529 | if (set != 0 | |
f8cfc6aa | 2530 | && REG_P (SET_DEST (set)) |
fb6754f0 | 2531 | && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) |
6e73e666 | 2532 | { |
fb6754f0 | 2533 | unsigned int regno = REGNO (SET_DEST (set)); |
713f41f9 | 2534 | rtx src = SET_SRC (set); |
bb1acb3e | 2535 | rtx t; |
713f41f9 BS |
2536 | |
2537 | if (REG_NOTES (insn) != 0 | |
2538 | && (((note = find_reg_note (insn, REG_EQUAL, 0)) != 0 | |
2539 | && REG_N_SETS (regno) == 1) | |
2540 | || (note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) != 0) | |
2541 | && GET_CODE (XEXP (note, 0)) != EXPR_LIST | |
bb2cf916 | 2542 | && ! rtx_varies_p (XEXP (note, 0), 1) |
bb1acb3e RH |
2543 | && ! reg_overlap_mentioned_p (SET_DEST (set), |
2544 | XEXP (note, 0))) | |
713f41f9 | 2545 | { |
bb1acb3e RH |
2546 | set_reg_known_value (regno, XEXP (note, 0)); |
2547 | set_reg_known_equiv_p (regno, | |
2548 | REG_NOTE_KIND (note) == REG_EQUIV); | |
713f41f9 BS |
2549 | } |
2550 | else if (REG_N_SETS (regno) == 1 | |
2551 | && GET_CODE (src) == PLUS | |
f8cfc6aa | 2552 | && REG_P (XEXP (src, 0)) |
bb1acb3e | 2553 | && (t = get_reg_known_value (REGNO (XEXP (src, 0)))) |
713f41f9 BS |
2554 | && GET_CODE (XEXP (src, 1)) == CONST_INT) |
2555 | { | |
bb1acb3e RH |
2556 | t = plus_constant (t, INTVAL (XEXP (src, 1))); |
2557 | set_reg_known_value (regno, t); | |
2558 | set_reg_known_equiv_p (regno, 0); | |
713f41f9 BS |
2559 | } |
2560 | else if (REG_N_SETS (regno) == 1 | |
2561 | && ! rtx_varies_p (src, 1)) | |
2562 | { | |
bb1acb3e RH |
2563 | set_reg_known_value (regno, src); |
2564 | set_reg_known_equiv_p (regno, 0); | |
713f41f9 | 2565 | } |
6e73e666 | 2566 | } |
ec907dd8 | 2567 | } |
4b4bf941 | 2568 | else if (NOTE_P (insn) |
ec907dd8 | 2569 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG) |
83bbd9b6 | 2570 | copying_arguments = false; |
6e73e666 | 2571 | } |
ec907dd8 | 2572 | |
6e73e666 | 2573 | /* Now propagate values from new_reg_base_value to reg_base_value. */ |
298e6adc NS |
2574 | gcc_assert (maxreg == (unsigned int) max_reg_num()); |
2575 | ||
c582d54a | 2576 | for (ui = 0; ui < maxreg; ui++) |
6e73e666 | 2577 | { |
e51712db | 2578 | if (new_reg_base_value[ui] |
c582d54a JH |
2579 | && new_reg_base_value[ui] != VARRAY_RTX (reg_base_value, ui) |
2580 | && ! rtx_equal_p (new_reg_base_value[ui], | |
2581 | VARRAY_RTX (reg_base_value, ui))) | |
ec907dd8 | 2582 | { |
c582d54a | 2583 | VARRAY_RTX (reg_base_value, ui) = new_reg_base_value[ui]; |
6e73e666 | 2584 | changed = 1; |
ec907dd8 | 2585 | } |
9ae8ffe7 | 2586 | } |
9ae8ffe7 | 2587 | } |
6e73e666 | 2588 | while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 JL |
2589 | |
2590 | /* Fill in the remaining entries. */ | |
bb1acb3e | 2591 | for (i = 0; i < (int)reg_known_value_size; i++) |
9ae8ffe7 | 2592 | if (reg_known_value[i] == 0) |
bb1acb3e | 2593 | reg_known_value[i] = regno_reg_rtx[i + FIRST_PSEUDO_REGISTER]; |
9ae8ffe7 | 2594 | |
9ae8ffe7 JL |
2595 | /* Simplify the reg_base_value array so that no register refers to |
2596 | another register, except to special registers indirectly through | |
2597 | ADDRESS expressions. | |
2598 | ||
2599 | In theory this loop can take as long as O(registers^2), but unless | |
2600 | there are very long dependency chains it will run in close to linear | |
ea64ef27 JL |
2601 | time. |
2602 | ||
2603 | This loop may not be needed any longer now that the main loop does | |
2604 | a better job at propagating alias information. */ | |
2605 | pass = 0; | |
9ae8ffe7 JL |
2606 | do |
2607 | { | |
2608 | changed = 0; | |
ea64ef27 | 2609 | pass++; |
c582d54a | 2610 | for (ui = 0; ui < maxreg; ui++) |
9ae8ffe7 | 2611 | { |
c582d54a | 2612 | rtx base = VARRAY_RTX (reg_base_value, ui); |
f8cfc6aa | 2613 | if (base && REG_P (base)) |
9ae8ffe7 | 2614 | { |
fb6754f0 | 2615 | unsigned int base_regno = REGNO (base); |
e51712db | 2616 | if (base_regno == ui) /* register set from itself */ |
c582d54a | 2617 | VARRAY_RTX (reg_base_value, ui) = 0; |
9ae8ffe7 | 2618 | else |
c582d54a JH |
2619 | VARRAY_RTX (reg_base_value, ui) |
2620 | = VARRAY_RTX (reg_base_value, base_regno); | |
9ae8ffe7 JL |
2621 | changed = 1; |
2622 | } | |
2623 | } | |
2624 | } | |
ea64ef27 | 2625 | while (changed && pass < MAX_ALIAS_LOOP_PASSES); |
9ae8ffe7 | 2626 | |
e05e2395 MM |
2627 | /* Clean up. */ |
2628 | free (new_reg_base_value); | |
ec907dd8 | 2629 | new_reg_base_value = 0; |
e05e2395 | 2630 | free (reg_seen); |
9ae8ffe7 | 2631 | reg_seen = 0; |
0d446150 | 2632 | timevar_pop (TV_ALIAS_ANALYSIS); |
9ae8ffe7 JL |
2633 | } |
2634 | ||
2635 | void | |
4682ae04 | 2636 | end_alias_analysis (void) |
9ae8ffe7 | 2637 | { |
c582d54a | 2638 | old_reg_base_value = reg_base_value; |
bb1acb3e | 2639 | ggc_free (reg_known_value); |
9ae8ffe7 | 2640 | reg_known_value = 0; |
ac606739 | 2641 | reg_known_value_size = 0; |
bb1acb3e | 2642 | free (reg_known_equiv_p); |
e05e2395 | 2643 | reg_known_equiv_p = 0; |
9ae8ffe7 | 2644 | } |
e2500fed GK |
2645 | |
2646 | #include "gt-alias.h" |