Mercurial > hg > CbC > CbC_gcc
annotate gcc/alias.c @ 55:77e2b8dfacca gcc-4.4.5
update it from 4.4.3 to 4.5.0
| author | ryoma <e075725@ie.u-ryukyu.ac.jp> |
|---|---|
| date | Fri, 12 Feb 2010 23:39:51 +0900 |
| parents | 855418dad1a3 |
| children | b7f97abdc517 |
| rev | line source |
|---|---|
| 0 | 1 /* Alias analysis for GNU C |
| 2 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, | |
| 3 2007, 2008, 2009 Free Software Foundation, Inc. | |
| 4 Contributed by John Carr (jfc@mit.edu). | |
| 5 | |
| 6 This file is part of GCC. | |
| 7 | |
| 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 3, or (at your option) any later | |
| 11 version. | |
| 12 | |
| 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. | |
| 17 | |
| 18 You should have received a copy of the GNU General Public License | |
| 19 along with GCC; see the file COPYING3. If not see | |
| 20 <http://www.gnu.org/licenses/>. */ | |
| 21 | |
| 22 #include "config.h" | |
| 23 #include "system.h" | |
| 24 #include "coretypes.h" | |
| 25 #include "tm.h" | |
| 26 #include "rtl.h" | |
| 27 #include "tree.h" | |
| 28 #include "tm_p.h" | |
| 29 #include "function.h" | |
| 30 #include "alias.h" | |
| 31 #include "emit-rtl.h" | |
| 32 #include "regs.h" | |
| 33 #include "hard-reg-set.h" | |
| 34 #include "basic-block.h" | |
| 35 #include "flags.h" | |
| 36 #include "output.h" | |
| 37 #include "toplev.h" | |
| 38 #include "cselib.h" | |
| 39 #include "splay-tree.h" | |
| 40 #include "ggc.h" | |
| 41 #include "langhooks.h" | |
| 42 #include "timevar.h" | |
| 43 #include "target.h" | |
| 44 #include "cgraph.h" | |
| 45 #include "varray.h" | |
| 46 #include "tree-pass.h" | |
| 47 #include "ipa-type-escape.h" | |
| 48 #include "df.h" | |
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49 #include "tree-ssa-alias.h" |
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50 #include "pointer-set.h" |
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51 #include "tree-flow.h" |
| 0 | 52 |
| 53 /* The aliasing API provided here solves related but different problems: | |
| 54 | |
| 55 Say there exists (in c) | |
| 56 | |
| 57 struct X { | |
| 58 struct Y y1; | |
| 59 struct Z z2; | |
| 60 } x1, *px1, *px2; | |
| 61 | |
| 62 struct Y y2, *py; | |
| 63 struct Z z2, *pz; | |
| 64 | |
| 65 | |
| 66 py = &px1.y1; | |
| 67 px2 = &x1; | |
| 68 | |
| 69 Consider the four questions: | |
| 70 | |
| 71 Can a store to x1 interfere with px2->y1? | |
| 72 Can a store to x1 interfere with px2->z2? | |
| 73 (*px2).z2 | |
| 74 Can a store to x1 change the value pointed to by with py? | |
| 75 Can a store to x1 change the value pointed to by with pz? | |
| 76 | |
| 77 The answer to these questions can be yes, yes, yes, and maybe. | |
| 78 | |
| 79 The first two questions can be answered with a simple examination | |
| 80 of the type system. If structure X contains a field of type Y then | |
| 81 a store thru a pointer to an X can overwrite any field that is | |
| 82 contained (recursively) in an X (unless we know that px1 != px2). | |
| 83 | |
| 84 The last two of the questions can be solved in the same way as the | |
| 85 first two questions but this is too conservative. The observation | |
| 86 is that in some cases analysis we can know if which (if any) fields | |
| 87 are addressed and if those addresses are used in bad ways. This | |
| 88 analysis may be language specific. In C, arbitrary operations may | |
| 89 be applied to pointers. However, there is some indication that | |
| 90 this may be too conservative for some C++ types. | |
| 91 | |
| 92 The pass ipa-type-escape does this analysis for the types whose | |
| 93 instances do not escape across the compilation boundary. | |
| 94 | |
| 95 Historically in GCC, these two problems were combined and a single | |
| 96 data structure was used to represent the solution to these | |
| 97 problems. We now have two similar but different data structures, | |
| 98 The data structure to solve the last two question is similar to the | |
| 99 first, but does not contain have the fields in it whose address are | |
| 100 never taken. For types that do escape the compilation unit, the | |
| 101 data structures will have identical information. | |
| 102 */ | |
| 103 | |
| 104 /* The alias sets assigned to MEMs assist the back-end in determining | |
| 105 which MEMs can alias which other MEMs. In general, two MEMs in | |
| 106 different alias sets cannot alias each other, with one important | |
| 107 exception. Consider something like: | |
| 108 | |
| 109 struct S { int i; double d; }; | |
| 110 | |
| 111 a store to an `S' can alias something of either type `int' or type | |
| 112 `double'. (However, a store to an `int' cannot alias a `double' | |
| 113 and vice versa.) We indicate this via a tree structure that looks | |
| 114 like: | |
| 115 struct S | |
| 116 / \ | |
| 117 / \ | |
| 118 |/_ _\| | |
| 119 int double | |
| 120 | |
| 121 (The arrows are directed and point downwards.) | |
| 122 In this situation we say the alias set for `struct S' is the | |
| 123 `superset' and that those for `int' and `double' are `subsets'. | |
| 124 | |
| 125 To see whether two alias sets can point to the same memory, we must | |
| 126 see if either alias set is a subset of the other. We need not trace | |
| 127 past immediate descendants, however, since we propagate all | |
| 128 grandchildren up one level. | |
| 129 | |
| 130 Alias set zero is implicitly a superset of all other alias sets. | |
| 131 However, this is no actual entry for alias set zero. It is an | |
| 132 error to attempt to explicitly construct a subset of zero. */ | |
| 133 | |
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134 struct GTY(()) alias_set_entry_d { |
| 0 | 135 /* The alias set number, as stored in MEM_ALIAS_SET. */ |
| 136 alias_set_type alias_set; | |
| 137 | |
| 138 /* Nonzero if would have a child of zero: this effectively makes this | |
| 139 alias set the same as alias set zero. */ | |
| 140 int has_zero_child; | |
| 141 | |
| 142 /* The children of the alias set. These are not just the immediate | |
| 143 children, but, in fact, all descendants. So, if we have: | |
| 144 | |
| 145 struct T { struct S s; float f; } | |
| 146 | |
| 147 continuing our example above, the children here will be all of | |
| 148 `int', `double', `float', and `struct S'. */ | |
| 149 splay_tree GTY((param1_is (int), param2_is (int))) children; | |
| 150 }; | |
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151 typedef struct alias_set_entry_d *alias_set_entry; |
| 0 | 152 |
| 153 static int rtx_equal_for_memref_p (const_rtx, const_rtx); | |
| 154 static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT); | |
| 155 static void record_set (rtx, const_rtx, void *); | |
| 156 static int base_alias_check (rtx, rtx, enum machine_mode, | |
| 157 enum machine_mode); | |
| 158 static rtx find_base_value (rtx); | |
| 159 static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx); | |
| 160 static int insert_subset_children (splay_tree_node, void*); | |
| 161 static alias_set_entry get_alias_set_entry (alias_set_type); | |
| 162 static const_rtx fixed_scalar_and_varying_struct_p (const_rtx, const_rtx, rtx, rtx, | |
| 163 bool (*) (const_rtx, bool)); | |
| 164 static int aliases_everything_p (const_rtx); | |
| 165 static bool nonoverlapping_component_refs_p (const_tree, const_tree); | |
| 166 static tree decl_for_component_ref (tree); | |
| 167 static rtx adjust_offset_for_component_ref (tree, rtx); | |
| 168 static int write_dependence_p (const_rtx, const_rtx, int); | |
| 169 | |
| 170 static void memory_modified_1 (rtx, const_rtx, void *); | |
| 171 | |
| 172 /* Set up all info needed to perform alias analysis on memory references. */ | |
| 173 | |
| 174 /* Returns the size in bytes of the mode of X. */ | |
| 175 #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X))) | |
| 176 | |
| 177 /* Returns nonzero if MEM1 and MEM2 do not alias because they are in | |
| 178 different alias sets. We ignore alias sets in functions making use | |
| 179 of variable arguments because the va_arg macros on some systems are | |
| 180 not legal ANSI C. */ | |
| 181 #define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2) \ | |
| 182 mems_in_disjoint_alias_sets_p (MEM1, MEM2) | |
| 183 | |
| 184 /* Cap the number of passes we make over the insns propagating alias | |
| 185 information through set chains. 10 is a completely arbitrary choice. */ | |
| 186 #define MAX_ALIAS_LOOP_PASSES 10 | |
| 187 | |
| 188 /* reg_base_value[N] gives an address to which register N is related. | |
| 189 If all sets after the first add or subtract to the current value | |
| 190 or otherwise modify it so it does not point to a different top level | |
| 191 object, reg_base_value[N] is equal to the address part of the source | |
| 192 of the first set. | |
| 193 | |
| 194 A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF. ADDRESS | |
| 195 expressions represent certain special values: function arguments and | |
| 196 the stack, frame, and argument pointers. | |
| 197 | |
| 198 The contents of an ADDRESS is not normally used, the mode of the | |
| 199 ADDRESS determines whether the ADDRESS is a function argument or some | |
| 200 other special value. Pointer equality, not rtx_equal_p, determines whether | |
| 201 two ADDRESS expressions refer to the same base address. | |
| 202 | |
| 203 The only use of the contents of an ADDRESS is for determining if the | |
| 204 current function performs nonlocal memory memory references for the | |
| 205 purposes of marking the function as a constant function. */ | |
| 206 | |
| 207 static GTY(()) VEC(rtx,gc) *reg_base_value; | |
| 208 static rtx *new_reg_base_value; | |
| 209 | |
| 210 /* We preserve the copy of old array around to avoid amount of garbage | |
| 211 produced. About 8% of garbage produced were attributed to this | |
| 212 array. */ | |
| 213 static GTY((deletable)) VEC(rtx,gc) *old_reg_base_value; | |
| 214 | |
| 215 /* Static hunks of RTL used by the aliasing code; these are initialized | |
| 216 once per function to avoid unnecessary RTL allocations. */ | |
| 217 static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER]; | |
| 218 | |
| 219 #define REG_BASE_VALUE(X) \ | |
| 220 (REGNO (X) < VEC_length (rtx, reg_base_value) \ | |
| 221 ? VEC_index (rtx, reg_base_value, REGNO (X)) : 0) | |
| 222 | |
| 223 /* Vector indexed by N giving the initial (unchanging) value known for | |
| 224 pseudo-register N. This array is initialized in init_alias_analysis, | |
| 225 and does not change until end_alias_analysis is called. */ | |
| 226 static GTY((length("reg_known_value_size"))) rtx *reg_known_value; | |
| 227 | |
| 228 /* Indicates number of valid entries in reg_known_value. */ | |
| 229 static GTY(()) unsigned int reg_known_value_size; | |
| 230 | |
| 231 /* Vector recording for each reg_known_value whether it is due to a | |
| 232 REG_EQUIV note. Future passes (viz., reload) may replace the | |
| 233 pseudo with the equivalent expression and so we account for the | |
| 234 dependences that would be introduced if that happens. | |
| 235 | |
| 236 The REG_EQUIV notes created in assign_parms may mention the arg | |
| 237 pointer, and there are explicit insns in the RTL that modify the | |
| 238 arg pointer. Thus we must ensure that such insns don't get | |
| 239 scheduled across each other because that would invalidate the | |
| 240 REG_EQUIV notes. One could argue that the REG_EQUIV notes are | |
| 241 wrong, but solving the problem in the scheduler will likely give | |
| 242 better code, so we do it here. */ | |
| 243 static bool *reg_known_equiv_p; | |
| 244 | |
| 245 /* True when scanning insns from the start of the rtl to the | |
| 246 NOTE_INSN_FUNCTION_BEG note. */ | |
| 247 static bool copying_arguments; | |
| 248 | |
| 249 DEF_VEC_P(alias_set_entry); | |
| 250 DEF_VEC_ALLOC_P(alias_set_entry,gc); | |
| 251 | |
| 252 /* The splay-tree used to store the various alias set entries. */ | |
| 253 static GTY (()) VEC(alias_set_entry,gc) *alias_sets; | |
| 254 | |
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255 /* Build a decomposed reference object for querying the alias-oracle |
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256 from the MEM rtx and store it in *REF. |
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257 Returns false if MEM is not suitable for the alias-oracle. */ |
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258 |
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259 static bool |
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260 ao_ref_from_mem (ao_ref *ref, const_rtx mem) |
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261 { |
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262 tree expr = MEM_EXPR (mem); |
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263 tree base; |
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264 |
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265 if (!expr) |
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266 return false; |
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267 |
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268 /* If MEM_OFFSET or MEM_SIZE are NULL punt. */ |
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269 if (!MEM_OFFSET (mem) |
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270 || !MEM_SIZE (mem)) |
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271 return false; |
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272 |
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273 ao_ref_init (ref, expr); |
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274 |
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275 /* Get the base of the reference and see if we have to reject or |
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276 adjust it. */ |
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277 base = ao_ref_base (ref); |
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278 if (base == NULL_TREE) |
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279 return false; |
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280 |
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281 /* If this is a pointer dereference of a non-SSA_NAME punt. |
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282 ??? We could replace it with a pointer to anything. */ |
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283 if (INDIRECT_REF_P (base) |
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284 && TREE_CODE (TREE_OPERAND (base, 0)) != SSA_NAME) |
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285 return false; |
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286 |
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287 /* The tree oracle doesn't like to have these. */ |
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288 if (TREE_CODE (base) == FUNCTION_DECL |
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289 || TREE_CODE (base) == LABEL_DECL) |
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290 return false; |
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291 |
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292 /* If this is a reference based on a partitioned decl replace the |
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293 base with an INDIRECT_REF of the pointer representative we |
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294 created during stack slot partitioning. */ |
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295 if (TREE_CODE (base) == VAR_DECL |
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296 && ! TREE_STATIC (base) |
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297 && cfun->gimple_df->decls_to_pointers != NULL) |
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298 { |
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299 void *namep; |
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300 namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, base); |
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301 if (namep) |
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302 { |
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303 ref->base_alias_set = get_alias_set (base); |
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304 ref->base = build1 (INDIRECT_REF, TREE_TYPE (base), *(tree *)namep); |
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305 } |
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306 } |
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307 |
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308 ref->ref_alias_set = MEM_ALIAS_SET (mem); |
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309 |
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310 /* If the base decl is a parameter we can have negative MEM_OFFSET in |
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311 case of promoted subregs on bigendian targets. Trust the MEM_EXPR |
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312 here. */ |
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313 if (INTVAL (MEM_OFFSET (mem)) < 0 |
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314 && ((INTVAL (MEM_SIZE (mem)) + INTVAL (MEM_OFFSET (mem))) |
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315 * BITS_PER_UNIT) == ref->size) |
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316 return true; |
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317 |
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318 ref->offset += INTVAL (MEM_OFFSET (mem)) * BITS_PER_UNIT; |
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319 ref->size = INTVAL (MEM_SIZE (mem)) * BITS_PER_UNIT; |
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320 |
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321 /* The MEM may extend into adjacent fields, so adjust max_size if |
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322 necessary. */ |
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323 if (ref->max_size != -1 |
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324 && ref->size > ref->max_size) |
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325 ref->max_size = ref->size; |
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326 |
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327 /* If MEM_OFFSET and MEM_SIZE get us outside of the base object of |
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328 the MEM_EXPR punt. This happens for STRICT_ALIGNMENT targets a lot. */ |
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329 if (MEM_EXPR (mem) != get_spill_slot_decl (false) |
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330 && (ref->offset < 0 |
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331 || (DECL_P (ref->base) |
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332 && (!host_integerp (DECL_SIZE (ref->base), 1) |
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333 || (TREE_INT_CST_LOW (DECL_SIZE ((ref->base))) |
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334 < (unsigned HOST_WIDE_INT)(ref->offset + ref->size)))))) |
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335 return false; |
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336 |
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337 return true; |
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338 } |
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339 |
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340 /* Query the alias-oracle on whether the two memory rtx X and MEM may |
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341 alias. If TBAA_P is set also apply TBAA. Returns true if the |
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342 two rtxen may alias, false otherwise. */ |
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343 |
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344 static bool |
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345 rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p) |
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346 { |
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347 ao_ref ref1, ref2; |
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348 |
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349 if (!ao_ref_from_mem (&ref1, x) |
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350 || !ao_ref_from_mem (&ref2, mem)) |
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351 return true; |
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352 |
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353 return refs_may_alias_p_1 (&ref1, &ref2, tbaa_p); |
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354 } |
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355 |
| 0 | 356 /* Returns a pointer to the alias set entry for ALIAS_SET, if there is |
| 357 such an entry, or NULL otherwise. */ | |
| 358 | |
| 359 static inline alias_set_entry | |
| 360 get_alias_set_entry (alias_set_type alias_set) | |
| 361 { | |
| 362 return VEC_index (alias_set_entry, alias_sets, alias_set); | |
| 363 } | |
| 364 | |
| 365 /* Returns nonzero if the alias sets for MEM1 and MEM2 are such that | |
| 366 the two MEMs cannot alias each other. */ | |
| 367 | |
| 368 static inline int | |
| 369 mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2) | |
| 370 { | |
| 371 /* Perform a basic sanity check. Namely, that there are no alias sets | |
| 372 if we're not using strict aliasing. This helps to catch bugs | |
| 373 whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or | |
| 374 where a MEM is allocated in some way other than by the use of | |
| 375 gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared. If we begin to | |
| 376 use alias sets to indicate that spilled registers cannot alias each | |
| 377 other, we might need to remove this check. */ | |
| 378 gcc_assert (flag_strict_aliasing | |
| 379 || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2))); | |
| 380 | |
| 381 return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2)); | |
| 382 } | |
| 383 | |
| 384 /* Insert the NODE into the splay tree given by DATA. Used by | |
| 385 record_alias_subset via splay_tree_foreach. */ | |
| 386 | |
| 387 static int | |
| 388 insert_subset_children (splay_tree_node node, void *data) | |
| 389 { | |
| 390 splay_tree_insert ((splay_tree) data, node->key, node->value); | |
| 391 | |
| 392 return 0; | |
| 393 } | |
| 394 | |
| 395 /* Return true if the first alias set is a subset of the second. */ | |
| 396 | |
| 397 bool | |
| 398 alias_set_subset_of (alias_set_type set1, alias_set_type set2) | |
| 399 { | |
| 400 alias_set_entry ase; | |
| 401 | |
| 402 /* Everything is a subset of the "aliases everything" set. */ | |
| 403 if (set2 == 0) | |
| 404 return true; | |
| 405 | |
| 406 /* Otherwise, check if set1 is a subset of set2. */ | |
| 407 ase = get_alias_set_entry (set2); | |
| 408 if (ase != 0 | |
| 409 && ((ase->has_zero_child && set1 == 0) | |
| 410 || splay_tree_lookup (ase->children, | |
| 411 (splay_tree_key) set1))) | |
| 412 return true; | |
| 413 return false; | |
| 414 } | |
| 415 | |
| 416 /* Return 1 if the two specified alias sets may conflict. */ | |
| 417 | |
| 418 int | |
| 419 alias_sets_conflict_p (alias_set_type set1, alias_set_type set2) | |
| 420 { | |
| 421 alias_set_entry ase; | |
| 422 | |
| 423 /* The easy case. */ | |
| 424 if (alias_sets_must_conflict_p (set1, set2)) | |
| 425 return 1; | |
| 426 | |
| 427 /* See if the first alias set is a subset of the second. */ | |
| 428 ase = get_alias_set_entry (set1); | |
| 429 if (ase != 0 | |
| 430 && (ase->has_zero_child | |
| 431 || splay_tree_lookup (ase->children, | |
| 432 (splay_tree_key) set2))) | |
| 433 return 1; | |
| 434 | |
| 435 /* Now do the same, but with the alias sets reversed. */ | |
| 436 ase = get_alias_set_entry (set2); | |
| 437 if (ase != 0 | |
| 438 && (ase->has_zero_child | |
| 439 || splay_tree_lookup (ase->children, | |
| 440 (splay_tree_key) set1))) | |
| 441 return 1; | |
| 442 | |
| 443 /* The two alias sets are distinct and neither one is the | |
| 444 child of the other. Therefore, they cannot conflict. */ | |
| 445 return 0; | |
| 446 } | |
| 447 | |
| 448 static int | |
| 449 walk_mems_2 (rtx *x, rtx mem) | |
| 450 { | |
| 451 if (MEM_P (*x)) | |
| 452 { | |
| 453 if (alias_sets_conflict_p (MEM_ALIAS_SET(*x), MEM_ALIAS_SET(mem))) | |
| 454 return 1; | |
|
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455 |
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456 return -1; |
| 0 | 457 } |
| 458 return 0; | |
| 459 } | |
| 460 | |
| 461 static int | |
| 462 walk_mems_1 (rtx *x, rtx *pat) | |
| 463 { | |
| 464 if (MEM_P (*x)) | |
| 465 { | |
| 466 /* Visit all MEMs in *PAT and check indepedence. */ | |
| 467 if (for_each_rtx (pat, (rtx_function) walk_mems_2, *x)) | |
| 468 /* Indicate that dependence was determined and stop traversal. */ | |
| 469 return 1; | |
|
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470 |
| 0 | 471 return -1; |
| 472 } | |
| 473 return 0; | |
| 474 } | |
| 475 | |
| 476 /* Return 1 if two specified instructions have mem expr with conflict alias sets*/ | |
| 477 bool | |
| 478 insn_alias_sets_conflict_p (rtx insn1, rtx insn2) | |
| 479 { | |
| 480 /* For each pair of MEMs in INSN1 and INSN2 check their independence. */ | |
| 481 return for_each_rtx (&PATTERN (insn1), (rtx_function) walk_mems_1, | |
| 482 &PATTERN (insn2)); | |
| 483 } | |
| 484 | |
| 485 /* Return 1 if the two specified alias sets will always conflict. */ | |
| 486 | |
| 487 int | |
| 488 alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2) | |
| 489 { | |
| 490 if (set1 == 0 || set2 == 0 || set1 == set2) | |
| 491 return 1; | |
| 492 | |
| 493 return 0; | |
| 494 } | |
| 495 | |
| 496 /* Return 1 if any MEM object of type T1 will always conflict (using the | |
| 497 dependency routines in this file) with any MEM object of type T2. | |
| 498 This is used when allocating temporary storage. If T1 and/or T2 are | |
| 499 NULL_TREE, it means we know nothing about the storage. */ | |
| 500 | |
| 501 int | |
| 502 objects_must_conflict_p (tree t1, tree t2) | |
| 503 { | |
| 504 alias_set_type set1, set2; | |
| 505 | |
| 506 /* If neither has a type specified, we don't know if they'll conflict | |
| 507 because we may be using them to store objects of various types, for | |
| 508 example the argument and local variables areas of inlined functions. */ | |
| 509 if (t1 == 0 && t2 == 0) | |
| 510 return 0; | |
| 511 | |
| 512 /* If they are the same type, they must conflict. */ | |
| 513 if (t1 == t2 | |
| 514 /* Likewise if both are volatile. */ | |
| 515 || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2))) | |
| 516 return 1; | |
| 517 | |
| 518 set1 = t1 ? get_alias_set (t1) : 0; | |
| 519 set2 = t2 ? get_alias_set (t2) : 0; | |
| 520 | |
| 521 /* We can't use alias_sets_conflict_p because we must make sure | |
| 522 that every subtype of t1 will conflict with every subtype of | |
| 523 t2 for which a pair of subobjects of these respective subtypes | |
| 524 overlaps on the stack. */ | |
| 525 return alias_sets_must_conflict_p (set1, set2); | |
| 526 } | |
| 527 | |
| 528 /* Return true if all nested component references handled by | |
| 529 get_inner_reference in T are such that we should use the alias set | |
| 530 provided by the object at the heart of T. | |
| 531 | |
| 532 This is true for non-addressable components (which don't have their | |
| 533 own alias set), as well as components of objects in alias set zero. | |
| 534 This later point is a special case wherein we wish to override the | |
| 535 alias set used by the component, but we don't have per-FIELD_DECL | |
| 536 assignable alias sets. */ | |
| 537 | |
| 538 bool | |
| 539 component_uses_parent_alias_set (const_tree t) | |
| 540 { | |
| 541 while (1) | |
| 542 { | |
| 543 /* If we're at the end, it vacuously uses its own alias set. */ | |
| 544 if (!handled_component_p (t)) | |
| 545 return false; | |
| 546 | |
| 547 switch (TREE_CODE (t)) | |
| 548 { | |
| 549 case COMPONENT_REF: | |
| 550 if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1))) | |
| 551 return true; | |
| 552 break; | |
| 553 | |
| 554 case ARRAY_REF: | |
| 555 case ARRAY_RANGE_REF: | |
| 556 if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0)))) | |
| 557 return true; | |
| 558 break; | |
| 559 | |
| 560 case REALPART_EXPR: | |
| 561 case IMAGPART_EXPR: | |
| 562 break; | |
| 563 | |
| 564 default: | |
| 565 /* Bitfields and casts are never addressable. */ | |
| 566 return true; | |
| 567 } | |
| 568 | |
| 569 t = TREE_OPERAND (t, 0); | |
| 570 if (get_alias_set (TREE_TYPE (t)) == 0) | |
| 571 return true; | |
| 572 } | |
| 573 } | |
| 574 | |
|
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575 /* Return the alias set for the memory pointed to by T, which may be |
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576 either a type or an expression. Return -1 if there is nothing |
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577 special about dereferencing T. */ |
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578 |
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579 static alias_set_type |
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580 get_deref_alias_set_1 (tree t) |
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581 { |
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582 /* If we're not doing any alias analysis, just assume everything |
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583 aliases everything else. */ |
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584 if (!flag_strict_aliasing) |
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585 return 0; |
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586 |
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587 /* All we care about is the type. */ |
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588 if (! TYPE_P (t)) |
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589 t = TREE_TYPE (t); |
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590 |
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591 /* If we have an INDIRECT_REF via a void pointer, we don't |
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592 know anything about what that might alias. Likewise if the |
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593 pointer is marked that way. */ |
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594 if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE |
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595 || TYPE_REF_CAN_ALIAS_ALL (t)) |
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596 return 0; |
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597 |
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598 return -1; |
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599 } |
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600 |
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601 /* Return the alias set for the memory pointed to by T, which may be |
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602 either a type or an expression. */ |
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603 |
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604 alias_set_type |
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605 get_deref_alias_set (tree t) |
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606 { |
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607 alias_set_type set = get_deref_alias_set_1 (t); |
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608 |
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609 /* Fall back to the alias-set of the pointed-to type. */ |
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610 if (set == -1) |
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611 { |
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612 if (! TYPE_P (t)) |
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613 t = TREE_TYPE (t); |
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614 set = get_alias_set (TREE_TYPE (t)); |
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615 } |
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616 |
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617 return set; |
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618 } |
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619 |
| 0 | 620 /* Return the alias set for T, which may be either a type or an |
| 621 expression. Call language-specific routine for help, if needed. */ | |
| 622 | |
| 623 alias_set_type | |
| 624 get_alias_set (tree t) | |
| 625 { | |
| 626 alias_set_type set; | |
| 627 | |
| 628 /* If we're not doing any alias analysis, just assume everything | |
| 629 aliases everything else. Also return 0 if this or its type is | |
| 630 an error. */ | |
| 631 if (! flag_strict_aliasing || t == error_mark_node | |
| 632 || (! TYPE_P (t) | |
| 633 && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node))) | |
| 634 return 0; | |
| 635 | |
| 636 /* We can be passed either an expression or a type. This and the | |
| 637 language-specific routine may make mutually-recursive calls to each other | |
| 638 to figure out what to do. At each juncture, we see if this is a tree | |
| 639 that the language may need to handle specially. First handle things that | |
| 640 aren't types. */ | |
| 641 if (! TYPE_P (t)) | |
| 642 { | |
|
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643 tree inner; |
| 0 | 644 |
| 645 /* Remove any nops, then give the language a chance to do | |
| 646 something with this tree before we look at it. */ | |
| 647 STRIP_NOPS (t); | |
| 648 set = lang_hooks.get_alias_set (t); | |
| 649 if (set != -1) | |
| 650 return set; | |
| 651 | |
|
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652 /* Retrieve the original memory reference if needed. */ |
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653 if (TREE_CODE (t) == TARGET_MEM_REF) |
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654 t = TMR_ORIGINAL (t); |
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655 |
| 0 | 656 /* First see if the actual object referenced is an INDIRECT_REF from a |
| 657 restrict-qualified pointer or a "void *". */ | |
|
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658 inner = t; |
| 0 | 659 while (handled_component_p (inner)) |
| 660 { | |
| 661 inner = TREE_OPERAND (inner, 0); | |
| 662 STRIP_NOPS (inner); | |
| 663 } | |
| 664 | |
| 665 if (INDIRECT_REF_P (inner)) | |
| 666 { | |
|
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667 set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0)); |
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668 if (set != -1) |
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669 return set; |
| 0 | 670 } |
| 671 | |
| 672 /* Otherwise, pick up the outermost object that we could have a pointer | |
| 673 to, processing conversions as above. */ | |
| 674 while (component_uses_parent_alias_set (t)) | |
| 675 { | |
| 676 t = TREE_OPERAND (t, 0); | |
| 677 STRIP_NOPS (t); | |
| 678 } | |
| 679 | |
| 680 /* If we've already determined the alias set for a decl, just return | |
| 681 it. This is necessary for C++ anonymous unions, whose component | |
| 682 variables don't look like union members (boo!). */ | |
| 683 if (TREE_CODE (t) == VAR_DECL | |
| 684 && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t))) | |
| 685 return MEM_ALIAS_SET (DECL_RTL (t)); | |
| 686 | |
| 687 /* Now all we care about is the type. */ | |
| 688 t = TREE_TYPE (t); | |
| 689 } | |
| 690 | |
| 691 /* Variant qualifiers don't affect the alias set, so get the main | |
|
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692 variant. */ |
| 0 | 693 t = TYPE_MAIN_VARIANT (t); |
|
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694 |
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695 /* Always use the canonical type as well. If this is a type that |
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696 requires structural comparisons to identify compatible types |
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697 use alias set zero. */ |
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698 if (TYPE_STRUCTURAL_EQUALITY_P (t)) |
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699 { |
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700 /* Allow the language to specify another alias set for this |
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701 type. */ |
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702 set = lang_hooks.get_alias_set (t); |
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703 if (set != -1) |
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704 return set; |
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705 return 0; |
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706 } |
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707 t = TYPE_CANONICAL (t); |
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708 /* Canonical types shouldn't form a tree nor should the canonical |
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709 type require structural equality checks. */ |
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710 gcc_assert (!TYPE_STRUCTURAL_EQUALITY_P (t) && TYPE_CANONICAL (t) == t); |
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711 |
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712 /* If this is a type with a known alias set, return it. */ |
| 0 | 713 if (TYPE_ALIAS_SET_KNOWN_P (t)) |
| 714 return TYPE_ALIAS_SET (t); | |
| 715 | |
| 716 /* We don't want to set TYPE_ALIAS_SET for incomplete types. */ | |
| 717 if (!COMPLETE_TYPE_P (t)) | |
| 718 { | |
| 719 /* For arrays with unknown size the conservative answer is the | |
| 720 alias set of the element type. */ | |
| 721 if (TREE_CODE (t) == ARRAY_TYPE) | |
| 722 return get_alias_set (TREE_TYPE (t)); | |
| 723 | |
| 724 /* But return zero as a conservative answer for incomplete types. */ | |
| 725 return 0; | |
| 726 } | |
| 727 | |
| 728 /* See if the language has special handling for this type. */ | |
| 729 set = lang_hooks.get_alias_set (t); | |
| 730 if (set != -1) | |
| 731 return set; | |
| 732 | |
| 733 /* There are no objects of FUNCTION_TYPE, so there's no point in | |
| 734 using up an alias set for them. (There are, of course, pointers | |
| 735 and references to functions, but that's different.) */ | |
| 736 else if (TREE_CODE (t) == FUNCTION_TYPE | |
| 737 || TREE_CODE (t) == METHOD_TYPE) | |
| 738 set = 0; | |
| 739 | |
| 740 /* Unless the language specifies otherwise, let vector types alias | |
| 741 their components. This avoids some nasty type punning issues in | |
| 742 normal usage. And indeed lets vectors be treated more like an | |
| 743 array slice. */ | |
| 744 else if (TREE_CODE (t) == VECTOR_TYPE) | |
| 745 set = get_alias_set (TREE_TYPE (t)); | |
| 746 | |
| 747 /* Unless the language specifies otherwise, treat array types the | |
| 748 same as their components. This avoids the asymmetry we get | |
| 749 through recording the components. Consider accessing a | |
| 750 character(kind=1) through a reference to a character(kind=1)[1:1]. | |
| 751 Or consider if we want to assign integer(kind=4)[0:D.1387] and | |
| 752 integer(kind=4)[4] the same alias set or not. | |
| 753 Just be pragmatic here and make sure the array and its element | |
| 754 type get the same alias set assigned. */ | |
| 755 else if (TREE_CODE (t) == ARRAY_TYPE | |
| 756 && !TYPE_NONALIASED_COMPONENT (t)) | |
| 757 set = get_alias_set (TREE_TYPE (t)); | |
| 758 | |
| 759 else | |
| 760 /* Otherwise make a new alias set for this type. */ | |
| 761 set = new_alias_set (); | |
| 762 | |
| 763 TYPE_ALIAS_SET (t) = set; | |
| 764 | |
| 765 /* If this is an aggregate type, we must record any component aliasing | |
| 766 information. */ | |
| 767 if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE) | |
| 768 record_component_aliases (t); | |
| 769 | |
| 770 return set; | |
| 771 } | |
| 772 | |
| 773 /* Return a brand-new alias set. */ | |
| 774 | |
| 775 alias_set_type | |
| 776 new_alias_set (void) | |
| 777 { | |
| 778 if (flag_strict_aliasing) | |
| 779 { | |
| 780 if (alias_sets == 0) | |
| 781 VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
| 782 VEC_safe_push (alias_set_entry, gc, alias_sets, 0); | |
| 783 return VEC_length (alias_set_entry, alias_sets) - 1; | |
| 784 } | |
| 785 else | |
| 786 return 0; | |
| 787 } | |
| 788 | |
| 789 /* Indicate that things in SUBSET can alias things in SUPERSET, but that | |
| 790 not everything that aliases SUPERSET also aliases SUBSET. For example, | |
| 791 in C, a store to an `int' can alias a load of a structure containing an | |
| 792 `int', and vice versa. But it can't alias a load of a 'double' member | |
| 793 of the same structure. Here, the structure would be the SUPERSET and | |
| 794 `int' the SUBSET. This relationship is also described in the comment at | |
| 795 the beginning of this file. | |
| 796 | |
| 797 This function should be called only once per SUPERSET/SUBSET pair. | |
| 798 | |
| 799 It is illegal for SUPERSET to be zero; everything is implicitly a | |
| 800 subset of alias set zero. */ | |
| 801 | |
| 802 void | |
| 803 record_alias_subset (alias_set_type superset, alias_set_type subset) | |
| 804 { | |
| 805 alias_set_entry superset_entry; | |
| 806 alias_set_entry subset_entry; | |
| 807 | |
| 808 /* It is possible in complex type situations for both sets to be the same, | |
| 809 in which case we can ignore this operation. */ | |
| 810 if (superset == subset) | |
| 811 return; | |
| 812 | |
| 813 gcc_assert (superset); | |
| 814 | |
| 815 superset_entry = get_alias_set_entry (superset); | |
| 816 if (superset_entry == 0) | |
| 817 { | |
| 818 /* Create an entry for the SUPERSET, so that we have a place to | |
| 819 attach the SUBSET. */ | |
|
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|
820 superset_entry = GGC_NEW (struct alias_set_entry_d); |
| 0 | 821 superset_entry->alias_set = superset; |
| 822 superset_entry->children | |
| 823 = splay_tree_new_ggc (splay_tree_compare_ints); | |
| 824 superset_entry->has_zero_child = 0; | |
| 825 VEC_replace (alias_set_entry, alias_sets, superset, superset_entry); | |
| 826 } | |
| 827 | |
| 828 if (subset == 0) | |
| 829 superset_entry->has_zero_child = 1; | |
| 830 else | |
| 831 { | |
| 832 subset_entry = get_alias_set_entry (subset); | |
| 833 /* If there is an entry for the subset, enter all of its children | |
| 834 (if they are not already present) as children of the SUPERSET. */ | |
| 835 if (subset_entry) | |
| 836 { | |
| 837 if (subset_entry->has_zero_child) | |
| 838 superset_entry->has_zero_child = 1; | |
| 839 | |
| 840 splay_tree_foreach (subset_entry->children, insert_subset_children, | |
| 841 superset_entry->children); | |
| 842 } | |
| 843 | |
| 844 /* Enter the SUBSET itself as a child of the SUPERSET. */ | |
| 845 splay_tree_insert (superset_entry->children, | |
| 846 (splay_tree_key) subset, 0); | |
| 847 } | |
| 848 } | |
| 849 | |
| 850 /* Record that component types of TYPE, if any, are part of that type for | |
| 851 aliasing purposes. For record types, we only record component types | |
| 852 for fields that are not marked non-addressable. For array types, we | |
| 853 only record the component type if it is not marked non-aliased. */ | |
| 854 | |
| 855 void | |
| 856 record_component_aliases (tree type) | |
| 857 { | |
| 858 alias_set_type superset = get_alias_set (type); | |
| 859 tree field; | |
| 860 | |
| 861 if (superset == 0) | |
| 862 return; | |
| 863 | |
| 864 switch (TREE_CODE (type)) | |
| 865 { | |
| 866 case RECORD_TYPE: | |
| 867 case UNION_TYPE: | |
| 868 case QUAL_UNION_TYPE: | |
| 869 /* Recursively record aliases for the base classes, if there are any. */ | |
| 870 if (TYPE_BINFO (type)) | |
| 871 { | |
| 872 int i; | |
| 873 tree binfo, base_binfo; | |
| 874 | |
| 875 for (binfo = TYPE_BINFO (type), i = 0; | |
| 876 BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) | |
| 877 record_alias_subset (superset, | |
| 878 get_alias_set (BINFO_TYPE (base_binfo))); | |
| 879 } | |
| 880 for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field)) | |
| 881 if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field)) | |
| 882 record_alias_subset (superset, get_alias_set (TREE_TYPE (field))); | |
| 883 break; | |
| 884 | |
| 885 case COMPLEX_TYPE: | |
| 886 record_alias_subset (superset, get_alias_set (TREE_TYPE (type))); | |
| 887 break; | |
| 888 | |
| 889 /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their | |
| 890 element type. */ | |
| 891 | |
| 892 default: | |
| 893 break; | |
| 894 } | |
| 895 } | |
| 896 | |
| 897 /* Allocate an alias set for use in storing and reading from the varargs | |
| 898 spill area. */ | |
| 899 | |
| 900 static GTY(()) alias_set_type varargs_set = -1; | |
| 901 | |
| 902 alias_set_type | |
| 903 get_varargs_alias_set (void) | |
| 904 { | |
| 905 #if 1 | |
| 906 /* We now lower VA_ARG_EXPR, and there's currently no way to attach the | |
| 907 varargs alias set to an INDIRECT_REF (FIXME!), so we can't | |
| 908 consistently use the varargs alias set for loads from the varargs | |
| 909 area. So don't use it anywhere. */ | |
| 910 return 0; | |
| 911 #else | |
| 912 if (varargs_set == -1) | |
| 913 varargs_set = new_alias_set (); | |
| 914 | |
| 915 return varargs_set; | |
| 916 #endif | |
| 917 } | |
| 918 | |
| 919 /* Likewise, but used for the fixed portions of the frame, e.g., register | |
| 920 save areas. */ | |
| 921 | |
| 922 static GTY(()) alias_set_type frame_set = -1; | |
| 923 | |
| 924 alias_set_type | |
| 925 get_frame_alias_set (void) | |
| 926 { | |
| 927 if (frame_set == -1) | |
| 928 frame_set = new_alias_set (); | |
| 929 | |
| 930 return frame_set; | |
| 931 } | |
| 932 | |
| 933 /* Inside SRC, the source of a SET, find a base address. */ | |
| 934 | |
| 935 static rtx | |
| 936 find_base_value (rtx src) | |
| 937 { | |
| 938 unsigned int regno; | |
| 939 | |
| 940 #if defined (FIND_BASE_TERM) | |
| 941 /* Try machine-dependent ways to find the base term. */ | |
| 942 src = FIND_BASE_TERM (src); | |
| 943 #endif | |
| 944 | |
| 945 switch (GET_CODE (src)) | |
| 946 { | |
| 947 case SYMBOL_REF: | |
| 948 case LABEL_REF: | |
| 949 return src; | |
| 950 | |
| 951 case REG: | |
| 952 regno = REGNO (src); | |
| 953 /* At the start of a function, argument registers have known base | |
| 954 values which may be lost later. Returning an ADDRESS | |
| 955 expression here allows optimization based on argument values | |
| 956 even when the argument registers are used for other purposes. */ | |
| 957 if (regno < FIRST_PSEUDO_REGISTER && copying_arguments) | |
| 958 return new_reg_base_value[regno]; | |
| 959 | |
| 960 /* If a pseudo has a known base value, return it. Do not do this | |
| 961 for non-fixed hard regs since it can result in a circular | |
| 962 dependency chain for registers which have values at function entry. | |
| 963 | |
| 964 The test above is not sufficient because the scheduler may move | |
| 965 a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN. */ | |
| 966 if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno]) | |
| 967 && regno < VEC_length (rtx, reg_base_value)) | |
| 968 { | |
| 969 /* If we're inside init_alias_analysis, use new_reg_base_value | |
| 970 to reduce the number of relaxation iterations. */ | |
| 971 if (new_reg_base_value && new_reg_base_value[regno] | |
| 972 && DF_REG_DEF_COUNT (regno) == 1) | |
| 973 return new_reg_base_value[regno]; | |
| 974 | |
| 975 if (VEC_index (rtx, reg_base_value, regno)) | |
| 976 return VEC_index (rtx, reg_base_value, regno); | |
| 977 } | |
| 978 | |
| 979 return 0; | |
| 980 | |
| 981 case MEM: | |
| 982 /* Check for an argument passed in memory. Only record in the | |
| 983 copying-arguments block; it is too hard to track changes | |
| 984 otherwise. */ | |
| 985 if (copying_arguments | |
| 986 && (XEXP (src, 0) == arg_pointer_rtx | |
| 987 || (GET_CODE (XEXP (src, 0)) == PLUS | |
| 988 && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx))) | |
| 989 return gen_rtx_ADDRESS (VOIDmode, src); | |
| 990 return 0; | |
| 991 | |
| 992 case CONST: | |
| 993 src = XEXP (src, 0); | |
| 994 if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS) | |
| 995 break; | |
| 996 | |
| 997 /* ... fall through ... */ | |
| 998 | |
| 999 case PLUS: | |
| 1000 case MINUS: | |
| 1001 { | |
| 1002 rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1); | |
| 1003 | |
| 1004 /* If either operand is a REG that is a known pointer, then it | |
| 1005 is the base. */ | |
| 1006 if (REG_P (src_0) && REG_POINTER (src_0)) | |
| 1007 return find_base_value (src_0); | |
| 1008 if (REG_P (src_1) && REG_POINTER (src_1)) | |
| 1009 return find_base_value (src_1); | |
| 1010 | |
| 1011 /* If either operand is a REG, then see if we already have | |
| 1012 a known value for it. */ | |
| 1013 if (REG_P (src_0)) | |
| 1014 { | |
| 1015 temp = find_base_value (src_0); | |
| 1016 if (temp != 0) | |
| 1017 src_0 = temp; | |
| 1018 } | |
| 1019 | |
| 1020 if (REG_P (src_1)) | |
| 1021 { | |
| 1022 temp = find_base_value (src_1); | |
| 1023 if (temp!= 0) | |
| 1024 src_1 = temp; | |
| 1025 } | |
| 1026 | |
| 1027 /* If either base is named object or a special address | |
| 1028 (like an argument or stack reference), then use it for the | |
| 1029 base term. */ | |
| 1030 if (src_0 != 0 | |
| 1031 && (GET_CODE (src_0) == SYMBOL_REF | |
| 1032 || GET_CODE (src_0) == LABEL_REF | |
| 1033 || (GET_CODE (src_0) == ADDRESS | |
| 1034 && GET_MODE (src_0) != VOIDmode))) | |
| 1035 return src_0; | |
| 1036 | |
| 1037 if (src_1 != 0 | |
| 1038 && (GET_CODE (src_1) == SYMBOL_REF | |
| 1039 || GET_CODE (src_1) == LABEL_REF | |
| 1040 || (GET_CODE (src_1) == ADDRESS | |
| 1041 && GET_MODE (src_1) != VOIDmode))) | |
| 1042 return src_1; | |
| 1043 | |
| 1044 /* Guess which operand is the base address: | |
| 1045 If either operand is a symbol, then it is the base. If | |
| 1046 either operand is a CONST_INT, then the other is the base. */ | |
|
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1047 if (CONST_INT_P (src_1) || CONSTANT_P (src_0)) |
| 0 | 1048 return find_base_value (src_0); |
|
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1049 else if (CONST_INT_P (src_0) || CONSTANT_P (src_1)) |
| 0 | 1050 return find_base_value (src_1); |
| 1051 | |
| 1052 return 0; | |
| 1053 } | |
| 1054 | |
| 1055 case LO_SUM: | |
| 1056 /* The standard form is (lo_sum reg sym) so look only at the | |
| 1057 second operand. */ | |
| 1058 return find_base_value (XEXP (src, 1)); | |
| 1059 | |
| 1060 case AND: | |
| 1061 /* If the second operand is constant set the base | |
| 1062 address to the first operand. */ | |
|
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1063 if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0) |
| 0 | 1064 return find_base_value (XEXP (src, 0)); |
| 1065 return 0; | |
| 1066 | |
| 1067 case TRUNCATE: | |
|
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1068 /* As we do not know which address space the pointer is refering to, we can |
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1069 handle this only if the target does not support different pointer or |
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1070 address modes depending on the address space. */ |
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1071 if (!target_default_pointer_address_modes_p ()) |
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1072 break; |
| 0 | 1073 if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode)) |
| 1074 break; | |
| 1075 /* Fall through. */ | |
| 1076 case HIGH: | |
| 1077 case PRE_INC: | |
| 1078 case PRE_DEC: | |
| 1079 case POST_INC: | |
| 1080 case POST_DEC: | |
| 1081 case PRE_MODIFY: | |
| 1082 case POST_MODIFY: | |
| 1083 return find_base_value (XEXP (src, 0)); | |
| 1084 | |
| 1085 case ZERO_EXTEND: | |
| 1086 case SIGN_EXTEND: /* used for NT/Alpha pointers */ | |
|
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1087 /* As we do not know which address space the pointer is refering to, we can |
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1088 handle this only if the target does not support different pointer or |
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1089 address modes depending on the address space. */ |
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1090 if (!target_default_pointer_address_modes_p ()) |
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1091 break; |
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1092 |
| 0 | 1093 { |
| 1094 rtx temp = find_base_value (XEXP (src, 0)); | |
| 1095 | |
| 1096 if (temp != 0 && CONSTANT_P (temp)) | |
| 1097 temp = convert_memory_address (Pmode, temp); | |
| 1098 | |
| 1099 return temp; | |
| 1100 } | |
| 1101 | |
| 1102 default: | |
| 1103 break; | |
| 1104 } | |
| 1105 | |
| 1106 return 0; | |
| 1107 } | |
| 1108 | |
| 1109 /* Called from init_alias_analysis indirectly through note_stores. */ | |
| 1110 | |
| 1111 /* While scanning insns to find base values, reg_seen[N] is nonzero if | |
| 1112 register N has been set in this function. */ | |
| 1113 static char *reg_seen; | |
| 1114 | |
| 1115 /* Addresses which are known not to alias anything else are identified | |
| 1116 by a unique integer. */ | |
| 1117 static int unique_id; | |
| 1118 | |
| 1119 static void | |
| 1120 record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED) | |
| 1121 { | |
| 1122 unsigned regno; | |
| 1123 rtx src; | |
| 1124 int n; | |
| 1125 | |
| 1126 if (!REG_P (dest)) | |
| 1127 return; | |
| 1128 | |
| 1129 regno = REGNO (dest); | |
| 1130 | |
| 1131 gcc_assert (regno < VEC_length (rtx, reg_base_value)); | |
| 1132 | |
| 1133 /* If this spans multiple hard registers, then we must indicate that every | |
| 1134 register has an unusable value. */ | |
| 1135 if (regno < FIRST_PSEUDO_REGISTER) | |
| 1136 n = hard_regno_nregs[regno][GET_MODE (dest)]; | |
| 1137 else | |
| 1138 n = 1; | |
| 1139 if (n != 1) | |
| 1140 { | |
| 1141 while (--n >= 0) | |
| 1142 { | |
| 1143 reg_seen[regno + n] = 1; | |
| 1144 new_reg_base_value[regno + n] = 0; | |
| 1145 } | |
| 1146 return; | |
| 1147 } | |
| 1148 | |
| 1149 if (set) | |
| 1150 { | |
| 1151 /* A CLOBBER wipes out any old value but does not prevent a previously | |
| 1152 unset register from acquiring a base address (i.e. reg_seen is not | |
| 1153 set). */ | |
| 1154 if (GET_CODE (set) == CLOBBER) | |
| 1155 { | |
| 1156 new_reg_base_value[regno] = 0; | |
| 1157 return; | |
| 1158 } | |
| 1159 src = SET_SRC (set); | |
| 1160 } | |
| 1161 else | |
| 1162 { | |
| 1163 if (reg_seen[regno]) | |
| 1164 { | |
| 1165 new_reg_base_value[regno] = 0; | |
| 1166 return; | |
| 1167 } | |
| 1168 reg_seen[regno] = 1; | |
| 1169 new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode, | |
| 1170 GEN_INT (unique_id++)); | |
| 1171 return; | |
| 1172 } | |
| 1173 | |
| 1174 /* If this is not the first set of REGNO, see whether the new value | |
| 1175 is related to the old one. There are two cases of interest: | |
| 1176 | |
| 1177 (1) The register might be assigned an entirely new value | |
| 1178 that has the same base term as the original set. | |
| 1179 | |
| 1180 (2) The set might be a simple self-modification that | |
| 1181 cannot change REGNO's base value. | |
| 1182 | |
| 1183 If neither case holds, reject the original base value as invalid. | |
| 1184 Note that the following situation is not detected: | |
| 1185 | |
| 1186 extern int x, y; int *p = &x; p += (&y-&x); | |
| 1187 | |
| 1188 ANSI C does not allow computing the difference of addresses | |
| 1189 of distinct top level objects. */ | |
| 1190 if (new_reg_base_value[regno] != 0 | |
| 1191 && find_base_value (src) != new_reg_base_value[regno]) | |
| 1192 switch (GET_CODE (src)) | |
| 1193 { | |
| 1194 case LO_SUM: | |
| 1195 case MINUS: | |
| 1196 if (XEXP (src, 0) != dest && XEXP (src, 1) != dest) | |
| 1197 new_reg_base_value[regno] = 0; | |
| 1198 break; | |
| 1199 case PLUS: | |
| 1200 /* If the value we add in the PLUS is also a valid base value, | |
| 1201 this might be the actual base value, and the original value | |
| 1202 an index. */ | |
| 1203 { | |
| 1204 rtx other = NULL_RTX; | |
| 1205 | |
| 1206 if (XEXP (src, 0) == dest) | |
| 1207 other = XEXP (src, 1); | |
| 1208 else if (XEXP (src, 1) == dest) | |
| 1209 other = XEXP (src, 0); | |
| 1210 | |
| 1211 if (! other || find_base_value (other)) | |
| 1212 new_reg_base_value[regno] = 0; | |
| 1213 break; | |
| 1214 } | |
| 1215 case AND: | |
|
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1216 if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1))) |
| 0 | 1217 new_reg_base_value[regno] = 0; |
| 1218 break; | |
| 1219 default: | |
| 1220 new_reg_base_value[regno] = 0; | |
| 1221 break; | |
| 1222 } | |
| 1223 /* If this is the first set of a register, record the value. */ | |
| 1224 else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno]) | |
| 1225 && ! reg_seen[regno] && new_reg_base_value[regno] == 0) | |
| 1226 new_reg_base_value[regno] = find_base_value (src); | |
| 1227 | |
| 1228 reg_seen[regno] = 1; | |
| 1229 } | |
| 1230 | |
| 1231 /* If a value is known for REGNO, return it. */ | |
| 1232 | |
| 1233 rtx | |
| 1234 get_reg_known_value (unsigned int regno) | |
| 1235 { | |
| 1236 if (regno >= FIRST_PSEUDO_REGISTER) | |
| 1237 { | |
| 1238 regno -= FIRST_PSEUDO_REGISTER; | |
| 1239 if (regno < reg_known_value_size) | |
| 1240 return reg_known_value[regno]; | |
| 1241 } | |
| 1242 return NULL; | |
| 1243 } | |
| 1244 | |
| 1245 /* Set it. */ | |
| 1246 | |
| 1247 static void | |
| 1248 set_reg_known_value (unsigned int regno, rtx val) | |
| 1249 { | |
| 1250 if (regno >= FIRST_PSEUDO_REGISTER) | |
| 1251 { | |
| 1252 regno -= FIRST_PSEUDO_REGISTER; | |
| 1253 if (regno < reg_known_value_size) | |
| 1254 reg_known_value[regno] = val; | |
| 1255 } | |
| 1256 } | |
| 1257 | |
| 1258 /* Similarly for reg_known_equiv_p. */ | |
| 1259 | |
| 1260 bool | |
| 1261 get_reg_known_equiv_p (unsigned int regno) | |
| 1262 { | |
| 1263 if (regno >= FIRST_PSEUDO_REGISTER) | |
| 1264 { | |
| 1265 regno -= FIRST_PSEUDO_REGISTER; | |
| 1266 if (regno < reg_known_value_size) | |
| 1267 return reg_known_equiv_p[regno]; | |
| 1268 } | |
| 1269 return false; | |
| 1270 } | |
| 1271 | |
| 1272 static void | |
| 1273 set_reg_known_equiv_p (unsigned int regno, bool val) | |
| 1274 { | |
| 1275 if (regno >= FIRST_PSEUDO_REGISTER) | |
| 1276 { | |
| 1277 regno -= FIRST_PSEUDO_REGISTER; | |
| 1278 if (regno < reg_known_value_size) | |
| 1279 reg_known_equiv_p[regno] = val; | |
| 1280 } | |
| 1281 } | |
| 1282 | |
| 1283 | |
| 1284 /* Returns a canonical version of X, from the point of view alias | |
| 1285 analysis. (For example, if X is a MEM whose address is a register, | |
| 1286 and the register has a known value (say a SYMBOL_REF), then a MEM | |
| 1287 whose address is the SYMBOL_REF is returned.) */ | |
| 1288 | |
| 1289 rtx | |
| 1290 canon_rtx (rtx x) | |
| 1291 { | |
| 1292 /* Recursively look for equivalences. */ | |
| 1293 if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER) | |
| 1294 { | |
| 1295 rtx t = get_reg_known_value (REGNO (x)); | |
| 1296 if (t == x) | |
| 1297 return x; | |
| 1298 if (t) | |
| 1299 return canon_rtx (t); | |
| 1300 } | |
| 1301 | |
| 1302 if (GET_CODE (x) == PLUS) | |
| 1303 { | |
| 1304 rtx x0 = canon_rtx (XEXP (x, 0)); | |
| 1305 rtx x1 = canon_rtx (XEXP (x, 1)); | |
| 1306 | |
| 1307 if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1)) | |
| 1308 { | |
|
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1309 if (CONST_INT_P (x0)) |
| 0 | 1310 return plus_constant (x1, INTVAL (x0)); |
|
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1311 else if (CONST_INT_P (x1)) |
| 0 | 1312 return plus_constant (x0, INTVAL (x1)); |
| 1313 return gen_rtx_PLUS (GET_MODE (x), x0, x1); | |
| 1314 } | |
| 1315 } | |
| 1316 | |
| 1317 /* This gives us much better alias analysis when called from | |
| 1318 the loop optimizer. Note we want to leave the original | |
| 1319 MEM alone, but need to return the canonicalized MEM with | |
| 1320 all the flags with their original values. */ | |
| 1321 else if (MEM_P (x)) | |
| 1322 x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0))); | |
| 1323 | |
| 1324 return x; | |
| 1325 } | |
| 1326 | |
| 1327 /* Return 1 if X and Y are identical-looking rtx's. | |
| 1328 Expect that X and Y has been already canonicalized. | |
| 1329 | |
| 1330 We use the data in reg_known_value above to see if two registers with | |
| 1331 different numbers are, in fact, equivalent. */ | |
| 1332 | |
| 1333 static int | |
| 1334 rtx_equal_for_memref_p (const_rtx x, const_rtx y) | |
| 1335 { | |
| 1336 int i; | |
| 1337 int j; | |
| 1338 enum rtx_code code; | |
| 1339 const char *fmt; | |
| 1340 | |
| 1341 if (x == 0 && y == 0) | |
| 1342 return 1; | |
| 1343 if (x == 0 || y == 0) | |
| 1344 return 0; | |
| 1345 | |
| 1346 if (x == y) | |
| 1347 return 1; | |
| 1348 | |
| 1349 code = GET_CODE (x); | |
| 1350 /* Rtx's of different codes cannot be equal. */ | |
| 1351 if (code != GET_CODE (y)) | |
| 1352 return 0; | |
| 1353 | |
| 1354 /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent. | |
| 1355 (REG:SI x) and (REG:HI x) are NOT equivalent. */ | |
| 1356 | |
| 1357 if (GET_MODE (x) != GET_MODE (y)) | |
| 1358 return 0; | |
| 1359 | |
| 1360 /* Some RTL can be compared without a recursive examination. */ | |
| 1361 switch (code) | |
| 1362 { | |
| 1363 case REG: | |
| 1364 return REGNO (x) == REGNO (y); | |
| 1365 | |
| 1366 case LABEL_REF: | |
| 1367 return XEXP (x, 0) == XEXP (y, 0); | |
| 1368 | |
| 1369 case SYMBOL_REF: | |
| 1370 return XSTR (x, 0) == XSTR (y, 0); | |
| 1371 | |
| 1372 case VALUE: | |
| 1373 case CONST_INT: | |
| 1374 case CONST_DOUBLE: | |
| 1375 case CONST_FIXED: | |
| 1376 /* There's no need to compare the contents of CONST_DOUBLEs or | |
| 1377 CONST_INTs because pointer equality is a good enough | |
| 1378 comparison for these nodes. */ | |
| 1379 return 0; | |
| 1380 | |
| 1381 default: | |
| 1382 break; | |
| 1383 } | |
| 1384 | |
| 1385 /* canon_rtx knows how to handle plus. No need to canonicalize. */ | |
| 1386 if (code == PLUS) | |
| 1387 return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0)) | |
| 1388 && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1))) | |
| 1389 || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1)) | |
| 1390 && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0)))); | |
| 1391 /* For commutative operations, the RTX match if the operand match in any | |
| 1392 order. Also handle the simple binary and unary cases without a loop. */ | |
| 1393 if (COMMUTATIVE_P (x)) | |
| 1394 { | |
| 1395 rtx xop0 = canon_rtx (XEXP (x, 0)); | |
| 1396 rtx yop0 = canon_rtx (XEXP (y, 0)); | |
| 1397 rtx yop1 = canon_rtx (XEXP (y, 1)); | |
| 1398 | |
| 1399 return ((rtx_equal_for_memref_p (xop0, yop0) | |
| 1400 && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1)) | |
| 1401 || (rtx_equal_for_memref_p (xop0, yop1) | |
| 1402 && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0))); | |
| 1403 } | |
| 1404 else if (NON_COMMUTATIVE_P (x)) | |
| 1405 { | |
| 1406 return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
| 1407 canon_rtx (XEXP (y, 0))) | |
| 1408 && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), | |
| 1409 canon_rtx (XEXP (y, 1)))); | |
| 1410 } | |
| 1411 else if (UNARY_P (x)) | |
| 1412 return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)), | |
| 1413 canon_rtx (XEXP (y, 0))); | |
| 1414 | |
| 1415 /* Compare the elements. If any pair of corresponding elements | |
| 1416 fail to match, return 0 for the whole things. | |
| 1417 | |
| 1418 Limit cases to types which actually appear in addresses. */ | |
| 1419 | |
| 1420 fmt = GET_RTX_FORMAT (code); | |
| 1421 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) | |
| 1422 { | |
| 1423 switch (fmt[i]) | |
| 1424 { | |
| 1425 case 'i': | |
| 1426 if (XINT (x, i) != XINT (y, i)) | |
| 1427 return 0; | |
| 1428 break; | |
| 1429 | |
| 1430 case 'E': | |
| 1431 /* Two vectors must have the same length. */ | |
| 1432 if (XVECLEN (x, i) != XVECLEN (y, i)) | |
| 1433 return 0; | |
| 1434 | |
| 1435 /* And the corresponding elements must match. */ | |
| 1436 for (j = 0; j < XVECLEN (x, i); j++) | |
| 1437 if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)), | |
| 1438 canon_rtx (XVECEXP (y, i, j))) == 0) | |
| 1439 return 0; | |
| 1440 break; | |
| 1441 | |
| 1442 case 'e': | |
| 1443 if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)), | |
| 1444 canon_rtx (XEXP (y, i))) == 0) | |
| 1445 return 0; | |
| 1446 break; | |
| 1447 | |
| 1448 /* This can happen for asm operands. */ | |
| 1449 case 's': | |
| 1450 if (strcmp (XSTR (x, i), XSTR (y, i))) | |
| 1451 return 0; | |
| 1452 break; | |
| 1453 | |
| 1454 /* This can happen for an asm which clobbers memory. */ | |
| 1455 case '0': | |
| 1456 break; | |
| 1457 | |
| 1458 /* It is believed that rtx's at this level will never | |
| 1459 contain anything but integers and other rtx's, | |
| 1460 except for within LABEL_REFs and SYMBOL_REFs. */ | |
| 1461 default: | |
| 1462 gcc_unreachable (); | |
| 1463 } | |
| 1464 } | |
| 1465 return 1; | |
| 1466 } | |
| 1467 | |
| 1468 rtx | |
| 1469 find_base_term (rtx x) | |
| 1470 { | |
| 1471 cselib_val *val; | |
| 1472 struct elt_loc_list *l; | |
| 1473 | |
| 1474 #if defined (FIND_BASE_TERM) | |
| 1475 /* Try machine-dependent ways to find the base term. */ | |
| 1476 x = FIND_BASE_TERM (x); | |
| 1477 #endif | |
| 1478 | |
| 1479 switch (GET_CODE (x)) | |
| 1480 { | |
| 1481 case REG: | |
| 1482 return REG_BASE_VALUE (x); | |
| 1483 | |
| 1484 case TRUNCATE: | |
|
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1485 /* As we do not know which address space the pointer is refering to, we can |
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1486 handle this only if the target does not support different pointer or |
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1487 address modes depending on the address space. */ |
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1488 if (!target_default_pointer_address_modes_p ()) |
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1489 return 0; |
| 0 | 1490 if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode)) |
| 1491 return 0; | |
| 1492 /* Fall through. */ | |
| 1493 case HIGH: | |
| 1494 case PRE_INC: | |
| 1495 case PRE_DEC: | |
| 1496 case POST_INC: | |
| 1497 case POST_DEC: | |
| 1498 case PRE_MODIFY: | |
| 1499 case POST_MODIFY: | |
| 1500 return find_base_term (XEXP (x, 0)); | |
| 1501 | |
| 1502 case ZERO_EXTEND: | |
| 1503 case SIGN_EXTEND: /* Used for Alpha/NT pointers */ | |
|
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1504 /* As we do not know which address space the pointer is refering to, we can |
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1505 handle this only if the target does not support different pointer or |
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1506 address modes depending on the address space. */ |
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1507 if (!target_default_pointer_address_modes_p ()) |
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1508 return 0; |
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1509 |
| 0 | 1510 { |
| 1511 rtx temp = find_base_term (XEXP (x, 0)); | |
| 1512 | |
| 1513 if (temp != 0 && CONSTANT_P (temp)) | |
| 1514 temp = convert_memory_address (Pmode, temp); | |
| 1515 | |
| 1516 return temp; | |
| 1517 } | |
| 1518 | |
| 1519 case VALUE: | |
| 1520 val = CSELIB_VAL_PTR (x); | |
| 1521 if (!val) | |
| 1522 return 0; | |
| 1523 for (l = val->locs; l; l = l->next) | |
| 1524 if ((x = find_base_term (l->loc)) != 0) | |
| 1525 return x; | |
| 1526 return 0; | |
| 1527 | |
|
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1528 case LO_SUM: |
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1529 /* The standard form is (lo_sum reg sym) so look only at the |
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1530 second operand. */ |
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1531 return find_base_term (XEXP (x, 1)); |
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1532 |
| 0 | 1533 case CONST: |
| 1534 x = XEXP (x, 0); | |
| 1535 if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS) | |
| 1536 return 0; | |
| 1537 /* Fall through. */ | |
| 1538 case PLUS: | |
| 1539 case MINUS: | |
| 1540 { | |
| 1541 rtx tmp1 = XEXP (x, 0); | |
| 1542 rtx tmp2 = XEXP (x, 1); | |
| 1543 | |
| 1544 /* This is a little bit tricky since we have to determine which of | |
| 1545 the two operands represents the real base address. Otherwise this | |
| 1546 routine may return the index register instead of the base register. | |
| 1547 | |
| 1548 That may cause us to believe no aliasing was possible, when in | |
| 1549 fact aliasing is possible. | |
| 1550 | |
| 1551 We use a few simple tests to guess the base register. Additional | |
| 1552 tests can certainly be added. For example, if one of the operands | |
| 1553 is a shift or multiply, then it must be the index register and the | |
| 1554 other operand is the base register. */ | |
| 1555 | |
| 1556 if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2)) | |
| 1557 return find_base_term (tmp2); | |
| 1558 | |
| 1559 /* If either operand is known to be a pointer, then use it | |
| 1560 to determine the base term. */ | |
| 1561 if (REG_P (tmp1) && REG_POINTER (tmp1)) | |
|
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1562 { |
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1563 rtx base = find_base_term (tmp1); |
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1564 if (base) |
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1565 return base; |
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1566 } |
| 0 | 1567 |
| 1568 if (REG_P (tmp2) && REG_POINTER (tmp2)) | |
|
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1569 { |
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1570 rtx base = find_base_term (tmp2); |
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1571 if (base) |
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1572 return base; |
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1573 } |
| 0 | 1574 |
| 1575 /* Neither operand was known to be a pointer. Go ahead and find the | |
| 1576 base term for both operands. */ | |
| 1577 tmp1 = find_base_term (tmp1); | |
| 1578 tmp2 = find_base_term (tmp2); | |
| 1579 | |
| 1580 /* If either base term is named object or a special address | |
| 1581 (like an argument or stack reference), then use it for the | |
| 1582 base term. */ | |
| 1583 if (tmp1 != 0 | |
| 1584 && (GET_CODE (tmp1) == SYMBOL_REF | |
| 1585 || GET_CODE (tmp1) == LABEL_REF | |
| 1586 || (GET_CODE (tmp1) == ADDRESS | |
| 1587 && GET_MODE (tmp1) != VOIDmode))) | |
| 1588 return tmp1; | |
| 1589 | |
| 1590 if (tmp2 != 0 | |
| 1591 && (GET_CODE (tmp2) == SYMBOL_REF | |
| 1592 || GET_CODE (tmp2) == LABEL_REF | |
| 1593 || (GET_CODE (tmp2) == ADDRESS | |
| 1594 && GET_MODE (tmp2) != VOIDmode))) | |
| 1595 return tmp2; | |
| 1596 | |
| 1597 /* We could not determine which of the two operands was the | |
| 1598 base register and which was the index. So we can determine | |
| 1599 nothing from the base alias check. */ | |
| 1600 return 0; | |
| 1601 } | |
| 1602 | |
| 1603 case AND: | |
|
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1604 if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0) |
| 0 | 1605 return find_base_term (XEXP (x, 0)); |
| 1606 return 0; | |
| 1607 | |
| 1608 case SYMBOL_REF: | |
| 1609 case LABEL_REF: | |
| 1610 return x; | |
| 1611 | |
| 1612 default: | |
| 1613 return 0; | |
| 1614 } | |
| 1615 } | |
| 1616 | |
| 1617 /* Return 0 if the addresses X and Y are known to point to different | |
| 1618 objects, 1 if they might be pointers to the same object. */ | |
| 1619 | |
| 1620 static int | |
| 1621 base_alias_check (rtx x, rtx y, enum machine_mode x_mode, | |
| 1622 enum machine_mode y_mode) | |
| 1623 { | |
| 1624 rtx x_base = find_base_term (x); | |
| 1625 rtx y_base = find_base_term (y); | |
| 1626 | |
| 1627 /* If the address itself has no known base see if a known equivalent | |
| 1628 value has one. If either address still has no known base, nothing | |
| 1629 is known about aliasing. */ | |
| 1630 if (x_base == 0) | |
| 1631 { | |
| 1632 rtx x_c; | |
| 1633 | |
| 1634 if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x) | |
| 1635 return 1; | |
| 1636 | |
| 1637 x_base = find_base_term (x_c); | |
| 1638 if (x_base == 0) | |
| 1639 return 1; | |
| 1640 } | |
| 1641 | |
| 1642 if (y_base == 0) | |
| 1643 { | |
| 1644 rtx y_c; | |
| 1645 if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y) | |
| 1646 return 1; | |
| 1647 | |
| 1648 y_base = find_base_term (y_c); | |
| 1649 if (y_base == 0) | |
| 1650 return 1; | |
| 1651 } | |
| 1652 | |
| 1653 /* If the base addresses are equal nothing is known about aliasing. */ | |
| 1654 if (rtx_equal_p (x_base, y_base)) | |
| 1655 return 1; | |
| 1656 | |
| 1657 /* The base addresses are different expressions. If they are not accessed | |
| 1658 via AND, there is no conflict. We can bring knowledge of object | |
| 1659 alignment into play here. For example, on alpha, "char a, b;" can | |
| 1660 alias one another, though "char a; long b;" cannot. AND addesses may | |
| 1661 implicitly alias surrounding objects; i.e. unaligned access in DImode | |
| 1662 via AND address can alias all surrounding object types except those | |
| 1663 with aligment 8 or higher. */ | |
| 1664 if (GET_CODE (x) == AND && GET_CODE (y) == AND) | |
| 1665 return 1; | |
| 1666 if (GET_CODE (x) == AND | |
|
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1667 && (!CONST_INT_P (XEXP (x, 1)) |
| 0 | 1668 || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1)))) |
| 1669 return 1; | |
| 1670 if (GET_CODE (y) == AND | |
|
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1671 && (!CONST_INT_P (XEXP (y, 1)) |
| 0 | 1672 || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1)))) |
| 1673 return 1; | |
| 1674 | |
| 1675 /* Differing symbols not accessed via AND never alias. */ | |
| 1676 if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS) | |
| 1677 return 0; | |
| 1678 | |
| 1679 /* If one address is a stack reference there can be no alias: | |
| 1680 stack references using different base registers do not alias, | |
| 1681 a stack reference can not alias a parameter, and a stack reference | |
| 1682 can not alias a global. */ | |
| 1683 if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode) | |
| 1684 || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode)) | |
| 1685 return 0; | |
| 1686 | |
| 1687 if (! flag_argument_noalias) | |
| 1688 return 1; | |
| 1689 | |
| 1690 if (flag_argument_noalias > 1) | |
| 1691 return 0; | |
| 1692 | |
| 1693 /* Weak noalias assertion (arguments are distinct, but may match globals). */ | |
| 1694 return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode); | |
| 1695 } | |
| 1696 | |
| 1697 /* Convert the address X into something we can use. This is done by returning | |
| 1698 it unchanged unless it is a value; in the latter case we call cselib to get | |
| 1699 a more useful rtx. */ | |
| 1700 | |
| 1701 rtx | |
| 1702 get_addr (rtx x) | |
| 1703 { | |
| 1704 cselib_val *v; | |
| 1705 struct elt_loc_list *l; | |
| 1706 | |
| 1707 if (GET_CODE (x) != VALUE) | |
| 1708 return x; | |
| 1709 v = CSELIB_VAL_PTR (x); | |
| 1710 if (v) | |
| 1711 { | |
| 1712 for (l = v->locs; l; l = l->next) | |
| 1713 if (CONSTANT_P (l->loc)) | |
| 1714 return l->loc; | |
| 1715 for (l = v->locs; l; l = l->next) | |
| 1716 if (!REG_P (l->loc) && !MEM_P (l->loc)) | |
| 1717 return l->loc; | |
| 1718 if (v->locs) | |
| 1719 return v->locs->loc; | |
| 1720 } | |
| 1721 return x; | |
| 1722 } | |
| 1723 | |
| 1724 /* Return the address of the (N_REFS + 1)th memory reference to ADDR | |
| 1725 where SIZE is the size in bytes of the memory reference. If ADDR | |
| 1726 is not modified by the memory reference then ADDR is returned. */ | |
| 1727 | |
| 1728 static rtx | |
| 1729 addr_side_effect_eval (rtx addr, int size, int n_refs) | |
| 1730 { | |
| 1731 int offset = 0; | |
| 1732 | |
| 1733 switch (GET_CODE (addr)) | |
| 1734 { | |
| 1735 case PRE_INC: | |
| 1736 offset = (n_refs + 1) * size; | |
| 1737 break; | |
| 1738 case PRE_DEC: | |
| 1739 offset = -(n_refs + 1) * size; | |
| 1740 break; | |
| 1741 case POST_INC: | |
| 1742 offset = n_refs * size; | |
| 1743 break; | |
| 1744 case POST_DEC: | |
| 1745 offset = -n_refs * size; | |
| 1746 break; | |
| 1747 | |
| 1748 default: | |
| 1749 return addr; | |
| 1750 } | |
| 1751 | |
| 1752 if (offset) | |
| 1753 addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0), | |
| 1754 GEN_INT (offset)); | |
| 1755 else | |
| 1756 addr = XEXP (addr, 0); | |
| 1757 addr = canon_rtx (addr); | |
| 1758 | |
| 1759 return addr; | |
| 1760 } | |
| 1761 | |
| 1762 /* Return nonzero if X and Y (memory addresses) could reference the | |
| 1763 same location in memory. C is an offset accumulator. When | |
| 1764 C is nonzero, we are testing aliases between X and Y + C. | |
| 1765 XSIZE is the size in bytes of the X reference, | |
| 1766 similarly YSIZE is the size in bytes for Y. | |
| 1767 Expect that canon_rtx has been already called for X and Y. | |
| 1768 | |
| 1769 If XSIZE or YSIZE is zero, we do not know the amount of memory being | |
| 1770 referenced (the reference was BLKmode), so make the most pessimistic | |
| 1771 assumptions. | |
| 1772 | |
| 1773 If XSIZE or YSIZE is negative, we may access memory outside the object | |
| 1774 being referenced as a side effect. This can happen when using AND to | |
| 1775 align memory references, as is done on the Alpha. | |
| 1776 | |
| 1777 Nice to notice that varying addresses cannot conflict with fp if no | |
| 1778 local variables had their addresses taken, but that's too hard now. */ | |
| 1779 | |
| 1780 static int | |
| 1781 memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c) | |
| 1782 { | |
| 1783 if (GET_CODE (x) == VALUE) | |
| 1784 x = get_addr (x); | |
| 1785 if (GET_CODE (y) == VALUE) | |
| 1786 y = get_addr (y); | |
| 1787 if (GET_CODE (x) == HIGH) | |
| 1788 x = XEXP (x, 0); | |
| 1789 else if (GET_CODE (x) == LO_SUM) | |
| 1790 x = XEXP (x, 1); | |
| 1791 else | |
| 1792 x = addr_side_effect_eval (x, xsize, 0); | |
| 1793 if (GET_CODE (y) == HIGH) | |
| 1794 y = XEXP (y, 0); | |
| 1795 else if (GET_CODE (y) == LO_SUM) | |
| 1796 y = XEXP (y, 1); | |
| 1797 else | |
| 1798 y = addr_side_effect_eval (y, ysize, 0); | |
| 1799 | |
| 1800 if (rtx_equal_for_memref_p (x, y)) | |
| 1801 { | |
| 1802 if (xsize <= 0 || ysize <= 0) | |
| 1803 return 1; | |
| 1804 if (c >= 0 && xsize > c) | |
| 1805 return 1; | |
| 1806 if (c < 0 && ysize+c > 0) | |
| 1807 return 1; | |
| 1808 return 0; | |
| 1809 } | |
| 1810 | |
| 1811 /* This code used to check for conflicts involving stack references and | |
| 1812 globals but the base address alias code now handles these cases. */ | |
| 1813 | |
| 1814 if (GET_CODE (x) == PLUS) | |
| 1815 { | |
| 1816 /* The fact that X is canonicalized means that this | |
| 1817 PLUS rtx is canonicalized. */ | |
| 1818 rtx x0 = XEXP (x, 0); | |
| 1819 rtx x1 = XEXP (x, 1); | |
| 1820 | |
| 1821 if (GET_CODE (y) == PLUS) | |
| 1822 { | |
| 1823 /* The fact that Y is canonicalized means that this | |
| 1824 PLUS rtx is canonicalized. */ | |
| 1825 rtx y0 = XEXP (y, 0); | |
| 1826 rtx y1 = XEXP (y, 1); | |
| 1827 | |
| 1828 if (rtx_equal_for_memref_p (x1, y1)) | |
| 1829 return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
| 1830 if (rtx_equal_for_memref_p (x0, y0)) | |
| 1831 return memrefs_conflict_p (xsize, x1, ysize, y1, c); | |
|
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1832 if (CONST_INT_P (x1)) |
| 0 | 1833 { |
|
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1834 if (CONST_INT_P (y1)) |
| 0 | 1835 return memrefs_conflict_p (xsize, x0, ysize, y0, |
| 1836 c - INTVAL (x1) + INTVAL (y1)); | |
| 1837 else | |
| 1838 return memrefs_conflict_p (xsize, x0, ysize, y, | |
| 1839 c - INTVAL (x1)); | |
| 1840 } | |
|
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1841 else if (CONST_INT_P (y1)) |
| 0 | 1842 return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
| 1843 | |
| 1844 return 1; | |
| 1845 } | |
|
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1846 else if (CONST_INT_P (x1)) |
| 0 | 1847 return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1)); |
| 1848 } | |
| 1849 else if (GET_CODE (y) == PLUS) | |
| 1850 { | |
| 1851 /* The fact that Y is canonicalized means that this | |
| 1852 PLUS rtx is canonicalized. */ | |
| 1853 rtx y0 = XEXP (y, 0); | |
| 1854 rtx y1 = XEXP (y, 1); | |
| 1855 | |
|
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1856 if (CONST_INT_P (y1)) |
| 0 | 1857 return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1)); |
| 1858 else | |
| 1859 return 1; | |
| 1860 } | |
| 1861 | |
| 1862 if (GET_CODE (x) == GET_CODE (y)) | |
| 1863 switch (GET_CODE (x)) | |
| 1864 { | |
| 1865 case MULT: | |
| 1866 { | |
| 1867 /* Handle cases where we expect the second operands to be the | |
| 1868 same, and check only whether the first operand would conflict | |
| 1869 or not. */ | |
| 1870 rtx x0, y0; | |
| 1871 rtx x1 = canon_rtx (XEXP (x, 1)); | |
| 1872 rtx y1 = canon_rtx (XEXP (y, 1)); | |
| 1873 if (! rtx_equal_for_memref_p (x1, y1)) | |
| 1874 return 1; | |
| 1875 x0 = canon_rtx (XEXP (x, 0)); | |
| 1876 y0 = canon_rtx (XEXP (y, 0)); | |
| 1877 if (rtx_equal_for_memref_p (x0, y0)) | |
| 1878 return (xsize == 0 || ysize == 0 | |
| 1879 || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
| 1880 | |
| 1881 /* Can't properly adjust our sizes. */ | |
|
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1882 if (!CONST_INT_P (x1)) |
| 0 | 1883 return 1; |
| 1884 xsize /= INTVAL (x1); | |
| 1885 ysize /= INTVAL (x1); | |
| 1886 c /= INTVAL (x1); | |
| 1887 return memrefs_conflict_p (xsize, x0, ysize, y0, c); | |
| 1888 } | |
| 1889 | |
| 1890 default: | |
| 1891 break; | |
| 1892 } | |
| 1893 | |
| 1894 /* Treat an access through an AND (e.g. a subword access on an Alpha) | |
| 1895 as an access with indeterminate size. Assume that references | |
| 1896 besides AND are aligned, so if the size of the other reference is | |
| 1897 at least as large as the alignment, assume no other overlap. */ | |
|
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1898 if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1))) |
| 0 | 1899 { |
| 1900 if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1))) | |
| 1901 xsize = -1; | |
| 1902 return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c); | |
| 1903 } | |
|
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1904 if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1))) |
| 0 | 1905 { |
| 1906 /* ??? If we are indexing far enough into the array/structure, we | |
| 1907 may yet be able to determine that we can not overlap. But we | |
| 1908 also need to that we are far enough from the end not to overlap | |
| 1909 a following reference, so we do nothing with that for now. */ | |
| 1910 if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1))) | |
| 1911 ysize = -1; | |
| 1912 return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c); | |
| 1913 } | |
| 1914 | |
| 1915 if (CONSTANT_P (x)) | |
| 1916 { | |
|
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1917 if (CONST_INT_P (x) && CONST_INT_P (y)) |
| 0 | 1918 { |
| 1919 c += (INTVAL (y) - INTVAL (x)); | |
| 1920 return (xsize <= 0 || ysize <= 0 | |
| 1921 || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)); | |
| 1922 } | |
| 1923 | |
| 1924 if (GET_CODE (x) == CONST) | |
| 1925 { | |
| 1926 if (GET_CODE (y) == CONST) | |
| 1927 return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
| 1928 ysize, canon_rtx (XEXP (y, 0)), c); | |
| 1929 else | |
| 1930 return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), | |
| 1931 ysize, y, c); | |
| 1932 } | |
| 1933 if (GET_CODE (y) == CONST) | |
| 1934 return memrefs_conflict_p (xsize, x, ysize, | |
| 1935 canon_rtx (XEXP (y, 0)), c); | |
| 1936 | |
| 1937 if (CONSTANT_P (y)) | |
| 1938 return (xsize <= 0 || ysize <= 0 | |
| 1939 || (rtx_equal_for_memref_p (x, y) | |
| 1940 && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0)))); | |
| 1941 | |
| 1942 return 1; | |
| 1943 } | |
| 1944 return 1; | |
| 1945 } | |
| 1946 | |
| 1947 /* Functions to compute memory dependencies. | |
| 1948 | |
| 1949 Since we process the insns in execution order, we can build tables | |
| 1950 to keep track of what registers are fixed (and not aliased), what registers | |
| 1951 are varying in known ways, and what registers are varying in unknown | |
| 1952 ways. | |
| 1953 | |
| 1954 If both memory references are volatile, then there must always be a | |
| 1955 dependence between the two references, since their order can not be | |
| 1956 changed. A volatile and non-volatile reference can be interchanged | |
| 1957 though. | |
| 1958 | |
| 1959 A MEM_IN_STRUCT reference at a non-AND varying address can never | |
| 1960 conflict with a non-MEM_IN_STRUCT reference at a fixed address. We | |
| 1961 also must allow AND addresses, because they may generate accesses | |
| 1962 outside the object being referenced. This is used to generate | |
| 1963 aligned addresses from unaligned addresses, for instance, the alpha | |
| 1964 storeqi_unaligned pattern. */ | |
| 1965 | |
| 1966 /* Read dependence: X is read after read in MEM takes place. There can | |
| 1967 only be a dependence here if both reads are volatile. */ | |
| 1968 | |
| 1969 int | |
| 1970 read_dependence (const_rtx mem, const_rtx x) | |
| 1971 { | |
| 1972 return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem); | |
| 1973 } | |
| 1974 | |
| 1975 /* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and | |
| 1976 MEM2 is a reference to a structure at a varying address, or returns | |
| 1977 MEM2 if vice versa. Otherwise, returns NULL_RTX. If a non-NULL | |
| 1978 value is returned MEM1 and MEM2 can never alias. VARIES_P is used | |
| 1979 to decide whether or not an address may vary; it should return | |
| 1980 nonzero whenever variation is possible. | |
| 1981 MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2. */ | |
| 1982 | |
| 1983 static const_rtx | |
| 1984 fixed_scalar_and_varying_struct_p (const_rtx mem1, const_rtx mem2, rtx mem1_addr, | |
| 1985 rtx mem2_addr, | |
| 1986 bool (*varies_p) (const_rtx, bool)) | |
| 1987 { | |
| 1988 if (! flag_strict_aliasing) | |
| 1989 return NULL_RTX; | |
| 1990 | |
| 1991 if (MEM_ALIAS_SET (mem2) | |
| 1992 && MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2) | |
| 1993 && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1)) | |
| 1994 /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a | |
| 1995 varying address. */ | |
| 1996 return mem1; | |
| 1997 | |
| 1998 if (MEM_ALIAS_SET (mem1) | |
| 1999 && MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2) | |
| 2000 && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1)) | |
| 2001 /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a | |
| 2002 varying address. */ | |
| 2003 return mem2; | |
| 2004 | |
| 2005 return NULL_RTX; | |
| 2006 } | |
| 2007 | |
| 2008 /* Returns nonzero if something about the mode or address format MEM1 | |
| 2009 indicates that it might well alias *anything*. */ | |
| 2010 | |
| 2011 static int | |
| 2012 aliases_everything_p (const_rtx mem) | |
| 2013 { | |
| 2014 if (GET_CODE (XEXP (mem, 0)) == AND) | |
| 2015 /* If the address is an AND, it's very hard to know at what it is | |
| 2016 actually pointing. */ | |
| 2017 return 1; | |
| 2018 | |
| 2019 return 0; | |
| 2020 } | |
| 2021 | |
| 2022 /* Return true if we can determine that the fields referenced cannot | |
| 2023 overlap for any pair of objects. */ | |
| 2024 | |
| 2025 static bool | |
| 2026 nonoverlapping_component_refs_p (const_tree x, const_tree y) | |
| 2027 { | |
| 2028 const_tree fieldx, fieldy, typex, typey, orig_y; | |
| 2029 | |
| 36 | 2030 if (!flag_strict_aliasing) |
| 2031 return false; | |
| 2032 | |
| 0 | 2033 do |
| 2034 { | |
| 2035 /* The comparison has to be done at a common type, since we don't | |
| 2036 know how the inheritance hierarchy works. */ | |
| 2037 orig_y = y; | |
| 2038 do | |
| 2039 { | |
| 2040 fieldx = TREE_OPERAND (x, 1); | |
| 2041 typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx)); | |
| 2042 | |
| 2043 y = orig_y; | |
| 2044 do | |
| 2045 { | |
| 2046 fieldy = TREE_OPERAND (y, 1); | |
| 2047 typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy)); | |
| 2048 | |
| 2049 if (typex == typey) | |
| 2050 goto found; | |
| 2051 | |
| 2052 y = TREE_OPERAND (y, 0); | |
| 2053 } | |
| 2054 while (y && TREE_CODE (y) == COMPONENT_REF); | |
| 2055 | |
| 2056 x = TREE_OPERAND (x, 0); | |
| 2057 } | |
| 2058 while (x && TREE_CODE (x) == COMPONENT_REF); | |
| 2059 /* Never found a common type. */ | |
| 2060 return false; | |
| 2061 | |
| 2062 found: | |
| 2063 /* If we're left with accessing different fields of a structure, | |
| 2064 then no overlap. */ | |
| 2065 if (TREE_CODE (typex) == RECORD_TYPE | |
| 2066 && fieldx != fieldy) | |
| 2067 return true; | |
| 2068 | |
| 2069 /* The comparison on the current field failed. If we're accessing | |
| 2070 a very nested structure, look at the next outer level. */ | |
| 2071 x = TREE_OPERAND (x, 0); | |
| 2072 y = TREE_OPERAND (y, 0); | |
| 2073 } | |
| 2074 while (x && y | |
| 2075 && TREE_CODE (x) == COMPONENT_REF | |
| 2076 && TREE_CODE (y) == COMPONENT_REF); | |
| 2077 | |
| 2078 return false; | |
| 2079 } | |
| 2080 | |
| 2081 /* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */ | |
| 2082 | |
| 2083 static tree | |
| 2084 decl_for_component_ref (tree x) | |
| 2085 { | |
| 2086 do | |
| 2087 { | |
| 2088 x = TREE_OPERAND (x, 0); | |
| 2089 } | |
| 2090 while (x && TREE_CODE (x) == COMPONENT_REF); | |
| 2091 | |
| 2092 return x && DECL_P (x) ? x : NULL_TREE; | |
| 2093 } | |
| 2094 | |
| 2095 /* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the | |
| 2096 offset of the field reference. */ | |
| 2097 | |
| 2098 static rtx | |
| 2099 adjust_offset_for_component_ref (tree x, rtx offset) | |
| 2100 { | |
| 2101 HOST_WIDE_INT ioffset; | |
| 2102 | |
| 2103 if (! offset) | |
| 2104 return NULL_RTX; | |
| 2105 | |
| 2106 ioffset = INTVAL (offset); | |
| 2107 do | |
| 2108 { | |
| 2109 tree offset = component_ref_field_offset (x); | |
| 2110 tree field = TREE_OPERAND (x, 1); | |
| 2111 | |
| 2112 if (! host_integerp (offset, 1)) | |
| 2113 return NULL_RTX; | |
| 2114 ioffset += (tree_low_cst (offset, 1) | |
| 2115 + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1) | |
| 2116 / BITS_PER_UNIT)); | |
| 2117 | |
| 2118 x = TREE_OPERAND (x, 0); | |
| 2119 } | |
| 2120 while (x && TREE_CODE (x) == COMPONENT_REF); | |
| 2121 | |
| 2122 return GEN_INT (ioffset); | |
| 2123 } | |
| 2124 | |
| 2125 /* Return nonzero if we can determine the exprs corresponding to memrefs | |
| 2126 X and Y and they do not overlap. */ | |
| 2127 | |
| 2128 int | |
| 2129 nonoverlapping_memrefs_p (const_rtx x, const_rtx y) | |
| 2130 { | |
| 2131 tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y); | |
| 2132 rtx rtlx, rtly; | |
| 2133 rtx basex, basey; | |
| 2134 rtx moffsetx, moffsety; | |
| 2135 HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem; | |
| 2136 | |
| 2137 /* Unless both have exprs, we can't tell anything. */ | |
| 2138 if (exprx == 0 || expry == 0) | |
| 2139 return 0; | |
| 2140 | |
| 2141 /* If both are field references, we may be able to determine something. */ | |
| 2142 if (TREE_CODE (exprx) == COMPONENT_REF | |
| 2143 && TREE_CODE (expry) == COMPONENT_REF | |
| 2144 && nonoverlapping_component_refs_p (exprx, expry)) | |
| 2145 return 1; | |
| 2146 | |
| 2147 | |
| 2148 /* If the field reference test failed, look at the DECLs involved. */ | |
| 2149 moffsetx = MEM_OFFSET (x); | |
| 2150 if (TREE_CODE (exprx) == COMPONENT_REF) | |
| 2151 { | |
| 2152 if (TREE_CODE (expry) == VAR_DECL | |
| 2153 && POINTER_TYPE_P (TREE_TYPE (expry))) | |
| 2154 { | |
| 2155 tree field = TREE_OPERAND (exprx, 1); | |
| 2156 tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
| 2157 if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
| 2158 TREE_TYPE (field))) | |
| 2159 return 1; | |
| 2160 } | |
| 2161 { | |
| 2162 tree t = decl_for_component_ref (exprx); | |
| 2163 if (! t) | |
| 2164 return 0; | |
| 2165 moffsetx = adjust_offset_for_component_ref (exprx, moffsetx); | |
| 2166 exprx = t; | |
| 2167 } | |
| 2168 } | |
| 2169 else if (INDIRECT_REF_P (exprx)) | |
| 2170 { | |
| 2171 exprx = TREE_OPERAND (exprx, 0); | |
| 2172 if (flag_argument_noalias < 2 | |
| 2173 || TREE_CODE (exprx) != PARM_DECL) | |
| 2174 return 0; | |
| 2175 } | |
| 2176 | |
| 2177 moffsety = MEM_OFFSET (y); | |
| 2178 if (TREE_CODE (expry) == COMPONENT_REF) | |
| 2179 { | |
| 2180 if (TREE_CODE (exprx) == VAR_DECL | |
| 2181 && POINTER_TYPE_P (TREE_TYPE (exprx))) | |
| 2182 { | |
| 2183 tree field = TREE_OPERAND (expry, 1); | |
| 2184 tree fieldcontext = DECL_FIELD_CONTEXT (field); | |
| 2185 if (ipa_type_escape_field_does_not_clobber_p (fieldcontext, | |
| 2186 TREE_TYPE (field))) | |
| 2187 return 1; | |
| 2188 } | |
| 2189 { | |
| 2190 tree t = decl_for_component_ref (expry); | |
| 2191 if (! t) | |
| 2192 return 0; | |
| 2193 moffsety = adjust_offset_for_component_ref (expry, moffsety); | |
| 2194 expry = t; | |
| 2195 } | |
| 2196 } | |
| 2197 else if (INDIRECT_REF_P (expry)) | |
| 2198 { | |
| 2199 expry = TREE_OPERAND (expry, 0); | |
| 2200 if (flag_argument_noalias < 2 | |
| 2201 || TREE_CODE (expry) != PARM_DECL) | |
| 2202 return 0; | |
| 2203 } | |
| 2204 | |
| 2205 if (! DECL_P (exprx) || ! DECL_P (expry)) | |
| 2206 return 0; | |
| 2207 | |
|
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diff
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|
2208 /* With invalid code we can end up storing into the constant pool. |
|
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diff
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|
2209 Bail out to avoid ICEing when creating RTL for this. |
|
77e2b8dfacca
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36
diff
changeset
|
2210 See gfortran.dg/lto/20091028-2_0.f90. */ |
|
77e2b8dfacca
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parents:
36
diff
changeset
|
2211 if (TREE_CODE (exprx) == CONST_DECL |
|
77e2b8dfacca
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36
diff
changeset
|
2212 || TREE_CODE (expry) == CONST_DECL) |
|
77e2b8dfacca
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parents:
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diff
changeset
|
2213 return 1; |
|
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diff
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|
2214 |
| 0 | 2215 rtlx = DECL_RTL (exprx); |
| 2216 rtly = DECL_RTL (expry); | |
| 2217 | |
| 2218 /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they | |
| 2219 can't overlap unless they are the same because we never reuse that part | |
| 2220 of the stack frame used for locals for spilled pseudos. */ | |
| 2221 if ((!MEM_P (rtlx) || !MEM_P (rtly)) | |
| 2222 && ! rtx_equal_p (rtlx, rtly)) | |
| 2223 return 1; | |
| 2224 | |
|
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diff
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|
2225 /* If we have MEMs refering to different address spaces (which can |
|
77e2b8dfacca
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36
diff
changeset
|
2226 potentially overlap), we cannot easily tell from the addresses |
|
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diff
changeset
|
2227 whether the references overlap. */ |
|
77e2b8dfacca
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diff
changeset
|
2228 if (MEM_P (rtlx) && MEM_P (rtly) |
|
77e2b8dfacca
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diff
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|
2229 && MEM_ADDR_SPACE (rtlx) != MEM_ADDR_SPACE (rtly)) |
|
77e2b8dfacca
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diff
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|
2230 return 0; |
|
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diff
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|
2231 |
| 0 | 2232 /* Get the base and offsets of both decls. If either is a register, we |
| 2233 know both are and are the same, so use that as the base. The only | |
| 2234 we can avoid overlap is if we can deduce that they are nonoverlapping | |
| 2235 pieces of that decl, which is very rare. */ | |
| 2236 basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx; | |
|
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diff
changeset
|
2237 if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1))) |
| 0 | 2238 offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0); |
| 2239 | |
| 2240 basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly; | |
|
55
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diff
changeset
|
2241 if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1))) |
| 0 | 2242 offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0); |
| 2243 | |
| 2244 /* If the bases are different, we know they do not overlap if both | |
| 2245 are constants or if one is a constant and the other a pointer into the | |
| 2246 stack frame. Otherwise a different base means we can't tell if they | |
| 2247 overlap or not. */ | |
| 2248 if (! rtx_equal_p (basex, basey)) | |
| 2249 return ((CONSTANT_P (basex) && CONSTANT_P (basey)) | |
| 2250 || (CONSTANT_P (basex) && REG_P (basey) | |
| 2251 && REGNO_PTR_FRAME_P (REGNO (basey))) | |
| 2252 || (CONSTANT_P (basey) && REG_P (basex) | |
| 2253 && REGNO_PTR_FRAME_P (REGNO (basex)))); | |
| 2254 | |
| 2255 sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx)) | |
| 2256 : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx)) | |
| 2257 : -1); | |
| 2258 sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly)) | |
| 2259 : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) : | |
| 2260 -1); | |
| 2261 | |
| 2262 /* If we have an offset for either memref, it can update the values computed | |
| 2263 above. */ | |
| 2264 if (moffsetx) | |
| 2265 offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx); | |
| 2266 if (moffsety) | |
| 2267 offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety); | |
| 2268 | |
| 2269 /* If a memref has both a size and an offset, we can use the smaller size. | |
| 2270 We can't do this if the offset isn't known because we must view this | |
| 2271 memref as being anywhere inside the DECL's MEM. */ | |
| 2272 if (MEM_SIZE (x) && moffsetx) | |
| 2273 sizex = INTVAL (MEM_SIZE (x)); | |
| 2274 if (MEM_SIZE (y) && moffsety) | |
| 2275 sizey = INTVAL (MEM_SIZE (y)); | |
| 2276 | |
| 2277 /* Put the values of the memref with the lower offset in X's values. */ | |
| 2278 if (offsetx > offsety) | |
| 2279 { | |
| 2280 tem = offsetx, offsetx = offsety, offsety = tem; | |
| 2281 tem = sizex, sizex = sizey, sizey = tem; | |
| 2282 } | |
| 2283 | |
| 2284 /* If we don't know the size of the lower-offset value, we can't tell | |
| 2285 if they conflict. Otherwise, we do the test. */ | |
| 2286 return sizex >= 0 && offsety >= offsetx + sizex; | |
| 2287 } | |
| 2288 | |
| 2289 /* True dependence: X is read after store in MEM takes place. */ | |
| 2290 | |
| 2291 int | |
| 2292 true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x, | |
| 2293 bool (*varies) (const_rtx, bool)) | |
| 2294 { | |
| 2295 rtx x_addr, mem_addr; | |
| 2296 rtx base; | |
| 2297 | |
| 2298 if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
| 2299 return 1; | |
| 2300 | |
| 2301 /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. | |
| 2302 This is used in epilogue deallocation functions, and in cselib. */ | |
| 2303 if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
| 2304 return 1; | |
| 2305 if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
| 2306 return 1; | |
| 2307 if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER | |
| 2308 || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
| 2309 return 1; | |
| 2310 | |
| 2311 if (DIFFERENT_ALIAS_SETS_P (x, mem)) | |
| 2312 return 0; | |
| 2313 | |
| 2314 /* Read-only memory is by definition never modified, and therefore can't | |
| 2315 conflict with anything. We don't expect to find read-only set on MEM, | |
| 2316 but stupid user tricks can produce them, so don't die. */ | |
| 2317 if (MEM_READONLY_P (x)) | |
| 2318 return 0; | |
| 2319 | |
| 2320 if (nonoverlapping_memrefs_p (mem, x)) | |
| 2321 return 0; | |
| 2322 | |
|
55
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diff
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|
2323 /* If we have MEMs refering to different address spaces (which can |
|
77e2b8dfacca
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36
diff
changeset
|
2324 potentially overlap), we cannot easily tell from the addresses |
|
77e2b8dfacca
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36
diff
changeset
|
2325 whether the references overlap. */ |
|
77e2b8dfacca
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36
diff
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|
2326 if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) |
|
77e2b8dfacca
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diff
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|
2327 return 1; |
|
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diff
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|
2328 |
| 0 | 2329 if (mem_mode == VOIDmode) |
| 2330 mem_mode = GET_MODE (mem); | |
| 2331 | |
| 2332 x_addr = get_addr (XEXP (x, 0)); | |
| 2333 mem_addr = get_addr (XEXP (mem, 0)); | |
| 2334 | |
| 2335 base = find_base_term (x_addr); | |
| 2336 if (base && (GET_CODE (base) == LABEL_REF | |
| 2337 || (GET_CODE (base) == SYMBOL_REF | |
| 2338 && CONSTANT_POOL_ADDRESS_P (base)))) | |
| 2339 return 0; | |
| 2340 | |
| 2341 if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
| 2342 return 0; | |
| 2343 | |
| 2344 x_addr = canon_rtx (x_addr); | |
| 2345 mem_addr = canon_rtx (mem_addr); | |
| 2346 | |
| 2347 if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
| 2348 SIZE_FOR_MODE (x), x_addr, 0)) | |
| 2349 return 0; | |
| 2350 | |
| 2351 if (aliases_everything_p (x)) | |
| 2352 return 1; | |
| 2353 | |
| 2354 /* We cannot use aliases_everything_p to test MEM, since we must look | |
| 2355 at MEM_MODE, rather than GET_MODE (MEM). */ | |
| 2356 if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
| 2357 return 1; | |
| 2358 | |
| 2359 /* In true_dependence we also allow BLKmode to alias anything. Why | |
| 2360 don't we do this in anti_dependence and output_dependence? */ | |
| 2361 if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
| 2362 return 1; | |
| 2363 | |
|
55
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36
diff
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|
2364 if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
36
diff
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|
2365 return 0; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
36
diff
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|
2366 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
36
diff
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|
2367 return rtx_refs_may_alias_p (x, mem, true); |
| 0 | 2368 } |
| 2369 | |
| 2370 /* Canonical true dependence: X is read after store in MEM takes place. | |
| 2371 Variant of true_dependence which assumes MEM has already been | |
| 2372 canonicalized (hence we no longer do that here). | |
| 2373 The mem_addr argument has been added, since true_dependence computed | |
|
19
58ad6c70ea60
update gcc from 4.4.0 to 4.4.1.
kent@firefly.cr.ie.u-ryukyu.ac.jp
parents:
0
diff
changeset
|
2374 this value prior to canonicalizing. |
|
58ad6c70ea60
update gcc from 4.4.0 to 4.4.1.
kent@firefly.cr.ie.u-ryukyu.ac.jp
parents:
0
diff
changeset
|
2375 If x_addr is non-NULL, it is used in preference of XEXP (x, 0). */ |
| 0 | 2376 |
| 2377 int | |
| 2378 canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, | |
|
19
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update gcc from 4.4.0 to 4.4.1.
kent@firefly.cr.ie.u-ryukyu.ac.jp
parents:
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diff
changeset
|
2379 const_rtx x, rtx x_addr, bool (*varies) (const_rtx, bool)) |
| 0 | 2380 { |
| 2381 if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
| 2382 return 1; | |
| 2383 | |
| 2384 /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. | |
| 2385 This is used in epilogue deallocation functions. */ | |
| 2386 if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
| 2387 return 1; | |
| 2388 if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
| 2389 return 1; | |
| 2390 if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER | |
| 2391 || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
| 2392 return 1; | |
| 2393 | |
| 2394 if (DIFFERENT_ALIAS_SETS_P (x, mem)) | |
| 2395 return 0; | |
| 2396 | |
| 2397 /* Read-only memory is by definition never modified, and therefore can't | |
| 2398 conflict with anything. We don't expect to find read-only set on MEM, | |
| 2399 but stupid user tricks can produce them, so don't die. */ | |
| 2400 if (MEM_READONLY_P (x)) | |
| 2401 return 0; | |
| 2402 | |
| 2403 if (nonoverlapping_memrefs_p (x, mem)) | |
| 2404 return 0; | |
| 2405 | |
|
55
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36
diff
changeset
|
2406 /* If we have MEMs refering to different address spaces (which can |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
36
diff
changeset
|
2407 potentially overlap), we cannot easily tell from the addresses |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
36
diff
changeset
|
2408 whether the references overlap. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
36
diff
changeset
|
2409 if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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36
diff
changeset
|
2410 return 1; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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36
diff
changeset
|
2411 |
|
19
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kent@firefly.cr.ie.u-ryukyu.ac.jp
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0
diff
changeset
|
2412 if (! x_addr) |
|
58ad6c70ea60
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diff
changeset
|
2413 x_addr = get_addr (XEXP (x, 0)); |
| 0 | 2414 |
| 2415 if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode)) | |
| 2416 return 0; | |
| 2417 | |
| 2418 x_addr = canon_rtx (x_addr); | |
| 2419 if (! memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr, | |
| 2420 SIZE_FOR_MODE (x), x_addr, 0)) | |
| 2421 return 0; | |
| 2422 | |
| 2423 if (aliases_everything_p (x)) | |
| 2424 return 1; | |
| 2425 | |
| 2426 /* We cannot use aliases_everything_p to test MEM, since we must look | |
| 2427 at MEM_MODE, rather than GET_MODE (MEM). */ | |
| 2428 if (mem_mode == QImode || GET_CODE (mem_addr) == AND) | |
| 2429 return 1; | |
| 2430 | |
| 2431 /* In true_dependence we also allow BLKmode to alias anything. Why | |
| 2432 don't we do this in anti_dependence and output_dependence? */ | |
| 2433 if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) | |
| 2434 return 1; | |
| 2435 | |
|
55
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36
diff
changeset
|
2436 if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
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36
diff
changeset
|
2437 return 0; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
36
diff
changeset
|
2438 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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36
diff
changeset
|
2439 return rtx_refs_may_alias_p (x, mem, true); |
| 0 | 2440 } |
| 2441 | |
| 2442 /* Returns nonzero if a write to X might alias a previous read from | |
| 2443 (or, if WRITEP is nonzero, a write to) MEM. */ | |
| 2444 | |
| 2445 static int | |
| 2446 write_dependence_p (const_rtx mem, const_rtx x, int writep) | |
| 2447 { | |
| 2448 rtx x_addr, mem_addr; | |
| 2449 const_rtx fixed_scalar; | |
| 2450 rtx base; | |
| 2451 | |
| 2452 if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem)) | |
| 2453 return 1; | |
| 2454 | |
| 2455 /* (mem:BLK (scratch)) is a special mechanism to conflict with everything. | |
| 2456 This is used in epilogue deallocation functions. */ | |
| 2457 if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH) | |
| 2458 return 1; | |
| 2459 if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH) | |
| 2460 return 1; | |
| 2461 if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER | |
| 2462 || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER) | |
| 2463 return 1; | |
| 2464 | |
| 2465 /* A read from read-only memory can't conflict with read-write memory. */ | |
| 2466 if (!writep && MEM_READONLY_P (mem)) | |
| 2467 return 0; | |
| 2468 | |
| 2469 if (nonoverlapping_memrefs_p (x, mem)) | |
| 2470 return 0; | |
| 2471 | |
|
55
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36
diff
changeset
|
2472 /* If we have MEMs refering to different address spaces (which can |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
36
diff
changeset
|
2473 potentially overlap), we cannot easily tell from the addresses |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
36
diff
changeset
|
2474 whether the references overlap. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
36
diff
changeset
|
2475 if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
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36
diff
changeset
|
2476 return 1; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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36
diff
changeset
|
2477 |
| 0 | 2478 x_addr = get_addr (XEXP (x, 0)); |
| 2479 mem_addr = get_addr (XEXP (mem, 0)); | |
| 2480 | |
| 2481 if (! writep) | |
| 2482 { | |
| 2483 base = find_base_term (mem_addr); | |
| 2484 if (base && (GET_CODE (base) == LABEL_REF | |
| 2485 || (GET_CODE (base) == SYMBOL_REF | |
| 2486 && CONSTANT_POOL_ADDRESS_P (base)))) | |
| 2487 return 0; | |
| 2488 } | |
| 2489 | |
| 2490 if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), | |
| 2491 GET_MODE (mem))) | |
| 2492 return 0; | |
| 2493 | |
| 2494 x_addr = canon_rtx (x_addr); | |
| 2495 mem_addr = canon_rtx (mem_addr); | |
| 2496 | |
| 2497 if (!memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr, | |
| 2498 SIZE_FOR_MODE (x), x_addr, 0)) | |
| 2499 return 0; | |
| 2500 | |
| 2501 fixed_scalar | |
| 2502 = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, | |
| 2503 rtx_addr_varies_p); | |
| 2504 | |
|
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2505 if ((fixed_scalar == mem && !aliases_everything_p (x)) |
|
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2506 || (fixed_scalar == x && !aliases_everything_p (mem))) |
|
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2507 return 0; |
|
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2508 |
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|
2509 return rtx_refs_may_alias_p (x, mem, false); |
| 0 | 2510 } |
| 2511 | |
| 2512 /* Anti dependence: X is written after read in MEM takes place. */ | |
| 2513 | |
| 2514 int | |
| 2515 anti_dependence (const_rtx mem, const_rtx x) | |
| 2516 { | |
| 2517 return write_dependence_p (mem, x, /*writep=*/0); | |
| 2518 } | |
| 2519 | |
| 2520 /* Output dependence: X is written after store in MEM takes place. */ | |
| 2521 | |
| 2522 int | |
| 2523 output_dependence (const_rtx mem, const_rtx x) | |
| 2524 { | |
| 2525 return write_dependence_p (mem, x, /*writep=*/1); | |
| 2526 } | |
| 2527 | |
| 2528 | |
| 2529 void | |
| 2530 init_alias_target (void) | |
| 2531 { | |
| 2532 int i; | |
| 2533 | |
| 2534 memset (static_reg_base_value, 0, sizeof static_reg_base_value); | |
| 2535 | |
| 2536 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) | |
| 2537 /* Check whether this register can hold an incoming pointer | |
| 2538 argument. FUNCTION_ARG_REGNO_P tests outgoing register | |
| 2539 numbers, so translate if necessary due to register windows. */ | |
| 2540 if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i)) | |
| 2541 && HARD_REGNO_MODE_OK (i, Pmode)) | |
| 2542 static_reg_base_value[i] | |
| 2543 = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i)); | |
| 2544 | |
| 2545 static_reg_base_value[STACK_POINTER_REGNUM] | |
| 2546 = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx); | |
| 2547 static_reg_base_value[ARG_POINTER_REGNUM] | |
| 2548 = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx); | |
| 2549 static_reg_base_value[FRAME_POINTER_REGNUM] | |
| 2550 = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx); | |
| 2551 #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM | |
| 2552 static_reg_base_value[HARD_FRAME_POINTER_REGNUM] | |
| 2553 = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx); | |
| 2554 #endif | |
| 2555 } | |
| 2556 | |
| 2557 /* Set MEMORY_MODIFIED when X modifies DATA (that is assumed | |
| 2558 to be memory reference. */ | |
| 2559 static bool memory_modified; | |
| 2560 static void | |
| 2561 memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data) | |
| 2562 { | |
| 2563 if (MEM_P (x)) | |
| 2564 { | |
| 2565 if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data)) | |
| 2566 memory_modified = true; | |
| 2567 } | |
| 2568 } | |
| 2569 | |
| 2570 | |
| 2571 /* Return true when INSN possibly modify memory contents of MEM | |
| 2572 (i.e. address can be modified). */ | |
| 2573 bool | |
| 2574 memory_modified_in_insn_p (const_rtx mem, const_rtx insn) | |
| 2575 { | |
| 2576 if (!INSN_P (insn)) | |
| 2577 return false; | |
| 2578 memory_modified = false; | |
| 2579 note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); | |
| 2580 return memory_modified; | |
| 2581 } | |
| 2582 | |
| 2583 /* Initialize the aliasing machinery. Initialize the REG_KNOWN_VALUE | |
| 2584 array. */ | |
| 2585 | |
| 2586 void | |
| 2587 init_alias_analysis (void) | |
| 2588 { | |
| 2589 unsigned int maxreg = max_reg_num (); | |
| 2590 int changed, pass; | |
| 2591 int i; | |
| 2592 unsigned int ui; | |
| 2593 rtx insn; | |
| 2594 | |
| 2595 timevar_push (TV_ALIAS_ANALYSIS); | |
| 2596 | |
| 2597 reg_known_value_size = maxreg - FIRST_PSEUDO_REGISTER; | |
| 2598 reg_known_value = GGC_CNEWVEC (rtx, reg_known_value_size); | |
| 2599 reg_known_equiv_p = XCNEWVEC (bool, reg_known_value_size); | |
| 2600 | |
| 2601 /* If we have memory allocated from the previous run, use it. */ | |
| 2602 if (old_reg_base_value) | |
| 2603 reg_base_value = old_reg_base_value; | |
| 2604 | |
| 2605 if (reg_base_value) | |
| 2606 VEC_truncate (rtx, reg_base_value, 0); | |
| 2607 | |
| 2608 VEC_safe_grow_cleared (rtx, gc, reg_base_value, maxreg); | |
| 2609 | |
| 2610 new_reg_base_value = XNEWVEC (rtx, maxreg); | |
| 2611 reg_seen = XNEWVEC (char, maxreg); | |
| 2612 | |
| 2613 /* The basic idea is that each pass through this loop will use the | |
| 2614 "constant" information from the previous pass to propagate alias | |
| 2615 information through another level of assignments. | |
| 2616 | |
| 2617 This could get expensive if the assignment chains are long. Maybe | |
| 2618 we should throttle the number of iterations, possibly based on | |
| 2619 the optimization level or flag_expensive_optimizations. | |
| 2620 | |
| 2621 We could propagate more information in the first pass by making use | |
| 2622 of DF_REG_DEF_COUNT to determine immediately that the alias information | |
| 2623 for a pseudo is "constant". | |
| 2624 | |
| 2625 A program with an uninitialized variable can cause an infinite loop | |
| 2626 here. Instead of doing a full dataflow analysis to detect such problems | |
| 2627 we just cap the number of iterations for the loop. | |
| 2628 | |
| 2629 The state of the arrays for the set chain in question does not matter | |
| 2630 since the program has undefined behavior. */ | |
| 2631 | |
| 2632 pass = 0; | |
| 2633 do | |
| 2634 { | |
| 2635 /* Assume nothing will change this iteration of the loop. */ | |
| 2636 changed = 0; | |
| 2637 | |
| 2638 /* We want to assign the same IDs each iteration of this loop, so | |
| 2639 start counting from zero each iteration of the loop. */ | |
| 2640 unique_id = 0; | |
| 2641 | |
| 2642 /* We're at the start of the function each iteration through the | |
| 2643 loop, so we're copying arguments. */ | |
| 2644 copying_arguments = true; | |
| 2645 | |
| 2646 /* Wipe the potential alias information clean for this pass. */ | |
| 2647 memset (new_reg_base_value, 0, maxreg * sizeof (rtx)); | |
| 2648 | |
| 2649 /* Wipe the reg_seen array clean. */ | |
| 2650 memset (reg_seen, 0, maxreg); | |
| 2651 | |
| 2652 /* Mark all hard registers which may contain an address. | |
| 2653 The stack, frame and argument pointers may contain an address. | |
| 2654 An argument register which can hold a Pmode value may contain | |
| 2655 an address even if it is not in BASE_REGS. | |
| 2656 | |
| 2657 The address expression is VOIDmode for an argument and | |
| 2658 Pmode for other registers. */ | |
| 2659 | |
| 2660 memcpy (new_reg_base_value, static_reg_base_value, | |
| 2661 FIRST_PSEUDO_REGISTER * sizeof (rtx)); | |
| 2662 | |
| 2663 /* Walk the insns adding values to the new_reg_base_value array. */ | |
| 2664 for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) | |
| 2665 { | |
| 2666 if (INSN_P (insn)) | |
| 2667 { | |
| 2668 rtx note, set; | |
| 2669 | |
| 2670 #if defined (HAVE_prologue) || defined (HAVE_epilogue) | |
| 2671 /* The prologue/epilogue insns are not threaded onto the | |
| 2672 insn chain until after reload has completed. Thus, | |
| 2673 there is no sense wasting time checking if INSN is in | |
| 2674 the prologue/epilogue until after reload has completed. */ | |
| 2675 if (reload_completed | |
| 2676 && prologue_epilogue_contains (insn)) | |
| 2677 continue; | |
| 2678 #endif | |
| 2679 | |
| 2680 /* If this insn has a noalias note, process it, Otherwise, | |
| 2681 scan for sets. A simple set will have no side effects | |
| 2682 which could change the base value of any other register. */ | |
| 2683 | |
| 2684 if (GET_CODE (PATTERN (insn)) == SET | |
| 2685 && REG_NOTES (insn) != 0 | |
| 2686 && find_reg_note (insn, REG_NOALIAS, NULL_RTX)) | |
| 2687 record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL); | |
| 2688 else | |
| 2689 note_stores (PATTERN (insn), record_set, NULL); | |
| 2690 | |
| 2691 set = single_set (insn); | |
| 2692 | |
| 2693 if (set != 0 | |
| 2694 && REG_P (SET_DEST (set)) | |
| 2695 && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER) | |
| 2696 { | |
| 2697 unsigned int regno = REGNO (SET_DEST (set)); | |
| 2698 rtx src = SET_SRC (set); | |
| 2699 rtx t; | |
| 2700 | |
| 2701 note = find_reg_equal_equiv_note (insn); | |
| 2702 if (note && REG_NOTE_KIND (note) == REG_EQUAL | |
| 2703 && DF_REG_DEF_COUNT (regno) != 1) | |
| 2704 note = NULL_RTX; | |
| 2705 | |
| 2706 if (note != NULL_RTX | |
| 2707 && GET_CODE (XEXP (note, 0)) != EXPR_LIST | |
| 2708 && ! rtx_varies_p (XEXP (note, 0), 1) | |
| 2709 && ! reg_overlap_mentioned_p (SET_DEST (set), | |
| 2710 XEXP (note, 0))) | |
| 2711 { | |
| 2712 set_reg_known_value (regno, XEXP (note, 0)); | |
| 2713 set_reg_known_equiv_p (regno, | |
| 2714 REG_NOTE_KIND (note) == REG_EQUIV); | |
| 2715 } | |
| 2716 else if (DF_REG_DEF_COUNT (regno) == 1 | |
| 2717 && GET_CODE (src) == PLUS | |
| 2718 && REG_P (XEXP (src, 0)) | |
| 2719 && (t = get_reg_known_value (REGNO (XEXP (src, 0)))) | |
|
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|
2720 && CONST_INT_P (XEXP (src, 1))) |
| 0 | 2721 { |
| 2722 t = plus_constant (t, INTVAL (XEXP (src, 1))); | |
| 2723 set_reg_known_value (regno, t); | |
| 2724 set_reg_known_equiv_p (regno, 0); | |
| 2725 } | |
| 2726 else if (DF_REG_DEF_COUNT (regno) == 1 | |
| 2727 && ! rtx_varies_p (src, 1)) | |
| 2728 { | |
| 2729 set_reg_known_value (regno, src); | |
| 2730 set_reg_known_equiv_p (regno, 0); | |
| 2731 } | |
| 2732 } | |
| 2733 } | |
| 2734 else if (NOTE_P (insn) | |
| 2735 && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG) | |
| 2736 copying_arguments = false; | |
| 2737 } | |
| 2738 | |
| 2739 /* Now propagate values from new_reg_base_value to reg_base_value. */ | |
| 2740 gcc_assert (maxreg == (unsigned int) max_reg_num ()); | |
| 2741 | |
| 2742 for (ui = 0; ui < maxreg; ui++) | |
| 2743 { | |
| 2744 if (new_reg_base_value[ui] | |
| 2745 && new_reg_base_value[ui] != VEC_index (rtx, reg_base_value, ui) | |
| 2746 && ! rtx_equal_p (new_reg_base_value[ui], | |
| 2747 VEC_index (rtx, reg_base_value, ui))) | |
| 2748 { | |
| 2749 VEC_replace (rtx, reg_base_value, ui, new_reg_base_value[ui]); | |
| 2750 changed = 1; | |
| 2751 } | |
| 2752 } | |
| 2753 } | |
| 2754 while (changed && ++pass < MAX_ALIAS_LOOP_PASSES); | |
| 2755 | |
| 2756 /* Fill in the remaining entries. */ | |
| 2757 for (i = 0; i < (int)reg_known_value_size; i++) | |
| 2758 if (reg_known_value[i] == 0) | |
| 2759 reg_known_value[i] = regno_reg_rtx[i + FIRST_PSEUDO_REGISTER]; | |
| 2760 | |
| 2761 /* Clean up. */ | |
| 2762 free (new_reg_base_value); | |
| 2763 new_reg_base_value = 0; | |
| 2764 free (reg_seen); | |
| 2765 reg_seen = 0; | |
| 2766 timevar_pop (TV_ALIAS_ANALYSIS); | |
| 2767 } | |
| 2768 | |
| 2769 void | |
| 2770 end_alias_analysis (void) | |
| 2771 { | |
| 2772 old_reg_base_value = reg_base_value; | |
| 2773 ggc_free (reg_known_value); | |
| 2774 reg_known_value = 0; | |
| 2775 reg_known_value_size = 0; | |
| 2776 free (reg_known_equiv_p); | |
| 2777 reg_known_equiv_p = 0; | |
| 2778 } | |
| 2779 | |
| 2780 #include "gt-alias.h" |