Mercurial > hg > CbC > CbC_gcc
annotate gcc/tree-ssa-ccp.c @ 19:58ad6c70ea60
update gcc from 4.4.0 to 4.4.1.
| author | kent@firefly.cr.ie.u-ryukyu.ac.jp |
|---|---|
| date | Thu, 24 Sep 2009 13:21:57 +0900 |
| parents | a06113de4d67 |
| children | 3bfb6c00c1e0 |
| rev | line source |
|---|---|
| 0 | 1 /* Conditional constant propagation pass for the GNU compiler. |
| 2 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 | |
| 3 Free Software Foundation, Inc. | |
| 4 Adapted from original RTL SSA-CCP by Daniel Berlin <dberlin@dberlin.org> | |
| 5 Adapted to GIMPLE trees by Diego Novillo <dnovillo@redhat.com> | |
| 6 | |
| 7 This file is part of GCC. | |
| 8 | |
| 9 GCC is free software; you can redistribute it and/or modify it | |
| 10 under the terms of the GNU General Public License as published by the | |
| 11 Free Software Foundation; either version 3, or (at your option) any | |
| 12 later version. | |
| 13 | |
| 14 GCC is distributed in the hope that it will be useful, but WITHOUT | |
| 15 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 16 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 17 for more details. | |
| 18 | |
| 19 You should have received a copy of the GNU General Public License | |
| 20 along with GCC; see the file COPYING3. If not see | |
| 21 <http://www.gnu.org/licenses/>. */ | |
| 22 | |
| 23 /* Conditional constant propagation (CCP) is based on the SSA | |
| 24 propagation engine (tree-ssa-propagate.c). Constant assignments of | |
| 25 the form VAR = CST are propagated from the assignments into uses of | |
| 26 VAR, which in turn may generate new constants. The simulation uses | |
| 27 a four level lattice to keep track of constant values associated | |
| 28 with SSA names. Given an SSA name V_i, it may take one of the | |
| 29 following values: | |
| 30 | |
| 31 UNINITIALIZED -> the initial state of the value. This value | |
| 32 is replaced with a correct initial value | |
| 33 the first time the value is used, so the | |
| 34 rest of the pass does not need to care about | |
| 35 it. Using this value simplifies initialization | |
| 36 of the pass, and prevents us from needlessly | |
| 37 scanning statements that are never reached. | |
| 38 | |
| 39 UNDEFINED -> V_i is a local variable whose definition | |
| 40 has not been processed yet. Therefore we | |
| 41 don't yet know if its value is a constant | |
| 42 or not. | |
| 43 | |
| 44 CONSTANT -> V_i has been found to hold a constant | |
| 45 value C. | |
| 46 | |
| 47 VARYING -> V_i cannot take a constant value, or if it | |
| 48 does, it is not possible to determine it | |
| 49 at compile time. | |
| 50 | |
| 51 The core of SSA-CCP is in ccp_visit_stmt and ccp_visit_phi_node: | |
| 52 | |
| 53 1- In ccp_visit_stmt, we are interested in assignments whose RHS | |
| 54 evaluates into a constant and conditional jumps whose predicate | |
| 55 evaluates into a boolean true or false. When an assignment of | |
| 56 the form V_i = CONST is found, V_i's lattice value is set to | |
| 57 CONSTANT and CONST is associated with it. This causes the | |
| 58 propagation engine to add all the SSA edges coming out the | |
| 59 assignment into the worklists, so that statements that use V_i | |
| 60 can be visited. | |
| 61 | |
| 62 If the statement is a conditional with a constant predicate, we | |
| 63 mark the outgoing edges as executable or not executable | |
| 64 depending on the predicate's value. This is then used when | |
| 65 visiting PHI nodes to know when a PHI argument can be ignored. | |
| 66 | |
| 67 | |
| 68 2- In ccp_visit_phi_node, if all the PHI arguments evaluate to the | |
| 69 same constant C, then the LHS of the PHI is set to C. This | |
| 70 evaluation is known as the "meet operation". Since one of the | |
| 71 goals of this evaluation is to optimistically return constant | |
| 72 values as often as possible, it uses two main short cuts: | |
| 73 | |
| 74 - If an argument is flowing in through a non-executable edge, it | |
| 75 is ignored. This is useful in cases like this: | |
| 76 | |
| 77 if (PRED) | |
| 78 a_9 = 3; | |
| 79 else | |
| 80 a_10 = 100; | |
| 81 a_11 = PHI (a_9, a_10) | |
| 82 | |
| 83 If PRED is known to always evaluate to false, then we can | |
| 84 assume that a_11 will always take its value from a_10, meaning | |
| 85 that instead of consider it VARYING (a_9 and a_10 have | |
| 86 different values), we can consider it CONSTANT 100. | |
| 87 | |
| 88 - If an argument has an UNDEFINED value, then it does not affect | |
| 89 the outcome of the meet operation. If a variable V_i has an | |
| 90 UNDEFINED value, it means that either its defining statement | |
| 91 hasn't been visited yet or V_i has no defining statement, in | |
| 92 which case the original symbol 'V' is being used | |
| 93 uninitialized. Since 'V' is a local variable, the compiler | |
| 94 may assume any initial value for it. | |
| 95 | |
| 96 | |
| 97 After propagation, every variable V_i that ends up with a lattice | |
| 98 value of CONSTANT will have the associated constant value in the | |
| 99 array CONST_VAL[i].VALUE. That is fed into substitute_and_fold for | |
| 100 final substitution and folding. | |
| 101 | |
| 102 | |
| 103 Constant propagation in stores and loads (STORE-CCP) | |
| 104 ---------------------------------------------------- | |
| 105 | |
| 106 While CCP has all the logic to propagate constants in GIMPLE | |
| 107 registers, it is missing the ability to associate constants with | |
| 108 stores and loads (i.e., pointer dereferences, structures and | |
| 109 global/aliased variables). We don't keep loads and stores in | |
| 110 SSA, but we do build a factored use-def web for them (in the | |
| 111 virtual operands). | |
| 112 | |
| 113 For instance, consider the following code fragment: | |
| 114 | |
| 115 struct A a; | |
| 116 const int B = 42; | |
| 117 | |
| 118 void foo (int i) | |
| 119 { | |
| 120 if (i > 10) | |
| 121 a.a = 42; | |
| 122 else | |
| 123 { | |
| 124 a.b = 21; | |
| 125 a.a = a.b + 21; | |
| 126 } | |
| 127 | |
| 128 if (a.a != B) | |
| 129 never_executed (); | |
| 130 } | |
| 131 | |
| 132 We should be able to deduce that the predicate 'a.a != B' is always | |
| 133 false. To achieve this, we associate constant values to the SSA | |
| 134 names in the VDEF operands for each store. Additionally, | |
| 135 since we also glob partial loads/stores with the base symbol, we | |
| 136 also keep track of the memory reference where the constant value | |
| 137 was stored (in the MEM_REF field of PROP_VALUE_T). For instance, | |
| 138 | |
| 139 # a_5 = VDEF <a_4> | |
| 140 a.a = 2; | |
| 141 | |
| 142 # VUSE <a_5> | |
| 143 x_3 = a.b; | |
| 144 | |
| 145 In the example above, CCP will associate value '2' with 'a_5', but | |
| 146 it would be wrong to replace the load from 'a.b' with '2', because | |
| 147 '2' had been stored into a.a. | |
| 148 | |
| 149 Note that the initial value of virtual operands is VARYING, not | |
| 150 UNDEFINED. Consider, for instance global variables: | |
| 151 | |
| 152 int A; | |
| 153 | |
| 154 foo (int i) | |
| 155 { | |
| 156 if (i_3 > 10) | |
| 157 A_4 = 3; | |
| 158 # A_5 = PHI (A_4, A_2); | |
| 159 | |
| 160 # VUSE <A_5> | |
| 161 A.0_6 = A; | |
| 162 | |
| 163 return A.0_6; | |
| 164 } | |
| 165 | |
| 166 The value of A_2 cannot be assumed to be UNDEFINED, as it may have | |
| 167 been defined outside of foo. If we were to assume it UNDEFINED, we | |
| 168 would erroneously optimize the above into 'return 3;'. | |
| 169 | |
| 170 Though STORE-CCP is not too expensive, it does have to do more work | |
| 171 than regular CCP, so it is only enabled at -O2. Both regular CCP | |
| 172 and STORE-CCP use the exact same algorithm. The only distinction | |
| 173 is that when doing STORE-CCP, the boolean variable DO_STORE_CCP is | |
| 174 set to true. This affects the evaluation of statements and PHI | |
| 175 nodes. | |
| 176 | |
| 177 References: | |
| 178 | |
| 179 Constant propagation with conditional branches, | |
| 180 Wegman and Zadeck, ACM TOPLAS 13(2):181-210. | |
| 181 | |
| 182 Building an Optimizing Compiler, | |
| 183 Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9. | |
| 184 | |
| 185 Advanced Compiler Design and Implementation, | |
| 186 Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */ | |
| 187 | |
| 188 #include "config.h" | |
| 189 #include "system.h" | |
| 190 #include "coretypes.h" | |
| 191 #include "tm.h" | |
| 192 #include "tree.h" | |
| 193 #include "flags.h" | |
| 194 #include "rtl.h" | |
| 195 #include "tm_p.h" | |
| 196 #include "ggc.h" | |
| 197 #include "basic-block.h" | |
| 198 #include "output.h" | |
| 199 #include "expr.h" | |
| 200 #include "function.h" | |
| 201 #include "diagnostic.h" | |
| 202 #include "timevar.h" | |
| 203 #include "tree-dump.h" | |
| 204 #include "tree-flow.h" | |
| 205 #include "tree-pass.h" | |
| 206 #include "tree-ssa-propagate.h" | |
| 207 #include "value-prof.h" | |
| 208 #include "langhooks.h" | |
| 209 #include "target.h" | |
| 210 #include "toplev.h" | |
| 211 | |
| 212 | |
| 213 /* Possible lattice values. */ | |
| 214 typedef enum | |
| 215 { | |
| 216 UNINITIALIZED, | |
| 217 UNDEFINED, | |
| 218 CONSTANT, | |
| 219 VARYING | |
| 220 } ccp_lattice_t; | |
| 221 | |
| 222 /* Array of propagated constant values. After propagation, | |
| 223 CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If | |
| 224 the constant is held in an SSA name representing a memory store | |
| 225 (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual | |
| 226 memory reference used to store (i.e., the LHS of the assignment | |
| 227 doing the store). */ | |
| 228 static prop_value_t *const_val; | |
| 229 | |
| 230 static void canonicalize_float_value (prop_value_t *); | |
| 231 | |
| 232 /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ | |
| 233 | |
| 234 static void | |
| 235 dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val) | |
| 236 { | |
| 237 switch (val.lattice_val) | |
| 238 { | |
| 239 case UNINITIALIZED: | |
| 240 fprintf (outf, "%sUNINITIALIZED", prefix); | |
| 241 break; | |
| 242 case UNDEFINED: | |
| 243 fprintf (outf, "%sUNDEFINED", prefix); | |
| 244 break; | |
| 245 case VARYING: | |
| 246 fprintf (outf, "%sVARYING", prefix); | |
| 247 break; | |
| 248 case CONSTANT: | |
| 249 fprintf (outf, "%sCONSTANT ", prefix); | |
| 250 print_generic_expr (outf, val.value, dump_flags); | |
| 251 break; | |
| 252 default: | |
| 253 gcc_unreachable (); | |
| 254 } | |
| 255 } | |
| 256 | |
| 257 | |
| 258 /* Print lattice value VAL to stderr. */ | |
| 259 | |
| 260 void debug_lattice_value (prop_value_t val); | |
| 261 | |
| 262 void | |
| 263 debug_lattice_value (prop_value_t val) | |
| 264 { | |
| 265 dump_lattice_value (stderr, "", val); | |
| 266 fprintf (stderr, "\n"); | |
| 267 } | |
| 268 | |
| 269 | |
| 270 | |
| 271 /* If SYM is a constant variable with known value, return the value. | |
| 272 NULL_TREE is returned otherwise. */ | |
| 273 | |
| 274 tree | |
| 275 get_symbol_constant_value (tree sym) | |
| 276 { | |
| 277 if (TREE_STATIC (sym) | |
| 278 && TREE_READONLY (sym) | |
| 279 && !MTAG_P (sym)) | |
| 280 { | |
| 281 tree val = DECL_INITIAL (sym); | |
| 282 if (val) | |
| 283 { | |
| 284 STRIP_USELESS_TYPE_CONVERSION (val); | |
| 285 if (is_gimple_min_invariant (val)) | |
| 286 return val; | |
| 287 } | |
| 288 /* Variables declared 'const' without an initializer | |
| 289 have zero as the initializer if they may not be | |
| 290 overridden at link or run time. */ | |
| 291 if (!val | |
| 292 && !DECL_EXTERNAL (sym) | |
| 293 && targetm.binds_local_p (sym) | |
| 294 && (INTEGRAL_TYPE_P (TREE_TYPE (sym)) | |
| 295 || SCALAR_FLOAT_TYPE_P (TREE_TYPE (sym)))) | |
| 296 return fold_convert (TREE_TYPE (sym), integer_zero_node); | |
| 297 } | |
| 298 | |
| 299 return NULL_TREE; | |
| 300 } | |
| 301 | |
| 302 /* Compute a default value for variable VAR and store it in the | |
| 303 CONST_VAL array. The following rules are used to get default | |
| 304 values: | |
| 305 | |
| 306 1- Global and static variables that are declared constant are | |
| 307 considered CONSTANT. | |
| 308 | |
| 309 2- Any other value is considered UNDEFINED. This is useful when | |
| 310 considering PHI nodes. PHI arguments that are undefined do not | |
| 311 change the constant value of the PHI node, which allows for more | |
| 312 constants to be propagated. | |
| 313 | |
| 314 3- Variables defined by statements other than assignments and PHI | |
| 315 nodes are considered VARYING. | |
| 316 | |
| 317 4- Initial values of variables that are not GIMPLE registers are | |
| 318 considered VARYING. */ | |
| 319 | |
| 320 static prop_value_t | |
| 321 get_default_value (tree var) | |
| 322 { | |
| 323 tree sym = SSA_NAME_VAR (var); | |
| 324 prop_value_t val = { UNINITIALIZED, NULL_TREE }; | |
| 325 tree cst_val; | |
| 326 | |
| 327 if (!is_gimple_reg (var)) | |
| 328 { | |
| 329 /* Short circuit for regular CCP. We are not interested in any | |
| 330 non-register when DO_STORE_CCP is false. */ | |
| 331 val.lattice_val = VARYING; | |
| 332 } | |
| 333 else if ((cst_val = get_symbol_constant_value (sym)) != NULL_TREE) | |
| 334 { | |
| 335 /* Globals and static variables declared 'const' take their | |
| 336 initial value. */ | |
| 337 val.lattice_val = CONSTANT; | |
| 338 val.value = cst_val; | |
| 339 } | |
| 340 else | |
| 341 { | |
| 342 gimple stmt = SSA_NAME_DEF_STMT (var); | |
| 343 | |
| 344 if (gimple_nop_p (stmt)) | |
| 345 { | |
| 346 /* Variables defined by an empty statement are those used | |
| 347 before being initialized. If VAR is a local variable, we | |
| 348 can assume initially that it is UNDEFINED, otherwise we must | |
| 349 consider it VARYING. */ | |
| 350 if (is_gimple_reg (sym) && TREE_CODE (sym) != PARM_DECL) | |
| 351 val.lattice_val = UNDEFINED; | |
| 352 else | |
| 353 val.lattice_val = VARYING; | |
| 354 } | |
| 355 else if (is_gimple_assign (stmt) | |
| 356 /* Value-returning GIMPLE_CALL statements assign to | |
| 357 a variable, and are treated similarly to GIMPLE_ASSIGN. */ | |
| 358 || (is_gimple_call (stmt) | |
| 359 && gimple_call_lhs (stmt) != NULL_TREE) | |
| 360 || gimple_code (stmt) == GIMPLE_PHI) | |
| 361 { | |
| 362 /* Any other variable defined by an assignment or a PHI node | |
| 363 is considered UNDEFINED. */ | |
| 364 val.lattice_val = UNDEFINED; | |
| 365 } | |
| 366 else | |
| 367 { | |
| 368 /* Otherwise, VAR will never take on a constant value. */ | |
| 369 val.lattice_val = VARYING; | |
| 370 } | |
| 371 } | |
| 372 | |
| 373 return val; | |
| 374 } | |
| 375 | |
| 376 | |
| 377 /* Get the constant value associated with variable VAR. */ | |
| 378 | |
| 379 static inline prop_value_t * | |
| 380 get_value (tree var) | |
| 381 { | |
| 382 prop_value_t *val; | |
| 383 | |
| 384 if (const_val == NULL) | |
| 385 return NULL; | |
| 386 | |
| 387 val = &const_val[SSA_NAME_VERSION (var)]; | |
| 388 if (val->lattice_val == UNINITIALIZED) | |
| 389 *val = get_default_value (var); | |
| 390 | |
| 391 canonicalize_float_value (val); | |
| 392 | |
| 393 return val; | |
| 394 } | |
| 395 | |
| 396 /* Sets the value associated with VAR to VARYING. */ | |
| 397 | |
| 398 static inline void | |
| 399 set_value_varying (tree var) | |
| 400 { | |
| 401 prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; | |
| 402 | |
| 403 val->lattice_val = VARYING; | |
| 404 val->value = NULL_TREE; | |
| 405 } | |
| 406 | |
| 407 /* For float types, modify the value of VAL to make ccp work correctly | |
| 408 for non-standard values (-0, NaN): | |
| 409 | |
| 410 If HONOR_SIGNED_ZEROS is false, and VAL = -0, we canonicalize it to 0. | |
| 411 If HONOR_NANS is false, and VAL is NaN, we canonicalize it to UNDEFINED. | |
| 412 This is to fix the following problem (see PR 29921): Suppose we have | |
| 413 | |
| 414 x = 0.0 * y | |
| 415 | |
| 416 and we set value of y to NaN. This causes value of x to be set to NaN. | |
| 417 When we later determine that y is in fact VARYING, fold uses the fact | |
| 418 that HONOR_NANS is false, and we try to change the value of x to 0, | |
| 419 causing an ICE. With HONOR_NANS being false, the real appearance of | |
| 420 NaN would cause undefined behavior, though, so claiming that y (and x) | |
| 421 are UNDEFINED initially is correct. */ | |
| 422 | |
| 423 static void | |
| 424 canonicalize_float_value (prop_value_t *val) | |
| 425 { | |
| 426 enum machine_mode mode; | |
| 427 tree type; | |
| 428 REAL_VALUE_TYPE d; | |
| 429 | |
| 430 if (val->lattice_val != CONSTANT | |
| 431 || TREE_CODE (val->value) != REAL_CST) | |
| 432 return; | |
| 433 | |
| 434 d = TREE_REAL_CST (val->value); | |
| 435 type = TREE_TYPE (val->value); | |
| 436 mode = TYPE_MODE (type); | |
| 437 | |
| 438 if (!HONOR_SIGNED_ZEROS (mode) | |
| 439 && REAL_VALUE_MINUS_ZERO (d)) | |
| 440 { | |
| 441 val->value = build_real (type, dconst0); | |
| 442 return; | |
| 443 } | |
| 444 | |
| 445 if (!HONOR_NANS (mode) | |
| 446 && REAL_VALUE_ISNAN (d)) | |
| 447 { | |
| 448 val->lattice_val = UNDEFINED; | |
| 449 val->value = NULL; | |
| 450 return; | |
| 451 } | |
| 452 } | |
| 453 | |
| 454 /* Set the value for variable VAR to NEW_VAL. Return true if the new | |
| 455 value is different from VAR's previous value. */ | |
| 456 | |
| 457 static bool | |
| 458 set_lattice_value (tree var, prop_value_t new_val) | |
| 459 { | |
| 460 prop_value_t *old_val = get_value (var); | |
| 461 | |
| 462 canonicalize_float_value (&new_val); | |
| 463 | |
| 464 /* Lattice transitions must always be monotonically increasing in | |
| 465 value. If *OLD_VAL and NEW_VAL are the same, return false to | |
| 466 inform the caller that this was a non-transition. */ | |
| 467 | |
| 468 gcc_assert (old_val->lattice_val < new_val.lattice_val | |
| 469 || (old_val->lattice_val == new_val.lattice_val | |
| 470 && ((!old_val->value && !new_val.value) | |
| 471 || operand_equal_p (old_val->value, new_val.value, 0)))); | |
| 472 | |
| 473 if (old_val->lattice_val != new_val.lattice_val) | |
| 474 { | |
| 475 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 476 { | |
| 477 dump_lattice_value (dump_file, "Lattice value changed to ", new_val); | |
| 478 fprintf (dump_file, ". Adding SSA edges to worklist.\n"); | |
| 479 } | |
| 480 | |
| 481 *old_val = new_val; | |
| 482 | |
| 483 gcc_assert (new_val.lattice_val != UNDEFINED); | |
| 484 return true; | |
| 485 } | |
| 486 | |
| 487 return false; | |
| 488 } | |
| 489 | |
| 490 | |
| 491 /* Return the likely CCP lattice value for STMT. | |
| 492 | |
| 493 If STMT has no operands, then return CONSTANT. | |
| 494 | |
| 495 Else if undefinedness of operands of STMT cause its value to be | |
| 496 undefined, then return UNDEFINED. | |
| 497 | |
| 498 Else if any operands of STMT are constants, then return CONSTANT. | |
| 499 | |
| 500 Else return VARYING. */ | |
| 501 | |
| 502 static ccp_lattice_t | |
| 503 likely_value (gimple stmt) | |
| 504 { | |
| 505 bool has_constant_operand, has_undefined_operand, all_undefined_operands; | |
| 506 tree use; | |
| 507 ssa_op_iter iter; | |
| 508 | |
| 509 enum gimple_code code = gimple_code (stmt); | |
| 510 | |
| 511 /* This function appears to be called only for assignments, calls, | |
| 512 conditionals, and switches, due to the logic in visit_stmt. */ | |
| 513 gcc_assert (code == GIMPLE_ASSIGN | |
| 514 || code == GIMPLE_CALL | |
| 515 || code == GIMPLE_COND | |
| 516 || code == GIMPLE_SWITCH); | |
| 517 | |
| 518 /* If the statement has volatile operands, it won't fold to a | |
| 519 constant value. */ | |
| 520 if (gimple_has_volatile_ops (stmt)) | |
| 521 return VARYING; | |
| 522 | |
| 523 /* If we are not doing store-ccp, statements with loads | |
| 524 and/or stores will never fold into a constant. */ | |
| 525 if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) | |
| 526 return VARYING; | |
| 527 | |
| 528 /* Note that only a GIMPLE_SINGLE_RHS assignment can satisfy | |
| 529 is_gimple_min_invariant, so we do not consider calls or | |
| 530 other forms of assignment. */ | |
| 531 if (gimple_assign_single_p (stmt) | |
| 532 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt))) | |
| 533 return CONSTANT; | |
| 534 | |
| 535 if (code == GIMPLE_COND | |
| 536 && is_gimple_min_invariant (gimple_cond_lhs (stmt)) | |
| 537 && is_gimple_min_invariant (gimple_cond_rhs (stmt))) | |
| 538 return CONSTANT; | |
| 539 | |
| 540 if (code == GIMPLE_SWITCH | |
| 541 && is_gimple_min_invariant (gimple_switch_index (stmt))) | |
| 542 return CONSTANT; | |
| 543 | |
| 544 /* Arrive here for more complex cases. */ | |
| 545 | |
| 546 has_constant_operand = false; | |
| 547 has_undefined_operand = false; | |
| 548 all_undefined_operands = true; | |
| 549 FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE | SSA_OP_VUSE) | |
| 550 { | |
| 551 prop_value_t *val = get_value (use); | |
| 552 | |
| 553 if (val->lattice_val == UNDEFINED) | |
| 554 has_undefined_operand = true; | |
| 555 else | |
| 556 all_undefined_operands = false; | |
| 557 | |
| 558 if (val->lattice_val == CONSTANT) | |
| 559 has_constant_operand = true; | |
| 560 } | |
| 561 | |
| 562 /* If the operation combines operands like COMPLEX_EXPR make sure to | |
| 563 not mark the result UNDEFINED if only one part of the result is | |
| 564 undefined. */ | |
| 565 if (has_undefined_operand && all_undefined_operands) | |
| 566 return UNDEFINED; | |
| 567 else if (code == GIMPLE_ASSIGN && has_undefined_operand) | |
| 568 { | |
| 569 switch (gimple_assign_rhs_code (stmt)) | |
| 570 { | |
| 571 /* Unary operators are handled with all_undefined_operands. */ | |
| 572 case PLUS_EXPR: | |
| 573 case MINUS_EXPR: | |
| 574 case POINTER_PLUS_EXPR: | |
| 575 /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected. | |
| 576 Not bitwise operators, one VARYING operand may specify the | |
| 577 result completely. Not logical operators for the same reason. | |
| 578 Not COMPLEX_EXPR as one VARYING operand makes the result partly | |
| 579 not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because | |
| 580 the undefined operand may be promoted. */ | |
| 581 return UNDEFINED; | |
| 582 | |
| 583 default: | |
| 584 ; | |
| 585 } | |
| 586 } | |
| 587 /* If there was an UNDEFINED operand but the result may be not UNDEFINED | |
| 588 fall back to VARYING even if there were CONSTANT operands. */ | |
| 589 if (has_undefined_operand) | |
| 590 return VARYING; | |
| 591 | |
| 592 if (has_constant_operand | |
| 593 /* We do not consider virtual operands here -- load from read-only | |
| 594 memory may have only VARYING virtual operands, but still be | |
| 595 constant. */ | |
| 596 || ZERO_SSA_OPERANDS (stmt, SSA_OP_USE)) | |
| 597 return CONSTANT; | |
| 598 | |
| 599 return VARYING; | |
| 600 } | |
| 601 | |
| 602 /* Returns true if STMT cannot be constant. */ | |
| 603 | |
| 604 static bool | |
| 605 surely_varying_stmt_p (gimple stmt) | |
| 606 { | |
| 607 /* If the statement has operands that we cannot handle, it cannot be | |
| 608 constant. */ | |
| 609 if (gimple_has_volatile_ops (stmt)) | |
| 610 return true; | |
| 611 | |
| 612 if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) | |
| 613 return true; | |
| 614 | |
| 615 /* If it is a call and does not return a value or is not a | |
| 616 builtin and not an indirect call, it is varying. */ | |
| 617 if (is_gimple_call (stmt)) | |
| 618 { | |
| 619 tree fndecl; | |
| 620 if (!gimple_call_lhs (stmt) | |
| 621 || ((fndecl = gimple_call_fndecl (stmt)) != NULL_TREE | |
| 622 && !DECL_BUILT_IN (fndecl))) | |
| 623 return true; | |
| 624 } | |
| 625 | |
| 626 /* Anything other than assignments and conditional jumps are not | |
| 627 interesting for CCP. */ | |
| 628 if (gimple_code (stmt) != GIMPLE_ASSIGN | |
| 629 && gimple_code (stmt) != GIMPLE_COND | |
| 630 && gimple_code (stmt) != GIMPLE_SWITCH | |
| 631 && gimple_code (stmt) != GIMPLE_CALL) | |
| 632 return true; | |
| 633 | |
| 634 return false; | |
| 635 } | |
| 636 | |
| 637 /* Initialize local data structures for CCP. */ | |
| 638 | |
| 639 static void | |
| 640 ccp_initialize (void) | |
| 641 { | |
| 642 basic_block bb; | |
| 643 | |
| 644 const_val = XCNEWVEC (prop_value_t, num_ssa_names); | |
| 645 | |
| 646 /* Initialize simulation flags for PHI nodes and statements. */ | |
| 647 FOR_EACH_BB (bb) | |
| 648 { | |
| 649 gimple_stmt_iterator i; | |
| 650 | |
| 651 for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) | |
| 652 { | |
| 653 gimple stmt = gsi_stmt (i); | |
| 654 bool is_varying = surely_varying_stmt_p (stmt); | |
| 655 | |
| 656 if (is_varying) | |
| 657 { | |
| 658 tree def; | |
| 659 ssa_op_iter iter; | |
| 660 | |
| 661 /* If the statement will not produce a constant, mark | |
| 662 all its outputs VARYING. */ | |
| 663 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) | |
| 664 { | |
| 665 if (is_varying) | |
| 666 set_value_varying (def); | |
| 667 } | |
| 668 } | |
| 669 prop_set_simulate_again (stmt, !is_varying); | |
| 670 } | |
| 671 } | |
| 672 | |
| 673 /* Now process PHI nodes. We never clear the simulate_again flag on | |
| 674 phi nodes, since we do not know which edges are executable yet, | |
| 675 except for phi nodes for virtual operands when we do not do store ccp. */ | |
| 676 FOR_EACH_BB (bb) | |
| 677 { | |
| 678 gimple_stmt_iterator i; | |
| 679 | |
| 680 for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) | |
| 681 { | |
| 682 gimple phi = gsi_stmt (i); | |
| 683 | |
| 684 if (!is_gimple_reg (gimple_phi_result (phi))) | |
| 685 prop_set_simulate_again (phi, false); | |
| 686 else | |
| 687 prop_set_simulate_again (phi, true); | |
| 688 } | |
| 689 } | |
| 690 } | |
| 691 | |
| 692 | |
| 693 /* Do final substitution of propagated values, cleanup the flowgraph and | |
| 694 free allocated storage. | |
| 695 | |
| 696 Return TRUE when something was optimized. */ | |
| 697 | |
| 698 static bool | |
| 699 ccp_finalize (void) | |
| 700 { | |
| 701 /* Perform substitutions based on the known constant values. */ | |
| 702 bool something_changed = substitute_and_fold (const_val, false); | |
| 703 | |
| 704 free (const_val); | |
| 705 const_val = NULL; | |
| 706 return something_changed;; | |
| 707 } | |
| 708 | |
| 709 | |
| 710 /* Compute the meet operator between *VAL1 and *VAL2. Store the result | |
| 711 in VAL1. | |
| 712 | |
| 713 any M UNDEFINED = any | |
| 714 any M VARYING = VARYING | |
| 715 Ci M Cj = Ci if (i == j) | |
| 716 Ci M Cj = VARYING if (i != j) | |
| 717 */ | |
| 718 | |
| 719 static void | |
| 720 ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2) | |
| 721 { | |
| 722 if (val1->lattice_val == UNDEFINED) | |
| 723 { | |
| 724 /* UNDEFINED M any = any */ | |
| 725 *val1 = *val2; | |
| 726 } | |
| 727 else if (val2->lattice_val == UNDEFINED) | |
| 728 { | |
| 729 /* any M UNDEFINED = any | |
| 730 Nothing to do. VAL1 already contains the value we want. */ | |
| 731 ; | |
| 732 } | |
| 733 else if (val1->lattice_val == VARYING | |
| 734 || val2->lattice_val == VARYING) | |
| 735 { | |
| 736 /* any M VARYING = VARYING. */ | |
| 737 val1->lattice_val = VARYING; | |
| 738 val1->value = NULL_TREE; | |
| 739 } | |
| 740 else if (val1->lattice_val == CONSTANT | |
| 741 && val2->lattice_val == CONSTANT | |
| 742 && simple_cst_equal (val1->value, val2->value) == 1) | |
| 743 { | |
| 744 /* Ci M Cj = Ci if (i == j) | |
| 745 Ci M Cj = VARYING if (i != j) | |
| 746 | |
| 747 If these two values come from memory stores, make sure that | |
| 748 they come from the same memory reference. */ | |
| 749 val1->lattice_val = CONSTANT; | |
| 750 val1->value = val1->value; | |
| 751 } | |
| 752 else | |
| 753 { | |
| 754 /* Any other combination is VARYING. */ | |
| 755 val1->lattice_val = VARYING; | |
| 756 val1->value = NULL_TREE; | |
| 757 } | |
| 758 } | |
| 759 | |
| 760 | |
| 761 /* Loop through the PHI_NODE's parameters for BLOCK and compare their | |
| 762 lattice values to determine PHI_NODE's lattice value. The value of a | |
| 763 PHI node is determined calling ccp_lattice_meet with all the arguments | |
| 764 of the PHI node that are incoming via executable edges. */ | |
| 765 | |
| 766 static enum ssa_prop_result | |
| 767 ccp_visit_phi_node (gimple phi) | |
| 768 { | |
| 769 unsigned i; | |
| 770 prop_value_t *old_val, new_val; | |
| 771 | |
| 772 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 773 { | |
| 774 fprintf (dump_file, "\nVisiting PHI node: "); | |
| 775 print_gimple_stmt (dump_file, phi, 0, dump_flags); | |
| 776 } | |
| 777 | |
| 778 old_val = get_value (gimple_phi_result (phi)); | |
| 779 switch (old_val->lattice_val) | |
| 780 { | |
| 781 case VARYING: | |
| 782 return SSA_PROP_VARYING; | |
| 783 | |
| 784 case CONSTANT: | |
| 785 new_val = *old_val; | |
| 786 break; | |
| 787 | |
| 788 case UNDEFINED: | |
| 789 new_val.lattice_val = UNDEFINED; | |
| 790 new_val.value = NULL_TREE; | |
| 791 break; | |
| 792 | |
| 793 default: | |
| 794 gcc_unreachable (); | |
| 795 } | |
| 796 | |
| 797 for (i = 0; i < gimple_phi_num_args (phi); i++) | |
| 798 { | |
| 799 /* Compute the meet operator over all the PHI arguments flowing | |
| 800 through executable edges. */ | |
| 801 edge e = gimple_phi_arg_edge (phi, i); | |
| 802 | |
| 803 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 804 { | |
| 805 fprintf (dump_file, | |
| 806 "\n Argument #%d (%d -> %d %sexecutable)\n", | |
| 807 i, e->src->index, e->dest->index, | |
| 808 (e->flags & EDGE_EXECUTABLE) ? "" : "not "); | |
| 809 } | |
| 810 | |
| 811 /* If the incoming edge is executable, Compute the meet operator for | |
| 812 the existing value of the PHI node and the current PHI argument. */ | |
| 813 if (e->flags & EDGE_EXECUTABLE) | |
| 814 { | |
| 815 tree arg = gimple_phi_arg (phi, i)->def; | |
| 816 prop_value_t arg_val; | |
| 817 | |
| 818 if (is_gimple_min_invariant (arg)) | |
| 819 { | |
| 820 arg_val.lattice_val = CONSTANT; | |
| 821 arg_val.value = arg; | |
| 822 } | |
| 823 else | |
| 824 arg_val = *(get_value (arg)); | |
| 825 | |
| 826 ccp_lattice_meet (&new_val, &arg_val); | |
| 827 | |
| 828 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 829 { | |
| 830 fprintf (dump_file, "\t"); | |
| 831 print_generic_expr (dump_file, arg, dump_flags); | |
| 832 dump_lattice_value (dump_file, "\tValue: ", arg_val); | |
| 833 fprintf (dump_file, "\n"); | |
| 834 } | |
| 835 | |
| 836 if (new_val.lattice_val == VARYING) | |
| 837 break; | |
| 838 } | |
| 839 } | |
| 840 | |
| 841 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 842 { | |
| 843 dump_lattice_value (dump_file, "\n PHI node value: ", new_val); | |
| 844 fprintf (dump_file, "\n\n"); | |
| 845 } | |
| 846 | |
| 847 /* Make the transition to the new value. */ | |
| 848 if (set_lattice_value (gimple_phi_result (phi), new_val)) | |
| 849 { | |
| 850 if (new_val.lattice_val == VARYING) | |
| 851 return SSA_PROP_VARYING; | |
| 852 else | |
| 853 return SSA_PROP_INTERESTING; | |
| 854 } | |
| 855 else | |
| 856 return SSA_PROP_NOT_INTERESTING; | |
| 857 } | |
| 858 | |
| 859 /* Return true if we may propagate the address expression ADDR into the | |
| 860 dereference DEREF and cancel them. */ | |
| 861 | |
| 862 bool | |
| 863 may_propagate_address_into_dereference (tree addr, tree deref) | |
| 864 { | |
| 865 gcc_assert (INDIRECT_REF_P (deref) | |
| 866 && TREE_CODE (addr) == ADDR_EXPR); | |
| 867 | |
| 868 /* Don't propagate if ADDR's operand has incomplete type. */ | |
| 869 if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_OPERAND (addr, 0)))) | |
| 870 return false; | |
| 871 | |
| 872 /* If the address is invariant then we do not need to preserve restrict | |
| 873 qualifications. But we do need to preserve volatile qualifiers until | |
| 874 we can annotate the folded dereference itself properly. */ | |
| 875 if (is_gimple_min_invariant (addr) | |
| 876 && (!TREE_THIS_VOLATILE (deref) | |
| 877 || TYPE_VOLATILE (TREE_TYPE (addr)))) | |
| 878 return useless_type_conversion_p (TREE_TYPE (deref), | |
| 879 TREE_TYPE (TREE_OPERAND (addr, 0))); | |
| 880 | |
| 881 /* Else both the address substitution and the folding must result in | |
| 882 a valid useless type conversion sequence. */ | |
| 883 return (useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (deref, 0)), | |
| 884 TREE_TYPE (addr)) | |
| 885 && useless_type_conversion_p (TREE_TYPE (deref), | |
| 886 TREE_TYPE (TREE_OPERAND (addr, 0)))); | |
| 887 } | |
| 888 | |
| 889 /* CCP specific front-end to the non-destructive constant folding | |
| 890 routines. | |
| 891 | |
| 892 Attempt to simplify the RHS of STMT knowing that one or more | |
| 893 operands are constants. | |
| 894 | |
| 895 If simplification is possible, return the simplified RHS, | |
| 896 otherwise return the original RHS or NULL_TREE. */ | |
| 897 | |
| 898 static tree | |
| 899 ccp_fold (gimple stmt) | |
| 900 { | |
| 901 switch (gimple_code (stmt)) | |
| 902 { | |
| 903 case GIMPLE_ASSIGN: | |
| 904 { | |
| 905 enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
| 906 | |
| 907 switch (get_gimple_rhs_class (subcode)) | |
| 908 { | |
| 909 case GIMPLE_SINGLE_RHS: | |
| 910 { | |
| 911 tree rhs = gimple_assign_rhs1 (stmt); | |
| 912 enum tree_code_class kind = TREE_CODE_CLASS (subcode); | |
| 913 | |
| 914 if (TREE_CODE (rhs) == SSA_NAME) | |
| 915 { | |
| 916 /* If the RHS is an SSA_NAME, return its known constant value, | |
| 917 if any. */ | |
| 918 return get_value (rhs)->value; | |
| 919 } | |
| 920 /* Handle propagating invariant addresses into address operations. | |
| 921 The folding we do here matches that in tree-ssa-forwprop.c. */ | |
| 922 else if (TREE_CODE (rhs) == ADDR_EXPR) | |
| 923 { | |
| 924 tree *base; | |
| 925 base = &TREE_OPERAND (rhs, 0); | |
| 926 while (handled_component_p (*base)) | |
| 927 base = &TREE_OPERAND (*base, 0); | |
| 928 if (TREE_CODE (*base) == INDIRECT_REF | |
| 929 && TREE_CODE (TREE_OPERAND (*base, 0)) == SSA_NAME) | |
| 930 { | |
| 931 prop_value_t *val = get_value (TREE_OPERAND (*base, 0)); | |
| 932 if (val->lattice_val == CONSTANT | |
| 933 && TREE_CODE (val->value) == ADDR_EXPR | |
| 934 && may_propagate_address_into_dereference | |
| 935 (val->value, *base)) | |
| 936 { | |
| 937 /* We need to return a new tree, not modify the IL | |
| 938 or share parts of it. So play some tricks to | |
| 939 avoid manually building it. */ | |
| 940 tree ret, save = *base; | |
| 941 *base = TREE_OPERAND (val->value, 0); | |
| 942 ret = unshare_expr (rhs); | |
| 943 recompute_tree_invariant_for_addr_expr (ret); | |
| 944 *base = save; | |
| 945 return ret; | |
| 946 } | |
| 947 } | |
| 948 } | |
| 949 | |
| 950 if (kind == tcc_reference) | |
| 951 { | |
| 952 if (TREE_CODE (rhs) == VIEW_CONVERT_EXPR | |
| 953 && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME) | |
| 954 { | |
| 955 prop_value_t *val = get_value (TREE_OPERAND (rhs, 0)); | |
| 956 if (val->lattice_val == CONSTANT) | |
| 957 return fold_unary (VIEW_CONVERT_EXPR, | |
| 958 TREE_TYPE (rhs), val->value); | |
| 959 } | |
| 960 return fold_const_aggregate_ref (rhs); | |
| 961 } | |
| 962 else if (kind == tcc_declaration) | |
| 963 return get_symbol_constant_value (rhs); | |
| 964 return rhs; | |
| 965 } | |
| 966 | |
| 967 case GIMPLE_UNARY_RHS: | |
| 968 { | |
| 969 /* Handle unary operators that can appear in GIMPLE form. | |
| 970 Note that we know the single operand must be a constant, | |
| 971 so this should almost always return a simplified RHS. */ | |
| 972 tree lhs = gimple_assign_lhs (stmt); | |
| 973 tree op0 = gimple_assign_rhs1 (stmt); | |
| 974 | |
| 975 /* Simplify the operand down to a constant. */ | |
| 976 if (TREE_CODE (op0) == SSA_NAME) | |
| 977 { | |
| 978 prop_value_t *val = get_value (op0); | |
| 979 if (val->lattice_val == CONSTANT) | |
| 980 op0 = get_value (op0)->value; | |
| 981 } | |
| 982 | |
| 983 /* Conversions are useless for CCP purposes if they are | |
| 984 value-preserving. Thus the restrictions that | |
| 985 useless_type_conversion_p places for pointer type conversions | |
| 986 do not apply here. Substitution later will only substitute to | |
| 987 allowed places. */ | |
| 988 if (CONVERT_EXPR_CODE_P (subcode) | |
| 989 && POINTER_TYPE_P (TREE_TYPE (lhs)) | |
| 990 && POINTER_TYPE_P (TREE_TYPE (op0)) | |
| 991 /* Do not allow differences in volatile qualification | |
| 992 as this might get us confused as to whether a | |
| 993 propagation destination statement is volatile | |
| 994 or not. See PR36988. */ | |
| 995 && (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (lhs))) | |
| 996 == TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (op0))))) | |
| 997 { | |
| 998 tree tem; | |
| 999 /* Still try to generate a constant of correct type. */ | |
| 1000 if (!useless_type_conversion_p (TREE_TYPE (lhs), | |
| 1001 TREE_TYPE (op0)) | |
| 1002 && ((tem = maybe_fold_offset_to_address | |
| 1003 (op0, integer_zero_node, TREE_TYPE (lhs))) | |
| 1004 != NULL_TREE)) | |
| 1005 return tem; | |
| 1006 return op0; | |
| 1007 } | |
| 1008 | |
| 1009 return fold_unary_ignore_overflow (subcode, | |
| 1010 gimple_expr_type (stmt), op0); | |
| 1011 } | |
| 1012 | |
| 1013 case GIMPLE_BINARY_RHS: | |
| 1014 { | |
| 1015 /* Handle binary operators that can appear in GIMPLE form. */ | |
| 1016 tree op0 = gimple_assign_rhs1 (stmt); | |
| 1017 tree op1 = gimple_assign_rhs2 (stmt); | |
| 1018 | |
| 1019 /* Simplify the operands down to constants when appropriate. */ | |
| 1020 if (TREE_CODE (op0) == SSA_NAME) | |
| 1021 { | |
| 1022 prop_value_t *val = get_value (op0); | |
| 1023 if (val->lattice_val == CONSTANT) | |
| 1024 op0 = val->value; | |
| 1025 } | |
| 1026 | |
| 1027 if (TREE_CODE (op1) == SSA_NAME) | |
| 1028 { | |
| 1029 prop_value_t *val = get_value (op1); | |
| 1030 if (val->lattice_val == CONSTANT) | |
| 1031 op1 = val->value; | |
| 1032 } | |
| 1033 | |
| 1034 /* Fold &foo + CST into an invariant reference if possible. */ | |
| 1035 if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR | |
| 1036 && TREE_CODE (op0) == ADDR_EXPR | |
| 1037 && TREE_CODE (op1) == INTEGER_CST) | |
| 1038 { | |
| 1039 tree lhs = gimple_assign_lhs (stmt); | |
| 1040 tree tem = maybe_fold_offset_to_address (op0, op1, | |
| 1041 TREE_TYPE (lhs)); | |
| 1042 if (tem != NULL_TREE) | |
| 1043 return tem; | |
| 1044 } | |
| 1045 | |
| 1046 return fold_binary (subcode, gimple_expr_type (stmt), op0, op1); | |
| 1047 } | |
| 1048 | |
| 1049 default: | |
| 1050 gcc_unreachable (); | |
| 1051 } | |
| 1052 } | |
| 1053 break; | |
| 1054 | |
| 1055 case GIMPLE_CALL: | |
| 1056 { | |
| 1057 tree fn = gimple_call_fn (stmt); | |
| 1058 prop_value_t *val; | |
| 1059 | |
| 1060 if (TREE_CODE (fn) == SSA_NAME) | |
| 1061 { | |
| 1062 val = get_value (fn); | |
| 1063 if (val->lattice_val == CONSTANT) | |
| 1064 fn = val->value; | |
| 1065 } | |
| 1066 if (TREE_CODE (fn) == ADDR_EXPR | |
| 1067 && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL | |
| 1068 && DECL_BUILT_IN (TREE_OPERAND (fn, 0))) | |
| 1069 { | |
| 1070 tree *args = XALLOCAVEC (tree, gimple_call_num_args (stmt)); | |
| 1071 tree call, retval; | |
| 1072 unsigned i; | |
| 1073 for (i = 0; i < gimple_call_num_args (stmt); ++i) | |
| 1074 { | |
| 1075 args[i] = gimple_call_arg (stmt, i); | |
| 1076 if (TREE_CODE (args[i]) == SSA_NAME) | |
| 1077 { | |
| 1078 val = get_value (args[i]); | |
| 1079 if (val->lattice_val == CONSTANT) | |
| 1080 args[i] = val->value; | |
| 1081 } | |
| 1082 } | |
| 1083 call = build_call_array (gimple_call_return_type (stmt), | |
| 1084 fn, gimple_call_num_args (stmt), args); | |
| 1085 retval = fold_call_expr (call, false); | |
| 1086 if (retval) | |
| 1087 /* fold_call_expr wraps the result inside a NOP_EXPR. */ | |
| 1088 STRIP_NOPS (retval); | |
| 1089 return retval; | |
| 1090 } | |
| 1091 return NULL_TREE; | |
| 1092 } | |
| 1093 | |
| 1094 case GIMPLE_COND: | |
| 1095 { | |
| 1096 /* Handle comparison operators that can appear in GIMPLE form. */ | |
| 1097 tree op0 = gimple_cond_lhs (stmt); | |
| 1098 tree op1 = gimple_cond_rhs (stmt); | |
| 1099 enum tree_code code = gimple_cond_code (stmt); | |
| 1100 | |
| 1101 /* Simplify the operands down to constants when appropriate. */ | |
| 1102 if (TREE_CODE (op0) == SSA_NAME) | |
| 1103 { | |
| 1104 prop_value_t *val = get_value (op0); | |
| 1105 if (val->lattice_val == CONSTANT) | |
| 1106 op0 = val->value; | |
| 1107 } | |
| 1108 | |
| 1109 if (TREE_CODE (op1) == SSA_NAME) | |
| 1110 { | |
| 1111 prop_value_t *val = get_value (op1); | |
| 1112 if (val->lattice_val == CONSTANT) | |
| 1113 op1 = val->value; | |
| 1114 } | |
| 1115 | |
| 1116 return fold_binary (code, boolean_type_node, op0, op1); | |
| 1117 } | |
| 1118 | |
| 1119 case GIMPLE_SWITCH: | |
| 1120 { | |
| 1121 tree rhs = gimple_switch_index (stmt); | |
| 1122 | |
| 1123 if (TREE_CODE (rhs) == SSA_NAME) | |
| 1124 { | |
| 1125 /* If the RHS is an SSA_NAME, return its known constant value, | |
| 1126 if any. */ | |
| 1127 return get_value (rhs)->value; | |
| 1128 } | |
| 1129 | |
| 1130 return rhs; | |
| 1131 } | |
| 1132 | |
| 1133 default: | |
| 1134 gcc_unreachable (); | |
| 1135 } | |
| 1136 } | |
| 1137 | |
| 1138 | |
| 1139 /* Return the tree representing the element referenced by T if T is an | |
| 1140 ARRAY_REF or COMPONENT_REF into constant aggregates. Return | |
| 1141 NULL_TREE otherwise. */ | |
| 1142 | |
| 1143 tree | |
| 1144 fold_const_aggregate_ref (tree t) | |
| 1145 { | |
| 1146 prop_value_t *value; | |
| 1147 tree base, ctor, idx, field; | |
| 1148 unsigned HOST_WIDE_INT cnt; | |
| 1149 tree cfield, cval; | |
| 1150 | |
| 1151 switch (TREE_CODE (t)) | |
| 1152 { | |
| 1153 case ARRAY_REF: | |
| 1154 /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
| 1155 DECL_INITIAL. If BASE is a nested reference into another | |
| 1156 ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
| 1157 the inner reference. */ | |
| 1158 base = TREE_OPERAND (t, 0); | |
| 1159 switch (TREE_CODE (base)) | |
| 1160 { | |
| 1161 case VAR_DECL: | |
| 1162 if (!TREE_READONLY (base) | |
| 1163 || TREE_CODE (TREE_TYPE (base)) != ARRAY_TYPE | |
| 1164 || !targetm.binds_local_p (base)) | |
| 1165 return NULL_TREE; | |
| 1166 | |
| 1167 ctor = DECL_INITIAL (base); | |
| 1168 break; | |
| 1169 | |
| 1170 case ARRAY_REF: | |
| 1171 case COMPONENT_REF: | |
| 1172 ctor = fold_const_aggregate_ref (base); | |
| 1173 break; | |
| 1174 | |
| 1175 case STRING_CST: | |
| 1176 case CONSTRUCTOR: | |
| 1177 ctor = base; | |
| 1178 break; | |
| 1179 | |
| 1180 default: | |
| 1181 return NULL_TREE; | |
| 1182 } | |
| 1183 | |
| 1184 if (ctor == NULL_TREE | |
| 1185 || (TREE_CODE (ctor) != CONSTRUCTOR | |
| 1186 && TREE_CODE (ctor) != STRING_CST) | |
| 1187 || !TREE_STATIC (ctor)) | |
| 1188 return NULL_TREE; | |
| 1189 | |
| 1190 /* Get the index. If we have an SSA_NAME, try to resolve it | |
| 1191 with the current lattice value for the SSA_NAME. */ | |
| 1192 idx = TREE_OPERAND (t, 1); | |
| 1193 switch (TREE_CODE (idx)) | |
| 1194 { | |
| 1195 case SSA_NAME: | |
| 1196 if ((value = get_value (idx)) | |
| 1197 && value->lattice_val == CONSTANT | |
| 1198 && TREE_CODE (value->value) == INTEGER_CST) | |
| 1199 idx = value->value; | |
| 1200 else | |
| 1201 return NULL_TREE; | |
| 1202 break; | |
| 1203 | |
| 1204 case INTEGER_CST: | |
| 1205 break; | |
| 1206 | |
| 1207 default: | |
| 1208 return NULL_TREE; | |
| 1209 } | |
| 1210 | |
| 1211 /* Fold read from constant string. */ | |
| 1212 if (TREE_CODE (ctor) == STRING_CST) | |
| 1213 { | |
| 1214 if ((TYPE_MODE (TREE_TYPE (t)) | |
| 1215 == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
| 1216 && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) | |
| 1217 == MODE_INT) | |
| 1218 && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1 | |
| 1219 && compare_tree_int (idx, TREE_STRING_LENGTH (ctor)) < 0) | |
| 1220 return build_int_cst_type (TREE_TYPE (t), | |
| 1221 (TREE_STRING_POINTER (ctor) | |
| 1222 [TREE_INT_CST_LOW (idx)])); | |
| 1223 return NULL_TREE; | |
| 1224 } | |
| 1225 | |
| 1226 /* Whoo-hoo! I'll fold ya baby. Yeah! */ | |
| 1227 FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) | |
| 1228 if (tree_int_cst_equal (cfield, idx)) | |
| 1229 { | |
| 1230 STRIP_USELESS_TYPE_CONVERSION (cval); | |
| 1231 return cval; | |
| 1232 } | |
| 1233 break; | |
| 1234 | |
| 1235 case COMPONENT_REF: | |
| 1236 /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its | |
| 1237 DECL_INITIAL. If BASE is a nested reference into another | |
| 1238 ARRAY_REF or COMPONENT_REF, make a recursive call to resolve | |
| 1239 the inner reference. */ | |
| 1240 base = TREE_OPERAND (t, 0); | |
| 1241 switch (TREE_CODE (base)) | |
| 1242 { | |
| 1243 case VAR_DECL: | |
| 1244 if (!TREE_READONLY (base) | |
| 1245 || TREE_CODE (TREE_TYPE (base)) != RECORD_TYPE | |
| 1246 || !targetm.binds_local_p (base)) | |
| 1247 return NULL_TREE; | |
| 1248 | |
| 1249 ctor = DECL_INITIAL (base); | |
| 1250 break; | |
| 1251 | |
| 1252 case ARRAY_REF: | |
| 1253 case COMPONENT_REF: | |
| 1254 ctor = fold_const_aggregate_ref (base); | |
| 1255 break; | |
| 1256 | |
| 1257 default: | |
| 1258 return NULL_TREE; | |
| 1259 } | |
| 1260 | |
| 1261 if (ctor == NULL_TREE | |
| 1262 || TREE_CODE (ctor) != CONSTRUCTOR | |
| 1263 || !TREE_STATIC (ctor)) | |
| 1264 return NULL_TREE; | |
| 1265 | |
| 1266 field = TREE_OPERAND (t, 1); | |
| 1267 | |
| 1268 FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval) | |
| 1269 if (cfield == field | |
| 1270 /* FIXME: Handle bit-fields. */ | |
| 1271 && ! DECL_BIT_FIELD (cfield)) | |
| 1272 { | |
| 1273 STRIP_USELESS_TYPE_CONVERSION (cval); | |
| 1274 return cval; | |
| 1275 } | |
| 1276 break; | |
| 1277 | |
| 1278 case REALPART_EXPR: | |
| 1279 case IMAGPART_EXPR: | |
| 1280 { | |
| 1281 tree c = fold_const_aggregate_ref (TREE_OPERAND (t, 0)); | |
| 1282 if (c && TREE_CODE (c) == COMPLEX_CST) | |
| 1283 return fold_build1 (TREE_CODE (t), TREE_TYPE (t), c); | |
| 1284 break; | |
| 1285 } | |
| 1286 | |
| 1287 case INDIRECT_REF: | |
| 1288 { | |
| 1289 tree base = TREE_OPERAND (t, 0); | |
| 1290 if (TREE_CODE (base) == SSA_NAME | |
| 1291 && (value = get_value (base)) | |
| 1292 && value->lattice_val == CONSTANT | |
|
19
58ad6c70ea60
update gcc from 4.4.0 to 4.4.1.
kent@firefly.cr.ie.u-ryukyu.ac.jp
parents:
0
diff
changeset
|
1293 && TREE_CODE (value->value) == ADDR_EXPR |
|
58ad6c70ea60
update gcc from 4.4.0 to 4.4.1.
kent@firefly.cr.ie.u-ryukyu.ac.jp
parents:
0
diff
changeset
|
1294 && useless_type_conversion_p (TREE_TYPE (t), |
|
58ad6c70ea60
update gcc from 4.4.0 to 4.4.1.
kent@firefly.cr.ie.u-ryukyu.ac.jp
parents:
0
diff
changeset
|
1295 TREE_TYPE (TREE_TYPE (value->value)))) |
| 0 | 1296 return fold_const_aggregate_ref (TREE_OPERAND (value->value, 0)); |
| 1297 break; | |
| 1298 } | |
| 1299 | |
| 1300 default: | |
| 1301 break; | |
| 1302 } | |
| 1303 | |
| 1304 return NULL_TREE; | |
| 1305 } | |
| 1306 | |
| 1307 /* Evaluate statement STMT. | |
| 1308 Valid only for assignments, calls, conditionals, and switches. */ | |
| 1309 | |
| 1310 static prop_value_t | |
| 1311 evaluate_stmt (gimple stmt) | |
| 1312 { | |
| 1313 prop_value_t val; | |
| 1314 tree simplified = NULL_TREE; | |
| 1315 ccp_lattice_t likelyvalue = likely_value (stmt); | |
| 1316 bool is_constant; | |
| 1317 | |
| 1318 fold_defer_overflow_warnings (); | |
| 1319 | |
| 1320 /* If the statement is likely to have a CONSTANT result, then try | |
| 1321 to fold the statement to determine the constant value. */ | |
| 1322 /* FIXME. This is the only place that we call ccp_fold. | |
| 1323 Since likely_value never returns CONSTANT for calls, we will | |
| 1324 not attempt to fold them, including builtins that may profit. */ | |
| 1325 if (likelyvalue == CONSTANT) | |
| 1326 simplified = ccp_fold (stmt); | |
| 1327 /* If the statement is likely to have a VARYING result, then do not | |
| 1328 bother folding the statement. */ | |
| 1329 else if (likelyvalue == VARYING) | |
| 1330 { | |
| 1331 enum gimple_code code = gimple_code (stmt); | |
| 1332 if (code == GIMPLE_ASSIGN) | |
| 1333 { | |
| 1334 enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
| 1335 | |
| 1336 /* Other cases cannot satisfy is_gimple_min_invariant | |
| 1337 without folding. */ | |
| 1338 if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS) | |
| 1339 simplified = gimple_assign_rhs1 (stmt); | |
| 1340 } | |
| 1341 else if (code == GIMPLE_SWITCH) | |
| 1342 simplified = gimple_switch_index (stmt); | |
| 1343 else | |
| 1344 /* These cannot satisfy is_gimple_min_invariant without folding. */ | |
| 1345 gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND); | |
| 1346 } | |
| 1347 | |
| 1348 is_constant = simplified && is_gimple_min_invariant (simplified); | |
| 1349 | |
| 1350 fold_undefer_overflow_warnings (is_constant, stmt, 0); | |
| 1351 | |
| 1352 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1353 { | |
| 1354 fprintf (dump_file, "which is likely "); | |
| 1355 switch (likelyvalue) | |
| 1356 { | |
| 1357 case CONSTANT: | |
| 1358 fprintf (dump_file, "CONSTANT"); | |
| 1359 break; | |
| 1360 case UNDEFINED: | |
| 1361 fprintf (dump_file, "UNDEFINED"); | |
| 1362 break; | |
| 1363 case VARYING: | |
| 1364 fprintf (dump_file, "VARYING"); | |
| 1365 break; | |
| 1366 default:; | |
| 1367 } | |
| 1368 fprintf (dump_file, "\n"); | |
| 1369 } | |
| 1370 | |
| 1371 if (is_constant) | |
| 1372 { | |
| 1373 /* The statement produced a constant value. */ | |
| 1374 val.lattice_val = CONSTANT; | |
| 1375 val.value = simplified; | |
| 1376 } | |
| 1377 else | |
| 1378 { | |
| 1379 /* The statement produced a nonconstant value. If the statement | |
| 1380 had UNDEFINED operands, then the result of the statement | |
| 1381 should be UNDEFINED. Otherwise, the statement is VARYING. */ | |
| 1382 if (likelyvalue == UNDEFINED) | |
| 1383 val.lattice_val = likelyvalue; | |
| 1384 else | |
| 1385 val.lattice_val = VARYING; | |
| 1386 | |
| 1387 val.value = NULL_TREE; | |
| 1388 } | |
| 1389 | |
| 1390 return val; | |
| 1391 } | |
| 1392 | |
| 1393 /* Visit the assignment statement STMT. Set the value of its LHS to the | |
| 1394 value computed by the RHS and store LHS in *OUTPUT_P. If STMT | |
| 1395 creates virtual definitions, set the value of each new name to that | |
| 1396 of the RHS (if we can derive a constant out of the RHS). | |
| 1397 Value-returning call statements also perform an assignment, and | |
| 1398 are handled here. */ | |
| 1399 | |
| 1400 static enum ssa_prop_result | |
| 1401 visit_assignment (gimple stmt, tree *output_p) | |
| 1402 { | |
| 1403 prop_value_t val; | |
| 1404 enum ssa_prop_result retval; | |
| 1405 | |
| 1406 tree lhs = gimple_get_lhs (stmt); | |
| 1407 | |
| 1408 gcc_assert (gimple_code (stmt) != GIMPLE_CALL | |
| 1409 || gimple_call_lhs (stmt) != NULL_TREE); | |
| 1410 | |
| 1411 if (gimple_assign_copy_p (stmt)) | |
| 1412 { | |
| 1413 tree rhs = gimple_assign_rhs1 (stmt); | |
| 1414 | |
| 1415 if (TREE_CODE (rhs) == SSA_NAME) | |
| 1416 { | |
| 1417 /* For a simple copy operation, we copy the lattice values. */ | |
| 1418 prop_value_t *nval = get_value (rhs); | |
| 1419 val = *nval; | |
| 1420 } | |
| 1421 else | |
| 1422 val = evaluate_stmt (stmt); | |
| 1423 } | |
| 1424 else | |
| 1425 /* Evaluate the statement, which could be | |
| 1426 either a GIMPLE_ASSIGN or a GIMPLE_CALL. */ | |
| 1427 val = evaluate_stmt (stmt); | |
| 1428 | |
| 1429 retval = SSA_PROP_NOT_INTERESTING; | |
| 1430 | |
| 1431 /* Set the lattice value of the statement's output. */ | |
| 1432 if (TREE_CODE (lhs) == SSA_NAME) | |
| 1433 { | |
| 1434 /* If STMT is an assignment to an SSA_NAME, we only have one | |
| 1435 value to set. */ | |
| 1436 if (set_lattice_value (lhs, val)) | |
| 1437 { | |
| 1438 *output_p = lhs; | |
| 1439 if (val.lattice_val == VARYING) | |
| 1440 retval = SSA_PROP_VARYING; | |
| 1441 else | |
| 1442 retval = SSA_PROP_INTERESTING; | |
| 1443 } | |
| 1444 } | |
| 1445 | |
| 1446 return retval; | |
| 1447 } | |
| 1448 | |
| 1449 | |
| 1450 /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING | |
| 1451 if it can determine which edge will be taken. Otherwise, return | |
| 1452 SSA_PROP_VARYING. */ | |
| 1453 | |
| 1454 static enum ssa_prop_result | |
| 1455 visit_cond_stmt (gimple stmt, edge *taken_edge_p) | |
| 1456 { | |
| 1457 prop_value_t val; | |
| 1458 basic_block block; | |
| 1459 | |
| 1460 block = gimple_bb (stmt); | |
| 1461 val = evaluate_stmt (stmt); | |
| 1462 | |
| 1463 /* Find which edge out of the conditional block will be taken and add it | |
| 1464 to the worklist. If no single edge can be determined statically, | |
| 1465 return SSA_PROP_VARYING to feed all the outgoing edges to the | |
| 1466 propagation engine. */ | |
| 1467 *taken_edge_p = val.value ? find_taken_edge (block, val.value) : 0; | |
| 1468 if (*taken_edge_p) | |
| 1469 return SSA_PROP_INTERESTING; | |
| 1470 else | |
| 1471 return SSA_PROP_VARYING; | |
| 1472 } | |
| 1473 | |
| 1474 | |
| 1475 /* Evaluate statement STMT. If the statement produces an output value and | |
| 1476 its evaluation changes the lattice value of its output, return | |
| 1477 SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the | |
| 1478 output value. | |
| 1479 | |
| 1480 If STMT is a conditional branch and we can determine its truth | |
| 1481 value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying | |
| 1482 value, return SSA_PROP_VARYING. */ | |
| 1483 | |
| 1484 static enum ssa_prop_result | |
| 1485 ccp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p) | |
| 1486 { | |
| 1487 tree def; | |
| 1488 ssa_op_iter iter; | |
| 1489 | |
| 1490 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1491 { | |
| 1492 fprintf (dump_file, "\nVisiting statement:\n"); | |
| 1493 print_gimple_stmt (dump_file, stmt, 0, dump_flags); | |
| 1494 } | |
| 1495 | |
| 1496 switch (gimple_code (stmt)) | |
| 1497 { | |
| 1498 case GIMPLE_ASSIGN: | |
| 1499 /* If the statement is an assignment that produces a single | |
| 1500 output value, evaluate its RHS to see if the lattice value of | |
| 1501 its output has changed. */ | |
| 1502 return visit_assignment (stmt, output_p); | |
| 1503 | |
| 1504 case GIMPLE_CALL: | |
| 1505 /* A value-returning call also performs an assignment. */ | |
| 1506 if (gimple_call_lhs (stmt) != NULL_TREE) | |
| 1507 return visit_assignment (stmt, output_p); | |
| 1508 break; | |
| 1509 | |
| 1510 case GIMPLE_COND: | |
| 1511 case GIMPLE_SWITCH: | |
| 1512 /* If STMT is a conditional branch, see if we can determine | |
| 1513 which branch will be taken. */ | |
| 1514 /* FIXME. It appears that we should be able to optimize | |
| 1515 computed GOTOs here as well. */ | |
| 1516 return visit_cond_stmt (stmt, taken_edge_p); | |
| 1517 | |
| 1518 default: | |
| 1519 break; | |
| 1520 } | |
| 1521 | |
| 1522 /* Any other kind of statement is not interesting for constant | |
| 1523 propagation and, therefore, not worth simulating. */ | |
| 1524 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1525 fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); | |
| 1526 | |
| 1527 /* Definitions made by statements other than assignments to | |
| 1528 SSA_NAMEs represent unknown modifications to their outputs. | |
| 1529 Mark them VARYING. */ | |
| 1530 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) | |
| 1531 { | |
| 1532 prop_value_t v = { VARYING, NULL_TREE }; | |
| 1533 set_lattice_value (def, v); | |
| 1534 } | |
| 1535 | |
| 1536 return SSA_PROP_VARYING; | |
| 1537 } | |
| 1538 | |
| 1539 | |
| 1540 /* Main entry point for SSA Conditional Constant Propagation. */ | |
| 1541 | |
| 1542 static unsigned int | |
| 1543 do_ssa_ccp (void) | |
| 1544 { | |
| 1545 ccp_initialize (); | |
| 1546 ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); | |
| 1547 if (ccp_finalize ()) | |
| 1548 return (TODO_cleanup_cfg | TODO_update_ssa | TODO_remove_unused_locals); | |
| 1549 else | |
| 1550 return 0; | |
| 1551 } | |
| 1552 | |
| 1553 | |
| 1554 static bool | |
| 1555 gate_ccp (void) | |
| 1556 { | |
| 1557 return flag_tree_ccp != 0; | |
| 1558 } | |
| 1559 | |
| 1560 | |
| 1561 struct gimple_opt_pass pass_ccp = | |
| 1562 { | |
| 1563 { | |
| 1564 GIMPLE_PASS, | |
| 1565 "ccp", /* name */ | |
| 1566 gate_ccp, /* gate */ | |
| 1567 do_ssa_ccp, /* execute */ | |
| 1568 NULL, /* sub */ | |
| 1569 NULL, /* next */ | |
| 1570 0, /* static_pass_number */ | |
| 1571 TV_TREE_CCP, /* tv_id */ | |
| 1572 PROP_cfg | PROP_ssa, /* properties_required */ | |
| 1573 0, /* properties_provided */ | |
| 1574 0, /* properties_destroyed */ | |
| 1575 0, /* todo_flags_start */ | |
| 1576 TODO_dump_func | TODO_verify_ssa | |
| 1577 | TODO_verify_stmts | TODO_ggc_collect/* todo_flags_finish */ | |
| 1578 } | |
| 1579 }; | |
| 1580 | |
| 1581 | |
| 1582 /* A subroutine of fold_stmt_r. Attempts to fold *(A+O) to A[X]. | |
| 1583 BASE is an array type. OFFSET is a byte displacement. ORIG_TYPE | |
| 1584 is the desired result type. */ | |
| 1585 | |
| 1586 static tree | |
| 1587 maybe_fold_offset_to_array_ref (tree base, tree offset, tree orig_type, | |
| 1588 bool allow_negative_idx) | |
| 1589 { | |
| 1590 tree min_idx, idx, idx_type, elt_offset = integer_zero_node; | |
| 1591 tree array_type, elt_type, elt_size; | |
| 1592 tree domain_type; | |
| 1593 | |
| 1594 /* If BASE is an ARRAY_REF, we can pick up another offset (this time | |
| 1595 measured in units of the size of elements type) from that ARRAY_REF). | |
| 1596 We can't do anything if either is variable. | |
| 1597 | |
| 1598 The case we handle here is *(&A[N]+O). */ | |
| 1599 if (TREE_CODE (base) == ARRAY_REF) | |
| 1600 { | |
| 1601 tree low_bound = array_ref_low_bound (base); | |
| 1602 | |
| 1603 elt_offset = TREE_OPERAND (base, 1); | |
| 1604 if (TREE_CODE (low_bound) != INTEGER_CST | |
| 1605 || TREE_CODE (elt_offset) != INTEGER_CST) | |
| 1606 return NULL_TREE; | |
| 1607 | |
| 1608 elt_offset = int_const_binop (MINUS_EXPR, elt_offset, low_bound, 0); | |
| 1609 base = TREE_OPERAND (base, 0); | |
| 1610 } | |
| 1611 | |
| 1612 /* Ignore stupid user tricks of indexing non-array variables. */ | |
| 1613 array_type = TREE_TYPE (base); | |
| 1614 if (TREE_CODE (array_type) != ARRAY_TYPE) | |
| 1615 return NULL_TREE; | |
| 1616 elt_type = TREE_TYPE (array_type); | |
| 1617 if (!useless_type_conversion_p (orig_type, elt_type)) | |
| 1618 return NULL_TREE; | |
| 1619 | |
| 1620 /* Use signed size type for intermediate computation on the index. */ | |
| 1621 idx_type = signed_type_for (size_type_node); | |
| 1622 | |
| 1623 /* If OFFSET and ELT_OFFSET are zero, we don't care about the size of the | |
| 1624 element type (so we can use the alignment if it's not constant). | |
| 1625 Otherwise, compute the offset as an index by using a division. If the | |
| 1626 division isn't exact, then don't do anything. */ | |
| 1627 elt_size = TYPE_SIZE_UNIT (elt_type); | |
| 1628 if (!elt_size) | |
| 1629 return NULL; | |
| 1630 if (integer_zerop (offset)) | |
| 1631 { | |
| 1632 if (TREE_CODE (elt_size) != INTEGER_CST) | |
| 1633 elt_size = size_int (TYPE_ALIGN (elt_type)); | |
| 1634 | |
| 1635 idx = build_int_cst (idx_type, 0); | |
| 1636 } | |
| 1637 else | |
| 1638 { | |
| 1639 unsigned HOST_WIDE_INT lquo, lrem; | |
| 1640 HOST_WIDE_INT hquo, hrem; | |
| 1641 double_int soffset; | |
| 1642 | |
| 1643 /* The final array offset should be signed, so we need | |
| 1644 to sign-extend the (possibly pointer) offset here | |
| 1645 and use signed division. */ | |
| 1646 soffset = double_int_sext (tree_to_double_int (offset), | |
| 1647 TYPE_PRECISION (TREE_TYPE (offset))); | |
| 1648 if (TREE_CODE (elt_size) != INTEGER_CST | |
| 1649 || div_and_round_double (TRUNC_DIV_EXPR, 0, | |
| 1650 soffset.low, soffset.high, | |
| 1651 TREE_INT_CST_LOW (elt_size), | |
| 1652 TREE_INT_CST_HIGH (elt_size), | |
| 1653 &lquo, &hquo, &lrem, &hrem) | |
| 1654 || lrem || hrem) | |
| 1655 return NULL_TREE; | |
| 1656 | |
| 1657 idx = build_int_cst_wide (idx_type, lquo, hquo); | |
| 1658 } | |
| 1659 | |
| 1660 /* Assume the low bound is zero. If there is a domain type, get the | |
| 1661 low bound, if any, convert the index into that type, and add the | |
| 1662 low bound. */ | |
| 1663 min_idx = build_int_cst (idx_type, 0); | |
| 1664 domain_type = TYPE_DOMAIN (array_type); | |
| 1665 if (domain_type) | |
| 1666 { | |
| 1667 idx_type = domain_type; | |
| 1668 if (TYPE_MIN_VALUE (idx_type)) | |
| 1669 min_idx = TYPE_MIN_VALUE (idx_type); | |
| 1670 else | |
| 1671 min_idx = fold_convert (idx_type, min_idx); | |
| 1672 | |
| 1673 if (TREE_CODE (min_idx) != INTEGER_CST) | |
| 1674 return NULL_TREE; | |
| 1675 | |
| 1676 elt_offset = fold_convert (idx_type, elt_offset); | |
| 1677 } | |
| 1678 | |
| 1679 if (!integer_zerop (min_idx)) | |
| 1680 idx = int_const_binop (PLUS_EXPR, idx, min_idx, 0); | |
| 1681 if (!integer_zerop (elt_offset)) | |
| 1682 idx = int_const_binop (PLUS_EXPR, idx, elt_offset, 0); | |
| 1683 | |
| 1684 /* Make sure to possibly truncate late after offsetting. */ | |
| 1685 idx = fold_convert (idx_type, idx); | |
| 1686 | |
| 1687 /* We don't want to construct access past array bounds. For example | |
| 1688 char *(c[4]); | |
| 1689 c[3][2]; | |
| 1690 should not be simplified into (*c)[14] or tree-vrp will | |
| 1691 give false warnings. The same is true for | |
| 1692 struct A { long x; char d[0]; } *a; | |
| 1693 (char *)a - 4; | |
| 1694 which should be not folded to &a->d[-8]. */ | |
| 1695 if (domain_type | |
| 1696 && TYPE_MAX_VALUE (domain_type) | |
| 1697 && TREE_CODE (TYPE_MAX_VALUE (domain_type)) == INTEGER_CST) | |
| 1698 { | |
| 1699 tree up_bound = TYPE_MAX_VALUE (domain_type); | |
| 1700 | |
| 1701 if (tree_int_cst_lt (up_bound, idx) | |
| 1702 /* Accesses after the end of arrays of size 0 (gcc | |
| 1703 extension) and 1 are likely intentional ("struct | |
| 1704 hack"). */ | |
| 1705 && compare_tree_int (up_bound, 1) > 0) | |
| 1706 return NULL_TREE; | |
| 1707 } | |
| 1708 if (domain_type | |
| 1709 && TYPE_MIN_VALUE (domain_type)) | |
| 1710 { | |
| 1711 if (!allow_negative_idx | |
| 1712 && TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST | |
| 1713 && tree_int_cst_lt (idx, TYPE_MIN_VALUE (domain_type))) | |
| 1714 return NULL_TREE; | |
| 1715 } | |
| 1716 else if (!allow_negative_idx | |
| 1717 && compare_tree_int (idx, 0) < 0) | |
| 1718 return NULL_TREE; | |
| 1719 | |
| 1720 return build4 (ARRAY_REF, elt_type, base, idx, NULL_TREE, NULL_TREE); | |
| 1721 } | |
| 1722 | |
| 1723 | |
| 1724 /* Attempt to fold *(S+O) to S.X. | |
| 1725 BASE is a record type. OFFSET is a byte displacement. ORIG_TYPE | |
| 1726 is the desired result type. */ | |
| 1727 | |
| 1728 static tree | |
| 1729 maybe_fold_offset_to_component_ref (tree record_type, tree base, tree offset, | |
| 1730 tree orig_type, bool base_is_ptr) | |
| 1731 { | |
| 1732 tree f, t, field_type, tail_array_field, field_offset; | |
| 1733 tree ret; | |
| 1734 tree new_base; | |
| 1735 | |
| 1736 if (TREE_CODE (record_type) != RECORD_TYPE | |
| 1737 && TREE_CODE (record_type) != UNION_TYPE | |
| 1738 && TREE_CODE (record_type) != QUAL_UNION_TYPE) | |
| 1739 return NULL_TREE; | |
| 1740 | |
| 1741 /* Short-circuit silly cases. */ | |
| 1742 if (useless_type_conversion_p (record_type, orig_type)) | |
| 1743 return NULL_TREE; | |
| 1744 | |
| 1745 tail_array_field = NULL_TREE; | |
| 1746 for (f = TYPE_FIELDS (record_type); f ; f = TREE_CHAIN (f)) | |
| 1747 { | |
| 1748 int cmp; | |
| 1749 | |
| 1750 if (TREE_CODE (f) != FIELD_DECL) | |
| 1751 continue; | |
| 1752 if (DECL_BIT_FIELD (f)) | |
| 1753 continue; | |
| 1754 | |
| 1755 if (!DECL_FIELD_OFFSET (f)) | |
| 1756 continue; | |
| 1757 field_offset = byte_position (f); | |
| 1758 if (TREE_CODE (field_offset) != INTEGER_CST) | |
| 1759 continue; | |
| 1760 | |
| 1761 /* ??? Java creates "interesting" fields for representing base classes. | |
| 1762 They have no name, and have no context. With no context, we get into | |
| 1763 trouble with nonoverlapping_component_refs_p. Skip them. */ | |
| 1764 if (!DECL_FIELD_CONTEXT (f)) | |
| 1765 continue; | |
| 1766 | |
| 1767 /* The previous array field isn't at the end. */ | |
| 1768 tail_array_field = NULL_TREE; | |
| 1769 | |
| 1770 /* Check to see if this offset overlaps with the field. */ | |
| 1771 cmp = tree_int_cst_compare (field_offset, offset); | |
| 1772 if (cmp > 0) | |
| 1773 continue; | |
| 1774 | |
| 1775 field_type = TREE_TYPE (f); | |
| 1776 | |
| 1777 /* Here we exactly match the offset being checked. If the types match, | |
| 1778 then we can return that field. */ | |
| 1779 if (cmp == 0 | |
| 1780 && useless_type_conversion_p (orig_type, field_type)) | |
| 1781 { | |
| 1782 if (base_is_ptr) | |
| 1783 base = build1 (INDIRECT_REF, record_type, base); | |
| 1784 t = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE); | |
| 1785 return t; | |
| 1786 } | |
| 1787 | |
| 1788 /* Don't care about offsets into the middle of scalars. */ | |
| 1789 if (!AGGREGATE_TYPE_P (field_type)) | |
| 1790 continue; | |
| 1791 | |
| 1792 /* Check for array at the end of the struct. This is often | |
| 1793 used as for flexible array members. We should be able to | |
| 1794 turn this into an array access anyway. */ | |
| 1795 if (TREE_CODE (field_type) == ARRAY_TYPE) | |
| 1796 tail_array_field = f; | |
| 1797 | |
| 1798 /* Check the end of the field against the offset. */ | |
| 1799 if (!DECL_SIZE_UNIT (f) | |
| 1800 || TREE_CODE (DECL_SIZE_UNIT (f)) != INTEGER_CST) | |
| 1801 continue; | |
| 1802 t = int_const_binop (MINUS_EXPR, offset, field_offset, 1); | |
| 1803 if (!tree_int_cst_lt (t, DECL_SIZE_UNIT (f))) | |
| 1804 continue; | |
| 1805 | |
| 1806 /* If we matched, then set offset to the displacement into | |
| 1807 this field. */ | |
| 1808 if (base_is_ptr) | |
| 1809 new_base = build1 (INDIRECT_REF, record_type, base); | |
| 1810 else | |
| 1811 new_base = base; | |
| 1812 new_base = build3 (COMPONENT_REF, field_type, new_base, f, NULL_TREE); | |
| 1813 | |
| 1814 /* Recurse to possibly find the match. */ | |
| 1815 ret = maybe_fold_offset_to_array_ref (new_base, t, orig_type, | |
| 1816 f == TYPE_FIELDS (record_type)); | |
| 1817 if (ret) | |
| 1818 return ret; | |
| 1819 ret = maybe_fold_offset_to_component_ref (field_type, new_base, t, | |
| 1820 orig_type, false); | |
| 1821 if (ret) | |
| 1822 return ret; | |
| 1823 } | |
| 1824 | |
| 1825 if (!tail_array_field) | |
| 1826 return NULL_TREE; | |
| 1827 | |
| 1828 f = tail_array_field; | |
| 1829 field_type = TREE_TYPE (f); | |
| 1830 offset = int_const_binop (MINUS_EXPR, offset, byte_position (f), 1); | |
| 1831 | |
| 1832 /* If we get here, we've got an aggregate field, and a possibly | |
| 1833 nonzero offset into them. Recurse and hope for a valid match. */ | |
| 1834 if (base_is_ptr) | |
| 1835 base = build1 (INDIRECT_REF, record_type, base); | |
| 1836 base = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE); | |
| 1837 | |
| 1838 t = maybe_fold_offset_to_array_ref (base, offset, orig_type, | |
| 1839 f == TYPE_FIELDS (record_type)); | |
| 1840 if (t) | |
| 1841 return t; | |
| 1842 return maybe_fold_offset_to_component_ref (field_type, base, offset, | |
| 1843 orig_type, false); | |
| 1844 } | |
| 1845 | |
| 1846 /* Attempt to express (ORIG_TYPE)BASE+OFFSET as BASE->field_of_orig_type | |
| 1847 or BASE[index] or by combination of those. | |
| 1848 | |
| 1849 Before attempting the conversion strip off existing ADDR_EXPRs and | |
| 1850 handled component refs. */ | |
| 1851 | |
| 1852 tree | |
| 1853 maybe_fold_offset_to_reference (tree base, tree offset, tree orig_type) | |
| 1854 { | |
| 1855 tree ret; | |
| 1856 tree type; | |
| 1857 bool base_is_ptr = true; | |
| 1858 | |
| 1859 STRIP_NOPS (base); | |
| 1860 if (TREE_CODE (base) == ADDR_EXPR) | |
| 1861 { | |
| 1862 base_is_ptr = false; | |
| 1863 | |
| 1864 base = TREE_OPERAND (base, 0); | |
| 1865 | |
| 1866 /* Handle case where existing COMPONENT_REF pick e.g. wrong field of union, | |
| 1867 so it needs to be removed and new COMPONENT_REF constructed. | |
| 1868 The wrong COMPONENT_REF are often constructed by folding the | |
| 1869 (type *)&object within the expression (type *)&object+offset */ | |
| 1870 if (handled_component_p (base)) | |
| 1871 { | |
| 1872 HOST_WIDE_INT sub_offset, size, maxsize; | |
| 1873 tree newbase; | |
| 1874 newbase = get_ref_base_and_extent (base, &sub_offset, | |
| 1875 &size, &maxsize); | |
| 1876 gcc_assert (newbase); | |
| 1877 if (size == maxsize | |
| 1878 && size != -1 | |
| 1879 && !(sub_offset & (BITS_PER_UNIT - 1))) | |
| 1880 { | |
| 1881 base = newbase; | |
| 1882 if (sub_offset) | |
| 1883 offset = int_const_binop (PLUS_EXPR, offset, | |
| 1884 build_int_cst (TREE_TYPE (offset), | |
| 1885 sub_offset / BITS_PER_UNIT), 1); | |
| 1886 } | |
| 1887 } | |
| 1888 if (useless_type_conversion_p (orig_type, TREE_TYPE (base)) | |
| 1889 && integer_zerop (offset)) | |
| 1890 return base; | |
| 1891 type = TREE_TYPE (base); | |
| 1892 } | |
| 1893 else | |
| 1894 { | |
| 1895 base_is_ptr = true; | |
| 1896 if (!POINTER_TYPE_P (TREE_TYPE (base))) | |
| 1897 return NULL_TREE; | |
| 1898 type = TREE_TYPE (TREE_TYPE (base)); | |
| 1899 } | |
| 1900 ret = maybe_fold_offset_to_component_ref (type, base, offset, | |
| 1901 orig_type, base_is_ptr); | |
| 1902 if (!ret) | |
| 1903 { | |
| 1904 if (base_is_ptr) | |
| 1905 base = build1 (INDIRECT_REF, type, base); | |
| 1906 ret = maybe_fold_offset_to_array_ref (base, offset, orig_type, true); | |
| 1907 } | |
| 1908 return ret; | |
| 1909 } | |
| 1910 | |
| 1911 /* Attempt to express (ORIG_TYPE)&BASE+OFFSET as &BASE->field_of_orig_type | |
| 1912 or &BASE[index] or by combination of those. | |
| 1913 | |
| 1914 Before attempting the conversion strip off existing component refs. */ | |
| 1915 | |
| 1916 tree | |
| 1917 maybe_fold_offset_to_address (tree addr, tree offset, tree orig_type) | |
| 1918 { | |
| 1919 tree t; | |
| 1920 | |
| 1921 gcc_assert (POINTER_TYPE_P (TREE_TYPE (addr)) | |
| 1922 && POINTER_TYPE_P (orig_type)); | |
| 1923 | |
| 1924 t = maybe_fold_offset_to_reference (addr, offset, TREE_TYPE (orig_type)); | |
| 1925 if (t != NULL_TREE) | |
| 1926 { | |
| 1927 tree orig = addr; | |
| 1928 tree ptr_type; | |
| 1929 | |
| 1930 /* For __builtin_object_size to function correctly we need to | |
| 1931 make sure not to fold address arithmetic so that we change | |
| 1932 reference from one array to another. This would happen for | |
| 1933 example for | |
| 1934 | |
| 1935 struct X { char s1[10]; char s2[10] } s; | |
| 1936 char *foo (void) { return &s.s2[-4]; } | |
| 1937 | |
| 1938 where we need to avoid generating &s.s1[6]. As the C and | |
| 1939 C++ frontends create different initial trees | |
| 1940 (char *) &s.s1 + -4 vs. &s.s1[-4] we have to do some | |
| 1941 sophisticated comparisons here. Note that checking for the | |
| 1942 condition after the fact is easier than trying to avoid doing | |
| 1943 the folding. */ | |
| 1944 STRIP_NOPS (orig); | |
| 1945 if (TREE_CODE (orig) == ADDR_EXPR) | |
| 1946 orig = TREE_OPERAND (orig, 0); | |
| 1947 if ((TREE_CODE (orig) == ARRAY_REF | |
| 1948 || (TREE_CODE (orig) == COMPONENT_REF | |
| 1949 && TREE_CODE (TREE_TYPE (TREE_OPERAND (orig, 1))) == ARRAY_TYPE)) | |
| 1950 && (TREE_CODE (t) == ARRAY_REF | |
| 1951 || TREE_CODE (t) == COMPONENT_REF) | |
| 1952 && !operand_equal_p (TREE_CODE (orig) == ARRAY_REF | |
| 1953 ? TREE_OPERAND (orig, 0) : orig, | |
| 1954 TREE_CODE (t) == ARRAY_REF | |
| 1955 ? TREE_OPERAND (t, 0) : t, 0)) | |
| 1956 return NULL_TREE; | |
| 1957 | |
| 1958 ptr_type = build_pointer_type (TREE_TYPE (t)); | |
| 1959 if (!useless_type_conversion_p (orig_type, ptr_type)) | |
| 1960 return NULL_TREE; | |
| 1961 return build_fold_addr_expr_with_type (t, ptr_type); | |
| 1962 } | |
| 1963 | |
| 1964 return NULL_TREE; | |
| 1965 } | |
| 1966 | |
| 1967 /* A subroutine of fold_stmt_r. Attempt to simplify *(BASE+OFFSET). | |
| 1968 Return the simplified expression, or NULL if nothing could be done. */ | |
| 1969 | |
| 1970 static tree | |
| 1971 maybe_fold_stmt_indirect (tree expr, tree base, tree offset) | |
| 1972 { | |
| 1973 tree t; | |
| 1974 bool volatile_p = TREE_THIS_VOLATILE (expr); | |
| 1975 | |
| 1976 /* We may well have constructed a double-nested PLUS_EXPR via multiple | |
| 1977 substitutions. Fold that down to one. Remove NON_LVALUE_EXPRs that | |
| 1978 are sometimes added. */ | |
| 1979 base = fold (base); | |
| 1980 STRIP_TYPE_NOPS (base); | |
| 1981 TREE_OPERAND (expr, 0) = base; | |
| 1982 | |
| 1983 /* One possibility is that the address reduces to a string constant. */ | |
| 1984 t = fold_read_from_constant_string (expr); | |
| 1985 if (t) | |
| 1986 return t; | |
| 1987 | |
| 1988 /* Add in any offset from a POINTER_PLUS_EXPR. */ | |
| 1989 if (TREE_CODE (base) == POINTER_PLUS_EXPR) | |
| 1990 { | |
| 1991 tree offset2; | |
| 1992 | |
| 1993 offset2 = TREE_OPERAND (base, 1); | |
| 1994 if (TREE_CODE (offset2) != INTEGER_CST) | |
| 1995 return NULL_TREE; | |
| 1996 base = TREE_OPERAND (base, 0); | |
| 1997 | |
| 1998 offset = fold_convert (sizetype, | |
| 1999 int_const_binop (PLUS_EXPR, offset, offset2, 1)); | |
| 2000 } | |
| 2001 | |
| 2002 if (TREE_CODE (base) == ADDR_EXPR) | |
| 2003 { | |
| 2004 tree base_addr = base; | |
| 2005 | |
| 2006 /* Strip the ADDR_EXPR. */ | |
| 2007 base = TREE_OPERAND (base, 0); | |
| 2008 | |
| 2009 /* Fold away CONST_DECL to its value, if the type is scalar. */ | |
| 2010 if (TREE_CODE (base) == CONST_DECL | |
| 2011 && is_gimple_min_invariant (DECL_INITIAL (base))) | |
| 2012 return DECL_INITIAL (base); | |
| 2013 | |
| 2014 /* Try folding *(&B+O) to B.X. */ | |
| 2015 t = maybe_fold_offset_to_reference (base_addr, offset, | |
| 2016 TREE_TYPE (expr)); | |
| 2017 if (t) | |
| 2018 { | |
| 2019 /* Preserve volatileness of the original expression. | |
| 2020 We can end up with a plain decl here which is shared | |
| 2021 and we shouldn't mess with its flags. */ | |
| 2022 if (!SSA_VAR_P (t)) | |
| 2023 TREE_THIS_VOLATILE (t) = volatile_p; | |
| 2024 return t; | |
| 2025 } | |
| 2026 } | |
| 2027 else | |
| 2028 { | |
| 2029 /* We can get here for out-of-range string constant accesses, | |
| 2030 such as "_"[3]. Bail out of the entire substitution search | |
| 2031 and arrange for the entire statement to be replaced by a | |
| 2032 call to __builtin_trap. In all likelihood this will all be | |
| 2033 constant-folded away, but in the meantime we can't leave with | |
| 2034 something that get_expr_operands can't understand. */ | |
| 2035 | |
| 2036 t = base; | |
| 2037 STRIP_NOPS (t); | |
| 2038 if (TREE_CODE (t) == ADDR_EXPR | |
| 2039 && TREE_CODE (TREE_OPERAND (t, 0)) == STRING_CST) | |
| 2040 { | |
| 2041 /* FIXME: Except that this causes problems elsewhere with dead | |
| 2042 code not being deleted, and we die in the rtl expanders | |
| 2043 because we failed to remove some ssa_name. In the meantime, | |
| 2044 just return zero. */ | |
| 2045 /* FIXME2: This condition should be signaled by | |
| 2046 fold_read_from_constant_string directly, rather than | |
| 2047 re-checking for it here. */ | |
| 2048 return integer_zero_node; | |
| 2049 } | |
| 2050 | |
| 2051 /* Try folding *(B+O) to B->X. Still an improvement. */ | |
| 2052 if (POINTER_TYPE_P (TREE_TYPE (base))) | |
| 2053 { | |
| 2054 t = maybe_fold_offset_to_reference (base, offset, | |
| 2055 TREE_TYPE (expr)); | |
| 2056 if (t) | |
| 2057 return t; | |
| 2058 } | |
| 2059 } | |
| 2060 | |
| 2061 /* Otherwise we had an offset that we could not simplify. */ | |
| 2062 return NULL_TREE; | |
| 2063 } | |
| 2064 | |
| 2065 | |
| 2066 /* A quaint feature extant in our address arithmetic is that there | |
| 2067 can be hidden type changes here. The type of the result need | |
| 2068 not be the same as the type of the input pointer. | |
| 2069 | |
| 2070 What we're after here is an expression of the form | |
| 2071 (T *)(&array + const) | |
| 2072 where array is OP0, const is OP1, RES_TYPE is T and | |
| 2073 the cast doesn't actually exist, but is implicit in the | |
| 2074 type of the POINTER_PLUS_EXPR. We'd like to turn this into | |
| 2075 &array[x] | |
| 2076 which may be able to propagate further. */ | |
| 2077 | |
| 2078 tree | |
| 2079 maybe_fold_stmt_addition (tree res_type, tree op0, tree op1) | |
| 2080 { | |
| 2081 tree ptd_type; | |
| 2082 tree t; | |
| 2083 | |
| 2084 /* It had better be a constant. */ | |
| 2085 if (TREE_CODE (op1) != INTEGER_CST) | |
| 2086 return NULL_TREE; | |
| 2087 /* The first operand should be an ADDR_EXPR. */ | |
| 2088 if (TREE_CODE (op0) != ADDR_EXPR) | |
| 2089 return NULL_TREE; | |
| 2090 op0 = TREE_OPERAND (op0, 0); | |
| 2091 | |
| 2092 /* If the first operand is an ARRAY_REF, expand it so that we can fold | |
| 2093 the offset into it. */ | |
| 2094 while (TREE_CODE (op0) == ARRAY_REF) | |
| 2095 { | |
| 2096 tree array_obj = TREE_OPERAND (op0, 0); | |
| 2097 tree array_idx = TREE_OPERAND (op0, 1); | |
| 2098 tree elt_type = TREE_TYPE (op0); | |
| 2099 tree elt_size = TYPE_SIZE_UNIT (elt_type); | |
| 2100 tree min_idx; | |
| 2101 | |
| 2102 if (TREE_CODE (array_idx) != INTEGER_CST) | |
| 2103 break; | |
| 2104 if (TREE_CODE (elt_size) != INTEGER_CST) | |
| 2105 break; | |
| 2106 | |
| 2107 /* Un-bias the index by the min index of the array type. */ | |
| 2108 min_idx = TYPE_DOMAIN (TREE_TYPE (array_obj)); | |
| 2109 if (min_idx) | |
| 2110 { | |
| 2111 min_idx = TYPE_MIN_VALUE (min_idx); | |
| 2112 if (min_idx) | |
| 2113 { | |
| 2114 if (TREE_CODE (min_idx) != INTEGER_CST) | |
| 2115 break; | |
| 2116 | |
| 2117 array_idx = fold_convert (TREE_TYPE (min_idx), array_idx); | |
| 2118 if (!integer_zerop (min_idx)) | |
| 2119 array_idx = int_const_binop (MINUS_EXPR, array_idx, | |
| 2120 min_idx, 0); | |
| 2121 } | |
| 2122 } | |
| 2123 | |
| 2124 /* Convert the index to a byte offset. */ | |
| 2125 array_idx = fold_convert (sizetype, array_idx); | |
| 2126 array_idx = int_const_binop (MULT_EXPR, array_idx, elt_size, 0); | |
| 2127 | |
| 2128 /* Update the operands for the next round, or for folding. */ | |
| 2129 op1 = int_const_binop (PLUS_EXPR, | |
| 2130 array_idx, op1, 0); | |
| 2131 op0 = array_obj; | |
| 2132 } | |
| 2133 | |
| 2134 ptd_type = TREE_TYPE (res_type); | |
| 2135 /* If we want a pointer to void, reconstruct the reference from the | |
| 2136 array element type. A pointer to that can be trivially converted | |
| 2137 to void *. This happens as we fold (void *)(ptr p+ off). */ | |
| 2138 if (VOID_TYPE_P (ptd_type) | |
| 2139 && TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE) | |
| 2140 ptd_type = TREE_TYPE (TREE_TYPE (op0)); | |
| 2141 | |
| 2142 /* At which point we can try some of the same things as for indirects. */ | |
| 2143 t = maybe_fold_offset_to_array_ref (op0, op1, ptd_type, true); | |
| 2144 if (!t) | |
| 2145 t = maybe_fold_offset_to_component_ref (TREE_TYPE (op0), op0, op1, | |
| 2146 ptd_type, false); | |
| 2147 if (t) | |
| 2148 t = build1 (ADDR_EXPR, res_type, t); | |
| 2149 | |
| 2150 return t; | |
| 2151 } | |
| 2152 | |
| 2153 /* For passing state through walk_tree into fold_stmt_r and its | |
| 2154 children. */ | |
| 2155 | |
| 2156 struct fold_stmt_r_data | |
| 2157 { | |
| 2158 gimple stmt; | |
| 2159 bool *changed_p; | |
| 2160 bool *inside_addr_expr_p; | |
| 2161 }; | |
| 2162 | |
| 2163 /* Subroutine of fold_stmt called via walk_tree. We perform several | |
| 2164 simplifications of EXPR_P, mostly having to do with pointer arithmetic. */ | |
| 2165 | |
| 2166 static tree | |
| 2167 fold_stmt_r (tree *expr_p, int *walk_subtrees, void *data) | |
| 2168 { | |
| 2169 struct walk_stmt_info *wi = (struct walk_stmt_info *) data; | |
| 2170 struct fold_stmt_r_data *fold_stmt_r_data; | |
| 2171 bool *inside_addr_expr_p; | |
| 2172 bool *changed_p; | |
| 2173 tree expr = *expr_p, t; | |
| 2174 bool volatile_p = TREE_THIS_VOLATILE (expr); | |
| 2175 | |
| 2176 fold_stmt_r_data = (struct fold_stmt_r_data *) wi->info; | |
| 2177 inside_addr_expr_p = fold_stmt_r_data->inside_addr_expr_p; | |
| 2178 changed_p = fold_stmt_r_data->changed_p; | |
| 2179 | |
| 2180 /* ??? It'd be nice if walk_tree had a pre-order option. */ | |
| 2181 switch (TREE_CODE (expr)) | |
| 2182 { | |
| 2183 case INDIRECT_REF: | |
| 2184 t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
| 2185 if (t) | |
| 2186 return t; | |
| 2187 *walk_subtrees = 0; | |
| 2188 | |
| 2189 t = maybe_fold_stmt_indirect (expr, TREE_OPERAND (expr, 0), | |
| 2190 integer_zero_node); | |
| 2191 /* Avoid folding *"abc" = 5 into 'a' = 5. */ | |
| 2192 if (wi->is_lhs && t && TREE_CODE (t) == INTEGER_CST) | |
| 2193 t = NULL_TREE; | |
| 2194 if (!t | |
| 2195 && TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR) | |
| 2196 /* If we had a good reason for propagating the address here, | |
| 2197 make sure we end up with valid gimple. See PR34989. */ | |
| 2198 t = TREE_OPERAND (TREE_OPERAND (expr, 0), 0); | |
| 2199 break; | |
| 2200 | |
| 2201 case NOP_EXPR: | |
| 2202 t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
| 2203 if (t) | |
| 2204 return t; | |
| 2205 *walk_subtrees = 0; | |
| 2206 | |
| 2207 if (POINTER_TYPE_P (TREE_TYPE (expr)) | |
| 2208 && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (expr))) | |
| 2209 && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0))) | |
| 2210 && (t = maybe_fold_offset_to_address (TREE_OPERAND (expr, 0), | |
| 2211 integer_zero_node, | |
| 2212 TREE_TYPE (TREE_TYPE (expr))))) | |
| 2213 return t; | |
| 2214 break; | |
| 2215 | |
| 2216 /* ??? Could handle more ARRAY_REFs here, as a variant of INDIRECT_REF. | |
| 2217 We'd only want to bother decomposing an existing ARRAY_REF if | |
| 2218 the base array is found to have another offset contained within. | |
| 2219 Otherwise we'd be wasting time. */ | |
| 2220 case ARRAY_REF: | |
| 2221 /* If we are not processing expressions found within an | |
| 2222 ADDR_EXPR, then we can fold constant array references. | |
| 2223 Don't fold on LHS either, to avoid folding "abc"[0] = 5 | |
| 2224 into 'a' = 5. */ | |
| 2225 if (!*inside_addr_expr_p && !wi->is_lhs) | |
| 2226 t = fold_read_from_constant_string (expr); | |
| 2227 else | |
| 2228 t = NULL; | |
| 2229 break; | |
| 2230 | |
| 2231 case ADDR_EXPR: | |
| 2232 *inside_addr_expr_p = true; | |
| 2233 t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
| 2234 *inside_addr_expr_p = false; | |
| 2235 if (t) | |
| 2236 return t; | |
| 2237 *walk_subtrees = 0; | |
| 2238 | |
| 2239 /* Make sure the value is properly considered constant, and so gets | |
| 2240 propagated as expected. */ | |
| 2241 if (*changed_p) | |
| 2242 recompute_tree_invariant_for_addr_expr (expr); | |
| 2243 return NULL_TREE; | |
| 2244 | |
| 2245 case COMPONENT_REF: | |
| 2246 t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
| 2247 if (t) | |
| 2248 return t; | |
| 2249 *walk_subtrees = 0; | |
| 2250 | |
| 2251 /* Make sure the FIELD_DECL is actually a field in the type on the lhs. | |
| 2252 We've already checked that the records are compatible, so we should | |
| 2253 come up with a set of compatible fields. */ | |
| 2254 { | |
| 2255 tree expr_record = TREE_TYPE (TREE_OPERAND (expr, 0)); | |
| 2256 tree expr_field = TREE_OPERAND (expr, 1); | |
| 2257 | |
| 2258 if (DECL_FIELD_CONTEXT (expr_field) != TYPE_MAIN_VARIANT (expr_record)) | |
| 2259 { | |
| 2260 expr_field = find_compatible_field (expr_record, expr_field); | |
| 2261 TREE_OPERAND (expr, 1) = expr_field; | |
| 2262 } | |
| 2263 } | |
| 2264 break; | |
| 2265 | |
| 2266 case TARGET_MEM_REF: | |
| 2267 t = maybe_fold_tmr (expr); | |
| 2268 break; | |
| 2269 | |
| 2270 case POINTER_PLUS_EXPR: | |
| 2271 t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL); | |
| 2272 if (t) | |
| 2273 return t; | |
| 2274 t = walk_tree (&TREE_OPERAND (expr, 1), fold_stmt_r, data, NULL); | |
| 2275 if (t) | |
| 2276 return t; | |
| 2277 *walk_subtrees = 0; | |
| 2278 | |
| 2279 t = maybe_fold_stmt_addition (TREE_TYPE (expr), | |
| 2280 TREE_OPERAND (expr, 0), | |
| 2281 TREE_OPERAND (expr, 1)); | |
| 2282 break; | |
| 2283 | |
| 2284 case COND_EXPR: | |
| 2285 if (COMPARISON_CLASS_P (TREE_OPERAND (expr, 0))) | |
| 2286 { | |
| 2287 tree op0 = TREE_OPERAND (expr, 0); | |
| 2288 tree tem; | |
| 2289 bool set; | |
| 2290 | |
| 2291 fold_defer_overflow_warnings (); | |
| 2292 tem = fold_binary (TREE_CODE (op0), TREE_TYPE (op0), | |
| 2293 TREE_OPERAND (op0, 0), | |
| 2294 TREE_OPERAND (op0, 1)); | |
| 2295 /* This is actually a conditional expression, not a GIMPLE | |
| 2296 conditional statement, however, the valid_gimple_rhs_p | |
| 2297 test still applies. */ | |
| 2298 set = tem && is_gimple_condexpr (tem) && valid_gimple_rhs_p (tem); | |
| 2299 fold_undefer_overflow_warnings (set, fold_stmt_r_data->stmt, 0); | |
| 2300 if (set) | |
| 2301 { | |
| 2302 COND_EXPR_COND (expr) = tem; | |
| 2303 t = expr; | |
| 2304 break; | |
| 2305 } | |
| 2306 } | |
| 2307 return NULL_TREE; | |
| 2308 | |
| 2309 default: | |
| 2310 return NULL_TREE; | |
| 2311 } | |
| 2312 | |
| 2313 if (t) | |
| 2314 { | |
| 2315 /* Preserve volatileness of the original expression. | |
| 2316 We can end up with a plain decl here which is shared | |
| 2317 and we shouldn't mess with its flags. */ | |
| 2318 if (!SSA_VAR_P (t)) | |
| 2319 TREE_THIS_VOLATILE (t) = volatile_p; | |
| 2320 *expr_p = t; | |
| 2321 *changed_p = true; | |
| 2322 } | |
| 2323 | |
| 2324 return NULL_TREE; | |
| 2325 } | |
| 2326 | |
| 2327 /* Return the string length, maximum string length or maximum value of | |
| 2328 ARG in LENGTH. | |
| 2329 If ARG is an SSA name variable, follow its use-def chains. If LENGTH | |
| 2330 is not NULL and, for TYPE == 0, its value is not equal to the length | |
| 2331 we determine or if we are unable to determine the length or value, | |
| 2332 return false. VISITED is a bitmap of visited variables. | |
| 2333 TYPE is 0 if string length should be returned, 1 for maximum string | |
| 2334 length and 2 for maximum value ARG can have. */ | |
| 2335 | |
| 2336 static bool | |
| 2337 get_maxval_strlen (tree arg, tree *length, bitmap visited, int type) | |
| 2338 { | |
| 2339 tree var, val; | |
| 2340 gimple def_stmt; | |
| 2341 | |
| 2342 if (TREE_CODE (arg) != SSA_NAME) | |
| 2343 { | |
| 2344 if (TREE_CODE (arg) == COND_EXPR) | |
| 2345 return get_maxval_strlen (COND_EXPR_THEN (arg), length, visited, type) | |
| 2346 && get_maxval_strlen (COND_EXPR_ELSE (arg), length, visited, type); | |
| 2347 /* We can end up with &(*iftmp_1)[0] here as well, so handle it. */ | |
| 2348 else if (TREE_CODE (arg) == ADDR_EXPR | |
| 2349 && TREE_CODE (TREE_OPERAND (arg, 0)) == ARRAY_REF | |
| 2350 && integer_zerop (TREE_OPERAND (TREE_OPERAND (arg, 0), 1))) | |
| 2351 { | |
| 2352 tree aop0 = TREE_OPERAND (TREE_OPERAND (arg, 0), 0); | |
| 2353 if (TREE_CODE (aop0) == INDIRECT_REF | |
| 2354 && TREE_CODE (TREE_OPERAND (aop0, 0)) == SSA_NAME) | |
| 2355 return get_maxval_strlen (TREE_OPERAND (aop0, 0), | |
| 2356 length, visited, type); | |
| 2357 } | |
| 2358 | |
| 2359 if (type == 2) | |
| 2360 { | |
| 2361 val = arg; | |
| 2362 if (TREE_CODE (val) != INTEGER_CST | |
| 2363 || tree_int_cst_sgn (val) < 0) | |
| 2364 return false; | |
| 2365 } | |
| 2366 else | |
| 2367 val = c_strlen (arg, 1); | |
| 2368 if (!val) | |
| 2369 return false; | |
| 2370 | |
| 2371 if (*length) | |
| 2372 { | |
| 2373 if (type > 0) | |
| 2374 { | |
| 2375 if (TREE_CODE (*length) != INTEGER_CST | |
| 2376 || TREE_CODE (val) != INTEGER_CST) | |
| 2377 return false; | |
| 2378 | |
| 2379 if (tree_int_cst_lt (*length, val)) | |
| 2380 *length = val; | |
| 2381 return true; | |
| 2382 } | |
| 2383 else if (simple_cst_equal (val, *length) != 1) | |
| 2384 return false; | |
| 2385 } | |
| 2386 | |
| 2387 *length = val; | |
| 2388 return true; | |
| 2389 } | |
| 2390 | |
| 2391 /* If we were already here, break the infinite cycle. */ | |
| 2392 if (bitmap_bit_p (visited, SSA_NAME_VERSION (arg))) | |
| 2393 return true; | |
| 2394 bitmap_set_bit (visited, SSA_NAME_VERSION (arg)); | |
| 2395 | |
| 2396 var = arg; | |
| 2397 def_stmt = SSA_NAME_DEF_STMT (var); | |
| 2398 | |
| 2399 switch (gimple_code (def_stmt)) | |
| 2400 { | |
| 2401 case GIMPLE_ASSIGN: | |
| 2402 /* The RHS of the statement defining VAR must either have a | |
| 2403 constant length or come from another SSA_NAME with a constant | |
| 2404 length. */ | |
| 2405 if (gimple_assign_single_p (def_stmt) | |
| 2406 || gimple_assign_unary_nop_p (def_stmt)) | |
| 2407 { | |
| 2408 tree rhs = gimple_assign_rhs1 (def_stmt); | |
| 2409 return get_maxval_strlen (rhs, length, visited, type); | |
| 2410 } | |
| 2411 return false; | |
| 2412 | |
| 2413 case GIMPLE_PHI: | |
| 2414 { | |
| 2415 /* All the arguments of the PHI node must have the same constant | |
| 2416 length. */ | |
| 2417 unsigned i; | |
| 2418 | |
| 2419 for (i = 0; i < gimple_phi_num_args (def_stmt); i++) | |
| 2420 { | |
| 2421 tree arg = gimple_phi_arg (def_stmt, i)->def; | |
| 2422 | |
| 2423 /* If this PHI has itself as an argument, we cannot | |
| 2424 determine the string length of this argument. However, | |
| 2425 if we can find a constant string length for the other | |
| 2426 PHI args then we can still be sure that this is a | |
| 2427 constant string length. So be optimistic and just | |
| 2428 continue with the next argument. */ | |
| 2429 if (arg == gimple_phi_result (def_stmt)) | |
| 2430 continue; | |
| 2431 | |
| 2432 if (!get_maxval_strlen (arg, length, visited, type)) | |
| 2433 return false; | |
| 2434 } | |
| 2435 } | |
| 2436 return true; | |
| 2437 | |
| 2438 default: | |
| 2439 return false; | |
| 2440 } | |
| 2441 } | |
| 2442 | |
| 2443 | |
| 2444 /* Fold builtin call in statement STMT. Returns a simplified tree. | |
| 2445 We may return a non-constant expression, including another call | |
| 2446 to a different function and with different arguments, e.g., | |
| 2447 substituting memcpy for strcpy when the string length is known. | |
| 2448 Note that some builtins expand into inline code that may not | |
| 2449 be valid in GIMPLE. Callers must take care. */ | |
| 2450 | |
| 2451 static tree | |
| 2452 ccp_fold_builtin (gimple stmt) | |
| 2453 { | |
| 2454 tree result, val[3]; | |
| 2455 tree callee, a; | |
| 2456 int arg_idx, type; | |
| 2457 bitmap visited; | |
| 2458 bool ignore; | |
| 2459 int nargs; | |
| 2460 | |
| 2461 gcc_assert (is_gimple_call (stmt)); | |
| 2462 | |
| 2463 ignore = (gimple_call_lhs (stmt) == NULL); | |
| 2464 | |
| 2465 /* First try the generic builtin folder. If that succeeds, return the | |
| 2466 result directly. */ | |
| 2467 result = fold_call_stmt (stmt, ignore); | |
| 2468 if (result) | |
| 2469 { | |
| 2470 if (ignore) | |
| 2471 STRIP_NOPS (result); | |
| 2472 return result; | |
| 2473 } | |
| 2474 | |
| 2475 /* Ignore MD builtins. */ | |
| 2476 callee = gimple_call_fndecl (stmt); | |
| 2477 if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_MD) | |
| 2478 return NULL_TREE; | |
| 2479 | |
| 2480 /* If the builtin could not be folded, and it has no argument list, | |
| 2481 we're done. */ | |
| 2482 nargs = gimple_call_num_args (stmt); | |
| 2483 if (nargs == 0) | |
| 2484 return NULL_TREE; | |
| 2485 | |
| 2486 /* Limit the work only for builtins we know how to simplify. */ | |
| 2487 switch (DECL_FUNCTION_CODE (callee)) | |
| 2488 { | |
| 2489 case BUILT_IN_STRLEN: | |
| 2490 case BUILT_IN_FPUTS: | |
| 2491 case BUILT_IN_FPUTS_UNLOCKED: | |
| 2492 arg_idx = 0; | |
| 2493 type = 0; | |
| 2494 break; | |
| 2495 case BUILT_IN_STRCPY: | |
| 2496 case BUILT_IN_STRNCPY: | |
| 2497 arg_idx = 1; | |
| 2498 type = 0; | |
| 2499 break; | |
| 2500 case BUILT_IN_MEMCPY_CHK: | |
| 2501 case BUILT_IN_MEMPCPY_CHK: | |
| 2502 case BUILT_IN_MEMMOVE_CHK: | |
| 2503 case BUILT_IN_MEMSET_CHK: | |
| 2504 case BUILT_IN_STRNCPY_CHK: | |
| 2505 arg_idx = 2; | |
| 2506 type = 2; | |
| 2507 break; | |
| 2508 case BUILT_IN_STRCPY_CHK: | |
| 2509 case BUILT_IN_STPCPY_CHK: | |
| 2510 arg_idx = 1; | |
| 2511 type = 1; | |
| 2512 break; | |
| 2513 case BUILT_IN_SNPRINTF_CHK: | |
| 2514 case BUILT_IN_VSNPRINTF_CHK: | |
| 2515 arg_idx = 1; | |
| 2516 type = 2; | |
| 2517 break; | |
| 2518 default: | |
| 2519 return NULL_TREE; | |
| 2520 } | |
| 2521 | |
| 2522 if (arg_idx >= nargs) | |
| 2523 return NULL_TREE; | |
| 2524 | |
| 2525 /* Try to use the dataflow information gathered by the CCP process. */ | |
| 2526 visited = BITMAP_ALLOC (NULL); | |
| 2527 bitmap_clear (visited); | |
| 2528 | |
| 2529 memset (val, 0, sizeof (val)); | |
| 2530 a = gimple_call_arg (stmt, arg_idx); | |
| 2531 if (!get_maxval_strlen (a, &val[arg_idx], visited, type)) | |
| 2532 val[arg_idx] = NULL_TREE; | |
| 2533 | |
| 2534 BITMAP_FREE (visited); | |
| 2535 | |
| 2536 result = NULL_TREE; | |
| 2537 switch (DECL_FUNCTION_CODE (callee)) | |
| 2538 { | |
| 2539 case BUILT_IN_STRLEN: | |
| 2540 if (val[0] && nargs == 1) | |
| 2541 { | |
| 2542 tree new_val = | |
| 2543 fold_convert (TREE_TYPE (gimple_call_lhs (stmt)), val[0]); | |
| 2544 | |
| 2545 /* If the result is not a valid gimple value, or not a cast | |
| 2546 of a valid gimple value, then we can not use the result. */ | |
| 2547 if (is_gimple_val (new_val) | |
| 2548 || (is_gimple_cast (new_val) | |
| 2549 && is_gimple_val (TREE_OPERAND (new_val, 0)))) | |
| 2550 return new_val; | |
| 2551 } | |
| 2552 break; | |
| 2553 | |
| 2554 case BUILT_IN_STRCPY: | |
| 2555 if (val[1] && is_gimple_val (val[1]) && nargs == 2) | |
| 2556 result = fold_builtin_strcpy (callee, | |
| 2557 gimple_call_arg (stmt, 0), | |
| 2558 gimple_call_arg (stmt, 1), | |
| 2559 val[1]); | |
| 2560 break; | |
| 2561 | |
| 2562 case BUILT_IN_STRNCPY: | |
| 2563 if (val[1] && is_gimple_val (val[1]) && nargs == 3) | |
| 2564 result = fold_builtin_strncpy (callee, | |
| 2565 gimple_call_arg (stmt, 0), | |
| 2566 gimple_call_arg (stmt, 1), | |
| 2567 gimple_call_arg (stmt, 2), | |
| 2568 val[1]); | |
| 2569 break; | |
| 2570 | |
| 2571 case BUILT_IN_FPUTS: | |
| 2572 if (nargs == 2) | |
| 2573 result = fold_builtin_fputs (gimple_call_arg (stmt, 0), | |
| 2574 gimple_call_arg (stmt, 1), | |
| 2575 ignore, false, val[0]); | |
| 2576 break; | |
| 2577 | |
| 2578 case BUILT_IN_FPUTS_UNLOCKED: | |
| 2579 if (nargs == 2) | |
| 2580 result = fold_builtin_fputs (gimple_call_arg (stmt, 0), | |
| 2581 gimple_call_arg (stmt, 1), | |
| 2582 ignore, true, val[0]); | |
| 2583 break; | |
| 2584 | |
| 2585 case BUILT_IN_MEMCPY_CHK: | |
| 2586 case BUILT_IN_MEMPCPY_CHK: | |
| 2587 case BUILT_IN_MEMMOVE_CHK: | |
| 2588 case BUILT_IN_MEMSET_CHK: | |
| 2589 if (val[2] && is_gimple_val (val[2]) && nargs == 4) | |
| 2590 result = fold_builtin_memory_chk (callee, | |
| 2591 gimple_call_arg (stmt, 0), | |
| 2592 gimple_call_arg (stmt, 1), | |
| 2593 gimple_call_arg (stmt, 2), | |
| 2594 gimple_call_arg (stmt, 3), | |
| 2595 val[2], ignore, | |
| 2596 DECL_FUNCTION_CODE (callee)); | |
| 2597 break; | |
| 2598 | |
| 2599 case BUILT_IN_STRCPY_CHK: | |
| 2600 case BUILT_IN_STPCPY_CHK: | |
| 2601 if (val[1] && is_gimple_val (val[1]) && nargs == 3) | |
| 2602 result = fold_builtin_stxcpy_chk (callee, | |
| 2603 gimple_call_arg (stmt, 0), | |
| 2604 gimple_call_arg (stmt, 1), | |
| 2605 gimple_call_arg (stmt, 2), | |
| 2606 val[1], ignore, | |
| 2607 DECL_FUNCTION_CODE (callee)); | |
| 2608 break; | |
| 2609 | |
| 2610 case BUILT_IN_STRNCPY_CHK: | |
| 2611 if (val[2] && is_gimple_val (val[2]) && nargs == 4) | |
| 2612 result = fold_builtin_strncpy_chk (gimple_call_arg (stmt, 0), | |
| 2613 gimple_call_arg (stmt, 1), | |
| 2614 gimple_call_arg (stmt, 2), | |
| 2615 gimple_call_arg (stmt, 3), | |
| 2616 val[2]); | |
| 2617 break; | |
| 2618 | |
| 2619 case BUILT_IN_SNPRINTF_CHK: | |
| 2620 case BUILT_IN_VSNPRINTF_CHK: | |
| 2621 if (val[1] && is_gimple_val (val[1])) | |
| 2622 result = gimple_fold_builtin_snprintf_chk (stmt, val[1], | |
| 2623 DECL_FUNCTION_CODE (callee)); | |
| 2624 break; | |
| 2625 | |
| 2626 default: | |
| 2627 gcc_unreachable (); | |
| 2628 } | |
| 2629 | |
| 2630 if (result && ignore) | |
| 2631 result = fold_ignored_result (result); | |
| 2632 return result; | |
| 2633 } | |
| 2634 | |
| 2635 /* Attempt to fold an assignment statement pointed-to by SI. Returns a | |
| 2636 replacement rhs for the statement or NULL_TREE if no simplification | |
| 2637 could be made. It is assumed that the operands have been previously | |
| 2638 folded. */ | |
| 2639 | |
| 2640 static tree | |
| 2641 fold_gimple_assign (gimple_stmt_iterator *si) | |
| 2642 { | |
| 2643 gimple stmt = gsi_stmt (*si); | |
| 2644 enum tree_code subcode = gimple_assign_rhs_code (stmt); | |
| 2645 | |
| 2646 tree result = NULL; | |
| 2647 | |
| 2648 switch (get_gimple_rhs_class (subcode)) | |
| 2649 { | |
| 2650 case GIMPLE_SINGLE_RHS: | |
| 2651 { | |
| 2652 tree rhs = gimple_assign_rhs1 (stmt); | |
| 2653 | |
| 2654 /* Try to fold a conditional expression. */ | |
| 2655 if (TREE_CODE (rhs) == COND_EXPR) | |
| 2656 { | |
| 2657 tree temp = fold (COND_EXPR_COND (rhs)); | |
| 2658 if (temp != COND_EXPR_COND (rhs)) | |
| 2659 result = fold_build3 (COND_EXPR, TREE_TYPE (rhs), temp, | |
| 2660 COND_EXPR_THEN (rhs), COND_EXPR_ELSE (rhs)); | |
| 2661 } | |
| 2662 | |
| 2663 /* If we couldn't fold the RHS, hand over to the generic | |
| 2664 fold routines. */ | |
| 2665 if (result == NULL_TREE) | |
| 2666 result = fold (rhs); | |
| 2667 | |
| 2668 /* Strip away useless type conversions. Both the NON_LVALUE_EXPR | |
| 2669 that may have been added by fold, and "useless" type | |
| 2670 conversions that might now be apparent due to propagation. */ | |
| 2671 STRIP_USELESS_TYPE_CONVERSION (result); | |
| 2672 | |
| 2673 if (result != rhs && valid_gimple_rhs_p (result)) | |
| 2674 return result; | |
| 2675 else | |
| 2676 /* It is possible that fold_stmt_r simplified the RHS. | |
| 2677 Make sure that the subcode of this statement still | |
| 2678 reflects the principal operator of the rhs operand. */ | |
| 2679 return rhs; | |
| 2680 } | |
| 2681 break; | |
| 2682 | |
| 2683 case GIMPLE_UNARY_RHS: | |
| 2684 { | |
| 2685 tree rhs = gimple_assign_rhs1 (stmt); | |
| 2686 | |
| 2687 result = fold_unary (subcode, gimple_expr_type (stmt), rhs); | |
| 2688 if (result) | |
| 2689 { | |
| 2690 /* If the operation was a conversion do _not_ mark a | |
| 2691 resulting constant with TREE_OVERFLOW if the original | |
| 2692 constant was not. These conversions have implementation | |
| 2693 defined behavior and retaining the TREE_OVERFLOW flag | |
| 2694 here would confuse later passes such as VRP. */ | |
| 2695 if (CONVERT_EXPR_CODE_P (subcode) | |
| 2696 && TREE_CODE (result) == INTEGER_CST | |
| 2697 && TREE_CODE (rhs) == INTEGER_CST) | |
| 2698 TREE_OVERFLOW (result) = TREE_OVERFLOW (rhs); | |
| 2699 | |
| 2700 STRIP_USELESS_TYPE_CONVERSION (result); | |
| 2701 if (valid_gimple_rhs_p (result)) | |
| 2702 return result; | |
| 2703 } | |
| 2704 else if (CONVERT_EXPR_CODE_P (subcode) | |
| 2705 && POINTER_TYPE_P (gimple_expr_type (stmt)) | |
| 2706 && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))) | |
| 2707 { | |
| 2708 tree type = gimple_expr_type (stmt); | |
| 2709 tree t = maybe_fold_offset_to_address (gimple_assign_rhs1 (stmt), | |
| 2710 integer_zero_node, type); | |
| 2711 if (t) | |
| 2712 return t; | |
| 2713 } | |
| 2714 } | |
| 2715 break; | |
| 2716 | |
| 2717 case GIMPLE_BINARY_RHS: | |
| 2718 /* Try to fold pointer addition. */ | |
| 2719 if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR) | |
| 2720 { | |
| 2721 tree type = TREE_TYPE (gimple_assign_rhs1 (stmt)); | |
| 2722 if (TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE) | |
| 2723 { | |
| 2724 type = build_pointer_type (TREE_TYPE (TREE_TYPE (type))); | |
| 2725 if (!useless_type_conversion_p | |
| 2726 (TREE_TYPE (gimple_assign_lhs (stmt)), type)) | |
| 2727 type = TREE_TYPE (gimple_assign_rhs1 (stmt)); | |
| 2728 } | |
| 2729 result = maybe_fold_stmt_addition (type, | |
| 2730 gimple_assign_rhs1 (stmt), | |
| 2731 gimple_assign_rhs2 (stmt)); | |
| 2732 } | |
| 2733 | |
| 2734 if (!result) | |
| 2735 result = fold_binary (subcode, | |
| 2736 TREE_TYPE (gimple_assign_lhs (stmt)), | |
| 2737 gimple_assign_rhs1 (stmt), | |
| 2738 gimple_assign_rhs2 (stmt)); | |
| 2739 | |
| 2740 if (result) | |
| 2741 { | |
| 2742 STRIP_USELESS_TYPE_CONVERSION (result); | |
| 2743 if (valid_gimple_rhs_p (result)) | |
| 2744 return result; | |
| 2745 | |
| 2746 /* Fold might have produced non-GIMPLE, so if we trust it blindly | |
| 2747 we lose canonicalization opportunities. Do not go again | |
| 2748 through fold here though, or the same non-GIMPLE will be | |
| 2749 produced. */ | |
| 2750 if (commutative_tree_code (subcode) | |
| 2751 && tree_swap_operands_p (gimple_assign_rhs1 (stmt), | |
| 2752 gimple_assign_rhs2 (stmt), false)) | |
| 2753 return build2 (subcode, TREE_TYPE (gimple_assign_lhs (stmt)), | |
| 2754 gimple_assign_rhs2 (stmt), | |
| 2755 gimple_assign_rhs1 (stmt)); | |
| 2756 } | |
| 2757 break; | |
| 2758 | |
| 2759 case GIMPLE_INVALID_RHS: | |
| 2760 gcc_unreachable (); | |
| 2761 } | |
| 2762 | |
| 2763 return NULL_TREE; | |
| 2764 } | |
| 2765 | |
| 2766 /* Attempt to fold a conditional statement. Return true if any changes were | |
| 2767 made. We only attempt to fold the condition expression, and do not perform | |
| 2768 any transformation that would require alteration of the cfg. It is | |
| 2769 assumed that the operands have been previously folded. */ | |
| 2770 | |
| 2771 static bool | |
| 2772 fold_gimple_cond (gimple stmt) | |
| 2773 { | |
| 2774 tree result = fold_binary (gimple_cond_code (stmt), | |
| 2775 boolean_type_node, | |
| 2776 gimple_cond_lhs (stmt), | |
| 2777 gimple_cond_rhs (stmt)); | |
| 2778 | |
| 2779 if (result) | |
| 2780 { | |
| 2781 STRIP_USELESS_TYPE_CONVERSION (result); | |
| 2782 if (is_gimple_condexpr (result) && valid_gimple_rhs_p (result)) | |
| 2783 { | |
| 2784 gimple_cond_set_condition_from_tree (stmt, result); | |
| 2785 return true; | |
| 2786 } | |
| 2787 } | |
| 2788 | |
| 2789 return false; | |
| 2790 } | |
| 2791 | |
| 2792 | |
| 2793 /* Attempt to fold a call statement referenced by the statement iterator GSI. | |
| 2794 The statement may be replaced by another statement, e.g., if the call | |
| 2795 simplifies to a constant value. Return true if any changes were made. | |
| 2796 It is assumed that the operands have been previously folded. */ | |
| 2797 | |
| 2798 static bool | |
| 2799 fold_gimple_call (gimple_stmt_iterator *gsi) | |
| 2800 { | |
| 2801 gimple stmt = gsi_stmt (*gsi); | |
| 2802 | |
| 2803 tree callee = gimple_call_fndecl (stmt); | |
| 2804 | |
| 2805 /* Check for builtins that CCP can handle using information not | |
| 2806 available in the generic fold routines. */ | |
| 2807 if (callee && DECL_BUILT_IN (callee)) | |
| 2808 { | |
| 2809 tree result = ccp_fold_builtin (stmt); | |
| 2810 | |
| 2811 if (result) | |
| 2812 return update_call_from_tree (gsi, result); | |
| 2813 } | |
| 2814 else | |
| 2815 { | |
| 2816 /* Check for resolvable OBJ_TYPE_REF. The only sorts we can resolve | |
| 2817 here are when we've propagated the address of a decl into the | |
| 2818 object slot. */ | |
| 2819 /* ??? Should perhaps do this in fold proper. However, doing it | |
| 2820 there requires that we create a new CALL_EXPR, and that requires | |
| 2821 copying EH region info to the new node. Easier to just do it | |
| 2822 here where we can just smash the call operand. */ | |
| 2823 /* ??? Is there a good reason not to do this in fold_stmt_inplace? */ | |
| 2824 callee = gimple_call_fn (stmt); | |
| 2825 if (TREE_CODE (callee) == OBJ_TYPE_REF | |
| 2826 && lang_hooks.fold_obj_type_ref | |
| 2827 && TREE_CODE (OBJ_TYPE_REF_OBJECT (callee)) == ADDR_EXPR | |
| 2828 && DECL_P (TREE_OPERAND | |
| 2829 (OBJ_TYPE_REF_OBJECT (callee), 0))) | |
| 2830 { | |
| 2831 tree t; | |
| 2832 | |
| 2833 /* ??? Caution: Broken ADDR_EXPR semantics means that | |
| 2834 looking at the type of the operand of the addr_expr | |
| 2835 can yield an array type. See silly exception in | |
| 2836 check_pointer_types_r. */ | |
| 2837 t = TREE_TYPE (TREE_TYPE (OBJ_TYPE_REF_OBJECT (callee))); | |
| 2838 t = lang_hooks.fold_obj_type_ref (callee, t); | |
| 2839 if (t) | |
| 2840 { | |
| 2841 gimple_call_set_fn (stmt, t); | |
| 2842 return true; | |
| 2843 } | |
| 2844 } | |
| 2845 } | |
| 2846 | |
| 2847 return false; | |
| 2848 } | |
| 2849 | |
| 2850 /* Fold the statement pointed to by GSI. In some cases, this function may | |
| 2851 replace the whole statement with a new one. Returns true iff folding | |
| 2852 makes any changes. */ | |
| 2853 | |
| 2854 bool | |
| 2855 fold_stmt (gimple_stmt_iterator *gsi) | |
| 2856 { | |
| 2857 tree res; | |
| 2858 struct fold_stmt_r_data fold_stmt_r_data; | |
| 2859 struct walk_stmt_info wi; | |
| 2860 | |
| 2861 bool changed = false; | |
| 2862 bool inside_addr_expr = false; | |
| 2863 | |
| 2864 gimple stmt = gsi_stmt (*gsi); | |
| 2865 | |
| 2866 fold_stmt_r_data.stmt = stmt; | |
| 2867 fold_stmt_r_data.changed_p = &changed; | |
| 2868 fold_stmt_r_data.inside_addr_expr_p = &inside_addr_expr; | |
| 2869 | |
| 2870 memset (&wi, 0, sizeof (wi)); | |
| 2871 wi.info = &fold_stmt_r_data; | |
| 2872 | |
| 2873 /* Fold the individual operands. | |
| 2874 For example, fold instances of *&VAR into VAR, etc. */ | |
| 2875 res = walk_gimple_op (stmt, fold_stmt_r, &wi); | |
| 2876 gcc_assert (!res); | |
| 2877 | |
| 2878 /* Fold the main computation performed by the statement. */ | |
| 2879 switch (gimple_code (stmt)) | |
| 2880 { | |
| 2881 case GIMPLE_ASSIGN: | |
| 2882 { | |
| 2883 tree new_rhs = fold_gimple_assign (gsi); | |
| 2884 if (new_rhs != NULL_TREE) | |
| 2885 { | |
| 2886 gimple_assign_set_rhs_from_tree (gsi, new_rhs); | |
| 2887 changed = true; | |
| 2888 } | |
| 2889 stmt = gsi_stmt (*gsi); | |
| 2890 break; | |
| 2891 } | |
| 2892 case GIMPLE_COND: | |
| 2893 changed |= fold_gimple_cond (stmt); | |
| 2894 break; | |
| 2895 case GIMPLE_CALL: | |
| 2896 /* The entire statement may be replaced in this case. */ | |
| 2897 changed |= fold_gimple_call (gsi); | |
| 2898 break; | |
| 2899 | |
| 2900 default: | |
| 2901 return changed; | |
| 2902 break; | |
| 2903 } | |
| 2904 | |
| 2905 return changed; | |
| 2906 } | |
| 2907 | |
| 2908 /* Perform the minimal folding on statement STMT. Only operations like | |
| 2909 *&x created by constant propagation are handled. The statement cannot | |
| 2910 be replaced with a new one. Return true if the statement was | |
| 2911 changed, false otherwise. */ | |
| 2912 | |
| 2913 bool | |
| 2914 fold_stmt_inplace (gimple stmt) | |
| 2915 { | |
| 2916 tree res; | |
| 2917 struct fold_stmt_r_data fold_stmt_r_data; | |
| 2918 struct walk_stmt_info wi; | |
| 2919 gimple_stmt_iterator si; | |
| 2920 | |
| 2921 bool changed = false; | |
| 2922 bool inside_addr_expr = false; | |
| 2923 | |
| 2924 fold_stmt_r_data.stmt = stmt; | |
| 2925 fold_stmt_r_data.changed_p = &changed; | |
| 2926 fold_stmt_r_data.inside_addr_expr_p = &inside_addr_expr; | |
| 2927 | |
| 2928 memset (&wi, 0, sizeof (wi)); | |
| 2929 wi.info = &fold_stmt_r_data; | |
| 2930 | |
| 2931 /* Fold the individual operands. | |
| 2932 For example, fold instances of *&VAR into VAR, etc. | |
| 2933 | |
| 2934 It appears that, at one time, maybe_fold_stmt_indirect | |
| 2935 would cause the walk to return non-null in order to | |
| 2936 signal that the entire statement should be replaced with | |
| 2937 a call to _builtin_trap. This functionality is currently | |
| 2938 disabled, as noted in a FIXME, and cannot be supported here. */ | |
| 2939 res = walk_gimple_op (stmt, fold_stmt_r, &wi); | |
| 2940 gcc_assert (!res); | |
| 2941 | |
| 2942 /* Fold the main computation performed by the statement. */ | |
| 2943 switch (gimple_code (stmt)) | |
| 2944 { | |
| 2945 case GIMPLE_ASSIGN: | |
| 2946 { | |
| 2947 unsigned old_num_ops; | |
| 2948 tree new_rhs; | |
| 2949 old_num_ops = gimple_num_ops (stmt); | |
| 2950 si = gsi_for_stmt (stmt); | |
| 2951 new_rhs = fold_gimple_assign (&si); | |
| 2952 if (new_rhs != NULL_TREE | |
| 2953 && get_gimple_rhs_num_ops (TREE_CODE (new_rhs)) < old_num_ops) | |
| 2954 { | |
| 2955 gimple_assign_set_rhs_from_tree (&si, new_rhs); | |
| 2956 changed = true; | |
| 2957 } | |
| 2958 gcc_assert (gsi_stmt (si) == stmt); | |
| 2959 break; | |
| 2960 } | |
| 2961 case GIMPLE_COND: | |
| 2962 changed |= fold_gimple_cond (stmt); | |
| 2963 break; | |
| 2964 | |
| 2965 default: | |
| 2966 break; | |
| 2967 } | |
| 2968 | |
| 2969 return changed; | |
| 2970 } | |
| 2971 | |
| 2972 /* Try to optimize out __builtin_stack_restore. Optimize it out | |
| 2973 if there is another __builtin_stack_restore in the same basic | |
| 2974 block and no calls or ASM_EXPRs are in between, or if this block's | |
| 2975 only outgoing edge is to EXIT_BLOCK and there are no calls or | |
| 2976 ASM_EXPRs after this __builtin_stack_restore. */ | |
| 2977 | |
| 2978 static tree | |
| 2979 optimize_stack_restore (gimple_stmt_iterator i) | |
| 2980 { | |
| 2981 tree callee, rhs; | |
| 2982 gimple stmt, stack_save; | |
| 2983 gimple_stmt_iterator stack_save_gsi; | |
| 2984 | |
| 2985 basic_block bb = gsi_bb (i); | |
| 2986 gimple call = gsi_stmt (i); | |
| 2987 | |
| 2988 if (gimple_code (call) != GIMPLE_CALL | |
| 2989 || gimple_call_num_args (call) != 1 | |
| 2990 || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME | |
| 2991 || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0)))) | |
| 2992 return NULL_TREE; | |
| 2993 | |
| 2994 for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i)) | |
| 2995 { | |
| 2996 stmt = gsi_stmt (i); | |
| 2997 if (gimple_code (stmt) == GIMPLE_ASM) | |
| 2998 return NULL_TREE; | |
| 2999 if (gimple_code (stmt) != GIMPLE_CALL) | |
| 3000 continue; | |
| 3001 | |
| 3002 callee = gimple_call_fndecl (stmt); | |
| 3003 if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) | |
| 3004 return NULL_TREE; | |
| 3005 | |
| 3006 if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE) | |
| 3007 break; | |
| 3008 } | |
| 3009 | |
| 3010 if (gsi_end_p (i) | |
| 3011 && (! single_succ_p (bb) | |
| 3012 || single_succ_edge (bb)->dest != EXIT_BLOCK_PTR)) | |
| 3013 return NULL_TREE; | |
| 3014 | |
| 3015 stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0)); | |
| 3016 if (gimple_code (stack_save) != GIMPLE_CALL | |
| 3017 || gimple_call_lhs (stack_save) != gimple_call_arg (call, 0) | |
| 3018 || stmt_could_throw_p (stack_save) | |
| 3019 || !has_single_use (gimple_call_arg (call, 0))) | |
| 3020 return NULL_TREE; | |
| 3021 | |
| 3022 callee = gimple_call_fndecl (stack_save); | |
| 3023 if (!callee | |
| 3024 || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
| 3025 || DECL_FUNCTION_CODE (callee) != BUILT_IN_STACK_SAVE | |
| 3026 || gimple_call_num_args (stack_save) != 0) | |
| 3027 return NULL_TREE; | |
| 3028 | |
| 3029 stack_save_gsi = gsi_for_stmt (stack_save); | |
| 3030 push_stmt_changes (gsi_stmt_ptr (&stack_save_gsi)); | |
| 3031 rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0); | |
| 3032 if (!update_call_from_tree (&stack_save_gsi, rhs)) | |
| 3033 { | |
| 3034 discard_stmt_changes (gsi_stmt_ptr (&stack_save_gsi)); | |
| 3035 return NULL_TREE; | |
| 3036 } | |
| 3037 pop_stmt_changes (gsi_stmt_ptr (&stack_save_gsi)); | |
| 3038 | |
| 3039 /* No effect, so the statement will be deleted. */ | |
| 3040 return integer_zero_node; | |
| 3041 } | |
| 3042 | |
| 3043 /* If va_list type is a simple pointer and nothing special is needed, | |
| 3044 optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0), | |
| 3045 __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple | |
| 3046 pointer assignment. */ | |
| 3047 | |
| 3048 static tree | |
| 3049 optimize_stdarg_builtin (gimple call) | |
| 3050 { | |
| 3051 tree callee, lhs, rhs, cfun_va_list; | |
| 3052 bool va_list_simple_ptr; | |
| 3053 | |
| 3054 if (gimple_code (call) != GIMPLE_CALL) | |
| 3055 return NULL_TREE; | |
| 3056 | |
| 3057 callee = gimple_call_fndecl (call); | |
| 3058 | |
| 3059 cfun_va_list = targetm.fn_abi_va_list (callee); | |
| 3060 va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list) | |
| 3061 && (TREE_TYPE (cfun_va_list) == void_type_node | |
| 3062 || TREE_TYPE (cfun_va_list) == char_type_node); | |
| 3063 | |
| 3064 switch (DECL_FUNCTION_CODE (callee)) | |
| 3065 { | |
| 3066 case BUILT_IN_VA_START: | |
| 3067 if (!va_list_simple_ptr | |
| 3068 || targetm.expand_builtin_va_start != NULL | |
| 3069 || built_in_decls[BUILT_IN_NEXT_ARG] == NULL) | |
| 3070 return NULL_TREE; | |
| 3071 | |
| 3072 if (gimple_call_num_args (call) != 2) | |
| 3073 return NULL_TREE; | |
| 3074 | |
| 3075 lhs = gimple_call_arg (call, 0); | |
| 3076 if (!POINTER_TYPE_P (TREE_TYPE (lhs)) | |
| 3077 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
| 3078 != TYPE_MAIN_VARIANT (cfun_va_list)) | |
| 3079 return NULL_TREE; | |
| 3080 | |
| 3081 lhs = build_fold_indirect_ref (lhs); | |
| 3082 rhs = build_call_expr (built_in_decls[BUILT_IN_NEXT_ARG], | |
| 3083 1, integer_zero_node); | |
| 3084 rhs = fold_convert (TREE_TYPE (lhs), rhs); | |
| 3085 return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); | |
| 3086 | |
| 3087 case BUILT_IN_VA_COPY: | |
| 3088 if (!va_list_simple_ptr) | |
| 3089 return NULL_TREE; | |
| 3090 | |
| 3091 if (gimple_call_num_args (call) != 2) | |
| 3092 return NULL_TREE; | |
| 3093 | |
| 3094 lhs = gimple_call_arg (call, 0); | |
| 3095 if (!POINTER_TYPE_P (TREE_TYPE (lhs)) | |
| 3096 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) | |
| 3097 != TYPE_MAIN_VARIANT (cfun_va_list)) | |
| 3098 return NULL_TREE; | |
| 3099 | |
| 3100 lhs = build_fold_indirect_ref (lhs); | |
| 3101 rhs = gimple_call_arg (call, 1); | |
| 3102 if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs)) | |
| 3103 != TYPE_MAIN_VARIANT (cfun_va_list)) | |
| 3104 return NULL_TREE; | |
| 3105 | |
| 3106 rhs = fold_convert (TREE_TYPE (lhs), rhs); | |
| 3107 return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); | |
| 3108 | |
| 3109 case BUILT_IN_VA_END: | |
| 3110 /* No effect, so the statement will be deleted. */ | |
| 3111 return integer_zero_node; | |
| 3112 | |
| 3113 default: | |
| 3114 gcc_unreachable (); | |
| 3115 } | |
| 3116 } | |
| 3117 | |
| 3118 /* Convert EXPR into a GIMPLE value suitable for substitution on the | |
| 3119 RHS of an assignment. Insert the necessary statements before | |
| 3120 iterator *SI_P. The statement at *SI_P, which must be a GIMPLE_CALL | |
| 3121 is replaced. If the call is expected to produces a result, then it | |
| 3122 is replaced by an assignment of the new RHS to the result variable. | |
| 3123 If the result is to be ignored, then the call is replaced by a | |
| 3124 GIMPLE_NOP. */ | |
| 3125 | |
| 3126 static void | |
| 3127 gimplify_and_update_call_from_tree (gimple_stmt_iterator *si_p, tree expr) | |
| 3128 { | |
| 3129 tree lhs; | |
| 3130 tree tmp = NULL_TREE; /* Silence warning. */ | |
| 3131 gimple stmt, new_stmt; | |
| 3132 gimple_stmt_iterator i; | |
| 3133 gimple_seq stmts = gimple_seq_alloc(); | |
| 3134 struct gimplify_ctx gctx; | |
| 3135 | |
| 3136 stmt = gsi_stmt (*si_p); | |
| 3137 | |
| 3138 gcc_assert (is_gimple_call (stmt)); | |
| 3139 | |
| 3140 lhs = gimple_call_lhs (stmt); | |
| 3141 | |
| 3142 push_gimplify_context (&gctx); | |
| 3143 | |
| 3144 if (lhs == NULL_TREE) | |
| 3145 gimplify_and_add (expr, &stmts); | |
| 3146 else | |
| 3147 tmp = get_initialized_tmp_var (expr, &stmts, NULL); | |
| 3148 | |
| 3149 pop_gimplify_context (NULL); | |
| 3150 | |
| 3151 if (gimple_has_location (stmt)) | |
| 3152 annotate_all_with_location (stmts, gimple_location (stmt)); | |
| 3153 | |
| 3154 /* The replacement can expose previously unreferenced variables. */ | |
| 3155 for (i = gsi_start (stmts); !gsi_end_p (i); gsi_next (&i)) | |
| 3156 { | |
| 3157 new_stmt = gsi_stmt (i); | |
| 3158 find_new_referenced_vars (new_stmt); | |
| 3159 gsi_insert_before (si_p, new_stmt, GSI_NEW_STMT); | |
| 3160 mark_symbols_for_renaming (new_stmt); | |
| 3161 gsi_next (si_p); | |
| 3162 } | |
| 3163 | |
| 3164 if (lhs == NULL_TREE) | |
| 3165 new_stmt = gimple_build_nop (); | |
| 3166 else | |
| 3167 { | |
| 3168 new_stmt = gimple_build_assign (lhs, tmp); | |
| 3169 copy_virtual_operands (new_stmt, stmt); | |
| 3170 move_ssa_defining_stmt_for_defs (new_stmt, stmt); | |
| 3171 } | |
| 3172 | |
| 3173 gimple_set_location (new_stmt, gimple_location (stmt)); | |
| 3174 gsi_replace (si_p, new_stmt, false); | |
| 3175 } | |
| 3176 | |
| 3177 /* A simple pass that attempts to fold all builtin functions. This pass | |
| 3178 is run after we've propagated as many constants as we can. */ | |
| 3179 | |
| 3180 static unsigned int | |
| 3181 execute_fold_all_builtins (void) | |
| 3182 { | |
| 3183 bool cfg_changed = false; | |
| 3184 basic_block bb; | |
| 3185 unsigned int todoflags = 0; | |
| 3186 | |
| 3187 FOR_EACH_BB (bb) | |
| 3188 { | |
| 3189 gimple_stmt_iterator i; | |
| 3190 for (i = gsi_start_bb (bb); !gsi_end_p (i); ) | |
| 3191 { | |
| 3192 gimple stmt, old_stmt; | |
| 3193 tree callee, result; | |
| 3194 enum built_in_function fcode; | |
| 3195 | |
| 3196 stmt = gsi_stmt (i); | |
| 3197 | |
| 3198 if (gimple_code (stmt) != GIMPLE_CALL) | |
| 3199 { | |
| 3200 gsi_next (&i); | |
| 3201 continue; | |
| 3202 } | |
| 3203 callee = gimple_call_fndecl (stmt); | |
| 3204 if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) | |
| 3205 { | |
| 3206 gsi_next (&i); | |
| 3207 continue; | |
| 3208 } | |
| 3209 fcode = DECL_FUNCTION_CODE (callee); | |
| 3210 | |
| 3211 result = ccp_fold_builtin (stmt); | |
| 3212 | |
| 3213 if (result) | |
| 3214 gimple_remove_stmt_histograms (cfun, stmt); | |
| 3215 | |
| 3216 if (!result) | |
| 3217 switch (DECL_FUNCTION_CODE (callee)) | |
| 3218 { | |
| 3219 case BUILT_IN_CONSTANT_P: | |
| 3220 /* Resolve __builtin_constant_p. If it hasn't been | |
| 3221 folded to integer_one_node by now, it's fairly | |
| 3222 certain that the value simply isn't constant. */ | |
| 3223 result = integer_zero_node; | |
| 3224 break; | |
| 3225 | |
| 3226 case BUILT_IN_STACK_RESTORE: | |
| 3227 result = optimize_stack_restore (i); | |
| 3228 if (result) | |
| 3229 break; | |
| 3230 gsi_next (&i); | |
| 3231 continue; | |
| 3232 | |
| 3233 case BUILT_IN_VA_START: | |
| 3234 case BUILT_IN_VA_END: | |
| 3235 case BUILT_IN_VA_COPY: | |
| 3236 /* These shouldn't be folded before pass_stdarg. */ | |
| 3237 result = optimize_stdarg_builtin (stmt); | |
| 3238 if (result) | |
| 3239 break; | |
| 3240 /* FALLTHRU */ | |
| 3241 | |
| 3242 default: | |
| 3243 gsi_next (&i); | |
| 3244 continue; | |
| 3245 } | |
| 3246 | |
| 3247 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 3248 { | |
| 3249 fprintf (dump_file, "Simplified\n "); | |
| 3250 print_gimple_stmt (dump_file, stmt, 0, dump_flags); | |
| 3251 } | |
| 3252 | |
| 3253 old_stmt = stmt; | |
| 3254 push_stmt_changes (gsi_stmt_ptr (&i)); | |
| 3255 | |
| 3256 if (!update_call_from_tree (&i, result)) | |
| 3257 { | |
| 3258 gimplify_and_update_call_from_tree (&i, result); | |
| 3259 todoflags |= TODO_rebuild_alias; | |
| 3260 } | |
| 3261 | |
| 3262 stmt = gsi_stmt (i); | |
| 3263 pop_stmt_changes (gsi_stmt_ptr (&i)); | |
| 3264 | |
| 3265 if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt) | |
| 3266 && gimple_purge_dead_eh_edges (bb)) | |
| 3267 cfg_changed = true; | |
| 3268 | |
| 3269 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 3270 { | |
| 3271 fprintf (dump_file, "to\n "); | |
| 3272 print_gimple_stmt (dump_file, stmt, 0, dump_flags); | |
| 3273 fprintf (dump_file, "\n"); | |
| 3274 } | |
| 3275 | |
| 3276 /* Retry the same statement if it changed into another | |
| 3277 builtin, there might be new opportunities now. */ | |
| 3278 if (gimple_code (stmt) != GIMPLE_CALL) | |
| 3279 { | |
| 3280 gsi_next (&i); | |
| 3281 continue; | |
| 3282 } | |
| 3283 callee = gimple_call_fndecl (stmt); | |
| 3284 if (!callee | |
| 3285 || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL | |
| 3286 || DECL_FUNCTION_CODE (callee) == fcode) | |
| 3287 gsi_next (&i); | |
| 3288 } | |
| 3289 } | |
| 3290 | |
| 3291 /* Delete unreachable blocks. */ | |
| 3292 if (cfg_changed) | |
| 3293 todoflags |= TODO_cleanup_cfg; | |
| 3294 | |
| 3295 return todoflags; | |
| 3296 } | |
| 3297 | |
| 3298 | |
| 3299 struct gimple_opt_pass pass_fold_builtins = | |
| 3300 { | |
| 3301 { | |
| 3302 GIMPLE_PASS, | |
| 3303 "fab", /* name */ | |
| 3304 NULL, /* gate */ | |
| 3305 execute_fold_all_builtins, /* execute */ | |
| 3306 NULL, /* sub */ | |
| 3307 NULL, /* next */ | |
| 3308 0, /* static_pass_number */ | |
| 3309 0, /* tv_id */ | |
| 3310 PROP_cfg | PROP_ssa, /* properties_required */ | |
| 3311 0, /* properties_provided */ | |
| 3312 0, /* properties_destroyed */ | |
| 3313 0, /* todo_flags_start */ | |
| 3314 TODO_dump_func | |
| 3315 | TODO_verify_ssa | |
| 3316 | TODO_update_ssa /* todo_flags_finish */ | |
| 3317 } | |
| 3318 }; |