1 /* Conditional constant propagation pass for the GNU compiler. 2 Copyright (C) 2000-2015 Free Software Foundation, Inc. 3 Adapted from original RTL SSA-CCP by Daniel Berlin <dberlin@dberlin.org> 4 Adapted to GIMPLE trees by Diego Novillo <dnovillo@redhat.com> 5 6 This file is part of GCC. 7 8 GCC is free software; you can redistribute it and/or modify it 9 under the terms of the GNU General Public License as published by the 10 Free Software Foundation; either version 3, or (at your option) any 11 later version. 12 13 GCC is distributed in the hope that it will be useful, but WITHOUT 14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16 for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with GCC; see the file COPYING3. If not see 20 <http://www.gnu.org/licenses/>. */ 21 22 /* Conditional constant propagation (CCP) is based on the SSA 23 propagation engine (tree-ssa-propagate.c). Constant assignments of 24 the form VAR = CST are propagated from the assignments into uses of 25 VAR, which in turn may generate new constants. The simulation uses 26 a four level lattice to keep track of constant values associated 27 with SSA names. Given an SSA name V_i, it may take one of the 28 following values: 29 30 UNINITIALIZED -> the initial state of the value. This value 31 is replaced with a correct initial value 32 the first time the value is used, so the 33 rest of the pass does not need to care about 34 it. Using this value simplifies initialization 35 of the pass, and prevents us from needlessly 36 scanning statements that are never reached. 37 38 UNDEFINED -> V_i is a local variable whose definition 39 has not been processed yet. Therefore we 40 don't yet know if its value is a constant 41 or not. 42 43 CONSTANT -> V_i has been found to hold a constant 44 value C. 45 46 VARYING -> V_i cannot take a constant value, or if it 47 does, it is not possible to determine it 48 at compile time. 49 50 The core of SSA-CCP is in ccp_visit_stmt and ccp_visit_phi_node: 51 52 1- In ccp_visit_stmt, we are interested in assignments whose RHS 53 evaluates into a constant and conditional jumps whose predicate 54 evaluates into a boolean true or false. When an assignment of 55 the form V_i = CONST is found, V_i's lattice value is set to 56 CONSTANT and CONST is associated with it. This causes the 57 propagation engine to add all the SSA edges coming out the 58 assignment into the worklists, so that statements that use V_i 59 can be visited. 60 61 If the statement is a conditional with a constant predicate, we 62 mark the outgoing edges as executable or not executable 63 depending on the predicate's value. This is then used when 64 visiting PHI nodes to know when a PHI argument can be ignored. 65 66 67 2- In ccp_visit_phi_node, if all the PHI arguments evaluate to the 68 same constant C, then the LHS of the PHI is set to C. This 69 evaluation is known as the "meet operation". Since one of the 70 goals of this evaluation is to optimistically return constant 71 values as often as possible, it uses two main short cuts: 72 73 - If an argument is flowing in through a non-executable edge, it 74 is ignored. This is useful in cases like this: 75 76 if (PRED) 77 a_9 = 3; 78 else 79 a_10 = 100; 80 a_11 = PHI (a_9, a_10) 81 82 If PRED is known to always evaluate to false, then we can 83 assume that a_11 will always take its value from a_10, meaning 84 that instead of consider it VARYING (a_9 and a_10 have 85 different values), we can consider it CONSTANT 100. 86 87 - If an argument has an UNDEFINED value, then it does not affect 88 the outcome of the meet operation. If a variable V_i has an 89 UNDEFINED value, it means that either its defining statement 90 hasn't been visited yet or V_i has no defining statement, in 91 which case the original symbol 'V' is being used 92 uninitialized. Since 'V' is a local variable, the compiler 93 may assume any initial value for it. 94 95 96 After propagation, every variable V_i that ends up with a lattice 97 value of CONSTANT will have the associated constant value in the 98 array CONST_VAL[i].VALUE. That is fed into substitute_and_fold for 99 final substitution and folding. 100 101 This algorithm uses wide-ints at the max precision of the target. 102 This means that, with one uninteresting exception, variables with 103 UNSIGNED types never go to VARYING because the bits above the 104 precision of the type of the variable are always zero. The 105 uninteresting case is a variable of UNSIGNED type that has the 106 maximum precision of the target. Such variables can go to VARYING, 107 but this causes no loss of infomation since these variables will 108 never be extended. 109 110 References: 111 112 Constant propagation with conditional branches, 113 Wegman and Zadeck, ACM TOPLAS 13(2):181-210. 114 115 Building an Optimizing Compiler, 116 Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9. 117 118 Advanced Compiler Design and Implementation, 119 Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */ 120 121 #include "config.h" 122 #include "system.h" 123 #include "coretypes.h" 124 #include "tm.h" 125 #include "hash-set.h" 126 #include "machmode.h" 127 #include "vec.h" 128 #include "double-int.h" 129 #include "input.h" 130 #include "alias.h" 131 #include "symtab.h" 132 #include "wide-int.h" 133 #include "inchash.h" 134 #include "real.h" 135 #include "tree.h" 136 #include "fold-const.h" 137 #include "stor-layout.h" 138 #include "flags.h" 139 #include "tm_p.h" 140 #include "predict.h" 141 #include "hard-reg-set.h" 142 #include "input.h" 143 #include "function.h" 144 #include "dominance.h" 145 #include "cfg.h" 146 #include "basic-block.h" 147 #include "gimple-pretty-print.h" 148 #include "hash-table.h" 149 #include "tree-ssa-alias.h" 150 #include "internal-fn.h" 151 #include "gimple-fold.h" 152 #include "tree-eh.h" 153 #include "gimple-expr.h" 154 #include "is-a.h" 155 #include "gimple.h" 156 #include "gimplify.h" 157 #include "gimple-iterator.h" 158 #include "gimple-ssa.h" 159 #include "tree-cfg.h" 160 #include "tree-phinodes.h" 161 #include "ssa-iterators.h" 162 #include "stringpool.h" 163 #include "tree-ssanames.h" 164 #include "tree-pass.h" 165 #include "tree-ssa-propagate.h" 166 #include "value-prof.h" 167 #include "langhooks.h" 168 #include "target.h" 169 #include "diagnostic-core.h" 170 #include "dbgcnt.h" 171 #include "params.h" 172 #include "wide-int-print.h" 173 #include "builtins.h" 174 #include "tree-chkp.h" 175 176 177 /* Possible lattice values. */ 178 typedef enum 179 { 180 UNINITIALIZED, 181 UNDEFINED, 182 CONSTANT, 183 VARYING 184 } ccp_lattice_t; 185 186 struct ccp_prop_value_t { 187 /* Lattice value. */ 188 ccp_lattice_t lattice_val; 189 190 /* Propagated value. */ 191 tree value; 192 193 /* Mask that applies to the propagated value during CCP. For X 194 with a CONSTANT lattice value X & ~mask == value & ~mask. The 195 zero bits in the mask cover constant values. The ones mean no 196 information. */ 197 widest_int mask; 198 }; 199 200 /* Array of propagated constant values. After propagation, 201 CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If 202 the constant is held in an SSA name representing a memory store 203 (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual 204 memory reference used to store (i.e., the LHS of the assignment 205 doing the store). */ 206 static ccp_prop_value_t *const_val; 207 static unsigned n_const_val; 208 209 static void canonicalize_value (ccp_prop_value_t *); 210 static bool ccp_fold_stmt (gimple_stmt_iterator *); 211 212 /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ 213 214 static void 215 dump_lattice_value (FILE *outf, const char *prefix, ccp_prop_value_t val) 216 { 217 switch (val.lattice_val) 218 { 219 case UNINITIALIZED: 220 fprintf (outf, "%sUNINITIALIZED", prefix); 221 break; 222 case UNDEFINED: 223 fprintf (outf, "%sUNDEFINED", prefix); 224 break; 225 case VARYING: 226 fprintf (outf, "%sVARYING", prefix); 227 break; 228 case CONSTANT: 229 if (TREE_CODE (val.value) != INTEGER_CST 230 || val.mask == 0) 231 { 232 fprintf (outf, "%sCONSTANT ", prefix); 233 print_generic_expr (outf, val.value, dump_flags); 234 } 235 else 236 { 237 widest_int cval = wi::bit_and_not (wi::to_widest (val.value), 238 val.mask); 239 fprintf (outf, "%sCONSTANT ", prefix); 240 print_hex (cval, outf); 241 fprintf (outf, " ("); 242 print_hex (val.mask, outf); 243 fprintf (outf, ")"); 244 } 245 break; 246 default: 247 gcc_unreachable (); 248 } 249 } 250 251 252 /* Print lattice value VAL to stderr. */ 253 254 void debug_lattice_value (ccp_prop_value_t val); 255 256 DEBUG_FUNCTION void 257 debug_lattice_value (ccp_prop_value_t val) 258 { 259 dump_lattice_value (stderr, "", val); 260 fprintf (stderr, "\n"); 261 } 262 263 /* Extend NONZERO_BITS to a full mask, with the upper bits being set. */ 264 265 static widest_int 266 extend_mask (const wide_int &nonzero_bits) 267 { 268 return (wi::mask <widest_int> (wi::get_precision (nonzero_bits), true) 269 | widest_int::from (nonzero_bits, UNSIGNED)); 270 } 271 272 /* Compute a default value for variable VAR and store it in the 273 CONST_VAL array. The following rules are used to get default 274 values: 275 276 1- Global and static variables that are declared constant are 277 considered CONSTANT. 278 279 2- Any other value is considered UNDEFINED. This is useful when 280 considering PHI nodes. PHI arguments that are undefined do not 281 change the constant value of the PHI node, which allows for more 282 constants to be propagated. 283 284 3- Variables defined by statements other than assignments and PHI 285 nodes are considered VARYING. 286 287 4- Initial values of variables that are not GIMPLE registers are 288 considered VARYING. */ 289 290 static ccp_prop_value_t 291 get_default_value (tree var) 292 { 293 ccp_prop_value_t val = { UNINITIALIZED, NULL_TREE, 0 }; 294 gimple stmt; 295 296 stmt = SSA_NAME_DEF_STMT (var); 297 298 if (gimple_nop_p (stmt)) 299 { 300 /* Variables defined by an empty statement are those used 301 before being initialized. If VAR is a local variable, we 302 can assume initially that it is UNDEFINED, otherwise we must 303 consider it VARYING. */ 304 if (!virtual_operand_p (var) 305 && TREE_CODE (SSA_NAME_VAR (var)) == VAR_DECL) 306 val.lattice_val = UNDEFINED; 307 else 308 { 309 val.lattice_val = VARYING; 310 val.mask = -1; 311 if (flag_tree_bit_ccp) 312 { 313 wide_int nonzero_bits = get_nonzero_bits (var); 314 if (nonzero_bits != -1) 315 { 316 val.lattice_val = CONSTANT; 317 val.value = build_zero_cst (TREE_TYPE (var)); 318 val.mask = extend_mask (nonzero_bits); 319 } 320 } 321 } 322 } 323 else if (is_gimple_assign (stmt)) 324 { 325 tree cst; 326 if (gimple_assign_single_p (stmt) 327 && DECL_P (gimple_assign_rhs1 (stmt)) 328 && (cst = get_symbol_constant_value (gimple_assign_rhs1 (stmt)))) 329 { 330 val.lattice_val = CONSTANT; 331 val.value = cst; 332 } 333 else 334 { 335 /* Any other variable defined by an assignment is considered 336 UNDEFINED. */ 337 val.lattice_val = UNDEFINED; 338 } 339 } 340 else if ((is_gimple_call (stmt) 341 && gimple_call_lhs (stmt) != NULL_TREE) 342 || gimple_code (stmt) == GIMPLE_PHI) 343 { 344 /* A variable defined by a call or a PHI node is considered 345 UNDEFINED. */ 346 val.lattice_val = UNDEFINED; 347 } 348 else 349 { 350 /* Otherwise, VAR will never take on a constant value. */ 351 val.lattice_val = VARYING; 352 val.mask = -1; 353 } 354 355 return val; 356 } 357 358 359 /* Get the constant value associated with variable VAR. */ 360 361 static inline ccp_prop_value_t * 362 get_value (tree var) 363 { 364 ccp_prop_value_t *val; 365 366 if (const_val == NULL 367 || SSA_NAME_VERSION (var) >= n_const_val) 368 return NULL; 369 370 val = &const_val[SSA_NAME_VERSION (var)]; 371 if (val->lattice_val == UNINITIALIZED) 372 *val = get_default_value (var); 373 374 canonicalize_value (val); 375 376 return val; 377 } 378 379 /* Return the constant tree value associated with VAR. */ 380 381 static inline tree 382 get_constant_value (tree var) 383 { 384 ccp_prop_value_t *val; 385 if (TREE_CODE (var) != SSA_NAME) 386 { 387 if (is_gimple_min_invariant (var)) 388 return var; 389 return NULL_TREE; 390 } 391 val = get_value (var); 392 if (val 393 && val->lattice_val == CONSTANT 394 && (TREE_CODE (val->value) != INTEGER_CST 395 || val->mask == 0)) 396 return val->value; 397 return NULL_TREE; 398 } 399 400 /* Sets the value associated with VAR to VARYING. */ 401 402 static inline void 403 set_value_varying (tree var) 404 { 405 ccp_prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; 406 407 val->lattice_val = VARYING; 408 val->value = NULL_TREE; 409 val->mask = -1; 410 } 411 412 /* For integer constants, make sure to drop TREE_OVERFLOW. */ 413 414 static void 415 canonicalize_value (ccp_prop_value_t *val) 416 { 417 if (val->lattice_val != CONSTANT) 418 return; 419 420 if (TREE_OVERFLOW_P (val->value)) 421 val->value = drop_tree_overflow (val->value); 422 } 423 424 /* Return whether the lattice transition is valid. */ 425 426 static bool 427 valid_lattice_transition (ccp_prop_value_t old_val, ccp_prop_value_t new_val) 428 { 429 /* Lattice transitions must always be monotonically increasing in 430 value. */ 431 if (old_val.lattice_val < new_val.lattice_val) 432 return true; 433 434 if (old_val.lattice_val != new_val.lattice_val) 435 return false; 436 437 if (!old_val.value && !new_val.value) 438 return true; 439 440 /* Now both lattice values are CONSTANT. */ 441 442 /* Allow transitioning from PHI <&x, not executable> == &x 443 to PHI <&x, &y> == common alignment. */ 444 if (TREE_CODE (old_val.value) != INTEGER_CST 445 && TREE_CODE (new_val.value) == INTEGER_CST) 446 return true; 447 448 /* Bit-lattices have to agree in the still valid bits. */ 449 if (TREE_CODE (old_val.value) == INTEGER_CST 450 && TREE_CODE (new_val.value) == INTEGER_CST) 451 return (wi::bit_and_not (wi::to_widest (old_val.value), new_val.mask) 452 == wi::bit_and_not (wi::to_widest (new_val.value), new_val.mask)); 453 454 /* Otherwise constant values have to agree. */ 455 if (operand_equal_p (old_val.value, new_val.value, 0)) 456 return true; 457 458 /* At least the kinds and types should agree now. */ 459 if (TREE_CODE (old_val.value) != TREE_CODE (new_val.value) 460 || !types_compatible_p (TREE_TYPE (old_val.value), 461 TREE_TYPE (new_val.value))) 462 return false; 463 464 /* For floats and !HONOR_NANS allow transitions from (partial) NaN 465 to non-NaN. */ 466 tree type = TREE_TYPE (new_val.value); 467 if (SCALAR_FLOAT_TYPE_P (type) 468 && !HONOR_NANS (type)) 469 { 470 if (REAL_VALUE_ISNAN (TREE_REAL_CST (old_val.value))) 471 return true; 472 } 473 else if (VECTOR_FLOAT_TYPE_P (type) 474 && !HONOR_NANS (type)) 475 { 476 for (unsigned i = 0; i < VECTOR_CST_NELTS (old_val.value); ++i) 477 if (!REAL_VALUE_ISNAN 478 (TREE_REAL_CST (VECTOR_CST_ELT (old_val.value, i))) 479 && !operand_equal_p (VECTOR_CST_ELT (old_val.value, i), 480 VECTOR_CST_ELT (new_val.value, i), 0)) 481 return false; 482 return true; 483 } 484 else if (COMPLEX_FLOAT_TYPE_P (type) 485 && !HONOR_NANS (type)) 486 { 487 if (!REAL_VALUE_ISNAN (TREE_REAL_CST (TREE_REALPART (old_val.value))) 488 && !operand_equal_p (TREE_REALPART (old_val.value), 489 TREE_REALPART (new_val.value), 0)) 490 return false; 491 if (!REAL_VALUE_ISNAN (TREE_REAL_CST (TREE_IMAGPART (old_val.value))) 492 && !operand_equal_p (TREE_IMAGPART (old_val.value), 493 TREE_IMAGPART (new_val.value), 0)) 494 return false; 495 return true; 496 } 497 return false; 498 } 499 500 /* Set the value for variable VAR to NEW_VAL. Return true if the new 501 value is different from VAR's previous value. */ 502 503 static bool 504 set_lattice_value (tree var, ccp_prop_value_t new_val) 505 { 506 /* We can deal with old UNINITIALIZED values just fine here. */ 507 ccp_prop_value_t *old_val = &const_val[SSA_NAME_VERSION (var)]; 508 509 canonicalize_value (&new_val); 510 511 /* We have to be careful to not go up the bitwise lattice 512 represented by the mask. 513 ??? This doesn't seem to be the best place to enforce this. */ 514 if (new_val.lattice_val == CONSTANT 515 && old_val->lattice_val == CONSTANT 516 && TREE_CODE (new_val.value) == INTEGER_CST 517 && TREE_CODE (old_val->value) == INTEGER_CST) 518 { 519 widest_int diff = (wi::to_widest (new_val.value) 520 ^ wi::to_widest (old_val->value)); 521 new_val.mask = new_val.mask | old_val->mask | diff; 522 } 523 524 gcc_checking_assert (valid_lattice_transition (*old_val, new_val)); 525 526 /* If *OLD_VAL and NEW_VAL are the same, return false to inform the 527 caller that this was a non-transition. */ 528 if (old_val->lattice_val != new_val.lattice_val 529 || (new_val.lattice_val == CONSTANT 530 && TREE_CODE (new_val.value) == INTEGER_CST 531 && (TREE_CODE (old_val->value) != INTEGER_CST 532 || new_val.mask != old_val->mask))) 533 { 534 /* ??? We would like to delay creation of INTEGER_CSTs from 535 partially constants here. */ 536 537 if (dump_file && (dump_flags & TDF_DETAILS)) 538 { 539 dump_lattice_value (dump_file, "Lattice value changed to ", new_val); 540 fprintf (dump_file, ". Adding SSA edges to worklist.\n"); 541 } 542 543 *old_val = new_val; 544 545 gcc_assert (new_val.lattice_val != UNINITIALIZED); 546 return true; 547 } 548 549 return false; 550 } 551 552 static ccp_prop_value_t get_value_for_expr (tree, bool); 553 static ccp_prop_value_t bit_value_binop (enum tree_code, tree, tree, tree); 554 static void bit_value_binop_1 (enum tree_code, tree, widest_int *, widest_int *, 555 tree, const widest_int &, const widest_int &, 556 tree, const widest_int &, const widest_int &); 557 558 /* Return a widest_int that can be used for bitwise simplifications 559 from VAL. */ 560 561 static widest_int 562 value_to_wide_int (ccp_prop_value_t val) 563 { 564 if (val.value 565 && TREE_CODE (val.value) == INTEGER_CST) 566 return wi::to_widest (val.value); 567 568 return 0; 569 } 570 571 /* Return the value for the address expression EXPR based on alignment 572 information. */ 573 574 static ccp_prop_value_t 575 get_value_from_alignment (tree expr) 576 { 577 tree type = TREE_TYPE (expr); 578 ccp_prop_value_t val; 579 unsigned HOST_WIDE_INT bitpos; 580 unsigned int align; 581 582 gcc_assert (TREE_CODE (expr) == ADDR_EXPR); 583 584 get_pointer_alignment_1 (expr, &align, &bitpos); 585 val.mask = (POINTER_TYPE_P (type) || TYPE_UNSIGNED (type) 586 ? wi::mask <widest_int> (TYPE_PRECISION (type), false) 587 : -1).and_not (align / BITS_PER_UNIT - 1); 588 val.lattice_val = val.mask == -1 ? VARYING : CONSTANT; 589 if (val.lattice_val == CONSTANT) 590 val.value = build_int_cstu (type, bitpos / BITS_PER_UNIT); 591 else 592 val.value = NULL_TREE; 593 594 return val; 595 } 596 597 /* Return the value for the tree operand EXPR. If FOR_BITS_P is true 598 return constant bits extracted from alignment information for 599 invariant addresses. */ 600 601 static ccp_prop_value_t 602 get_value_for_expr (tree expr, bool for_bits_p) 603 { 604 ccp_prop_value_t val; 605 606 if (TREE_CODE (expr) == SSA_NAME) 607 { 608 val = *get_value (expr); 609 if (for_bits_p 610 && val.lattice_val == CONSTANT 611 && TREE_CODE (val.value) == ADDR_EXPR) 612 val = get_value_from_alignment (val.value); 613 } 614 else if (is_gimple_min_invariant (expr) 615 && (!for_bits_p || TREE_CODE (expr) != ADDR_EXPR)) 616 { 617 val.lattice_val = CONSTANT; 618 val.value = expr; 619 val.mask = 0; 620 canonicalize_value (&val); 621 } 622 else if (TREE_CODE (expr) == ADDR_EXPR) 623 val = get_value_from_alignment (expr); 624 else 625 { 626 val.lattice_val = VARYING; 627 val.mask = -1; 628 val.value = NULL_TREE; 629 } 630 return val; 631 } 632 633 /* Return the likely CCP lattice value for STMT. 634 635 If STMT has no operands, then return CONSTANT. 636 637 Else if undefinedness of operands of STMT cause its value to be 638 undefined, then return UNDEFINED. 639 640 Else if any operands of STMT are constants, then return CONSTANT. 641 642 Else return VARYING. */ 643 644 static ccp_lattice_t 645 likely_value (gimple stmt) 646 { 647 bool has_constant_operand, has_undefined_operand, all_undefined_operands; 648 tree use; 649 ssa_op_iter iter; 650 unsigned i; 651 652 enum gimple_code code = gimple_code (stmt); 653 654 /* This function appears to be called only for assignments, calls, 655 conditionals, and switches, due to the logic in visit_stmt. */ 656 gcc_assert (code == GIMPLE_ASSIGN 657 || code == GIMPLE_CALL 658 || code == GIMPLE_COND 659 || code == GIMPLE_SWITCH); 660 661 /* If the statement has volatile operands, it won't fold to a 662 constant value. */ 663 if (gimple_has_volatile_ops (stmt)) 664 return VARYING; 665 666 /* Arrive here for more complex cases. */ 667 has_constant_operand = false; 668 has_undefined_operand = false; 669 all_undefined_operands = true; 670 FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) 671 { 672 ccp_prop_value_t *val = get_value (use); 673 674 if (val->lattice_val == UNDEFINED) 675 has_undefined_operand = true; 676 else 677 all_undefined_operands = false; 678 679 if (val->lattice_val == CONSTANT) 680 has_constant_operand = true; 681 } 682 683 /* There may be constants in regular rhs operands. For calls we 684 have to ignore lhs, fndecl and static chain, otherwise only 685 the lhs. */ 686 for (i = (is_gimple_call (stmt) ? 2 : 0) + gimple_has_lhs (stmt); 687 i < gimple_num_ops (stmt); ++i) 688 { 689 tree op = gimple_op (stmt, i); 690 if (!op || TREE_CODE (op) == SSA_NAME) 691 continue; 692 if (is_gimple_min_invariant (op)) 693 has_constant_operand = true; 694 } 695 696 if (has_constant_operand) 697 all_undefined_operands = false; 698 699 if (has_undefined_operand 700 && code == GIMPLE_CALL 701 && gimple_call_internal_p (stmt)) 702 switch (gimple_call_internal_fn (stmt)) 703 { 704 /* These 3 builtins use the first argument just as a magic 705 way how to find out a decl uid. */ 706 case IFN_GOMP_SIMD_LANE: 707 case IFN_GOMP_SIMD_VF: 708 case IFN_GOMP_SIMD_LAST_LANE: 709 has_undefined_operand = false; 710 break; 711 default: 712 break; 713 } 714 715 /* If the operation combines operands like COMPLEX_EXPR make sure to 716 not mark the result UNDEFINED if only one part of the result is 717 undefined. */ 718 if (has_undefined_operand && all_undefined_operands) 719 return UNDEFINED; 720 else if (code == GIMPLE_ASSIGN && has_undefined_operand) 721 { 722 switch (gimple_assign_rhs_code (stmt)) 723 { 724 /* Unary operators are handled with all_undefined_operands. */ 725 case PLUS_EXPR: 726 case MINUS_EXPR: 727 case POINTER_PLUS_EXPR: 728 /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected. 729 Not bitwise operators, one VARYING operand may specify the 730 result completely. Not logical operators for the same reason. 731 Not COMPLEX_EXPR as one VARYING operand makes the result partly 732 not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because 733 the undefined operand may be promoted. */ 734 return UNDEFINED; 735 736 case ADDR_EXPR: 737 /* If any part of an address is UNDEFINED, like the index 738 of an ARRAY_EXPR, then treat the result as UNDEFINED. */ 739 return UNDEFINED; 740 741 default: 742 ; 743 } 744 } 745 /* If there was an UNDEFINED operand but the result may be not UNDEFINED 746 fall back to CONSTANT. During iteration UNDEFINED may still drop 747 to CONSTANT. */ 748 if (has_undefined_operand) 749 return CONSTANT; 750 751 /* We do not consider virtual operands here -- load from read-only 752 memory may have only VARYING virtual operands, but still be 753 constant. */ 754 if (has_constant_operand 755 || gimple_references_memory_p (stmt)) 756 return CONSTANT; 757 758 return VARYING; 759 } 760 761 /* Returns true if STMT cannot be constant. */ 762 763 static bool 764 surely_varying_stmt_p (gimple stmt) 765 { 766 /* If the statement has operands that we cannot handle, it cannot be 767 constant. */ 768 if (gimple_has_volatile_ops (stmt)) 769 return true; 770 771 /* If it is a call and does not return a value or is not a 772 builtin and not an indirect call or a call to function with 773 assume_aligned/alloc_align attribute, it is varying. */ 774 if (is_gimple_call (stmt)) 775 { 776 tree fndecl, fntype = gimple_call_fntype (stmt); 777 if (!gimple_call_lhs (stmt) 778 || ((fndecl = gimple_call_fndecl (stmt)) != NULL_TREE 779 && !DECL_BUILT_IN (fndecl) 780 && !lookup_attribute ("assume_aligned", 781 TYPE_ATTRIBUTES (fntype)) 782 && !lookup_attribute ("alloc_align", 783 TYPE_ATTRIBUTES (fntype)))) 784 return true; 785 } 786 787 /* Any other store operation is not interesting. */ 788 else if (gimple_vdef (stmt)) 789 return true; 790 791 /* Anything other than assignments and conditional jumps are not 792 interesting for CCP. */ 793 if (gimple_code (stmt) != GIMPLE_ASSIGN 794 && gimple_code (stmt) != GIMPLE_COND 795 && gimple_code (stmt) != GIMPLE_SWITCH 796 && gimple_code (stmt) != GIMPLE_CALL) 797 return true; 798 799 return false; 800 } 801 802 /* Initialize local data structures for CCP. */ 803 804 static void 805 ccp_initialize (void) 806 { 807 basic_block bb; 808 809 n_const_val = num_ssa_names; 810 const_val = XCNEWVEC (ccp_prop_value_t, n_const_val); 811 812 /* Initialize simulation flags for PHI nodes and statements. */ 813 FOR_EACH_BB_FN (bb, cfun) 814 { 815 gimple_stmt_iterator i; 816 817 for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) 818 { 819 gimple stmt = gsi_stmt (i); 820 bool is_varying; 821 822 /* If the statement is a control insn, then we do not 823 want to avoid simulating the statement once. Failure 824 to do so means that those edges will never get added. */ 825 if (stmt_ends_bb_p (stmt)) 826 is_varying = false; 827 else 828 is_varying = surely_varying_stmt_p (stmt); 829 830 if (is_varying) 831 { 832 tree def; 833 ssa_op_iter iter; 834 835 /* If the statement will not produce a constant, mark 836 all its outputs VARYING. */ 837 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) 838 set_value_varying (def); 839 } 840 prop_set_simulate_again (stmt, !is_varying); 841 } 842 } 843 844 /* Now process PHI nodes. We never clear the simulate_again flag on 845 phi nodes, since we do not know which edges are executable yet, 846 except for phi nodes for virtual operands when we do not do store ccp. */ 847 FOR_EACH_BB_FN (bb, cfun) 848 { 849 gphi_iterator i; 850 851 for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) 852 { 853 gphi *phi = i.phi (); 854 855 if (virtual_operand_p (gimple_phi_result (phi))) 856 prop_set_simulate_again (phi, false); 857 else 858 prop_set_simulate_again (phi, true); 859 } 860 } 861 } 862 863 /* Debug count support. Reset the values of ssa names 864 VARYING when the total number ssa names analyzed is 865 beyond the debug count specified. */ 866 867 static void 868 do_dbg_cnt (void) 869 { 870 unsigned i; 871 for (i = 0; i < num_ssa_names; i++) 872 { 873 if (!dbg_cnt (ccp)) 874 { 875 const_val[i].lattice_val = VARYING; 876 const_val[i].mask = -1; 877 const_val[i].value = NULL_TREE; 878 } 879 } 880 } 881 882 883 /* Do final substitution of propagated values, cleanup the flowgraph and 884 free allocated storage. 885 886 Return TRUE when something was optimized. */ 887 888 static bool 889 ccp_finalize (void) 890 { 891 bool something_changed; 892 unsigned i; 893 894 do_dbg_cnt (); 895 896 /* Derive alignment and misalignment information from partially 897 constant pointers in the lattice or nonzero bits from partially 898 constant integers. */ 899 for (i = 1; i < num_ssa_names; ++i) 900 { 901 tree name = ssa_name (i); 902 ccp_prop_value_t *val; 903 unsigned int tem, align; 904 905 if (!name 906 || (!POINTER_TYPE_P (TREE_TYPE (name)) 907 && (!INTEGRAL_TYPE_P (TREE_TYPE (name)) 908 /* Don't record nonzero bits before IPA to avoid 909 using too much memory. */ 910 || first_pass_instance))) 911 continue; 912 913 val = get_value (name); 914 if (val->lattice_val != CONSTANT 915 || TREE_CODE (val->value) != INTEGER_CST) 916 continue; 917 918 if (POINTER_TYPE_P (TREE_TYPE (name))) 919 { 920 /* Trailing mask bits specify the alignment, trailing value 921 bits the misalignment. */ 922 tem = val->mask.to_uhwi (); 923 align = (tem & -tem); 924 if (align > 1) 925 set_ptr_info_alignment (get_ptr_info (name), align, 926 (TREE_INT_CST_LOW (val->value) 927 & (align - 1))); 928 } 929 else 930 { 931 unsigned int precision = TYPE_PRECISION (TREE_TYPE (val->value)); 932 wide_int nonzero_bits = wide_int::from (val->mask, precision, 933 UNSIGNED) | val->value; 934 nonzero_bits &= get_nonzero_bits (name); 935 set_nonzero_bits (name, nonzero_bits); 936 } 937 } 938 939 /* Perform substitutions based on the known constant values. */ 940 something_changed = substitute_and_fold (get_constant_value, 941 ccp_fold_stmt, true); 942 943 free (const_val); 944 const_val = NULL; 945 return something_changed;; 946 } 947 948 949 /* Compute the meet operator between *VAL1 and *VAL2. Store the result 950 in VAL1. 951 952 any M UNDEFINED = any 953 any M VARYING = VARYING 954 Ci M Cj = Ci if (i == j) 955 Ci M Cj = VARYING if (i != j) 956 */ 957 958 static void 959 ccp_lattice_meet (ccp_prop_value_t *val1, ccp_prop_value_t *val2) 960 { 961 if (val1->lattice_val == UNDEFINED) 962 { 963 /* UNDEFINED M any = any */ 964 *val1 = *val2; 965 } 966 else if (val2->lattice_val == UNDEFINED) 967 { 968 /* any M UNDEFINED = any 969 Nothing to do. VAL1 already contains the value we want. */ 970 ; 971 } 972 else if (val1->lattice_val == VARYING 973 || val2->lattice_val == VARYING) 974 { 975 /* any M VARYING = VARYING. */ 976 val1->lattice_val = VARYING; 977 val1->mask = -1; 978 val1->value = NULL_TREE; 979 } 980 else if (val1->lattice_val == CONSTANT 981 && val2->lattice_val == CONSTANT 982 && TREE_CODE (val1->value) == INTEGER_CST 983 && TREE_CODE (val2->value) == INTEGER_CST) 984 { 985 /* Ci M Cj = Ci if (i == j) 986 Ci M Cj = VARYING if (i != j) 987 988 For INTEGER_CSTs mask unequal bits. If no equal bits remain, 989 drop to varying. */ 990 val1->mask = (val1->mask | val2->mask 991 | (wi::to_widest (val1->value) 992 ^ wi::to_widest (val2->value))); 993 if (val1->mask == -1) 994 { 995 val1->lattice_val = VARYING; 996 val1->value = NULL_TREE; 997 } 998 } 999 else if (val1->lattice_val == CONSTANT 1000 && val2->lattice_val == CONSTANT 1001 && simple_cst_equal (val1->value, val2->value) == 1) 1002 { 1003 /* Ci M Cj = Ci if (i == j) 1004 Ci M Cj = VARYING if (i != j) 1005 1006 VAL1 already contains the value we want for equivalent values. */ 1007 } 1008 else if (val1->lattice_val == CONSTANT 1009 && val2->lattice_val == CONSTANT 1010 && (TREE_CODE (val1->value) == ADDR_EXPR 1011 || TREE_CODE (val2->value) == ADDR_EXPR)) 1012 { 1013 /* When not equal addresses are involved try meeting for 1014 alignment. */ 1015 ccp_prop_value_t tem = *val2; 1016 if (TREE_CODE (val1->value) == ADDR_EXPR) 1017 *val1 = get_value_for_expr (val1->value, true); 1018 if (TREE_CODE (val2->value) == ADDR_EXPR) 1019 tem = get_value_for_expr (val2->value, true); 1020 ccp_lattice_meet (val1, &tem); 1021 } 1022 else 1023 { 1024 /* Any other combination is VARYING. */ 1025 val1->lattice_val = VARYING; 1026 val1->mask = -1; 1027 val1->value = NULL_TREE; 1028 } 1029 } 1030 1031 1032 /* Loop through the PHI_NODE's parameters for BLOCK and compare their 1033 lattice values to determine PHI_NODE's lattice value. The value of a 1034 PHI node is determined calling ccp_lattice_meet with all the arguments 1035 of the PHI node that are incoming via executable edges. */ 1036 1037 static enum ssa_prop_result 1038 ccp_visit_phi_node (gphi *phi) 1039 { 1040 unsigned i; 1041 ccp_prop_value_t *old_val, new_val; 1042 1043 if (dump_file && (dump_flags & TDF_DETAILS)) 1044 { 1045 fprintf (dump_file, "\nVisiting PHI node: "); 1046 print_gimple_stmt (dump_file, phi, 0, dump_flags); 1047 } 1048 1049 old_val = get_value (gimple_phi_result (phi)); 1050 switch (old_val->lattice_val) 1051 { 1052 case VARYING: 1053 return SSA_PROP_VARYING; 1054 1055 case CONSTANT: 1056 new_val = *old_val; 1057 break; 1058 1059 case UNDEFINED: 1060 new_val.lattice_val = UNDEFINED; 1061 new_val.value = NULL_TREE; 1062 break; 1063 1064 default: 1065 gcc_unreachable (); 1066 } 1067 1068 for (i = 0; i < gimple_phi_num_args (phi); i++) 1069 { 1070 /* Compute the meet operator over all the PHI arguments flowing 1071 through executable edges. */ 1072 edge e = gimple_phi_arg_edge (phi, i); 1073 1074 if (dump_file && (dump_flags & TDF_DETAILS)) 1075 { 1076 fprintf (dump_file, 1077 "\n Argument #%d (%d -> %d %sexecutable)\n", 1078 i, e->src->index, e->dest->index, 1079 (e->flags & EDGE_EXECUTABLE) ? "" : "not "); 1080 } 1081 1082 /* If the incoming edge is executable, Compute the meet operator for 1083 the existing value of the PHI node and the current PHI argument. */ 1084 if (e->flags & EDGE_EXECUTABLE) 1085 { 1086 tree arg = gimple_phi_arg (phi, i)->def; 1087 ccp_prop_value_t arg_val = get_value_for_expr (arg, false); 1088 1089 ccp_lattice_meet (&new_val, &arg_val); 1090 1091 if (dump_file && (dump_flags & TDF_DETAILS)) 1092 { 1093 fprintf (dump_file, "\t"); 1094 print_generic_expr (dump_file, arg, dump_flags); 1095 dump_lattice_value (dump_file, "\tValue: ", arg_val); 1096 fprintf (dump_file, "\n"); 1097 } 1098 1099 if (new_val.lattice_val == VARYING) 1100 break; 1101 } 1102 } 1103 1104 if (dump_file && (dump_flags & TDF_DETAILS)) 1105 { 1106 dump_lattice_value (dump_file, "\n PHI node value: ", new_val); 1107 fprintf (dump_file, "\n\n"); 1108 } 1109 1110 /* Make the transition to the new value. */ 1111 if (set_lattice_value (gimple_phi_result (phi), new_val)) 1112 { 1113 if (new_val.lattice_val == VARYING) 1114 return SSA_PROP_VARYING; 1115 else 1116 return SSA_PROP_INTERESTING; 1117 } 1118 else 1119 return SSA_PROP_NOT_INTERESTING; 1120 } 1121 1122 /* Return the constant value for OP or OP otherwise. */ 1123 1124 static tree 1125 valueize_op (tree op) 1126 { 1127 if (TREE_CODE (op) == SSA_NAME) 1128 { 1129 tree tem = get_constant_value (op); 1130 if (tem) 1131 return tem; 1132 } 1133 return op; 1134 } 1135 1136 /* Return the constant value for OP, but signal to not follow SSA 1137 edges if the definition may be simulated again. */ 1138 1139 static tree 1140 valueize_op_1 (tree op) 1141 { 1142 if (TREE_CODE (op) == SSA_NAME) 1143 { 1144 /* If the definition may be simulated again we cannot follow 1145 this SSA edge as the SSA propagator does not necessarily 1146 re-visit the use. */ 1147 gimple def_stmt = SSA_NAME_DEF_STMT (op); 1148 if (!gimple_nop_p (def_stmt) 1149 && prop_simulate_again_p (def_stmt)) 1150 return NULL_TREE; 1151 tree tem = get_constant_value (op); 1152 if (tem) 1153 return tem; 1154 } 1155 return op; 1156 } 1157 1158 /* CCP specific front-end to the non-destructive constant folding 1159 routines. 1160 1161 Attempt to simplify the RHS of STMT knowing that one or more 1162 operands are constants. 1163 1164 If simplification is possible, return the simplified RHS, 1165 otherwise return the original RHS or NULL_TREE. */ 1166 1167 static tree 1168 ccp_fold (gimple stmt) 1169 { 1170 location_t loc = gimple_location (stmt); 1171 switch (gimple_code (stmt)) 1172 { 1173 case GIMPLE_COND: 1174 { 1175 /* Handle comparison operators that can appear in GIMPLE form. */ 1176 tree op0 = valueize_op (gimple_cond_lhs (stmt)); 1177 tree op1 = valueize_op (gimple_cond_rhs (stmt)); 1178 enum tree_code code = gimple_cond_code (stmt); 1179 return fold_binary_loc (loc, code, boolean_type_node, op0, op1); 1180 } 1181 1182 case GIMPLE_SWITCH: 1183 { 1184 /* Return the constant switch index. */ 1185 return valueize_op (gimple_switch_index (as_a <gswitch *> (stmt))); 1186 } 1187 1188 case GIMPLE_ASSIGN: 1189 case GIMPLE_CALL: 1190 return gimple_fold_stmt_to_constant_1 (stmt, 1191 valueize_op, valueize_op_1); 1192 1193 default: 1194 gcc_unreachable (); 1195 } 1196 } 1197 1198 /* Apply the operation CODE in type TYPE to the value, mask pair 1199 RVAL and RMASK representing a value of type RTYPE and set 1200 the value, mask pair *VAL and *MASK to the result. */ 1201 1202 static void 1203 bit_value_unop_1 (enum tree_code code, tree type, 1204 widest_int *val, widest_int *mask, 1205 tree rtype, const widest_int &rval, const widest_int &rmask) 1206 { 1207 switch (code) 1208 { 1209 case BIT_NOT_EXPR: 1210 *mask = rmask; 1211 *val = ~rval; 1212 break; 1213 1214 case NEGATE_EXPR: 1215 { 1216 widest_int temv, temm; 1217 /* Return ~rval + 1. */ 1218 bit_value_unop_1 (BIT_NOT_EXPR, type, &temv, &temm, type, rval, rmask); 1219 bit_value_binop_1 (PLUS_EXPR, type, val, mask, 1220 type, temv, temm, type, 1, 0); 1221 break; 1222 } 1223 1224 CASE_CONVERT: 1225 { 1226 signop sgn; 1227 1228 /* First extend mask and value according to the original type. */ 1229 sgn = TYPE_SIGN (rtype); 1230 *mask = wi::ext (rmask, TYPE_PRECISION (rtype), sgn); 1231 *val = wi::ext (rval, TYPE_PRECISION (rtype), sgn); 1232 1233 /* Then extend mask and value according to the target type. */ 1234 sgn = TYPE_SIGN (type); 1235 *mask = wi::ext (*mask, TYPE_PRECISION (type), sgn); 1236 *val = wi::ext (*val, TYPE_PRECISION (type), sgn); 1237 break; 1238 } 1239 1240 default: 1241 *mask = -1; 1242 break; 1243 } 1244 } 1245 1246 /* Apply the operation CODE in type TYPE to the value, mask pairs 1247 R1VAL, R1MASK and R2VAL, R2MASK representing a values of type R1TYPE 1248 and R2TYPE and set the value, mask pair *VAL and *MASK to the result. */ 1249 1250 static void 1251 bit_value_binop_1 (enum tree_code code, tree type, 1252 widest_int *val, widest_int *mask, 1253 tree r1type, const widest_int &r1val, 1254 const widest_int &r1mask, tree r2type, 1255 const widest_int &r2val, const widest_int &r2mask) 1256 { 1257 signop sgn = TYPE_SIGN (type); 1258 int width = TYPE_PRECISION (type); 1259 bool swap_p = false; 1260 1261 /* Assume we'll get a constant result. Use an initial non varying 1262 value, we fall back to varying in the end if necessary. */ 1263 *mask = -1; 1264 1265 switch (code) 1266 { 1267 case BIT_AND_EXPR: 1268 /* The mask is constant where there is a known not 1269 set bit, (m1 | m2) & ((v1 | m1) & (v2 | m2)) */ 1270 *mask = (r1mask | r2mask) & (r1val | r1mask) & (r2val | r2mask); 1271 *val = r1val & r2val; 1272 break; 1273 1274 case BIT_IOR_EXPR: 1275 /* The mask is constant where there is a known 1276 set bit, (m1 | m2) & ~((v1 & ~m1) | (v2 & ~m2)). */ 1277 *mask = (r1mask | r2mask) 1278 .and_not (r1val.and_not (r1mask) | r2val.and_not (r2mask)); 1279 *val = r1val | r2val; 1280 break; 1281 1282 case BIT_XOR_EXPR: 1283 /* m1 | m2 */ 1284 *mask = r1mask | r2mask; 1285 *val = r1val ^ r2val; 1286 break; 1287 1288 case LROTATE_EXPR: 1289 case RROTATE_EXPR: 1290 if (r2mask == 0) 1291 { 1292 widest_int shift = r2val; 1293 if (shift == 0) 1294 { 1295 *mask = r1mask; 1296 *val = r1val; 1297 } 1298 else 1299 { 1300 if (wi::neg_p (shift)) 1301 { 1302 shift = -shift; 1303 if (code == RROTATE_EXPR) 1304 code = LROTATE_EXPR; 1305 else 1306 code = RROTATE_EXPR; 1307 } 1308 if (code == RROTATE_EXPR) 1309 { 1310 *mask = wi::rrotate (r1mask, shift, width); 1311 *val = wi::rrotate (r1val, shift, width); 1312 } 1313 else 1314 { 1315 *mask = wi::lrotate (r1mask, shift, width); 1316 *val = wi::lrotate (r1val, shift, width); 1317 } 1318 } 1319 } 1320 break; 1321 1322 case LSHIFT_EXPR: 1323 case RSHIFT_EXPR: 1324 /* ??? We can handle partially known shift counts if we know 1325 its sign. That way we can tell that (x << (y | 8)) & 255 1326 is zero. */ 1327 if (r2mask == 0) 1328 { 1329 widest_int shift = r2val; 1330 if (shift == 0) 1331 { 1332 *mask = r1mask; 1333 *val = r1val; 1334 } 1335 else 1336 { 1337 if (wi::neg_p (shift)) 1338 { 1339 shift = -shift; 1340 if (code == RSHIFT_EXPR) 1341 code = LSHIFT_EXPR; 1342 else 1343 code = RSHIFT_EXPR; 1344 } 1345 if (code == RSHIFT_EXPR) 1346 { 1347 *mask = wi::rshift (wi::ext (r1mask, width, sgn), shift, sgn); 1348 *val = wi::rshift (wi::ext (r1val, width, sgn), shift, sgn); 1349 } 1350 else 1351 { 1352 *mask = wi::ext (wi::lshift (r1mask, shift), width, sgn); 1353 *val = wi::ext (wi::lshift (r1val, shift), width, sgn); 1354 } 1355 } 1356 } 1357 break; 1358 1359 case PLUS_EXPR: 1360 case POINTER_PLUS_EXPR: 1361 { 1362 /* Do the addition with unknown bits set to zero, to give carry-ins of 1363 zero wherever possible. */ 1364 widest_int lo = r1val.and_not (r1mask) + r2val.and_not (r2mask); 1365 lo = wi::ext (lo, width, sgn); 1366 /* Do the addition with unknown bits set to one, to give carry-ins of 1367 one wherever possible. */ 1368 widest_int hi = (r1val | r1mask) + (r2val | r2mask); 1369 hi = wi::ext (hi, width, sgn); 1370 /* Each bit in the result is known if (a) the corresponding bits in 1371 both inputs are known, and (b) the carry-in to that bit position 1372 is known. We can check condition (b) by seeing if we got the same 1373 result with minimised carries as with maximised carries. */ 1374 *mask = r1mask | r2mask | (lo ^ hi); 1375 *mask = wi::ext (*mask, width, sgn); 1376 /* It shouldn't matter whether we choose lo or hi here. */ 1377 *val = lo; 1378 break; 1379 } 1380 1381 case MINUS_EXPR: 1382 { 1383 widest_int temv, temm; 1384 bit_value_unop_1 (NEGATE_EXPR, r2type, &temv, &temm, 1385 r2type, r2val, r2mask); 1386 bit_value_binop_1 (PLUS_EXPR, type, val, mask, 1387 r1type, r1val, r1mask, 1388 r2type, temv, temm); 1389 break; 1390 } 1391 1392 case MULT_EXPR: 1393 { 1394 /* Just track trailing zeros in both operands and transfer 1395 them to the other. */ 1396 int r1tz = wi::ctz (r1val | r1mask); 1397 int r2tz = wi::ctz (r2val | r2mask); 1398 if (r1tz + r2tz >= width) 1399 { 1400 *mask = 0; 1401 *val = 0; 1402 } 1403 else if (r1tz + r2tz > 0) 1404 { 1405 *mask = wi::ext (wi::mask <widest_int> (r1tz + r2tz, true), 1406 width, sgn); 1407 *val = 0; 1408 } 1409 break; 1410 } 1411 1412 case EQ_EXPR: 1413 case NE_EXPR: 1414 { 1415 widest_int m = r1mask | r2mask; 1416 if (r1val.and_not (m) != r2val.and_not (m)) 1417 { 1418 *mask = 0; 1419 *val = ((code == EQ_EXPR) ? 0 : 1); 1420 } 1421 else 1422 { 1423 /* We know the result of a comparison is always one or zero. */ 1424 *mask = 1; 1425 *val = 0; 1426 } 1427 break; 1428 } 1429 1430 case GE_EXPR: 1431 case GT_EXPR: 1432 swap_p = true; 1433 code = swap_tree_comparison (code); 1434 /* Fall through. */ 1435 case LT_EXPR: 1436 case LE_EXPR: 1437 { 1438 int minmax, maxmin; 1439 1440 const widest_int &o1val = swap_p ? r2val : r1val; 1441 const widest_int &o1mask = swap_p ? r2mask : r1mask; 1442 const widest_int &o2val = swap_p ? r1val : r2val; 1443 const widest_int &o2mask = swap_p ? r1mask : r2mask; 1444 1445 /* If the most significant bits are not known we know nothing. */ 1446 if (wi::neg_p (o1mask) || wi::neg_p (o2mask)) 1447 break; 1448 1449 /* For comparisons the signedness is in the comparison operands. */ 1450 sgn = TYPE_SIGN (r1type); 1451 1452 /* If we know the most significant bits we know the values 1453 value ranges by means of treating varying bits as zero 1454 or one. Do a cross comparison of the max/min pairs. */ 1455 maxmin = wi::cmp (o1val | o1mask, o2val.and_not (o2mask), sgn); 1456 minmax = wi::cmp (o1val.and_not (o1mask), o2val | o2mask, sgn); 1457 if (maxmin < 0) /* o1 is less than o2. */ 1458 { 1459 *mask = 0; 1460 *val = 1; 1461 } 1462 else if (minmax > 0) /* o1 is not less or equal to o2. */ 1463 { 1464 *mask = 0; 1465 *val = 0; 1466 } 1467 else if (maxmin == minmax) /* o1 and o2 are equal. */ 1468 { 1469 /* This probably should never happen as we'd have 1470 folded the thing during fully constant value folding. */ 1471 *mask = 0; 1472 *val = (code == LE_EXPR ? 1 : 0); 1473 } 1474 else 1475 { 1476 /* We know the result of a comparison is always one or zero. */ 1477 *mask = 1; 1478 *val = 0; 1479 } 1480 break; 1481 } 1482 1483 default:; 1484 } 1485 } 1486 1487 /* Return the propagation value when applying the operation CODE to 1488 the value RHS yielding type TYPE. */ 1489 1490 static ccp_prop_value_t 1491 bit_value_unop (enum tree_code code, tree type, tree rhs) 1492 { 1493 ccp_prop_value_t rval = get_value_for_expr (rhs, true); 1494 widest_int value, mask; 1495 ccp_prop_value_t val; 1496 1497 if (rval.lattice_val == UNDEFINED) 1498 return rval; 1499 1500 gcc_assert ((rval.lattice_val == CONSTANT 1501 && TREE_CODE (rval.value) == INTEGER_CST) 1502 || rval.mask == -1); 1503 bit_value_unop_1 (code, type, &value, &mask, 1504 TREE_TYPE (rhs), value_to_wide_int (rval), rval.mask); 1505 if (mask != -1) 1506 { 1507 val.lattice_val = CONSTANT; 1508 val.mask = mask; 1509 /* ??? Delay building trees here. */ 1510 val.value = wide_int_to_tree (type, value); 1511 } 1512 else 1513 { 1514 val.lattice_val = VARYING; 1515 val.value = NULL_TREE; 1516 val.mask = -1; 1517 } 1518 return val; 1519 } 1520 1521 /* Return the propagation value when applying the operation CODE to 1522 the values RHS1 and RHS2 yielding type TYPE. */ 1523 1524 static ccp_prop_value_t 1525 bit_value_binop (enum tree_code code, tree type, tree rhs1, tree rhs2) 1526 { 1527 ccp_prop_value_t r1val = get_value_for_expr (rhs1, true); 1528 ccp_prop_value_t r2val = get_value_for_expr (rhs2, true); 1529 widest_int value, mask; 1530 ccp_prop_value_t val; 1531 1532 if (r1val.lattice_val == UNDEFINED 1533 || r2val.lattice_val == UNDEFINED) 1534 { 1535 val.lattice_val = VARYING; 1536 val.value = NULL_TREE; 1537 val.mask = -1; 1538 return val; 1539 } 1540 1541 gcc_assert ((r1val.lattice_val == CONSTANT 1542 && TREE_CODE (r1val.value) == INTEGER_CST) 1543 || r1val.mask == -1); 1544 gcc_assert ((r2val.lattice_val == CONSTANT 1545 && TREE_CODE (r2val.value) == INTEGER_CST) 1546 || r2val.mask == -1); 1547 bit_value_binop_1 (code, type, &value, &mask, 1548 TREE_TYPE (rhs1), value_to_wide_int (r1val), r1val.mask, 1549 TREE_TYPE (rhs2), value_to_wide_int (r2val), r2val.mask); 1550 if (mask != -1) 1551 { 1552 val.lattice_val = CONSTANT; 1553 val.mask = mask; 1554 /* ??? Delay building trees here. */ 1555 val.value = wide_int_to_tree (type, value); 1556 } 1557 else 1558 { 1559 val.lattice_val = VARYING; 1560 val.value = NULL_TREE; 1561 val.mask = -1; 1562 } 1563 return val; 1564 } 1565 1566 /* Return the propagation value for __builtin_assume_aligned 1567 and functions with assume_aligned or alloc_aligned attribute. 1568 For __builtin_assume_aligned, ATTR is NULL_TREE, 1569 for assume_aligned attribute ATTR is non-NULL and ALLOC_ALIGNED 1570 is false, for alloc_aligned attribute ATTR is non-NULL and 1571 ALLOC_ALIGNED is true. */ 1572 1573 static ccp_prop_value_t 1574 bit_value_assume_aligned (gimple stmt, tree attr, ccp_prop_value_t ptrval, 1575 bool alloc_aligned) 1576 { 1577 tree align, misalign = NULL_TREE, type; 1578 unsigned HOST_WIDE_INT aligni, misaligni = 0; 1579 ccp_prop_value_t alignval; 1580 widest_int value, mask; 1581 ccp_prop_value_t val; 1582 1583 if (attr == NULL_TREE) 1584 { 1585 tree ptr = gimple_call_arg (stmt, 0); 1586 type = TREE_TYPE (ptr); 1587 ptrval = get_value_for_expr (ptr, true); 1588 } 1589 else 1590 { 1591 tree lhs = gimple_call_lhs (stmt); 1592 type = TREE_TYPE (lhs); 1593 } 1594 1595 if (ptrval.lattice_val == UNDEFINED) 1596 return ptrval; 1597 gcc_assert ((ptrval.lattice_val == CONSTANT 1598 && TREE_CODE (ptrval.value) == INTEGER_CST) 1599 || ptrval.mask == -1); 1600 if (attr == NULL_TREE) 1601 { 1602 /* Get aligni and misaligni from __builtin_assume_aligned. */ 1603 align = gimple_call_arg (stmt, 1); 1604 if (!tree_fits_uhwi_p (align)) 1605 return ptrval; 1606 aligni = tree_to_uhwi (align); 1607 if (gimple_call_num_args (stmt) > 2) 1608 { 1609 misalign = gimple_call_arg (stmt, 2); 1610 if (!tree_fits_uhwi_p (misalign)) 1611 return ptrval; 1612 misaligni = tree_to_uhwi (misalign); 1613 } 1614 } 1615 else 1616 { 1617 /* Get aligni and misaligni from assume_aligned or 1618 alloc_align attributes. */ 1619 if (TREE_VALUE (attr) == NULL_TREE) 1620 return ptrval; 1621 attr = TREE_VALUE (attr); 1622 align = TREE_VALUE (attr); 1623 if (!tree_fits_uhwi_p (align)) 1624 return ptrval; 1625 aligni = tree_to_uhwi (align); 1626 if (alloc_aligned) 1627 { 1628 if (aligni == 0 || aligni > gimple_call_num_args (stmt)) 1629 return ptrval; 1630 align = gimple_call_arg (stmt, aligni - 1); 1631 if (!tree_fits_uhwi_p (align)) 1632 return ptrval; 1633 aligni = tree_to_uhwi (align); 1634 } 1635 else if (TREE_CHAIN (attr) && TREE_VALUE (TREE_CHAIN (attr))) 1636 { 1637 misalign = TREE_VALUE (TREE_CHAIN (attr)); 1638 if (!tree_fits_uhwi_p (misalign)) 1639 return ptrval; 1640 misaligni = tree_to_uhwi (misalign); 1641 } 1642 } 1643 if (aligni <= 1 || (aligni & (aligni - 1)) != 0 || misaligni >= aligni) 1644 return ptrval; 1645 1646 align = build_int_cst_type (type, -aligni); 1647 alignval = get_value_for_expr (align, true); 1648 bit_value_binop_1 (BIT_AND_EXPR, type, &value, &mask, 1649 type, value_to_wide_int (ptrval), ptrval.mask, 1650 type, value_to_wide_int (alignval), alignval.mask); 1651 if (mask != -1) 1652 { 1653 val.lattice_val = CONSTANT; 1654 val.mask = mask; 1655 gcc_assert ((mask.to_uhwi () & (aligni - 1)) == 0); 1656 gcc_assert ((value.to_uhwi () & (aligni - 1)) == 0); 1657 value |= misaligni; 1658 /* ??? Delay building trees here. */ 1659 val.value = wide_int_to_tree (type, value); 1660 } 1661 else 1662 { 1663 val.lattice_val = VARYING; 1664 val.value = NULL_TREE; 1665 val.mask = -1; 1666 } 1667 return val; 1668 } 1669 1670 /* Evaluate statement STMT. 1671 Valid only for assignments, calls, conditionals, and switches. */ 1672 1673 static ccp_prop_value_t 1674 evaluate_stmt (gimple stmt) 1675 { 1676 ccp_prop_value_t val; 1677 tree simplified = NULL_TREE; 1678 ccp_lattice_t likelyvalue = likely_value (stmt); 1679 bool is_constant = false; 1680 unsigned int align; 1681 1682 if (dump_file && (dump_flags & TDF_DETAILS)) 1683 { 1684 fprintf (dump_file, "which is likely "); 1685 switch (likelyvalue) 1686 { 1687 case CONSTANT: 1688 fprintf (dump_file, "CONSTANT"); 1689 break; 1690 case UNDEFINED: 1691 fprintf (dump_file, "UNDEFINED"); 1692 break; 1693 case VARYING: 1694 fprintf (dump_file, "VARYING"); 1695 break; 1696 default:; 1697 } 1698 fprintf (dump_file, "\n"); 1699 } 1700 1701 /* If the statement is likely to have a CONSTANT result, then try 1702 to fold the statement to determine the constant value. */ 1703 /* FIXME. This is the only place that we call ccp_fold. 1704 Since likely_value never returns CONSTANT for calls, we will 1705 not attempt to fold them, including builtins that may profit. */ 1706 if (likelyvalue == CONSTANT) 1707 { 1708 fold_defer_overflow_warnings (); 1709 simplified = ccp_fold (stmt); 1710 is_constant = simplified && is_gimple_min_invariant (simplified); 1711 fold_undefer_overflow_warnings (is_constant, stmt, 0); 1712 if (is_constant) 1713 { 1714 /* The statement produced a constant value. */ 1715 val.lattice_val = CONSTANT; 1716 val.value = simplified; 1717 val.mask = 0; 1718 } 1719 } 1720 /* If the statement is likely to have a VARYING result, then do not 1721 bother folding the statement. */ 1722 else if (likelyvalue == VARYING) 1723 { 1724 enum gimple_code code = gimple_code (stmt); 1725 if (code == GIMPLE_ASSIGN) 1726 { 1727 enum tree_code subcode = gimple_assign_rhs_code (stmt); 1728 1729 /* Other cases cannot satisfy is_gimple_min_invariant 1730 without folding. */ 1731 if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS) 1732 simplified = gimple_assign_rhs1 (stmt); 1733 } 1734 else if (code == GIMPLE_SWITCH) 1735 simplified = gimple_switch_index (as_a <gswitch *> (stmt)); 1736 else 1737 /* These cannot satisfy is_gimple_min_invariant without folding. */ 1738 gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND); 1739 is_constant = simplified && is_gimple_min_invariant (simplified); 1740 if (is_constant) 1741 { 1742 /* The statement produced a constant value. */ 1743 val.lattice_val = CONSTANT; 1744 val.value = simplified; 1745 val.mask = 0; 1746 } 1747 } 1748 1749 /* Resort to simplification for bitwise tracking. */ 1750 if (flag_tree_bit_ccp 1751 && (likelyvalue == CONSTANT || is_gimple_call (stmt)) 1752 && !is_constant) 1753 { 1754 enum gimple_code code = gimple_code (stmt); 1755 val.lattice_val = VARYING; 1756 val.value = NULL_TREE; 1757 val.mask = -1; 1758 if (code == GIMPLE_ASSIGN) 1759 { 1760 enum tree_code subcode = gimple_assign_rhs_code (stmt); 1761 tree rhs1 = gimple_assign_rhs1 (stmt); 1762 switch (get_gimple_rhs_class (subcode)) 1763 { 1764 case GIMPLE_SINGLE_RHS: 1765 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) 1766 || POINTER_TYPE_P (TREE_TYPE (rhs1))) 1767 val = get_value_for_expr (rhs1, true); 1768 break; 1769 1770 case GIMPLE_UNARY_RHS: 1771 if ((INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) 1772 || POINTER_TYPE_P (TREE_TYPE (rhs1))) 1773 && (INTEGRAL_TYPE_P (gimple_expr_type (stmt)) 1774 || POINTER_TYPE_P (gimple_expr_type (stmt)))) 1775 val = bit_value_unop (subcode, gimple_expr_type (stmt), rhs1); 1776 break; 1777 1778 case GIMPLE_BINARY_RHS: 1779 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) 1780 || POINTER_TYPE_P (TREE_TYPE (rhs1))) 1781 { 1782 tree lhs = gimple_assign_lhs (stmt); 1783 tree rhs2 = gimple_assign_rhs2 (stmt); 1784 val = bit_value_binop (subcode, 1785 TREE_TYPE (lhs), rhs1, rhs2); 1786 } 1787 break; 1788 1789 default:; 1790 } 1791 } 1792 else if (code == GIMPLE_COND) 1793 { 1794 enum tree_code code = gimple_cond_code (stmt); 1795 tree rhs1 = gimple_cond_lhs (stmt); 1796 tree rhs2 = gimple_cond_rhs (stmt); 1797 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) 1798 || POINTER_TYPE_P (TREE_TYPE (rhs1))) 1799 val = bit_value_binop (code, TREE_TYPE (rhs1), rhs1, rhs2); 1800 } 1801 else if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) 1802 { 1803 tree fndecl = gimple_call_fndecl (stmt); 1804 switch (DECL_FUNCTION_CODE (fndecl)) 1805 { 1806 case BUILT_IN_MALLOC: 1807 case BUILT_IN_REALLOC: 1808 case BUILT_IN_CALLOC: 1809 case BUILT_IN_STRDUP: 1810 case BUILT_IN_STRNDUP: 1811 val.lattice_val = CONSTANT; 1812 val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); 1813 val.mask = ~((HOST_WIDE_INT) MALLOC_ABI_ALIGNMENT 1814 / BITS_PER_UNIT - 1); 1815 break; 1816 1817 case BUILT_IN_ALLOCA: 1818 case BUILT_IN_ALLOCA_WITH_ALIGN: 1819 align = (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_ALLOCA_WITH_ALIGN 1820 ? TREE_INT_CST_LOW (gimple_call_arg (stmt, 1)) 1821 : BIGGEST_ALIGNMENT); 1822 val.lattice_val = CONSTANT; 1823 val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); 1824 val.mask = ~((HOST_WIDE_INT) align / BITS_PER_UNIT - 1); 1825 break; 1826 1827 /* These builtins return their first argument, unmodified. */ 1828 case BUILT_IN_MEMCPY: 1829 case BUILT_IN_MEMMOVE: 1830 case BUILT_IN_MEMSET: 1831 case BUILT_IN_STRCPY: 1832 case BUILT_IN_STRNCPY: 1833 case BUILT_IN_MEMCPY_CHK: 1834 case BUILT_IN_MEMMOVE_CHK: 1835 case BUILT_IN_MEMSET_CHK: 1836 case BUILT_IN_STRCPY_CHK: 1837 case BUILT_IN_STRNCPY_CHK: 1838 val = get_value_for_expr (gimple_call_arg (stmt, 0), true); 1839 break; 1840 1841 case BUILT_IN_ASSUME_ALIGNED: 1842 val = bit_value_assume_aligned (stmt, NULL_TREE, val, false); 1843 break; 1844 1845 case BUILT_IN_ALIGNED_ALLOC: 1846 { 1847 tree align = get_constant_value (gimple_call_arg (stmt, 0)); 1848 if (align 1849 && tree_fits_uhwi_p (align)) 1850 { 1851 unsigned HOST_WIDE_INT aligni = tree_to_uhwi (align); 1852 if (aligni > 1 1853 /* align must be power-of-two */ 1854 && (aligni & (aligni - 1)) == 0) 1855 { 1856 val.lattice_val = CONSTANT; 1857 val.value = build_int_cst (ptr_type_node, 0); 1858 val.mask = -aligni; 1859 } 1860 } 1861 break; 1862 } 1863 1864 default:; 1865 } 1866 } 1867 if (is_gimple_call (stmt) && gimple_call_lhs (stmt)) 1868 { 1869 tree fntype = gimple_call_fntype (stmt); 1870 if (fntype) 1871 { 1872 tree attrs = lookup_attribute ("assume_aligned", 1873 TYPE_ATTRIBUTES (fntype)); 1874 if (attrs) 1875 val = bit_value_assume_aligned (stmt, attrs, val, false); 1876 attrs = lookup_attribute ("alloc_align", 1877 TYPE_ATTRIBUTES (fntype)); 1878 if (attrs) 1879 val = bit_value_assume_aligned (stmt, attrs, val, true); 1880 } 1881 } 1882 is_constant = (val.lattice_val == CONSTANT); 1883 } 1884 1885 if (flag_tree_bit_ccp 1886 && ((is_constant && TREE_CODE (val.value) == INTEGER_CST) 1887 || (!is_constant && likelyvalue != UNDEFINED)) 1888 && gimple_get_lhs (stmt) 1889 && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME) 1890 { 1891 tree lhs = gimple_get_lhs (stmt); 1892 wide_int nonzero_bits = get_nonzero_bits (lhs); 1893 if (nonzero_bits != -1) 1894 { 1895 if (!is_constant) 1896 { 1897 val.lattice_val = CONSTANT; 1898 val.value = build_zero_cst (TREE_TYPE (lhs)); 1899 val.mask = extend_mask (nonzero_bits); 1900 is_constant = true; 1901 } 1902 else 1903 { 1904 if (wi::bit_and_not (val.value, nonzero_bits) != 0) 1905 val.value = wide_int_to_tree (TREE_TYPE (lhs), 1906 nonzero_bits & val.value); 1907 if (nonzero_bits == 0) 1908 val.mask = 0; 1909 else 1910 val.mask = val.mask & extend_mask (nonzero_bits); 1911 } 1912 } 1913 } 1914 1915 if (!is_constant) 1916 { 1917 /* The statement produced a nonconstant value. If the statement 1918 had UNDEFINED operands, then the result of the statement 1919 should be UNDEFINED. Otherwise, the statement is VARYING. */ 1920 if (likelyvalue == UNDEFINED) 1921 { 1922 val.lattice_val = likelyvalue; 1923 val.mask = 0; 1924 } 1925 else 1926 { 1927 val.lattice_val = VARYING; 1928 val.mask = -1; 1929 } 1930 1931 val.value = NULL_TREE; 1932 } 1933 1934 return val; 1935 } 1936 1937 typedef hash_table<pointer_hash<gimple_statement_base> > gimple_htab; 1938 1939 /* Given a BUILT_IN_STACK_SAVE value SAVED_VAL, insert a clobber of VAR before 1940 each matching BUILT_IN_STACK_RESTORE. Mark visited phis in VISITED. */ 1941 1942 static void 1943 insert_clobber_before_stack_restore (tree saved_val, tree var, 1944 gimple_htab **visited) 1945 { 1946 gimple stmt; 1947 gassign *clobber_stmt; 1948 tree clobber; 1949 imm_use_iterator iter; 1950 gimple_stmt_iterator i; 1951 gimple *slot; 1952 1953 FOR_EACH_IMM_USE_STMT (stmt, iter, saved_val) 1954 if (gimple_call_builtin_p (stmt, BUILT_IN_STACK_RESTORE)) 1955 { 1956 clobber = build_constructor (TREE_TYPE (var), 1957 NULL); 1958 TREE_THIS_VOLATILE (clobber) = 1; 1959 clobber_stmt = gimple_build_assign (var, clobber); 1960 1961 i = gsi_for_stmt (stmt); 1962 gsi_insert_before (&i, clobber_stmt, GSI_SAME_STMT); 1963 } 1964 else if (gimple_code (stmt) == GIMPLE_PHI) 1965 { 1966 if (!*visited) 1967 *visited = new gimple_htab (10); 1968 1969 slot = (*visited)->find_slot (stmt, INSERT); 1970 if (*slot != NULL) 1971 continue; 1972 1973 *slot = stmt; 1974 insert_clobber_before_stack_restore (gimple_phi_result (stmt), var, 1975 visited); 1976 } 1977 else if (gimple_assign_ssa_name_copy_p (stmt)) 1978 insert_clobber_before_stack_restore (gimple_assign_lhs (stmt), var, 1979 visited); 1980 else if (chkp_gimple_call_builtin_p (stmt, BUILT_IN_CHKP_BNDRET)) 1981 continue; 1982 else 1983 gcc_assert (is_gimple_debug (stmt)); 1984 } 1985 1986 /* Advance the iterator to the previous non-debug gimple statement in the same 1987 or dominating basic block. */ 1988 1989 static inline void 1990 gsi_prev_dom_bb_nondebug (gimple_stmt_iterator *i) 1991 { 1992 basic_block dom; 1993 1994 gsi_prev_nondebug (i); 1995 while (gsi_end_p (*i)) 1996 { 1997 dom = get_immediate_dominator (CDI_DOMINATORS, i->bb); 1998 if (dom == NULL || dom == ENTRY_BLOCK_PTR_FOR_FN (cfun)) 1999 return; 2000 2001 *i = gsi_last_bb (dom); 2002 } 2003 } 2004 2005 /* Find a BUILT_IN_STACK_SAVE dominating gsi_stmt (I), and insert 2006 a clobber of VAR before each matching BUILT_IN_STACK_RESTORE. 2007 2008 It is possible that BUILT_IN_STACK_SAVE cannot be find in a dominator when a 2009 previous pass (such as DOM) duplicated it along multiple paths to a BB. In 2010 that case the function gives up without inserting the clobbers. */ 2011 2012 static void 2013 insert_clobbers_for_var (gimple_stmt_iterator i, tree var) 2014 { 2015 gimple stmt; 2016 tree saved_val; 2017 gimple_htab *visited = NULL; 2018 2019 for (; !gsi_end_p (i); gsi_prev_dom_bb_nondebug (&i)) 2020 { 2021 stmt = gsi_stmt (i); 2022 2023 if (!gimple_call_builtin_p (stmt, BUILT_IN_STACK_SAVE)) 2024 continue; 2025 2026 saved_val = gimple_call_lhs (stmt); 2027 if (saved_val == NULL_TREE) 2028 continue; 2029 2030 insert_clobber_before_stack_restore (saved_val, var, &visited); 2031 break; 2032 } 2033 2034 delete visited; 2035 } 2036 2037 /* Detects a __builtin_alloca_with_align with constant size argument. Declares 2038 fixed-size array and returns the address, if found, otherwise returns 2039 NULL_TREE. */ 2040 2041 static tree 2042 fold_builtin_alloca_with_align (gimple stmt) 2043 { 2044 unsigned HOST_WIDE_INT size, threshold, n_elem; 2045 tree lhs, arg, block, var, elem_type, array_type; 2046 2047 /* Get lhs. */ 2048 lhs = gimple_call_lhs (stmt); 2049 if (lhs == NULL_TREE) 2050 return NULL_TREE; 2051 2052 /* Detect constant argument. */ 2053 arg = get_constant_value (gimple_call_arg (stmt, 0)); 2054 if (arg == NULL_TREE 2055 || TREE_CODE (arg) != INTEGER_CST 2056 || !tree_fits_uhwi_p (arg)) 2057 return NULL_TREE; 2058 2059 size = tree_to_uhwi (arg); 2060 2061 /* Heuristic: don't fold large allocas. */ 2062 threshold = (unsigned HOST_WIDE_INT)PARAM_VALUE (PARAM_LARGE_STACK_FRAME); 2063 /* In case the alloca is located at function entry, it has the same lifetime 2064 as a declared array, so we allow a larger size. */ 2065 block = gimple_block (stmt); 2066 if (!(cfun->after_inlining 2067 && block 2068 && TREE_CODE (BLOCK_SUPERCONTEXT (block)) == FUNCTION_DECL)) 2069 threshold /= 10; 2070 if (size > threshold) 2071 return NULL_TREE; 2072 2073 /* Declare array. */ 2074 elem_type = build_nonstandard_integer_type (BITS_PER_UNIT, 1); 2075 n_elem = size * 8 / BITS_PER_UNIT; 2076 array_type = build_array_type_nelts (elem_type, n_elem); 2077 var = create_tmp_var (array_type); 2078 DECL_ALIGN (var) = TREE_INT_CST_LOW (gimple_call_arg (stmt, 1)); 2079 { 2080 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (lhs); 2081 if (pi != NULL && !pi->pt.anything) 2082 { 2083 bool singleton_p; 2084 unsigned uid; 2085 singleton_p = pt_solution_singleton_p (&pi->pt, &uid); 2086 gcc_assert (singleton_p); 2087 SET_DECL_PT_UID (var, uid); 2088 } 2089 } 2090 2091 /* Fold alloca to the address of the array. */ 2092 return fold_convert (TREE_TYPE (lhs), build_fold_addr_expr (var)); 2093 } 2094 2095 /* Fold the stmt at *GSI with CCP specific information that propagating 2096 and regular folding does not catch. */ 2097 2098 static bool 2099 ccp_fold_stmt (gimple_stmt_iterator *gsi) 2100 { 2101 gimple stmt = gsi_stmt (*gsi); 2102 2103 switch (gimple_code (stmt)) 2104 { 2105 case GIMPLE_COND: 2106 { 2107 gcond *cond_stmt = as_a <gcond *> (stmt); 2108 ccp_prop_value_t val; 2109 /* Statement evaluation will handle type mismatches in constants 2110 more gracefully than the final propagation. This allows us to 2111 fold more conditionals here. */ 2112 val = evaluate_stmt (stmt); 2113 if (val.lattice_val != CONSTANT 2114 || val.mask != 0) 2115 return false; 2116 2117 if (dump_file) 2118 { 2119 fprintf (dump_file, "Folding predicate "); 2120 print_gimple_expr (dump_file, stmt, 0, 0); 2121 fprintf (dump_file, " to "); 2122 print_generic_expr (dump_file, val.value, 0); 2123 fprintf (dump_file, "\n"); 2124 } 2125 2126 if (integer_zerop (val.value)) 2127 gimple_cond_make_false (cond_stmt); 2128 else 2129 gimple_cond_make_true (cond_stmt); 2130 2131 return true; 2132 } 2133 2134 case GIMPLE_CALL: 2135 { 2136 tree lhs = gimple_call_lhs (stmt); 2137 int flags = gimple_call_flags (stmt); 2138 tree val; 2139 tree argt; 2140 bool changed = false; 2141 unsigned i; 2142 2143 /* If the call was folded into a constant make sure it goes 2144 away even if we cannot propagate into all uses because of 2145 type issues. */ 2146 if (lhs 2147 && TREE_CODE (lhs) == SSA_NAME 2148 && (val = get_constant_value (lhs)) 2149 /* Don't optimize away calls that have side-effects. */ 2150 && (flags & (ECF_CONST|ECF_PURE)) != 0 2151 && (flags & ECF_LOOPING_CONST_OR_PURE) == 0) 2152 { 2153 tree new_rhs = unshare_expr (val); 2154 bool res; 2155 if (!useless_type_conversion_p (TREE_TYPE (lhs), 2156 TREE_TYPE (new_rhs))) 2157 new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs); 2158 res = update_call_from_tree (gsi, new_rhs); 2159 gcc_assert (res); 2160 return true; 2161 } 2162 2163 /* Internal calls provide no argument types, so the extra laxity 2164 for normal calls does not apply. */ 2165 if (gimple_call_internal_p (stmt)) 2166 return false; 2167 2168 /* The heuristic of fold_builtin_alloca_with_align differs before and 2169 after inlining, so we don't require the arg to be changed into a 2170 constant for folding, but just to be constant. */ 2171 if (gimple_call_builtin_p (stmt, BUILT_IN_ALLOCA_WITH_ALIGN)) 2172 { 2173 tree new_rhs = fold_builtin_alloca_with_align (stmt); 2174 if (new_rhs) 2175 { 2176 bool res = update_call_from_tree (gsi, new_rhs); 2177 tree var = TREE_OPERAND (TREE_OPERAND (new_rhs, 0),0); 2178 gcc_assert (res); 2179 insert_clobbers_for_var (*gsi, var); 2180 return true; 2181 } 2182 } 2183 2184 /* Propagate into the call arguments. Compared to replace_uses_in 2185 this can use the argument slot types for type verification 2186 instead of the current argument type. We also can safely 2187 drop qualifiers here as we are dealing with constants anyway. */ 2188 argt = TYPE_ARG_TYPES (gimple_call_fntype (stmt)); 2189 for (i = 0; i < gimple_call_num_args (stmt) && argt; 2190 ++i, argt = TREE_CHAIN (argt)) 2191 { 2192 tree arg = gimple_call_arg (stmt, i); 2193 if (TREE_CODE (arg) == SSA_NAME 2194 && (val = get_constant_value (arg)) 2195 && useless_type_conversion_p 2196 (TYPE_MAIN_VARIANT (TREE_VALUE (argt)), 2197 TYPE_MAIN_VARIANT (TREE_TYPE (val)))) 2198 { 2199 gimple_call_set_arg (stmt, i, unshare_expr (val)); 2200 changed = true; 2201 } 2202 } 2203 2204 return changed; 2205 } 2206 2207 case GIMPLE_ASSIGN: 2208 { 2209 tree lhs = gimple_assign_lhs (stmt); 2210 tree val; 2211 2212 /* If we have a load that turned out to be constant replace it 2213 as we cannot propagate into all uses in all cases. */ 2214 if (gimple_assign_single_p (stmt) 2215 && TREE_CODE (lhs) == SSA_NAME 2216 && (val = get_constant_value (lhs))) 2217 { 2218 tree rhs = unshare_expr (val); 2219 if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) 2220 rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs); 2221 gimple_assign_set_rhs_from_tree (gsi, rhs); 2222 return true; 2223 } 2224 2225 return false; 2226 } 2227 2228 default: 2229 return false; 2230 } 2231 } 2232 2233 /* Visit the assignment statement STMT. Set the value of its LHS to the 2234 value computed by the RHS and store LHS in *OUTPUT_P. If STMT 2235 creates virtual definitions, set the value of each new name to that 2236 of the RHS (if we can derive a constant out of the RHS). 2237 Value-returning call statements also perform an assignment, and 2238 are handled here. */ 2239 2240 static enum ssa_prop_result 2241 visit_assignment (gimple stmt, tree *output_p) 2242 { 2243 ccp_prop_value_t val; 2244 enum ssa_prop_result retval; 2245 2246 tree lhs = gimple_get_lhs (stmt); 2247 2248 gcc_assert (gimple_code (stmt) != GIMPLE_CALL 2249 || gimple_call_lhs (stmt) != NULL_TREE); 2250 2251 if (gimple_assign_single_p (stmt) 2252 && gimple_assign_rhs_code (stmt) == SSA_NAME) 2253 /* For a simple copy operation, we copy the lattice values. */ 2254 val = *get_value (gimple_assign_rhs1 (stmt)); 2255 else 2256 /* Evaluate the statement, which could be 2257 either a GIMPLE_ASSIGN or a GIMPLE_CALL. */ 2258 val = evaluate_stmt (stmt); 2259 2260 retval = SSA_PROP_NOT_INTERESTING; 2261 2262 /* Set the lattice value of the statement's output. */ 2263 if (TREE_CODE (lhs) == SSA_NAME) 2264 { 2265 /* If STMT is an assignment to an SSA_NAME, we only have one 2266 value to set. */ 2267 if (set_lattice_value (lhs, val)) 2268 { 2269 *output_p = lhs; 2270 if (val.lattice_val == VARYING) 2271 retval = SSA_PROP_VARYING; 2272 else 2273 retval = SSA_PROP_INTERESTING; 2274 } 2275 } 2276 2277 return retval; 2278 } 2279 2280 2281 /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING 2282 if it can determine which edge will be taken. Otherwise, return 2283 SSA_PROP_VARYING. */ 2284 2285 static enum ssa_prop_result 2286 visit_cond_stmt (gimple stmt, edge *taken_edge_p) 2287 { 2288 ccp_prop_value_t val; 2289 basic_block block; 2290 2291 block = gimple_bb (stmt); 2292 val = evaluate_stmt (stmt); 2293 if (val.lattice_val != CONSTANT 2294 || val.mask != 0) 2295 return SSA_PROP_VARYING; 2296 2297 /* Find which edge out of the conditional block will be taken and add it 2298 to the worklist. If no single edge can be determined statically, 2299 return SSA_PROP_VARYING to feed all the outgoing edges to the 2300 propagation engine. */ 2301 *taken_edge_p = find_taken_edge (block, val.value); 2302 if (*taken_edge_p) 2303 return SSA_PROP_INTERESTING; 2304 else 2305 return SSA_PROP_VARYING; 2306 } 2307 2308 2309 /* Evaluate statement STMT. If the statement produces an output value and 2310 its evaluation changes the lattice value of its output, return 2311 SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the 2312 output value. 2313 2314 If STMT is a conditional branch and we can determine its truth 2315 value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying 2316 value, return SSA_PROP_VARYING. */ 2317 2318 static enum ssa_prop_result 2319 ccp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p) 2320 { 2321 tree def; 2322 ssa_op_iter iter; 2323 2324 if (dump_file && (dump_flags & TDF_DETAILS)) 2325 { 2326 fprintf (dump_file, "\nVisiting statement:\n"); 2327 print_gimple_stmt (dump_file, stmt, 0, dump_flags); 2328 } 2329 2330 switch (gimple_code (stmt)) 2331 { 2332 case GIMPLE_ASSIGN: 2333 /* If the statement is an assignment that produces a single 2334 output value, evaluate its RHS to see if the lattice value of 2335 its output has changed. */ 2336 return visit_assignment (stmt, output_p); 2337 2338 case GIMPLE_CALL: 2339 /* A value-returning call also performs an assignment. */ 2340 if (gimple_call_lhs (stmt) != NULL_TREE) 2341 return visit_assignment (stmt, output_p); 2342 break; 2343 2344 case GIMPLE_COND: 2345 case GIMPLE_SWITCH: 2346 /* If STMT is a conditional branch, see if we can determine 2347 which branch will be taken. */ 2348 /* FIXME. It appears that we should be able to optimize 2349 computed GOTOs here as well. */ 2350 return visit_cond_stmt (stmt, taken_edge_p); 2351 2352 default: 2353 break; 2354 } 2355 2356 /* Any other kind of statement is not interesting for constant 2357 propagation and, therefore, not worth simulating. */ 2358 if (dump_file && (dump_flags & TDF_DETAILS)) 2359 fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); 2360 2361 /* Definitions made by statements other than assignments to 2362 SSA_NAMEs represent unknown modifications to their outputs. 2363 Mark them VARYING. */ 2364 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) 2365 { 2366 ccp_prop_value_t v = { VARYING, NULL_TREE, -1 }; 2367 set_lattice_value (def, v); 2368 } 2369 2370 return SSA_PROP_VARYING; 2371 } 2372 2373 2374 /* Main entry point for SSA Conditional Constant Propagation. */ 2375 2376 static unsigned int 2377 do_ssa_ccp (void) 2378 { 2379 unsigned int todo = 0; 2380 calculate_dominance_info (CDI_DOMINATORS); 2381 ccp_initialize (); 2382 ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); 2383 if (ccp_finalize ()) 2384 todo = (TODO_cleanup_cfg | TODO_update_ssa); 2385 free_dominance_info (CDI_DOMINATORS); 2386 return todo; 2387 } 2388 2389 2390 namespace { 2391 2392 const pass_data pass_data_ccp = 2393 { 2394 GIMPLE_PASS, /* type */ 2395 "ccp", /* name */ 2396 OPTGROUP_NONE, /* optinfo_flags */ 2397 TV_TREE_CCP, /* tv_id */ 2398 ( PROP_cfg | PROP_ssa ), /* properties_required */ 2399 0, /* properties_provided */ 2400 0, /* properties_destroyed */ 2401 0, /* todo_flags_start */ 2402 TODO_update_address_taken, /* todo_flags_finish */ 2403 }; 2404 2405 class pass_ccp : public gimple_opt_pass 2406 { 2407 public: 2408 pass_ccp (gcc::context *ctxt) 2409 : gimple_opt_pass (pass_data_ccp, ctxt) 2410 {} 2411 2412 /* opt_pass methods: */ 2413 opt_pass * clone () { return new pass_ccp (m_ctxt); } 2414 virtual bool gate (function *) { return flag_tree_ccp != 0; } 2415 virtual unsigned int execute (function *) { return do_ssa_ccp (); } 2416 2417 }; // class pass_ccp 2418 2419 } // anon namespace 2420 2421 gimple_opt_pass * 2422 make_pass_ccp (gcc::context *ctxt) 2423 { 2424 return new pass_ccp (ctxt); 2425 } 2426 2427 2428 2429 /* Try to optimize out __builtin_stack_restore. Optimize it out 2430 if there is another __builtin_stack_restore in the same basic 2431 block and no calls or ASM_EXPRs are in between, or if this block's 2432 only outgoing edge is to EXIT_BLOCK and there are no calls or 2433 ASM_EXPRs after this __builtin_stack_restore. */ 2434 2435 static tree 2436 optimize_stack_restore (gimple_stmt_iterator i) 2437 { 2438 tree callee; 2439 gimple stmt; 2440 2441 basic_block bb = gsi_bb (i); 2442 gimple call = gsi_stmt (i); 2443 2444 if (gimple_code (call) != GIMPLE_CALL 2445 || gimple_call_num_args (call) != 1 2446 || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME 2447 || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0)))) 2448 return NULL_TREE; 2449 2450 for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i)) 2451 { 2452 stmt = gsi_stmt (i); 2453 if (gimple_code (stmt) == GIMPLE_ASM) 2454 return NULL_TREE; 2455 if (gimple_code (stmt) != GIMPLE_CALL) 2456 continue; 2457 2458 callee = gimple_call_fndecl (stmt); 2459 if (!callee 2460 || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL 2461 /* All regular builtins are ok, just obviously not alloca. */ 2462 || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA 2463 || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA_WITH_ALIGN) 2464 return NULL_TREE; 2465 2466 if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE) 2467 goto second_stack_restore; 2468 } 2469 2470 if (!gsi_end_p (i)) 2471 return NULL_TREE; 2472 2473 /* Allow one successor of the exit block, or zero successors. */ 2474 switch (EDGE_COUNT (bb->succs)) 2475 { 2476 case 0: 2477 break; 2478 case 1: 2479 if (single_succ_edge (bb)->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) 2480 return NULL_TREE; 2481 break; 2482 default: 2483 return NULL_TREE; 2484 } 2485 second_stack_restore: 2486 2487 /* If there's exactly one use, then zap the call to __builtin_stack_save. 2488 If there are multiple uses, then the last one should remove the call. 2489 In any case, whether the call to __builtin_stack_save can be removed 2490 or not is irrelevant to removing the call to __builtin_stack_restore. */ 2491 if (has_single_use (gimple_call_arg (call, 0))) 2492 { 2493 gimple stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0)); 2494 if (is_gimple_call (stack_save)) 2495 { 2496 callee = gimple_call_fndecl (stack_save); 2497 if (callee 2498 && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL 2499 && DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_SAVE) 2500 { 2501 gimple_stmt_iterator stack_save_gsi; 2502 tree rhs; 2503 2504 stack_save_gsi = gsi_for_stmt (stack_save); 2505 rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0); 2506 update_call_from_tree (&stack_save_gsi, rhs); 2507 } 2508 } 2509 } 2510 2511 /* No effect, so the statement will be deleted. */ 2512 return integer_zero_node; 2513 } 2514 2515 /* If va_list type is a simple pointer and nothing special is needed, 2516 optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0), 2517 __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple 2518 pointer assignment. */ 2519 2520 static tree 2521 optimize_stdarg_builtin (gimple call) 2522 { 2523 tree callee, lhs, rhs, cfun_va_list; 2524 bool va_list_simple_ptr; 2525 location_t loc = gimple_location (call); 2526 2527 if (gimple_code (call) != GIMPLE_CALL) 2528 return NULL_TREE; 2529 2530 callee = gimple_call_fndecl (call); 2531 2532 cfun_va_list = targetm.fn_abi_va_list (callee); 2533 va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list) 2534 && (TREE_TYPE (cfun_va_list) == void_type_node 2535 || TREE_TYPE (cfun_va_list) == char_type_node); 2536 2537 switch (DECL_FUNCTION_CODE (callee)) 2538 { 2539 case BUILT_IN_VA_START: 2540 if (!va_list_simple_ptr 2541 || targetm.expand_builtin_va_start != NULL 2542 || !builtin_decl_explicit_p (BUILT_IN_NEXT_ARG)) 2543 return NULL_TREE; 2544 2545 if (gimple_call_num_args (call) != 2) 2546 return NULL_TREE; 2547 2548 lhs = gimple_call_arg (call, 0); 2549 if (!POINTER_TYPE_P (TREE_TYPE (lhs)) 2550 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) 2551 != TYPE_MAIN_VARIANT (cfun_va_list)) 2552 return NULL_TREE; 2553 2554 lhs = build_fold_indirect_ref_loc (loc, lhs); 2555 rhs = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_NEXT_ARG), 2556 1, integer_zero_node); 2557 rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); 2558 return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); 2559 2560 case BUILT_IN_VA_COPY: 2561 if (!va_list_simple_ptr) 2562 return NULL_TREE; 2563 2564 if (gimple_call_num_args (call) != 2) 2565 return NULL_TREE; 2566 2567 lhs = gimple_call_arg (call, 0); 2568 if (!POINTER_TYPE_P (TREE_TYPE (lhs)) 2569 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) 2570 != TYPE_MAIN_VARIANT (cfun_va_list)) 2571 return NULL_TREE; 2572 2573 lhs = build_fold_indirect_ref_loc (loc, lhs); 2574 rhs = gimple_call_arg (call, 1); 2575 if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs)) 2576 != TYPE_MAIN_VARIANT (cfun_va_list)) 2577 return NULL_TREE; 2578 2579 rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); 2580 return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); 2581 2582 case BUILT_IN_VA_END: 2583 /* No effect, so the statement will be deleted. */ 2584 return integer_zero_node; 2585 2586 default: 2587 gcc_unreachable (); 2588 } 2589 } 2590 2591 /* Attemp to make the block of __builtin_unreachable I unreachable by changing 2592 the incoming jumps. Return true if at least one jump was changed. */ 2593 2594 static bool 2595 optimize_unreachable (gimple_stmt_iterator i) 2596 { 2597 basic_block bb = gsi_bb (i); 2598 gimple_stmt_iterator gsi; 2599 gimple stmt; 2600 edge_iterator ei; 2601 edge e; 2602 bool ret; 2603 2604 if (flag_sanitize & SANITIZE_UNREACHABLE) 2605 return false; 2606 2607 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) 2608 { 2609 stmt = gsi_stmt (gsi); 2610 2611 if (is_gimple_debug (stmt)) 2612 continue; 2613 2614 if (glabel *label_stmt = dyn_cast <glabel *> (stmt)) 2615 { 2616 /* Verify we do not need to preserve the label. */ 2617 if (FORCED_LABEL (gimple_label_label (label_stmt))) 2618 return false; 2619 2620 continue; 2621 } 2622 2623 /* Only handle the case that __builtin_unreachable is the first statement 2624 in the block. We rely on DCE to remove stmts without side-effects 2625 before __builtin_unreachable. */ 2626 if (gsi_stmt (gsi) != gsi_stmt (i)) 2627 return false; 2628 } 2629 2630 ret = false; 2631 FOR_EACH_EDGE (e, ei, bb->preds) 2632 { 2633 gsi = gsi_last_bb (e->src); 2634 if (gsi_end_p (gsi)) 2635 continue; 2636 2637 stmt = gsi_stmt (gsi); 2638 if (gcond *cond_stmt = dyn_cast <gcond *> (stmt)) 2639 { 2640 if (e->flags & EDGE_TRUE_VALUE) 2641 gimple_cond_make_false (cond_stmt); 2642 else if (e->flags & EDGE_FALSE_VALUE) 2643 gimple_cond_make_true (cond_stmt); 2644 else 2645 gcc_unreachable (); 2646 update_stmt (cond_stmt); 2647 } 2648 else 2649 { 2650 /* Todo: handle other cases, f.i. switch statement. */ 2651 continue; 2652 } 2653 2654 ret = true; 2655 } 2656 2657 return ret; 2658 } 2659 2660 /* A simple pass that attempts to fold all builtin functions. This pass 2661 is run after we've propagated as many constants as we can. */ 2662 2663 namespace { 2664 2665 const pass_data pass_data_fold_builtins = 2666 { 2667 GIMPLE_PASS, /* type */ 2668 "fab", /* name */ 2669 OPTGROUP_NONE, /* optinfo_flags */ 2670 TV_NONE, /* tv_id */ 2671 ( PROP_cfg | PROP_ssa ), /* properties_required */ 2672 0, /* properties_provided */ 2673 0, /* properties_destroyed */ 2674 0, /* todo_flags_start */ 2675 TODO_update_ssa, /* todo_flags_finish */ 2676 }; 2677 2678 class pass_fold_builtins : public gimple_opt_pass 2679 { 2680 public: 2681 pass_fold_builtins (gcc::context *ctxt) 2682 : gimple_opt_pass (pass_data_fold_builtins, ctxt) 2683 {} 2684 2685 /* opt_pass methods: */ 2686 opt_pass * clone () { return new pass_fold_builtins (m_ctxt); } 2687 virtual unsigned int execute (function *); 2688 2689 }; // class pass_fold_builtins 2690 2691 unsigned int 2692 pass_fold_builtins::execute (function *fun) 2693 { 2694 bool cfg_changed = false; 2695 basic_block bb; 2696 unsigned int todoflags = 0; 2697 2698 FOR_EACH_BB_FN (bb, fun) 2699 { 2700 gimple_stmt_iterator i; 2701 for (i = gsi_start_bb (bb); !gsi_end_p (i); ) 2702 { 2703 gimple stmt, old_stmt; 2704 tree callee; 2705 enum built_in_function fcode; 2706 2707 stmt = gsi_stmt (i); 2708 2709 if (gimple_code (stmt) != GIMPLE_CALL) 2710 { 2711 /* Remove all *ssaname_N ={v} {CLOBBER}; stmts, 2712 after the last GIMPLE DSE they aren't needed and might 2713 unnecessarily keep the SSA_NAMEs live. */ 2714 if (gimple_clobber_p (stmt)) 2715 { 2716 tree lhs = gimple_assign_lhs (stmt); 2717 if (TREE_CODE (lhs) == MEM_REF 2718 && TREE_CODE (TREE_OPERAND (lhs, 0)) == SSA_NAME) 2719 { 2720 unlink_stmt_vdef (stmt); 2721 gsi_remove (&i, true); 2722 release_defs (stmt); 2723 continue; 2724 } 2725 } 2726 gsi_next (&i); 2727 continue; 2728 } 2729 2730 callee = gimple_call_fndecl (stmt); 2731 if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) 2732 { 2733 gsi_next (&i); 2734 continue; 2735 } 2736 2737 fcode = DECL_FUNCTION_CODE (callee); 2738 if (fold_stmt (&i)) 2739 ; 2740 else 2741 { 2742 tree result = NULL_TREE; 2743 switch (DECL_FUNCTION_CODE (callee)) 2744 { 2745 case BUILT_IN_CONSTANT_P: 2746 /* Resolve __builtin_constant_p. If it hasn't been 2747 folded to integer_one_node by now, it's fairly 2748 certain that the value simply isn't constant. */ 2749 result = integer_zero_node; 2750 break; 2751 2752 case BUILT_IN_ASSUME_ALIGNED: 2753 /* Remove __builtin_assume_aligned. */ 2754 result = gimple_call_arg (stmt, 0); 2755 break; 2756 2757 case BUILT_IN_STACK_RESTORE: 2758 result = optimize_stack_restore (i); 2759 if (result) 2760 break; 2761 gsi_next (&i); 2762 continue; 2763 2764 case BUILT_IN_UNREACHABLE: 2765 if (optimize_unreachable (i)) 2766 cfg_changed = true; 2767 break; 2768 2769 case BUILT_IN_VA_START: 2770 case BUILT_IN_VA_END: 2771 case BUILT_IN_VA_COPY: 2772 /* These shouldn't be folded before pass_stdarg. */ 2773 result = optimize_stdarg_builtin (stmt); 2774 if (result) 2775 break; 2776 /* FALLTHRU */ 2777 2778 default:; 2779 } 2780 2781 if (!result) 2782 { 2783 gsi_next (&i); 2784 continue; 2785 } 2786 2787 if (!update_call_from_tree (&i, result)) 2788 gimplify_and_update_call_from_tree (&i, result); 2789 } 2790 2791 todoflags |= TODO_update_address_taken; 2792 2793 if (dump_file && (dump_flags & TDF_DETAILS)) 2794 { 2795 fprintf (dump_file, "Simplified\n "); 2796 print_gimple_stmt (dump_file, stmt, 0, dump_flags); 2797 } 2798 2799 old_stmt = stmt; 2800 stmt = gsi_stmt (i); 2801 update_stmt (stmt); 2802 2803 if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt) 2804 && gimple_purge_dead_eh_edges (bb)) 2805 cfg_changed = true; 2806 2807 if (dump_file && (dump_flags & TDF_DETAILS)) 2808 { 2809 fprintf (dump_file, "to\n "); 2810 print_gimple_stmt (dump_file, stmt, 0, dump_flags); 2811 fprintf (dump_file, "\n"); 2812 } 2813 2814 /* Retry the same statement if it changed into another 2815 builtin, there might be new opportunities now. */ 2816 if (gimple_code (stmt) != GIMPLE_CALL) 2817 { 2818 gsi_next (&i); 2819 continue; 2820 } 2821 callee = gimple_call_fndecl (stmt); 2822 if (!callee 2823 || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL 2824 || DECL_FUNCTION_CODE (callee) == fcode) 2825 gsi_next (&i); 2826 } 2827 } 2828 2829 /* Delete unreachable blocks. */ 2830 if (cfg_changed) 2831 todoflags |= TODO_cleanup_cfg; 2832 2833 return todoflags; 2834 } 2835 2836 } // anon namespace 2837 2838 gimple_opt_pass * 2839 make_pass_fold_builtins (gcc::context *ctxt) 2840 { 2841 return new pass_fold_builtins (ctxt); 2842 } 2843 2844 #if defined(__NetBSD__) && defined(NETBSD_NATIVE) 2845 /* 2846 * This is a big, ugly, temporary hack: 2847 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59958 2848 * To make sure we have configured all our targets correctly, mimic the 2849 * #ifdef cascade from src/lib/libc/stdlib/jemalloc.c here and compile 2850 * time assert that the value matches gcc's MALLOC_ABI_ALIGNMENT here. 2851 */ 2852 2853 #if defined(__hppa__) 2854 #define JEMALLOC_TINY_MIN_2POW 4 2855 #elif defined(__alpha__) || defined(__amd64__) || defined(__sparc64__) \ 2856 || (defined(__arm__) && defined(__ARM_EABI__)) \ 2857 || defined(__ia64__) || defined(__powerpc__) \ 2858 || ((defined(__mips__) || defined(__riscv__)) && defined(_LP64)) 2859 #define JEMALLOC_TINY_MIN_2POW 3 2860 #endif 2861 2862 #ifndef JEMALLOC_TINY_MIN_2POW 2863 #define JEMALLOC_TINY_MIN_2POW 2 2864 #endif 2865 2866 /* make sure we test the (native) 64bit variant for targets supporting -m32 */ 2867 #undef TARGET_64BIT 2868 #ifdef _LP64 2869 #define TARGET_64BIT 1 2870 #else 2871 #ifdef __sh__ 2872 #undef UNITS_PER_WORD 2873 #define UNITS_PER_WORD 4 /* original definition varies depending on cpu */ 2874 #endif 2875 #define TARGET_64BIT 0 2876 #endif 2877 2878 /* ARM has a non-constant MALLOC_ABI_ALIGNMENT since GCC 5. */ 2879 #if !defined(__arm__) 2880 #ifdef __CTASSERT 2881 __CTASSERT((8<<JEMALLOC_TINY_MIN_2POW) == MALLOC_ABI_ALIGNMENT); 2882 #else 2883 #error compiling on an older NetBSD version? 2884 #endif 2885 #endif 2886 2887 #endif 2888