1 /* Conditional constant propagation pass for the GNU compiler. 2 Copyright (C) 2000-2017 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 "backend.h" 125 #include "target.h" 126 #include "tree.h" 127 #include "gimple.h" 128 #include "tree-pass.h" 129 #include "ssa.h" 130 #include "gimple-pretty-print.h" 131 #include "fold-const.h" 132 #include "gimple-fold.h" 133 #include "tree-eh.h" 134 #include "gimplify.h" 135 #include "gimple-iterator.h" 136 #include "tree-cfg.h" 137 #include "tree-ssa-propagate.h" 138 #include "dbgcnt.h" 139 #include "params.h" 140 #include "builtins.h" 141 #include "tree-chkp.h" 142 #include "cfgloop.h" 143 #include "stor-layout.h" 144 #include "optabs-query.h" 145 #include "tree-ssa-ccp.h" 146 #include "tree-dfa.h" 147 #include "diagnostic-core.h" 148 149 /* Possible lattice values. */ 150 typedef enum 151 { 152 UNINITIALIZED, 153 UNDEFINED, 154 CONSTANT, 155 VARYING 156 } ccp_lattice_t; 157 158 struct ccp_prop_value_t { 159 /* Lattice value. */ 160 ccp_lattice_t lattice_val; 161 162 /* Propagated value. */ 163 tree value; 164 165 /* Mask that applies to the propagated value during CCP. For X 166 with a CONSTANT lattice value X & ~mask == value & ~mask. The 167 zero bits in the mask cover constant values. The ones mean no 168 information. */ 169 widest_int mask; 170 }; 171 172 /* Array of propagated constant values. After propagation, 173 CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If 174 the constant is held in an SSA name representing a memory store 175 (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual 176 memory reference used to store (i.e., the LHS of the assignment 177 doing the store). */ 178 static ccp_prop_value_t *const_val; 179 static unsigned n_const_val; 180 181 static void canonicalize_value (ccp_prop_value_t *); 182 static bool ccp_fold_stmt (gimple_stmt_iterator *); 183 static void ccp_lattice_meet (ccp_prop_value_t *, ccp_prop_value_t *); 184 185 /* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */ 186 187 static void 188 dump_lattice_value (FILE *outf, const char *prefix, ccp_prop_value_t val) 189 { 190 switch (val.lattice_val) 191 { 192 case UNINITIALIZED: 193 fprintf (outf, "%sUNINITIALIZED", prefix); 194 break; 195 case UNDEFINED: 196 fprintf (outf, "%sUNDEFINED", prefix); 197 break; 198 case VARYING: 199 fprintf (outf, "%sVARYING", prefix); 200 break; 201 case CONSTANT: 202 if (TREE_CODE (val.value) != INTEGER_CST 203 || val.mask == 0) 204 { 205 fprintf (outf, "%sCONSTANT ", prefix); 206 print_generic_expr (outf, val.value, dump_flags); 207 } 208 else 209 { 210 widest_int cval = wi::bit_and_not (wi::to_widest (val.value), 211 val.mask); 212 fprintf (outf, "%sCONSTANT ", prefix); 213 print_hex (cval, outf); 214 fprintf (outf, " ("); 215 print_hex (val.mask, outf); 216 fprintf (outf, ")"); 217 } 218 break; 219 default: 220 gcc_unreachable (); 221 } 222 } 223 224 225 /* Print lattice value VAL to stderr. */ 226 227 void debug_lattice_value (ccp_prop_value_t val); 228 229 DEBUG_FUNCTION void 230 debug_lattice_value (ccp_prop_value_t val) 231 { 232 dump_lattice_value (stderr, "", val); 233 fprintf (stderr, "\n"); 234 } 235 236 /* Extend NONZERO_BITS to a full mask, based on sgn. */ 237 238 static widest_int 239 extend_mask (const wide_int &nonzero_bits, signop sgn) 240 { 241 return widest_int::from (nonzero_bits, sgn); 242 } 243 244 /* Compute a default value for variable VAR and store it in the 245 CONST_VAL array. The following rules are used to get default 246 values: 247 248 1- Global and static variables that are declared constant are 249 considered CONSTANT. 250 251 2- Any other value is considered UNDEFINED. This is useful when 252 considering PHI nodes. PHI arguments that are undefined do not 253 change the constant value of the PHI node, which allows for more 254 constants to be propagated. 255 256 3- Variables defined by statements other than assignments and PHI 257 nodes are considered VARYING. 258 259 4- Initial values of variables that are not GIMPLE registers are 260 considered VARYING. */ 261 262 static ccp_prop_value_t 263 get_default_value (tree var) 264 { 265 ccp_prop_value_t val = { UNINITIALIZED, NULL_TREE, 0 }; 266 gimple *stmt; 267 268 stmt = SSA_NAME_DEF_STMT (var); 269 270 if (gimple_nop_p (stmt)) 271 { 272 /* Variables defined by an empty statement are those used 273 before being initialized. If VAR is a local variable, we 274 can assume initially that it is UNDEFINED, otherwise we must 275 consider it VARYING. */ 276 if (!virtual_operand_p (var) 277 && SSA_NAME_VAR (var) 278 && TREE_CODE (SSA_NAME_VAR (var)) == VAR_DECL) 279 val.lattice_val = UNDEFINED; 280 else 281 { 282 val.lattice_val = VARYING; 283 val.mask = -1; 284 if (flag_tree_bit_ccp) 285 { 286 wide_int nonzero_bits = get_nonzero_bits (var); 287 if (nonzero_bits != -1) 288 { 289 val.lattice_val = CONSTANT; 290 val.value = build_zero_cst (TREE_TYPE (var)); 291 val.mask = extend_mask (nonzero_bits, TYPE_SIGN (TREE_TYPE (var))); 292 } 293 } 294 } 295 } 296 else if (is_gimple_assign (stmt)) 297 { 298 tree cst; 299 if (gimple_assign_single_p (stmt) 300 && DECL_P (gimple_assign_rhs1 (stmt)) 301 && (cst = get_symbol_constant_value (gimple_assign_rhs1 (stmt)))) 302 { 303 val.lattice_val = CONSTANT; 304 val.value = cst; 305 } 306 else 307 { 308 /* Any other variable defined by an assignment is considered 309 UNDEFINED. */ 310 val.lattice_val = UNDEFINED; 311 } 312 } 313 else if ((is_gimple_call (stmt) 314 && gimple_call_lhs (stmt) != NULL_TREE) 315 || gimple_code (stmt) == GIMPLE_PHI) 316 { 317 /* A variable defined by a call or a PHI node is considered 318 UNDEFINED. */ 319 val.lattice_val = UNDEFINED; 320 } 321 else 322 { 323 /* Otherwise, VAR will never take on a constant value. */ 324 val.lattice_val = VARYING; 325 val.mask = -1; 326 } 327 328 return val; 329 } 330 331 332 /* Get the constant value associated with variable VAR. */ 333 334 static inline ccp_prop_value_t * 335 get_value (tree var) 336 { 337 ccp_prop_value_t *val; 338 339 if (const_val == NULL 340 || SSA_NAME_VERSION (var) >= n_const_val) 341 return NULL; 342 343 val = &const_val[SSA_NAME_VERSION (var)]; 344 if (val->lattice_val == UNINITIALIZED) 345 *val = get_default_value (var); 346 347 canonicalize_value (val); 348 349 return val; 350 } 351 352 /* Return the constant tree value associated with VAR. */ 353 354 static inline tree 355 get_constant_value (tree var) 356 { 357 ccp_prop_value_t *val; 358 if (TREE_CODE (var) != SSA_NAME) 359 { 360 if (is_gimple_min_invariant (var)) 361 return var; 362 return NULL_TREE; 363 } 364 val = get_value (var); 365 if (val 366 && val->lattice_val == CONSTANT 367 && (TREE_CODE (val->value) != INTEGER_CST 368 || val->mask == 0)) 369 return val->value; 370 return NULL_TREE; 371 } 372 373 /* Sets the value associated with VAR to VARYING. */ 374 375 static inline void 376 set_value_varying (tree var) 377 { 378 ccp_prop_value_t *val = &const_val[SSA_NAME_VERSION (var)]; 379 380 val->lattice_val = VARYING; 381 val->value = NULL_TREE; 382 val->mask = -1; 383 } 384 385 /* For integer constants, make sure to drop TREE_OVERFLOW. */ 386 387 static void 388 canonicalize_value (ccp_prop_value_t *val) 389 { 390 if (val->lattice_val != CONSTANT) 391 return; 392 393 if (TREE_OVERFLOW_P (val->value)) 394 val->value = drop_tree_overflow (val->value); 395 } 396 397 /* Return whether the lattice transition is valid. */ 398 399 static bool 400 valid_lattice_transition (ccp_prop_value_t old_val, ccp_prop_value_t new_val) 401 { 402 /* Lattice transitions must always be monotonically increasing in 403 value. */ 404 if (old_val.lattice_val < new_val.lattice_val) 405 return true; 406 407 if (old_val.lattice_val != new_val.lattice_val) 408 return false; 409 410 if (!old_val.value && !new_val.value) 411 return true; 412 413 /* Now both lattice values are CONSTANT. */ 414 415 /* Allow arbitrary copy changes as we might look through PHI <a_1, ...> 416 when only a single copy edge is executable. */ 417 if (TREE_CODE (old_val.value) == SSA_NAME 418 && TREE_CODE (new_val.value) == SSA_NAME) 419 return true; 420 421 /* Allow transitioning from a constant to a copy. */ 422 if (is_gimple_min_invariant (old_val.value) 423 && TREE_CODE (new_val.value) == SSA_NAME) 424 return true; 425 426 /* Allow transitioning from PHI <&x, not executable> == &x 427 to PHI <&x, &y> == common alignment. */ 428 if (TREE_CODE (old_val.value) != INTEGER_CST 429 && TREE_CODE (new_val.value) == INTEGER_CST) 430 return true; 431 432 /* Bit-lattices have to agree in the still valid bits. */ 433 if (TREE_CODE (old_val.value) == INTEGER_CST 434 && TREE_CODE (new_val.value) == INTEGER_CST) 435 return (wi::bit_and_not (wi::to_widest (old_val.value), new_val.mask) 436 == wi::bit_and_not (wi::to_widest (new_val.value), new_val.mask)); 437 438 /* Otherwise constant values have to agree. */ 439 if (operand_equal_p (old_val.value, new_val.value, 0)) 440 return true; 441 442 /* At least the kinds and types should agree now. */ 443 if (TREE_CODE (old_val.value) != TREE_CODE (new_val.value) 444 || !types_compatible_p (TREE_TYPE (old_val.value), 445 TREE_TYPE (new_val.value))) 446 return false; 447 448 /* For floats and !HONOR_NANS allow transitions from (partial) NaN 449 to non-NaN. */ 450 tree type = TREE_TYPE (new_val.value); 451 if (SCALAR_FLOAT_TYPE_P (type) 452 && !HONOR_NANS (type)) 453 { 454 if (REAL_VALUE_ISNAN (TREE_REAL_CST (old_val.value))) 455 return true; 456 } 457 else if (VECTOR_FLOAT_TYPE_P (type) 458 && !HONOR_NANS (type)) 459 { 460 for (unsigned i = 0; i < VECTOR_CST_NELTS (old_val.value); ++i) 461 if (!REAL_VALUE_ISNAN 462 (TREE_REAL_CST (VECTOR_CST_ELT (old_val.value, i))) 463 && !operand_equal_p (VECTOR_CST_ELT (old_val.value, i), 464 VECTOR_CST_ELT (new_val.value, i), 0)) 465 return false; 466 return true; 467 } 468 else if (COMPLEX_FLOAT_TYPE_P (type) 469 && !HONOR_NANS (type)) 470 { 471 if (!REAL_VALUE_ISNAN (TREE_REAL_CST (TREE_REALPART (old_val.value))) 472 && !operand_equal_p (TREE_REALPART (old_val.value), 473 TREE_REALPART (new_val.value), 0)) 474 return false; 475 if (!REAL_VALUE_ISNAN (TREE_REAL_CST (TREE_IMAGPART (old_val.value))) 476 && !operand_equal_p (TREE_IMAGPART (old_val.value), 477 TREE_IMAGPART (new_val.value), 0)) 478 return false; 479 return true; 480 } 481 return false; 482 } 483 484 /* Set the value for variable VAR to NEW_VAL. Return true if the new 485 value is different from VAR's previous value. */ 486 487 static bool 488 set_lattice_value (tree var, ccp_prop_value_t *new_val) 489 { 490 /* We can deal with old UNINITIALIZED values just fine here. */ 491 ccp_prop_value_t *old_val = &const_val[SSA_NAME_VERSION (var)]; 492 493 canonicalize_value (new_val); 494 495 /* We have to be careful to not go up the bitwise lattice 496 represented by the mask. Instead of dropping to VARYING 497 use the meet operator to retain a conservative value. 498 Missed optimizations like PR65851 makes this necessary. 499 It also ensures we converge to a stable lattice solution. */ 500 if (old_val->lattice_val != UNINITIALIZED) 501 ccp_lattice_meet (new_val, old_val); 502 503 gcc_checking_assert (valid_lattice_transition (*old_val, *new_val)); 504 505 /* If *OLD_VAL and NEW_VAL are the same, return false to inform the 506 caller that this was a non-transition. */ 507 if (old_val->lattice_val != new_val->lattice_val 508 || (new_val->lattice_val == CONSTANT 509 && (TREE_CODE (new_val->value) != TREE_CODE (old_val->value) 510 || (TREE_CODE (new_val->value) == INTEGER_CST 511 && (new_val->mask != old_val->mask 512 || (wi::bit_and_not (wi::to_widest (old_val->value), 513 new_val->mask) 514 != wi::bit_and_not (wi::to_widest (new_val->value), 515 new_val->mask)))) 516 || (TREE_CODE (new_val->value) != INTEGER_CST 517 && !operand_equal_p (new_val->value, old_val->value, 0))))) 518 { 519 /* ??? We would like to delay creation of INTEGER_CSTs from 520 partially constants here. */ 521 522 if (dump_file && (dump_flags & TDF_DETAILS)) 523 { 524 dump_lattice_value (dump_file, "Lattice value changed to ", *new_val); 525 fprintf (dump_file, ". Adding SSA edges to worklist.\n"); 526 } 527 528 *old_val = *new_val; 529 530 gcc_assert (new_val->lattice_val != UNINITIALIZED); 531 return true; 532 } 533 534 return false; 535 } 536 537 static ccp_prop_value_t get_value_for_expr (tree, bool); 538 static ccp_prop_value_t bit_value_binop (enum tree_code, tree, tree, tree); 539 void bit_value_binop (enum tree_code, signop, int, widest_int *, widest_int *, 540 signop, int, const widest_int &, const widest_int &, 541 signop, int, const widest_int &, const widest_int &); 542 543 /* Return a widest_int that can be used for bitwise simplifications 544 from VAL. */ 545 546 static widest_int 547 value_to_wide_int (ccp_prop_value_t val) 548 { 549 if (val.value 550 && TREE_CODE (val.value) == INTEGER_CST) 551 return wi::to_widest (val.value); 552 553 return 0; 554 } 555 556 /* Return the value for the address expression EXPR based on alignment 557 information. */ 558 559 static ccp_prop_value_t 560 get_value_from_alignment (tree expr) 561 { 562 tree type = TREE_TYPE (expr); 563 ccp_prop_value_t val; 564 unsigned HOST_WIDE_INT bitpos; 565 unsigned int align; 566 567 gcc_assert (TREE_CODE (expr) == ADDR_EXPR); 568 569 get_pointer_alignment_1 (expr, &align, &bitpos); 570 val.mask = (POINTER_TYPE_P (type) || TYPE_UNSIGNED (type) 571 ? wi::mask <widest_int> (TYPE_PRECISION (type), false) 572 : -1).and_not (align / BITS_PER_UNIT - 1); 573 val.lattice_val 574 = wi::sext (val.mask, TYPE_PRECISION (type)) == -1 ? VARYING : CONSTANT; 575 if (val.lattice_val == CONSTANT) 576 val.value = build_int_cstu (type, bitpos / BITS_PER_UNIT); 577 else 578 val.value = NULL_TREE; 579 580 return val; 581 } 582 583 /* Return the value for the tree operand EXPR. If FOR_BITS_P is true 584 return constant bits extracted from alignment information for 585 invariant addresses. */ 586 587 static ccp_prop_value_t 588 get_value_for_expr (tree expr, bool for_bits_p) 589 { 590 ccp_prop_value_t val; 591 592 if (TREE_CODE (expr) == SSA_NAME) 593 { 594 ccp_prop_value_t *val_ = get_value (expr); 595 if (val_) 596 val = *val_; 597 else 598 { 599 val.lattice_val = VARYING; 600 val.value = NULL_TREE; 601 val.mask = -1; 602 } 603 if (for_bits_p 604 && val.lattice_val == CONSTANT 605 && TREE_CODE (val.value) == ADDR_EXPR) 606 val = get_value_from_alignment (val.value); 607 /* Fall back to a copy value. */ 608 if (!for_bits_p 609 && val.lattice_val == VARYING 610 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (expr)) 611 { 612 val.lattice_val = CONSTANT; 613 val.value = expr; 614 val.mask = -1; 615 } 616 } 617 else if (is_gimple_min_invariant (expr) 618 && (!for_bits_p || TREE_CODE (expr) != ADDR_EXPR)) 619 { 620 val.lattice_val = CONSTANT; 621 val.value = expr; 622 val.mask = 0; 623 canonicalize_value (&val); 624 } 625 else if (TREE_CODE (expr) == ADDR_EXPR) 626 val = get_value_from_alignment (expr); 627 else 628 { 629 val.lattice_val = VARYING; 630 val.mask = -1; 631 val.value = NULL_TREE; 632 } 633 634 if (val.lattice_val == VARYING 635 && TYPE_UNSIGNED (TREE_TYPE (expr))) 636 val.mask = wi::zext (val.mask, TYPE_PRECISION (TREE_TYPE (expr))); 637 638 return val; 639 } 640 641 /* Return the likely CCP lattice value for STMT. 642 643 If STMT has no operands, then return CONSTANT. 644 645 Else if undefinedness of operands of STMT cause its value to be 646 undefined, then return UNDEFINED. 647 648 Else if any operands of STMT are constants, then return CONSTANT. 649 650 Else return VARYING. */ 651 652 static ccp_lattice_t 653 likely_value (gimple *stmt) 654 { 655 bool has_constant_operand, has_undefined_operand, all_undefined_operands; 656 bool has_nsa_operand; 657 tree use; 658 ssa_op_iter iter; 659 unsigned i; 660 661 enum gimple_code code = gimple_code (stmt); 662 663 /* This function appears to be called only for assignments, calls, 664 conditionals, and switches, due to the logic in visit_stmt. */ 665 gcc_assert (code == GIMPLE_ASSIGN 666 || code == GIMPLE_CALL 667 || code == GIMPLE_COND 668 || code == GIMPLE_SWITCH); 669 670 /* If the statement has volatile operands, it won't fold to a 671 constant value. */ 672 if (gimple_has_volatile_ops (stmt)) 673 return VARYING; 674 675 /* Arrive here for more complex cases. */ 676 has_constant_operand = false; 677 has_undefined_operand = false; 678 all_undefined_operands = true; 679 has_nsa_operand = false; 680 FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) 681 { 682 ccp_prop_value_t *val = get_value (use); 683 684 if (val && val->lattice_val == UNDEFINED) 685 has_undefined_operand = true; 686 else 687 all_undefined_operands = false; 688 689 if (val && val->lattice_val == CONSTANT) 690 has_constant_operand = true; 691 692 if (SSA_NAME_IS_DEFAULT_DEF (use) 693 || !prop_simulate_again_p (SSA_NAME_DEF_STMT (use))) 694 has_nsa_operand = true; 695 } 696 697 /* There may be constants in regular rhs operands. For calls we 698 have to ignore lhs, fndecl and static chain, otherwise only 699 the lhs. */ 700 for (i = (is_gimple_call (stmt) ? 2 : 0) + gimple_has_lhs (stmt); 701 i < gimple_num_ops (stmt); ++i) 702 { 703 tree op = gimple_op (stmt, i); 704 if (!op || TREE_CODE (op) == SSA_NAME) 705 continue; 706 if (is_gimple_min_invariant (op)) 707 has_constant_operand = true; 708 } 709 710 if (has_constant_operand) 711 all_undefined_operands = false; 712 713 if (has_undefined_operand 714 && code == GIMPLE_CALL 715 && gimple_call_internal_p (stmt)) 716 switch (gimple_call_internal_fn (stmt)) 717 { 718 /* These 3 builtins use the first argument just as a magic 719 way how to find out a decl uid. */ 720 case IFN_GOMP_SIMD_LANE: 721 case IFN_GOMP_SIMD_VF: 722 case IFN_GOMP_SIMD_LAST_LANE: 723 has_undefined_operand = false; 724 break; 725 default: 726 break; 727 } 728 729 /* If the operation combines operands like COMPLEX_EXPR make sure to 730 not mark the result UNDEFINED if only one part of the result is 731 undefined. */ 732 if (has_undefined_operand && all_undefined_operands) 733 return UNDEFINED; 734 else if (code == GIMPLE_ASSIGN && has_undefined_operand) 735 { 736 switch (gimple_assign_rhs_code (stmt)) 737 { 738 /* Unary operators are handled with all_undefined_operands. */ 739 case PLUS_EXPR: 740 case MINUS_EXPR: 741 case POINTER_PLUS_EXPR: 742 case BIT_XOR_EXPR: 743 /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected. 744 Not bitwise operators, one VARYING operand may specify the 745 result completely. 746 Not logical operators for the same reason, apart from XOR. 747 Not COMPLEX_EXPR as one VARYING operand makes the result partly 748 not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because 749 the undefined operand may be promoted. */ 750 return UNDEFINED; 751 752 case ADDR_EXPR: 753 /* If any part of an address is UNDEFINED, like the index 754 of an ARRAY_EXPR, then treat the result as UNDEFINED. */ 755 return UNDEFINED; 756 757 default: 758 ; 759 } 760 } 761 /* If there was an UNDEFINED operand but the result may be not UNDEFINED 762 fall back to CONSTANT. During iteration UNDEFINED may still drop 763 to CONSTANT. */ 764 if (has_undefined_operand) 765 return CONSTANT; 766 767 /* We do not consider virtual operands here -- load from read-only 768 memory may have only VARYING virtual operands, but still be 769 constant. Also we can combine the stmt with definitions from 770 operands whose definitions are not simulated again. */ 771 if (has_constant_operand 772 || has_nsa_operand 773 || gimple_references_memory_p (stmt)) 774 return CONSTANT; 775 776 return VARYING; 777 } 778 779 /* Returns true if STMT cannot be constant. */ 780 781 static bool 782 surely_varying_stmt_p (gimple *stmt) 783 { 784 /* If the statement has operands that we cannot handle, it cannot be 785 constant. */ 786 if (gimple_has_volatile_ops (stmt)) 787 return true; 788 789 /* If it is a call and does not return a value or is not a 790 builtin and not an indirect call or a call to function with 791 assume_aligned/alloc_align attribute, it is varying. */ 792 if (is_gimple_call (stmt)) 793 { 794 tree fndecl, fntype = gimple_call_fntype (stmt); 795 if (!gimple_call_lhs (stmt) 796 || ((fndecl = gimple_call_fndecl (stmt)) != NULL_TREE 797 && !DECL_BUILT_IN (fndecl) 798 && !lookup_attribute ("assume_aligned", 799 TYPE_ATTRIBUTES (fntype)) 800 && !lookup_attribute ("alloc_align", 801 TYPE_ATTRIBUTES (fntype)))) 802 return true; 803 } 804 805 /* Any other store operation is not interesting. */ 806 else if (gimple_vdef (stmt)) 807 return true; 808 809 /* Anything other than assignments and conditional jumps are not 810 interesting for CCP. */ 811 if (gimple_code (stmt) != GIMPLE_ASSIGN 812 && gimple_code (stmt) != GIMPLE_COND 813 && gimple_code (stmt) != GIMPLE_SWITCH 814 && gimple_code (stmt) != GIMPLE_CALL) 815 return true; 816 817 return false; 818 } 819 820 /* Initialize local data structures for CCP. */ 821 822 static void 823 ccp_initialize (void) 824 { 825 basic_block bb; 826 827 n_const_val = num_ssa_names; 828 const_val = XCNEWVEC (ccp_prop_value_t, n_const_val); 829 830 /* Initialize simulation flags for PHI nodes and statements. */ 831 FOR_EACH_BB_FN (bb, cfun) 832 { 833 gimple_stmt_iterator i; 834 835 for (i = gsi_start_bb (bb); !gsi_end_p (i); gsi_next (&i)) 836 { 837 gimple *stmt = gsi_stmt (i); 838 bool is_varying; 839 840 /* If the statement is a control insn, then we do not 841 want to avoid simulating the statement once. Failure 842 to do so means that those edges will never get added. */ 843 if (stmt_ends_bb_p (stmt)) 844 is_varying = false; 845 else 846 is_varying = surely_varying_stmt_p (stmt); 847 848 if (is_varying) 849 { 850 tree def; 851 ssa_op_iter iter; 852 853 /* If the statement will not produce a constant, mark 854 all its outputs VARYING. */ 855 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) 856 set_value_varying (def); 857 } 858 prop_set_simulate_again (stmt, !is_varying); 859 } 860 } 861 862 /* Now process PHI nodes. We never clear the simulate_again flag on 863 phi nodes, since we do not know which edges are executable yet, 864 except for phi nodes for virtual operands when we do not do store ccp. */ 865 FOR_EACH_BB_FN (bb, cfun) 866 { 867 gphi_iterator i; 868 869 for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i)) 870 { 871 gphi *phi = i.phi (); 872 873 if (virtual_operand_p (gimple_phi_result (phi))) 874 prop_set_simulate_again (phi, false); 875 else 876 prop_set_simulate_again (phi, true); 877 } 878 } 879 } 880 881 /* Debug count support. Reset the values of ssa names 882 VARYING when the total number ssa names analyzed is 883 beyond the debug count specified. */ 884 885 static void 886 do_dbg_cnt (void) 887 { 888 unsigned i; 889 for (i = 0; i < num_ssa_names; i++) 890 { 891 if (!dbg_cnt (ccp)) 892 { 893 const_val[i].lattice_val = VARYING; 894 const_val[i].mask = -1; 895 const_val[i].value = NULL_TREE; 896 } 897 } 898 } 899 900 901 /* Do final substitution of propagated values, cleanup the flowgraph and 902 free allocated storage. If NONZERO_P, record nonzero bits. 903 904 Return TRUE when something was optimized. */ 905 906 static bool 907 ccp_finalize (bool nonzero_p) 908 { 909 bool something_changed; 910 unsigned i; 911 tree name; 912 913 do_dbg_cnt (); 914 915 /* Derive alignment and misalignment information from partially 916 constant pointers in the lattice or nonzero bits from partially 917 constant integers. */ 918 FOR_EACH_SSA_NAME (i, name, cfun) 919 { 920 ccp_prop_value_t *val; 921 unsigned int tem, align; 922 923 if (!POINTER_TYPE_P (TREE_TYPE (name)) 924 && (!INTEGRAL_TYPE_P (TREE_TYPE (name)) 925 /* Don't record nonzero bits before IPA to avoid 926 using too much memory. */ 927 || !nonzero_p)) 928 continue; 929 930 val = get_value (name); 931 if (val->lattice_val != CONSTANT 932 || TREE_CODE (val->value) != INTEGER_CST 933 || val->mask == 0) 934 continue; 935 936 if (POINTER_TYPE_P (TREE_TYPE (name))) 937 { 938 /* Trailing mask bits specify the alignment, trailing value 939 bits the misalignment. */ 940 tem = val->mask.to_uhwi (); 941 align = least_bit_hwi (tem); 942 if (align > 1) 943 set_ptr_info_alignment (get_ptr_info (name), align, 944 (TREE_INT_CST_LOW (val->value) 945 & (align - 1))); 946 } 947 else 948 { 949 unsigned int precision = TYPE_PRECISION (TREE_TYPE (val->value)); 950 wide_int nonzero_bits = wide_int::from (val->mask, precision, 951 UNSIGNED) | val->value; 952 nonzero_bits &= get_nonzero_bits (name); 953 set_nonzero_bits (name, nonzero_bits); 954 } 955 } 956 957 /* Perform substitutions based on the known constant values. */ 958 something_changed = substitute_and_fold (get_constant_value, ccp_fold_stmt); 959 960 free (const_val); 961 const_val = NULL; 962 return something_changed;; 963 } 964 965 966 /* Compute the meet operator between *VAL1 and *VAL2. Store the result 967 in VAL1. 968 969 any M UNDEFINED = any 970 any M VARYING = VARYING 971 Ci M Cj = Ci if (i == j) 972 Ci M Cj = VARYING if (i != j) 973 */ 974 975 static void 976 ccp_lattice_meet (ccp_prop_value_t *val1, ccp_prop_value_t *val2) 977 { 978 if (val1->lattice_val == UNDEFINED 979 /* For UNDEFINED M SSA we can't always SSA because its definition 980 may not dominate the PHI node. Doing optimistic copy propagation 981 also causes a lot of gcc.dg/uninit-pred*.c FAILs. */ 982 && (val2->lattice_val != CONSTANT 983 || TREE_CODE (val2->value) != SSA_NAME)) 984 { 985 /* UNDEFINED M any = any */ 986 *val1 = *val2; 987 } 988 else if (val2->lattice_val == UNDEFINED 989 /* See above. */ 990 && (val1->lattice_val != CONSTANT 991 || TREE_CODE (val1->value) != SSA_NAME)) 992 { 993 /* any M UNDEFINED = any 994 Nothing to do. VAL1 already contains the value we want. */ 995 ; 996 } 997 else if (val1->lattice_val == VARYING 998 || val2->lattice_val == VARYING) 999 { 1000 /* any M VARYING = VARYING. */ 1001 val1->lattice_val = VARYING; 1002 val1->mask = -1; 1003 val1->value = NULL_TREE; 1004 } 1005 else if (val1->lattice_val == CONSTANT 1006 && val2->lattice_val == CONSTANT 1007 && TREE_CODE (val1->value) == INTEGER_CST 1008 && TREE_CODE (val2->value) == INTEGER_CST) 1009 { 1010 /* Ci M Cj = Ci if (i == j) 1011 Ci M Cj = VARYING if (i != j) 1012 1013 For INTEGER_CSTs mask unequal bits. If no equal bits remain, 1014 drop to varying. */ 1015 val1->mask = (val1->mask | val2->mask 1016 | (wi::to_widest (val1->value) 1017 ^ wi::to_widest (val2->value))); 1018 if (wi::sext (val1->mask, TYPE_PRECISION (TREE_TYPE (val1->value))) == -1) 1019 { 1020 val1->lattice_val = VARYING; 1021 val1->value = NULL_TREE; 1022 } 1023 } 1024 else if (val1->lattice_val == CONSTANT 1025 && val2->lattice_val == CONSTANT 1026 && operand_equal_p (val1->value, val2->value, 0)) 1027 { 1028 /* Ci M Cj = Ci if (i == j) 1029 Ci M Cj = VARYING if (i != j) 1030 1031 VAL1 already contains the value we want for equivalent values. */ 1032 } 1033 else if (val1->lattice_val == CONSTANT 1034 && val2->lattice_val == CONSTANT 1035 && (TREE_CODE (val1->value) == ADDR_EXPR 1036 || TREE_CODE (val2->value) == ADDR_EXPR)) 1037 { 1038 /* When not equal addresses are involved try meeting for 1039 alignment. */ 1040 ccp_prop_value_t tem = *val2; 1041 if (TREE_CODE (val1->value) == ADDR_EXPR) 1042 *val1 = get_value_for_expr (val1->value, true); 1043 if (TREE_CODE (val2->value) == ADDR_EXPR) 1044 tem = get_value_for_expr (val2->value, true); 1045 ccp_lattice_meet (val1, &tem); 1046 } 1047 else 1048 { 1049 /* Any other combination is VARYING. */ 1050 val1->lattice_val = VARYING; 1051 val1->mask = -1; 1052 val1->value = NULL_TREE; 1053 } 1054 } 1055 1056 1057 /* Loop through the PHI_NODE's parameters for BLOCK and compare their 1058 lattice values to determine PHI_NODE's lattice value. The value of a 1059 PHI node is determined calling ccp_lattice_meet with all the arguments 1060 of the PHI node that are incoming via executable edges. */ 1061 1062 static enum ssa_prop_result 1063 ccp_visit_phi_node (gphi *phi) 1064 { 1065 unsigned i; 1066 ccp_prop_value_t new_val; 1067 1068 if (dump_file && (dump_flags & TDF_DETAILS)) 1069 { 1070 fprintf (dump_file, "\nVisiting PHI node: "); 1071 print_gimple_stmt (dump_file, phi, 0, dump_flags); 1072 } 1073 1074 new_val.lattice_val = UNDEFINED; 1075 new_val.value = NULL_TREE; 1076 new_val.mask = 0; 1077 1078 bool first = true; 1079 bool non_exec_edge = false; 1080 for (i = 0; i < gimple_phi_num_args (phi); i++) 1081 { 1082 /* Compute the meet operator over all the PHI arguments flowing 1083 through executable edges. */ 1084 edge e = gimple_phi_arg_edge (phi, i); 1085 1086 if (dump_file && (dump_flags & TDF_DETAILS)) 1087 { 1088 fprintf (dump_file, 1089 "\n Argument #%d (%d -> %d %sexecutable)\n", 1090 i, e->src->index, e->dest->index, 1091 (e->flags & EDGE_EXECUTABLE) ? "" : "not "); 1092 } 1093 1094 /* If the incoming edge is executable, Compute the meet operator for 1095 the existing value of the PHI node and the current PHI argument. */ 1096 if (e->flags & EDGE_EXECUTABLE) 1097 { 1098 tree arg = gimple_phi_arg (phi, i)->def; 1099 ccp_prop_value_t arg_val = get_value_for_expr (arg, false); 1100 1101 if (first) 1102 { 1103 new_val = arg_val; 1104 first = false; 1105 } 1106 else 1107 ccp_lattice_meet (&new_val, &arg_val); 1108 1109 if (dump_file && (dump_flags & TDF_DETAILS)) 1110 { 1111 fprintf (dump_file, "\t"); 1112 print_generic_expr (dump_file, arg, dump_flags); 1113 dump_lattice_value (dump_file, "\tValue: ", arg_val); 1114 fprintf (dump_file, "\n"); 1115 } 1116 1117 if (new_val.lattice_val == VARYING) 1118 break; 1119 } 1120 else 1121 non_exec_edge = true; 1122 } 1123 1124 /* In case there were non-executable edges and the value is a copy 1125 make sure its definition dominates the PHI node. */ 1126 if (non_exec_edge 1127 && new_val.lattice_val == CONSTANT 1128 && TREE_CODE (new_val.value) == SSA_NAME 1129 && ! SSA_NAME_IS_DEFAULT_DEF (new_val.value) 1130 && ! dominated_by_p (CDI_DOMINATORS, gimple_bb (phi), 1131 gimple_bb (SSA_NAME_DEF_STMT (new_val.value)))) 1132 { 1133 new_val.lattice_val = VARYING; 1134 new_val.value = NULL_TREE; 1135 new_val.mask = -1; 1136 } 1137 1138 if (dump_file && (dump_flags & TDF_DETAILS)) 1139 { 1140 dump_lattice_value (dump_file, "\n PHI node value: ", new_val); 1141 fprintf (dump_file, "\n\n"); 1142 } 1143 1144 /* Make the transition to the new value. */ 1145 if (set_lattice_value (gimple_phi_result (phi), &new_val)) 1146 { 1147 if (new_val.lattice_val == VARYING) 1148 return SSA_PROP_VARYING; 1149 else 1150 return SSA_PROP_INTERESTING; 1151 } 1152 else 1153 return SSA_PROP_NOT_INTERESTING; 1154 } 1155 1156 /* Return the constant value for OP or OP otherwise. */ 1157 1158 static tree 1159 valueize_op (tree op) 1160 { 1161 if (TREE_CODE (op) == SSA_NAME) 1162 { 1163 tree tem = get_constant_value (op); 1164 if (tem) 1165 return tem; 1166 } 1167 return op; 1168 } 1169 1170 /* Return the constant value for OP, but signal to not follow SSA 1171 edges if the definition may be simulated again. */ 1172 1173 static tree 1174 valueize_op_1 (tree op) 1175 { 1176 if (TREE_CODE (op) == SSA_NAME) 1177 { 1178 /* If the definition may be simulated again we cannot follow 1179 this SSA edge as the SSA propagator does not necessarily 1180 re-visit the use. */ 1181 gimple *def_stmt = SSA_NAME_DEF_STMT (op); 1182 if (!gimple_nop_p (def_stmt) 1183 && prop_simulate_again_p (def_stmt)) 1184 return NULL_TREE; 1185 tree tem = get_constant_value (op); 1186 if (tem) 1187 return tem; 1188 } 1189 return op; 1190 } 1191 1192 /* CCP specific front-end to the non-destructive constant folding 1193 routines. 1194 1195 Attempt to simplify the RHS of STMT knowing that one or more 1196 operands are constants. 1197 1198 If simplification is possible, return the simplified RHS, 1199 otherwise return the original RHS or NULL_TREE. */ 1200 1201 static tree 1202 ccp_fold (gimple *stmt) 1203 { 1204 location_t loc = gimple_location (stmt); 1205 switch (gimple_code (stmt)) 1206 { 1207 case GIMPLE_COND: 1208 { 1209 /* Handle comparison operators that can appear in GIMPLE form. */ 1210 tree op0 = valueize_op (gimple_cond_lhs (stmt)); 1211 tree op1 = valueize_op (gimple_cond_rhs (stmt)); 1212 enum tree_code code = gimple_cond_code (stmt); 1213 return fold_binary_loc (loc, code, boolean_type_node, op0, op1); 1214 } 1215 1216 case GIMPLE_SWITCH: 1217 { 1218 /* Return the constant switch index. */ 1219 return valueize_op (gimple_switch_index (as_a <gswitch *> (stmt))); 1220 } 1221 1222 case GIMPLE_ASSIGN: 1223 case GIMPLE_CALL: 1224 return gimple_fold_stmt_to_constant_1 (stmt, 1225 valueize_op, valueize_op_1); 1226 1227 default: 1228 gcc_unreachable (); 1229 } 1230 } 1231 1232 /* Apply the operation CODE in type TYPE to the value, mask pair 1233 RVAL and RMASK representing a value of type RTYPE and set 1234 the value, mask pair *VAL and *MASK to the result. */ 1235 1236 void 1237 bit_value_unop (enum tree_code code, signop type_sgn, int type_precision, 1238 widest_int *val, widest_int *mask, 1239 signop rtype_sgn, int rtype_precision, 1240 const widest_int &rval, const widest_int &rmask) 1241 { 1242 switch (code) 1243 { 1244 case BIT_NOT_EXPR: 1245 *mask = rmask; 1246 *val = ~rval; 1247 break; 1248 1249 case NEGATE_EXPR: 1250 { 1251 widest_int temv, temm; 1252 /* Return ~rval + 1. */ 1253 bit_value_unop (BIT_NOT_EXPR, type_sgn, type_precision, &temv, &temm, 1254 type_sgn, type_precision, rval, rmask); 1255 bit_value_binop (PLUS_EXPR, type_sgn, type_precision, val, mask, 1256 type_sgn, type_precision, temv, temm, 1257 type_sgn, type_precision, 1, 0); 1258 break; 1259 } 1260 1261 CASE_CONVERT: 1262 { 1263 /* First extend mask and value according to the original type. */ 1264 *mask = wi::ext (rmask, rtype_precision, rtype_sgn); 1265 *val = wi::ext (rval, rtype_precision, rtype_sgn); 1266 1267 /* Then extend mask and value according to the target type. */ 1268 *mask = wi::ext (*mask, type_precision, type_sgn); 1269 *val = wi::ext (*val, type_precision, type_sgn); 1270 break; 1271 } 1272 1273 default: 1274 *mask = -1; 1275 break; 1276 } 1277 } 1278 1279 /* Apply the operation CODE in type TYPE to the value, mask pairs 1280 R1VAL, R1MASK and R2VAL, R2MASK representing a values of type R1TYPE 1281 and R2TYPE and set the value, mask pair *VAL and *MASK to the result. */ 1282 1283 void 1284 bit_value_binop (enum tree_code code, signop sgn, int width, 1285 widest_int *val, widest_int *mask, 1286 signop r1type_sgn, int r1type_precision, 1287 const widest_int &r1val, const widest_int &r1mask, 1288 signop r2type_sgn, int r2type_precision, 1289 const widest_int &r2val, const widest_int &r2mask) 1290 { 1291 bool swap_p = false; 1292 1293 /* Assume we'll get a constant result. Use an initial non varying 1294 value, we fall back to varying in the end if necessary. */ 1295 *mask = -1; 1296 1297 switch (code) 1298 { 1299 case BIT_AND_EXPR: 1300 /* The mask is constant where there is a known not 1301 set bit, (m1 | m2) & ((v1 | m1) & (v2 | m2)) */ 1302 *mask = (r1mask | r2mask) & (r1val | r1mask) & (r2val | r2mask); 1303 *val = r1val & r2val; 1304 break; 1305 1306 case BIT_IOR_EXPR: 1307 /* The mask is constant where there is a known 1308 set bit, (m1 | m2) & ~((v1 & ~m1) | (v2 & ~m2)). */ 1309 *mask = (r1mask | r2mask) 1310 .and_not (r1val.and_not (r1mask) | r2val.and_not (r2mask)); 1311 *val = r1val | r2val; 1312 break; 1313 1314 case BIT_XOR_EXPR: 1315 /* m1 | m2 */ 1316 *mask = r1mask | r2mask; 1317 *val = r1val ^ r2val; 1318 break; 1319 1320 case LROTATE_EXPR: 1321 case RROTATE_EXPR: 1322 if (r2mask == 0) 1323 { 1324 widest_int shift = r2val; 1325 if (shift == 0) 1326 { 1327 *mask = r1mask; 1328 *val = r1val; 1329 } 1330 else 1331 { 1332 if (wi::neg_p (shift)) 1333 { 1334 shift = -shift; 1335 if (code == RROTATE_EXPR) 1336 code = LROTATE_EXPR; 1337 else 1338 code = RROTATE_EXPR; 1339 } 1340 if (code == RROTATE_EXPR) 1341 { 1342 *mask = wi::rrotate (r1mask, shift, width); 1343 *val = wi::rrotate (r1val, shift, width); 1344 } 1345 else 1346 { 1347 *mask = wi::lrotate (r1mask, shift, width); 1348 *val = wi::lrotate (r1val, shift, width); 1349 } 1350 } 1351 } 1352 break; 1353 1354 case LSHIFT_EXPR: 1355 case RSHIFT_EXPR: 1356 /* ??? We can handle partially known shift counts if we know 1357 its sign. That way we can tell that (x << (y | 8)) & 255 1358 is zero. */ 1359 if (r2mask == 0) 1360 { 1361 widest_int shift = r2val; 1362 if (shift == 0) 1363 { 1364 *mask = r1mask; 1365 *val = r1val; 1366 } 1367 else 1368 { 1369 if (wi::neg_p (shift)) 1370 { 1371 shift = -shift; 1372 if (code == RSHIFT_EXPR) 1373 code = LSHIFT_EXPR; 1374 else 1375 code = RSHIFT_EXPR; 1376 } 1377 if (code == RSHIFT_EXPR) 1378 { 1379 *mask = wi::rshift (wi::ext (r1mask, width, sgn), shift, sgn); 1380 *val = wi::rshift (wi::ext (r1val, width, sgn), shift, sgn); 1381 } 1382 else 1383 { 1384 *mask = wi::ext (r1mask << shift, width, sgn); 1385 *val = wi::ext (r1val << shift, width, sgn); 1386 } 1387 } 1388 } 1389 break; 1390 1391 case PLUS_EXPR: 1392 case POINTER_PLUS_EXPR: 1393 { 1394 /* Do the addition with unknown bits set to zero, to give carry-ins of 1395 zero wherever possible. */ 1396 widest_int lo = r1val.and_not (r1mask) + r2val.and_not (r2mask); 1397 lo = wi::ext (lo, width, sgn); 1398 /* Do the addition with unknown bits set to one, to give carry-ins of 1399 one wherever possible. */ 1400 widest_int hi = (r1val | r1mask) + (r2val | r2mask); 1401 hi = wi::ext (hi, width, sgn); 1402 /* Each bit in the result is known if (a) the corresponding bits in 1403 both inputs are known, and (b) the carry-in to that bit position 1404 is known. We can check condition (b) by seeing if we got the same 1405 result with minimised carries as with maximised carries. */ 1406 *mask = r1mask | r2mask | (lo ^ hi); 1407 *mask = wi::ext (*mask, width, sgn); 1408 /* It shouldn't matter whether we choose lo or hi here. */ 1409 *val = lo; 1410 break; 1411 } 1412 1413 case MINUS_EXPR: 1414 { 1415 widest_int temv, temm; 1416 bit_value_unop (NEGATE_EXPR, r2type_sgn, r2type_precision, &temv, &temm, 1417 r2type_sgn, r2type_precision, r2val, r2mask); 1418 bit_value_binop (PLUS_EXPR, sgn, width, val, mask, 1419 r1type_sgn, r1type_precision, r1val, r1mask, 1420 r2type_sgn, r2type_precision, temv, temm); 1421 break; 1422 } 1423 1424 case MULT_EXPR: 1425 { 1426 /* Just track trailing zeros in both operands and transfer 1427 them to the other. */ 1428 int r1tz = wi::ctz (r1val | r1mask); 1429 int r2tz = wi::ctz (r2val | r2mask); 1430 if (r1tz + r2tz >= width) 1431 { 1432 *mask = 0; 1433 *val = 0; 1434 } 1435 else if (r1tz + r2tz > 0) 1436 { 1437 *mask = wi::ext (wi::mask <widest_int> (r1tz + r2tz, true), 1438 width, sgn); 1439 *val = 0; 1440 } 1441 break; 1442 } 1443 1444 case EQ_EXPR: 1445 case NE_EXPR: 1446 { 1447 widest_int m = r1mask | r2mask; 1448 if (r1val.and_not (m) != r2val.and_not (m)) 1449 { 1450 *mask = 0; 1451 *val = ((code == EQ_EXPR) ? 0 : 1); 1452 } 1453 else 1454 { 1455 /* We know the result of a comparison is always one or zero. */ 1456 *mask = 1; 1457 *val = 0; 1458 } 1459 break; 1460 } 1461 1462 case GE_EXPR: 1463 case GT_EXPR: 1464 swap_p = true; 1465 code = swap_tree_comparison (code); 1466 /* Fall through. */ 1467 case LT_EXPR: 1468 case LE_EXPR: 1469 { 1470 int minmax, maxmin; 1471 1472 const widest_int &o1val = swap_p ? r2val : r1val; 1473 const widest_int &o1mask = swap_p ? r2mask : r1mask; 1474 const widest_int &o2val = swap_p ? r1val : r2val; 1475 const widest_int &o2mask = swap_p ? r1mask : r2mask; 1476 1477 /* If the most significant bits are not known we know nothing. */ 1478 if (wi::neg_p (o1mask) || wi::neg_p (o2mask)) 1479 break; 1480 1481 /* For comparisons the signedness is in the comparison operands. */ 1482 sgn = r1type_sgn; 1483 1484 /* If we know the most significant bits we know the values 1485 value ranges by means of treating varying bits as zero 1486 or one. Do a cross comparison of the max/min pairs. */ 1487 maxmin = wi::cmp (o1val | o1mask, o2val.and_not (o2mask), sgn); 1488 minmax = wi::cmp (o1val.and_not (o1mask), o2val | o2mask, sgn); 1489 if (maxmin < 0) /* o1 is less than o2. */ 1490 { 1491 *mask = 0; 1492 *val = 1; 1493 } 1494 else if (minmax > 0) /* o1 is not less or equal to o2. */ 1495 { 1496 *mask = 0; 1497 *val = 0; 1498 } 1499 else if (maxmin == minmax) /* o1 and o2 are equal. */ 1500 { 1501 /* This probably should never happen as we'd have 1502 folded the thing during fully constant value folding. */ 1503 *mask = 0; 1504 *val = (code == LE_EXPR ? 1 : 0); 1505 } 1506 else 1507 { 1508 /* We know the result of a comparison is always one or zero. */ 1509 *mask = 1; 1510 *val = 0; 1511 } 1512 break; 1513 } 1514 1515 default:; 1516 } 1517 } 1518 1519 /* Return the propagation value when applying the operation CODE to 1520 the value RHS yielding type TYPE. */ 1521 1522 static ccp_prop_value_t 1523 bit_value_unop (enum tree_code code, tree type, tree rhs) 1524 { 1525 ccp_prop_value_t rval = get_value_for_expr (rhs, true); 1526 widest_int value, mask; 1527 ccp_prop_value_t val; 1528 1529 if (rval.lattice_val == UNDEFINED) 1530 return rval; 1531 1532 gcc_assert ((rval.lattice_val == CONSTANT 1533 && TREE_CODE (rval.value) == INTEGER_CST) 1534 || wi::sext (rval.mask, TYPE_PRECISION (TREE_TYPE (rhs))) == -1); 1535 bit_value_unop (code, TYPE_SIGN (type), TYPE_PRECISION (type), &value, &mask, 1536 TYPE_SIGN (TREE_TYPE (rhs)), TYPE_PRECISION (TREE_TYPE (rhs)), 1537 value_to_wide_int (rval), rval.mask); 1538 if (wi::sext (mask, TYPE_PRECISION (type)) != -1) 1539 { 1540 val.lattice_val = CONSTANT; 1541 val.mask = mask; 1542 /* ??? Delay building trees here. */ 1543 val.value = wide_int_to_tree (type, value); 1544 } 1545 else 1546 { 1547 val.lattice_val = VARYING; 1548 val.value = NULL_TREE; 1549 val.mask = -1; 1550 } 1551 return val; 1552 } 1553 1554 /* Return the propagation value when applying the operation CODE to 1555 the values RHS1 and RHS2 yielding type TYPE. */ 1556 1557 static ccp_prop_value_t 1558 bit_value_binop (enum tree_code code, tree type, tree rhs1, tree rhs2) 1559 { 1560 ccp_prop_value_t r1val = get_value_for_expr (rhs1, true); 1561 ccp_prop_value_t r2val = get_value_for_expr (rhs2, true); 1562 widest_int value, mask; 1563 ccp_prop_value_t val; 1564 1565 if (r1val.lattice_val == UNDEFINED 1566 || r2val.lattice_val == UNDEFINED) 1567 { 1568 val.lattice_val = VARYING; 1569 val.value = NULL_TREE; 1570 val.mask = -1; 1571 return val; 1572 } 1573 1574 gcc_assert ((r1val.lattice_val == CONSTANT 1575 && TREE_CODE (r1val.value) == INTEGER_CST) 1576 || wi::sext (r1val.mask, 1577 TYPE_PRECISION (TREE_TYPE (rhs1))) == -1); 1578 gcc_assert ((r2val.lattice_val == CONSTANT 1579 && TREE_CODE (r2val.value) == INTEGER_CST) 1580 || wi::sext (r2val.mask, 1581 TYPE_PRECISION (TREE_TYPE (rhs2))) == -1); 1582 bit_value_binop (code, TYPE_SIGN (type), TYPE_PRECISION (type), &value, &mask, 1583 TYPE_SIGN (TREE_TYPE (rhs1)), TYPE_PRECISION (TREE_TYPE (rhs1)), 1584 value_to_wide_int (r1val), r1val.mask, 1585 TYPE_SIGN (TREE_TYPE (rhs2)), TYPE_PRECISION (TREE_TYPE (rhs2)), 1586 value_to_wide_int (r2val), r2val.mask); 1587 1588 if (wi::sext (mask, TYPE_PRECISION (type)) != -1) 1589 { 1590 val.lattice_val = CONSTANT; 1591 val.mask = mask; 1592 /* ??? Delay building trees here. */ 1593 val.value = wide_int_to_tree (type, value); 1594 } 1595 else 1596 { 1597 val.lattice_val = VARYING; 1598 val.value = NULL_TREE; 1599 val.mask = -1; 1600 } 1601 return val; 1602 } 1603 1604 /* Return the propagation value for __builtin_assume_aligned 1605 and functions with assume_aligned or alloc_aligned attribute. 1606 For __builtin_assume_aligned, ATTR is NULL_TREE, 1607 for assume_aligned attribute ATTR is non-NULL and ALLOC_ALIGNED 1608 is false, for alloc_aligned attribute ATTR is non-NULL and 1609 ALLOC_ALIGNED is true. */ 1610 1611 static ccp_prop_value_t 1612 bit_value_assume_aligned (gimple *stmt, tree attr, ccp_prop_value_t ptrval, 1613 bool alloc_aligned) 1614 { 1615 tree align, misalign = NULL_TREE, type; 1616 unsigned HOST_WIDE_INT aligni, misaligni = 0; 1617 ccp_prop_value_t alignval; 1618 widest_int value, mask; 1619 ccp_prop_value_t val; 1620 1621 if (attr == NULL_TREE) 1622 { 1623 tree ptr = gimple_call_arg (stmt, 0); 1624 type = TREE_TYPE (ptr); 1625 ptrval = get_value_for_expr (ptr, true); 1626 } 1627 else 1628 { 1629 tree lhs = gimple_call_lhs (stmt); 1630 type = TREE_TYPE (lhs); 1631 } 1632 1633 if (ptrval.lattice_val == UNDEFINED) 1634 return ptrval; 1635 gcc_assert ((ptrval.lattice_val == CONSTANT 1636 && TREE_CODE (ptrval.value) == INTEGER_CST) 1637 || wi::sext (ptrval.mask, TYPE_PRECISION (type)) == -1); 1638 if (attr == NULL_TREE) 1639 { 1640 /* Get aligni and misaligni from __builtin_assume_aligned. */ 1641 align = gimple_call_arg (stmt, 1); 1642 if (!tree_fits_uhwi_p (align)) 1643 return ptrval; 1644 aligni = tree_to_uhwi (align); 1645 if (gimple_call_num_args (stmt) > 2) 1646 { 1647 misalign = gimple_call_arg (stmt, 2); 1648 if (!tree_fits_uhwi_p (misalign)) 1649 return ptrval; 1650 misaligni = tree_to_uhwi (misalign); 1651 } 1652 } 1653 else 1654 { 1655 /* Get aligni and misaligni from assume_aligned or 1656 alloc_align attributes. */ 1657 if (TREE_VALUE (attr) == NULL_TREE) 1658 return ptrval; 1659 attr = TREE_VALUE (attr); 1660 align = TREE_VALUE (attr); 1661 if (!tree_fits_uhwi_p (align)) 1662 return ptrval; 1663 aligni = tree_to_uhwi (align); 1664 if (alloc_aligned) 1665 { 1666 if (aligni == 0 || aligni > gimple_call_num_args (stmt)) 1667 return ptrval; 1668 align = gimple_call_arg (stmt, aligni - 1); 1669 if (!tree_fits_uhwi_p (align)) 1670 return ptrval; 1671 aligni = tree_to_uhwi (align); 1672 } 1673 else if (TREE_CHAIN (attr) && TREE_VALUE (TREE_CHAIN (attr))) 1674 { 1675 misalign = TREE_VALUE (TREE_CHAIN (attr)); 1676 if (!tree_fits_uhwi_p (misalign)) 1677 return ptrval; 1678 misaligni = tree_to_uhwi (misalign); 1679 } 1680 } 1681 if (aligni <= 1 || (aligni & (aligni - 1)) != 0 || misaligni >= aligni) 1682 return ptrval; 1683 1684 align = build_int_cst_type (type, -aligni); 1685 alignval = get_value_for_expr (align, true); 1686 bit_value_binop (BIT_AND_EXPR, TYPE_SIGN (type), TYPE_PRECISION (type), &value, &mask, 1687 TYPE_SIGN (type), TYPE_PRECISION (type), value_to_wide_int (ptrval), ptrval.mask, 1688 TYPE_SIGN (type), TYPE_PRECISION (type), value_to_wide_int (alignval), alignval.mask); 1689 1690 if (wi::sext (mask, TYPE_PRECISION (type)) != -1) 1691 { 1692 val.lattice_val = CONSTANT; 1693 val.mask = mask; 1694 gcc_assert ((mask.to_uhwi () & (aligni - 1)) == 0); 1695 gcc_assert ((value.to_uhwi () & (aligni - 1)) == 0); 1696 value |= misaligni; 1697 /* ??? Delay building trees here. */ 1698 val.value = wide_int_to_tree (type, value); 1699 } 1700 else 1701 { 1702 val.lattice_val = VARYING; 1703 val.value = NULL_TREE; 1704 val.mask = -1; 1705 } 1706 return val; 1707 } 1708 1709 /* Evaluate statement STMT. 1710 Valid only for assignments, calls, conditionals, and switches. */ 1711 1712 static ccp_prop_value_t 1713 evaluate_stmt (gimple *stmt) 1714 { 1715 ccp_prop_value_t val; 1716 tree simplified = NULL_TREE; 1717 ccp_lattice_t likelyvalue = likely_value (stmt); 1718 bool is_constant = false; 1719 unsigned int align; 1720 1721 if (dump_file && (dump_flags & TDF_DETAILS)) 1722 { 1723 fprintf (dump_file, "which is likely "); 1724 switch (likelyvalue) 1725 { 1726 case CONSTANT: 1727 fprintf (dump_file, "CONSTANT"); 1728 break; 1729 case UNDEFINED: 1730 fprintf (dump_file, "UNDEFINED"); 1731 break; 1732 case VARYING: 1733 fprintf (dump_file, "VARYING"); 1734 break; 1735 default:; 1736 } 1737 fprintf (dump_file, "\n"); 1738 } 1739 1740 /* If the statement is likely to have a CONSTANT result, then try 1741 to fold the statement to determine the constant value. */ 1742 /* FIXME. This is the only place that we call ccp_fold. 1743 Since likely_value never returns CONSTANT for calls, we will 1744 not attempt to fold them, including builtins that may profit. */ 1745 if (likelyvalue == CONSTANT) 1746 { 1747 fold_defer_overflow_warnings (); 1748 simplified = ccp_fold (stmt); 1749 if (simplified 1750 && TREE_CODE (simplified) == SSA_NAME) 1751 { 1752 /* We may not use values of something that may be simulated again, 1753 see valueize_op_1. */ 1754 if (SSA_NAME_IS_DEFAULT_DEF (simplified) 1755 || ! prop_simulate_again_p (SSA_NAME_DEF_STMT (simplified))) 1756 { 1757 ccp_prop_value_t *val = get_value (simplified); 1758 if (val && val->lattice_val != VARYING) 1759 { 1760 fold_undefer_overflow_warnings (true, stmt, 0); 1761 return *val; 1762 } 1763 } 1764 else 1765 /* We may also not place a non-valueized copy in the lattice 1766 as that might become stale if we never re-visit this stmt. */ 1767 simplified = NULL_TREE; 1768 } 1769 is_constant = simplified && is_gimple_min_invariant (simplified); 1770 fold_undefer_overflow_warnings (is_constant, stmt, 0); 1771 if (is_constant) 1772 { 1773 /* The statement produced a constant value. */ 1774 val.lattice_val = CONSTANT; 1775 val.value = simplified; 1776 val.mask = 0; 1777 return val; 1778 } 1779 } 1780 /* If the statement is likely to have a VARYING result, then do not 1781 bother folding the statement. */ 1782 else if (likelyvalue == VARYING) 1783 { 1784 enum gimple_code code = gimple_code (stmt); 1785 if (code == GIMPLE_ASSIGN) 1786 { 1787 enum tree_code subcode = gimple_assign_rhs_code (stmt); 1788 1789 /* Other cases cannot satisfy is_gimple_min_invariant 1790 without folding. */ 1791 if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS) 1792 simplified = gimple_assign_rhs1 (stmt); 1793 } 1794 else if (code == GIMPLE_SWITCH) 1795 simplified = gimple_switch_index (as_a <gswitch *> (stmt)); 1796 else 1797 /* These cannot satisfy is_gimple_min_invariant without folding. */ 1798 gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND); 1799 is_constant = simplified && is_gimple_min_invariant (simplified); 1800 if (is_constant) 1801 { 1802 /* The statement produced a constant value. */ 1803 val.lattice_val = CONSTANT; 1804 val.value = simplified; 1805 val.mask = 0; 1806 } 1807 } 1808 /* If the statement result is likely UNDEFINED, make it so. */ 1809 else if (likelyvalue == UNDEFINED) 1810 { 1811 val.lattice_val = UNDEFINED; 1812 val.value = NULL_TREE; 1813 val.mask = 0; 1814 return val; 1815 } 1816 1817 /* Resort to simplification for bitwise tracking. */ 1818 if (flag_tree_bit_ccp 1819 && (likelyvalue == CONSTANT || is_gimple_call (stmt) 1820 || (gimple_assign_single_p (stmt) 1821 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)) 1822 && !is_constant) 1823 { 1824 enum gimple_code code = gimple_code (stmt); 1825 val.lattice_val = VARYING; 1826 val.value = NULL_TREE; 1827 val.mask = -1; 1828 if (code == GIMPLE_ASSIGN) 1829 { 1830 enum tree_code subcode = gimple_assign_rhs_code (stmt); 1831 tree rhs1 = gimple_assign_rhs1 (stmt); 1832 tree lhs = gimple_assign_lhs (stmt); 1833 if ((INTEGRAL_TYPE_P (TREE_TYPE (lhs)) 1834 || POINTER_TYPE_P (TREE_TYPE (lhs))) 1835 && (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) 1836 || POINTER_TYPE_P (TREE_TYPE (rhs1)))) 1837 switch (get_gimple_rhs_class (subcode)) 1838 { 1839 case GIMPLE_SINGLE_RHS: 1840 val = get_value_for_expr (rhs1, true); 1841 break; 1842 1843 case GIMPLE_UNARY_RHS: 1844 val = bit_value_unop (subcode, TREE_TYPE (lhs), rhs1); 1845 break; 1846 1847 case GIMPLE_BINARY_RHS: 1848 val = bit_value_binop (subcode, TREE_TYPE (lhs), rhs1, 1849 gimple_assign_rhs2 (stmt)); 1850 break; 1851 1852 default:; 1853 } 1854 } 1855 else if (code == GIMPLE_COND) 1856 { 1857 enum tree_code code = gimple_cond_code (stmt); 1858 tree rhs1 = gimple_cond_lhs (stmt); 1859 tree rhs2 = gimple_cond_rhs (stmt); 1860 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) 1861 || POINTER_TYPE_P (TREE_TYPE (rhs1))) 1862 val = bit_value_binop (code, TREE_TYPE (rhs1), rhs1, rhs2); 1863 } 1864 else if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) 1865 { 1866 tree fndecl = gimple_call_fndecl (stmt); 1867 switch (DECL_FUNCTION_CODE (fndecl)) 1868 { 1869 case BUILT_IN_MALLOC: 1870 case BUILT_IN_REALLOC: 1871 case BUILT_IN_CALLOC: 1872 case BUILT_IN_STRDUP: 1873 case BUILT_IN_STRNDUP: 1874 val.lattice_val = CONSTANT; 1875 val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); 1876 val.mask = ~((HOST_WIDE_INT) MALLOC_ABI_ALIGNMENT 1877 / BITS_PER_UNIT - 1); 1878 break; 1879 1880 case BUILT_IN_ALLOCA: 1881 case BUILT_IN_ALLOCA_WITH_ALIGN: 1882 align = (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_ALLOCA_WITH_ALIGN 1883 ? TREE_INT_CST_LOW (gimple_call_arg (stmt, 1)) 1884 : BIGGEST_ALIGNMENT); 1885 val.lattice_val = CONSTANT; 1886 val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0); 1887 val.mask = ~((HOST_WIDE_INT) align / BITS_PER_UNIT - 1); 1888 break; 1889 1890 /* These builtins return their first argument, unmodified. */ 1891 case BUILT_IN_MEMCPY: 1892 case BUILT_IN_MEMMOVE: 1893 case BUILT_IN_MEMSET: 1894 case BUILT_IN_STRCPY: 1895 case BUILT_IN_STRNCPY: 1896 case BUILT_IN_MEMCPY_CHK: 1897 case BUILT_IN_MEMMOVE_CHK: 1898 case BUILT_IN_MEMSET_CHK: 1899 case BUILT_IN_STRCPY_CHK: 1900 case BUILT_IN_STRNCPY_CHK: 1901 val = get_value_for_expr (gimple_call_arg (stmt, 0), true); 1902 break; 1903 1904 case BUILT_IN_ASSUME_ALIGNED: 1905 val = bit_value_assume_aligned (stmt, NULL_TREE, val, false); 1906 break; 1907 1908 case BUILT_IN_ALIGNED_ALLOC: 1909 { 1910 tree align = get_constant_value (gimple_call_arg (stmt, 0)); 1911 if (align 1912 && tree_fits_uhwi_p (align)) 1913 { 1914 unsigned HOST_WIDE_INT aligni = tree_to_uhwi (align); 1915 if (aligni > 1 1916 /* align must be power-of-two */ 1917 && (aligni & (aligni - 1)) == 0) 1918 { 1919 val.lattice_val = CONSTANT; 1920 val.value = build_int_cst (ptr_type_node, 0); 1921 val.mask = -aligni; 1922 } 1923 } 1924 break; 1925 } 1926 1927 default:; 1928 } 1929 } 1930 if (is_gimple_call (stmt) && gimple_call_lhs (stmt)) 1931 { 1932 tree fntype = gimple_call_fntype (stmt); 1933 if (fntype) 1934 { 1935 tree attrs = lookup_attribute ("assume_aligned", 1936 TYPE_ATTRIBUTES (fntype)); 1937 if (attrs) 1938 val = bit_value_assume_aligned (stmt, attrs, val, false); 1939 attrs = lookup_attribute ("alloc_align", 1940 TYPE_ATTRIBUTES (fntype)); 1941 if (attrs) 1942 val = bit_value_assume_aligned (stmt, attrs, val, true); 1943 } 1944 } 1945 is_constant = (val.lattice_val == CONSTANT); 1946 } 1947 1948 if (flag_tree_bit_ccp 1949 && ((is_constant && TREE_CODE (val.value) == INTEGER_CST) 1950 || !is_constant) 1951 && gimple_get_lhs (stmt) 1952 && TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME) 1953 { 1954 tree lhs = gimple_get_lhs (stmt); 1955 wide_int nonzero_bits = get_nonzero_bits (lhs); 1956 if (nonzero_bits != -1) 1957 { 1958 if (!is_constant) 1959 { 1960 val.lattice_val = CONSTANT; 1961 val.value = build_zero_cst (TREE_TYPE (lhs)); 1962 val.mask = extend_mask (nonzero_bits, TYPE_SIGN (TREE_TYPE (lhs))); 1963 is_constant = true; 1964 } 1965 else 1966 { 1967 if (wi::bit_and_not (val.value, nonzero_bits) != 0) 1968 val.value = wide_int_to_tree (TREE_TYPE (lhs), 1969 nonzero_bits & val.value); 1970 if (nonzero_bits == 0) 1971 val.mask = 0; 1972 else 1973 val.mask = val.mask & extend_mask (nonzero_bits, 1974 TYPE_SIGN (TREE_TYPE (lhs))); 1975 } 1976 } 1977 } 1978 1979 /* The statement produced a nonconstant value. */ 1980 if (!is_constant) 1981 { 1982 /* The statement produced a copy. */ 1983 if (simplified && TREE_CODE (simplified) == SSA_NAME 1984 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (simplified)) 1985 { 1986 val.lattice_val = CONSTANT; 1987 val.value = simplified; 1988 val.mask = -1; 1989 } 1990 /* The statement is VARYING. */ 1991 else 1992 { 1993 val.lattice_val = VARYING; 1994 val.value = NULL_TREE; 1995 val.mask = -1; 1996 } 1997 } 1998 1999 return val; 2000 } 2001 2002 typedef hash_table<nofree_ptr_hash<gimple> > gimple_htab; 2003 2004 /* Given a BUILT_IN_STACK_SAVE value SAVED_VAL, insert a clobber of VAR before 2005 each matching BUILT_IN_STACK_RESTORE. Mark visited phis in VISITED. */ 2006 2007 static void 2008 insert_clobber_before_stack_restore (tree saved_val, tree var, 2009 gimple_htab **visited) 2010 { 2011 gimple *stmt; 2012 gassign *clobber_stmt; 2013 tree clobber; 2014 imm_use_iterator iter; 2015 gimple_stmt_iterator i; 2016 gimple **slot; 2017 2018 FOR_EACH_IMM_USE_STMT (stmt, iter, saved_val) 2019 if (gimple_call_builtin_p (stmt, BUILT_IN_STACK_RESTORE)) 2020 { 2021 clobber = build_constructor (TREE_TYPE (var), 2022 NULL); 2023 TREE_THIS_VOLATILE (clobber) = 1; 2024 clobber_stmt = gimple_build_assign (var, clobber); 2025 2026 i = gsi_for_stmt (stmt); 2027 gsi_insert_before (&i, clobber_stmt, GSI_SAME_STMT); 2028 } 2029 else if (gimple_code (stmt) == GIMPLE_PHI) 2030 { 2031 if (!*visited) 2032 *visited = new gimple_htab (10); 2033 2034 slot = (*visited)->find_slot (stmt, INSERT); 2035 if (*slot != NULL) 2036 continue; 2037 2038 *slot = stmt; 2039 insert_clobber_before_stack_restore (gimple_phi_result (stmt), var, 2040 visited); 2041 } 2042 else if (gimple_assign_ssa_name_copy_p (stmt)) 2043 insert_clobber_before_stack_restore (gimple_assign_lhs (stmt), var, 2044 visited); 2045 else if (chkp_gimple_call_builtin_p (stmt, BUILT_IN_CHKP_BNDRET)) 2046 continue; 2047 else 2048 gcc_assert (is_gimple_debug (stmt)); 2049 } 2050 2051 /* Advance the iterator to the previous non-debug gimple statement in the same 2052 or dominating basic block. */ 2053 2054 static inline void 2055 gsi_prev_dom_bb_nondebug (gimple_stmt_iterator *i) 2056 { 2057 basic_block dom; 2058 2059 gsi_prev_nondebug (i); 2060 while (gsi_end_p (*i)) 2061 { 2062 dom = get_immediate_dominator (CDI_DOMINATORS, i->bb); 2063 if (dom == NULL || dom == ENTRY_BLOCK_PTR_FOR_FN (cfun)) 2064 return; 2065 2066 *i = gsi_last_bb (dom); 2067 } 2068 } 2069 2070 /* Find a BUILT_IN_STACK_SAVE dominating gsi_stmt (I), and insert 2071 a clobber of VAR before each matching BUILT_IN_STACK_RESTORE. 2072 2073 It is possible that BUILT_IN_STACK_SAVE cannot be find in a dominator when a 2074 previous pass (such as DOM) duplicated it along multiple paths to a BB. In 2075 that case the function gives up without inserting the clobbers. */ 2076 2077 static void 2078 insert_clobbers_for_var (gimple_stmt_iterator i, tree var) 2079 { 2080 gimple *stmt; 2081 tree saved_val; 2082 gimple_htab *visited = NULL; 2083 2084 for (; !gsi_end_p (i); gsi_prev_dom_bb_nondebug (&i)) 2085 { 2086 stmt = gsi_stmt (i); 2087 2088 if (!gimple_call_builtin_p (stmt, BUILT_IN_STACK_SAVE)) 2089 continue; 2090 2091 saved_val = gimple_call_lhs (stmt); 2092 if (saved_val == NULL_TREE) 2093 continue; 2094 2095 insert_clobber_before_stack_restore (saved_val, var, &visited); 2096 break; 2097 } 2098 2099 delete visited; 2100 } 2101 2102 /* Detects a __builtin_alloca_with_align with constant size argument. Declares 2103 fixed-size array and returns the address, if found, otherwise returns 2104 NULL_TREE. */ 2105 2106 static tree 2107 fold_builtin_alloca_with_align (gimple *stmt) 2108 { 2109 unsigned HOST_WIDE_INT size, threshold, n_elem; 2110 tree lhs, arg, block, var, elem_type, array_type; 2111 2112 /* Get lhs. */ 2113 lhs = gimple_call_lhs (stmt); 2114 if (lhs == NULL_TREE) 2115 return NULL_TREE; 2116 2117 /* Detect constant argument. */ 2118 arg = get_constant_value (gimple_call_arg (stmt, 0)); 2119 if (arg == NULL_TREE 2120 || TREE_CODE (arg) != INTEGER_CST 2121 || !tree_fits_uhwi_p (arg)) 2122 return NULL_TREE; 2123 2124 size = tree_to_uhwi (arg); 2125 2126 /* Heuristic: don't fold large allocas. */ 2127 threshold = (unsigned HOST_WIDE_INT)PARAM_VALUE (PARAM_LARGE_STACK_FRAME); 2128 /* In case the alloca is located at function entry, it has the same lifetime 2129 as a declared array, so we allow a larger size. */ 2130 block = gimple_block (stmt); 2131 if (!(cfun->after_inlining 2132 && block 2133 && TREE_CODE (BLOCK_SUPERCONTEXT (block)) == FUNCTION_DECL)) 2134 threshold /= 10; 2135 if (size > threshold) 2136 return NULL_TREE; 2137 2138 /* Declare array. */ 2139 elem_type = build_nonstandard_integer_type (BITS_PER_UNIT, 1); 2140 n_elem = size * 8 / BITS_PER_UNIT; 2141 array_type = build_array_type_nelts (elem_type, n_elem); 2142 var = create_tmp_var (array_type); 2143 SET_DECL_ALIGN (var, TREE_INT_CST_LOW (gimple_call_arg (stmt, 1))); 2144 { 2145 struct ptr_info_def *pi = SSA_NAME_PTR_INFO (lhs); 2146 if (pi != NULL && !pi->pt.anything) 2147 { 2148 bool singleton_p; 2149 unsigned uid; 2150 singleton_p = pt_solution_singleton_or_null_p (&pi->pt, &uid); 2151 gcc_assert (singleton_p); 2152 SET_DECL_PT_UID (var, uid); 2153 } 2154 } 2155 2156 /* Fold alloca to the address of the array. */ 2157 return fold_convert (TREE_TYPE (lhs), build_fold_addr_expr (var)); 2158 } 2159 2160 /* Fold the stmt at *GSI with CCP specific information that propagating 2161 and regular folding does not catch. */ 2162 2163 static bool 2164 ccp_fold_stmt (gimple_stmt_iterator *gsi) 2165 { 2166 gimple *stmt = gsi_stmt (*gsi); 2167 2168 switch (gimple_code (stmt)) 2169 { 2170 case GIMPLE_COND: 2171 { 2172 gcond *cond_stmt = as_a <gcond *> (stmt); 2173 ccp_prop_value_t val; 2174 /* Statement evaluation will handle type mismatches in constants 2175 more gracefully than the final propagation. This allows us to 2176 fold more conditionals here. */ 2177 val = evaluate_stmt (stmt); 2178 if (val.lattice_val != CONSTANT 2179 || val.mask != 0) 2180 return false; 2181 2182 if (dump_file) 2183 { 2184 fprintf (dump_file, "Folding predicate "); 2185 print_gimple_expr (dump_file, stmt, 0, 0); 2186 fprintf (dump_file, " to "); 2187 print_generic_expr (dump_file, val.value, 0); 2188 fprintf (dump_file, "\n"); 2189 } 2190 2191 if (integer_zerop (val.value)) 2192 gimple_cond_make_false (cond_stmt); 2193 else 2194 gimple_cond_make_true (cond_stmt); 2195 2196 return true; 2197 } 2198 2199 case GIMPLE_CALL: 2200 { 2201 tree lhs = gimple_call_lhs (stmt); 2202 int flags = gimple_call_flags (stmt); 2203 tree val; 2204 tree argt; 2205 bool changed = false; 2206 unsigned i; 2207 2208 /* If the call was folded into a constant make sure it goes 2209 away even if we cannot propagate into all uses because of 2210 type issues. */ 2211 if (lhs 2212 && TREE_CODE (lhs) == SSA_NAME 2213 && (val = get_constant_value (lhs)) 2214 /* Don't optimize away calls that have side-effects. */ 2215 && (flags & (ECF_CONST|ECF_PURE)) != 0 2216 && (flags & ECF_LOOPING_CONST_OR_PURE) == 0) 2217 { 2218 tree new_rhs = unshare_expr (val); 2219 bool res; 2220 if (!useless_type_conversion_p (TREE_TYPE (lhs), 2221 TREE_TYPE (new_rhs))) 2222 new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs); 2223 res = update_call_from_tree (gsi, new_rhs); 2224 gcc_assert (res); 2225 return true; 2226 } 2227 2228 /* Internal calls provide no argument types, so the extra laxity 2229 for normal calls does not apply. */ 2230 if (gimple_call_internal_p (stmt)) 2231 return false; 2232 2233 /* The heuristic of fold_builtin_alloca_with_align differs before and 2234 after inlining, so we don't require the arg to be changed into a 2235 constant for folding, but just to be constant. */ 2236 if (gimple_call_builtin_p (stmt, BUILT_IN_ALLOCA_WITH_ALIGN)) 2237 { 2238 tree new_rhs = fold_builtin_alloca_with_align (stmt); 2239 if (new_rhs) 2240 { 2241 bool res = update_call_from_tree (gsi, new_rhs); 2242 tree var = TREE_OPERAND (TREE_OPERAND (new_rhs, 0),0); 2243 gcc_assert (res); 2244 insert_clobbers_for_var (*gsi, var); 2245 return true; 2246 } 2247 } 2248 2249 /* Propagate into the call arguments. Compared to replace_uses_in 2250 this can use the argument slot types for type verification 2251 instead of the current argument type. We also can safely 2252 drop qualifiers here as we are dealing with constants anyway. */ 2253 argt = TYPE_ARG_TYPES (gimple_call_fntype (stmt)); 2254 for (i = 0; i < gimple_call_num_args (stmt) && argt; 2255 ++i, argt = TREE_CHAIN (argt)) 2256 { 2257 tree arg = gimple_call_arg (stmt, i); 2258 if (TREE_CODE (arg) == SSA_NAME 2259 && (val = get_constant_value (arg)) 2260 && useless_type_conversion_p 2261 (TYPE_MAIN_VARIANT (TREE_VALUE (argt)), 2262 TYPE_MAIN_VARIANT (TREE_TYPE (val)))) 2263 { 2264 gimple_call_set_arg (stmt, i, unshare_expr (val)); 2265 changed = true; 2266 } 2267 } 2268 2269 return changed; 2270 } 2271 2272 case GIMPLE_ASSIGN: 2273 { 2274 tree lhs = gimple_assign_lhs (stmt); 2275 tree val; 2276 2277 /* If we have a load that turned out to be constant replace it 2278 as we cannot propagate into all uses in all cases. */ 2279 if (gimple_assign_single_p (stmt) 2280 && TREE_CODE (lhs) == SSA_NAME 2281 && (val = get_constant_value (lhs))) 2282 { 2283 tree rhs = unshare_expr (val); 2284 if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs))) 2285 rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs); 2286 gimple_assign_set_rhs_from_tree (gsi, rhs); 2287 return true; 2288 } 2289 2290 return false; 2291 } 2292 2293 default: 2294 return false; 2295 } 2296 } 2297 2298 /* Visit the assignment statement STMT. Set the value of its LHS to the 2299 value computed by the RHS and store LHS in *OUTPUT_P. If STMT 2300 creates virtual definitions, set the value of each new name to that 2301 of the RHS (if we can derive a constant out of the RHS). 2302 Value-returning call statements also perform an assignment, and 2303 are handled here. */ 2304 2305 static enum ssa_prop_result 2306 visit_assignment (gimple *stmt, tree *output_p) 2307 { 2308 ccp_prop_value_t val; 2309 enum ssa_prop_result retval = SSA_PROP_NOT_INTERESTING; 2310 2311 tree lhs = gimple_get_lhs (stmt); 2312 if (TREE_CODE (lhs) == SSA_NAME) 2313 { 2314 /* Evaluate the statement, which could be 2315 either a GIMPLE_ASSIGN or a GIMPLE_CALL. */ 2316 val = evaluate_stmt (stmt); 2317 2318 /* If STMT is an assignment to an SSA_NAME, we only have one 2319 value to set. */ 2320 if (set_lattice_value (lhs, &val)) 2321 { 2322 *output_p = lhs; 2323 if (val.lattice_val == VARYING) 2324 retval = SSA_PROP_VARYING; 2325 else 2326 retval = SSA_PROP_INTERESTING; 2327 } 2328 } 2329 2330 return retval; 2331 } 2332 2333 2334 /* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING 2335 if it can determine which edge will be taken. Otherwise, return 2336 SSA_PROP_VARYING. */ 2337 2338 static enum ssa_prop_result 2339 visit_cond_stmt (gimple *stmt, edge *taken_edge_p) 2340 { 2341 ccp_prop_value_t val; 2342 basic_block block; 2343 2344 block = gimple_bb (stmt); 2345 val = evaluate_stmt (stmt); 2346 if (val.lattice_val != CONSTANT 2347 || val.mask != 0) 2348 return SSA_PROP_VARYING; 2349 2350 /* Find which edge out of the conditional block will be taken and add it 2351 to the worklist. If no single edge can be determined statically, 2352 return SSA_PROP_VARYING to feed all the outgoing edges to the 2353 propagation engine. */ 2354 *taken_edge_p = find_taken_edge (block, val.value); 2355 if (*taken_edge_p) 2356 return SSA_PROP_INTERESTING; 2357 else 2358 return SSA_PROP_VARYING; 2359 } 2360 2361 2362 /* Evaluate statement STMT. If the statement produces an output value and 2363 its evaluation changes the lattice value of its output, return 2364 SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the 2365 output value. 2366 2367 If STMT is a conditional branch and we can determine its truth 2368 value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying 2369 value, return SSA_PROP_VARYING. */ 2370 2371 static enum ssa_prop_result 2372 ccp_visit_stmt (gimple *stmt, edge *taken_edge_p, tree *output_p) 2373 { 2374 tree def; 2375 ssa_op_iter iter; 2376 2377 if (dump_file && (dump_flags & TDF_DETAILS)) 2378 { 2379 fprintf (dump_file, "\nVisiting statement:\n"); 2380 print_gimple_stmt (dump_file, stmt, 0, dump_flags); 2381 } 2382 2383 switch (gimple_code (stmt)) 2384 { 2385 case GIMPLE_ASSIGN: 2386 /* If the statement is an assignment that produces a single 2387 output value, evaluate its RHS to see if the lattice value of 2388 its output has changed. */ 2389 return visit_assignment (stmt, output_p); 2390 2391 case GIMPLE_CALL: 2392 /* A value-returning call also performs an assignment. */ 2393 if (gimple_call_lhs (stmt) != NULL_TREE) 2394 return visit_assignment (stmt, output_p); 2395 break; 2396 2397 case GIMPLE_COND: 2398 case GIMPLE_SWITCH: 2399 /* If STMT is a conditional branch, see if we can determine 2400 which branch will be taken. */ 2401 /* FIXME. It appears that we should be able to optimize 2402 computed GOTOs here as well. */ 2403 return visit_cond_stmt (stmt, taken_edge_p); 2404 2405 default: 2406 break; 2407 } 2408 2409 /* Any other kind of statement is not interesting for constant 2410 propagation and, therefore, not worth simulating. */ 2411 if (dump_file && (dump_flags & TDF_DETAILS)) 2412 fprintf (dump_file, "No interesting values produced. Marked VARYING.\n"); 2413 2414 /* Definitions made by statements other than assignments to 2415 SSA_NAMEs represent unknown modifications to their outputs. 2416 Mark them VARYING. */ 2417 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) 2418 set_value_varying (def); 2419 2420 return SSA_PROP_VARYING; 2421 } 2422 2423 2424 /* Main entry point for SSA Conditional Constant Propagation. If NONZERO_P, 2425 record nonzero bits. */ 2426 2427 static unsigned int 2428 do_ssa_ccp (bool nonzero_p) 2429 { 2430 unsigned int todo = 0; 2431 calculate_dominance_info (CDI_DOMINATORS); 2432 2433 ccp_initialize (); 2434 ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node); 2435 if (ccp_finalize (nonzero_p || flag_ipa_bit_cp)) 2436 { 2437 todo = (TODO_cleanup_cfg | TODO_update_ssa); 2438 2439 /* ccp_finalize does not preserve loop-closed ssa. */ 2440 loops_state_clear (LOOP_CLOSED_SSA); 2441 } 2442 2443 free_dominance_info (CDI_DOMINATORS); 2444 return todo; 2445 } 2446 2447 2448 namespace { 2449 2450 const pass_data pass_data_ccp = 2451 { 2452 GIMPLE_PASS, /* type */ 2453 "ccp", /* name */ 2454 OPTGROUP_NONE, /* optinfo_flags */ 2455 TV_TREE_CCP, /* tv_id */ 2456 ( PROP_cfg | PROP_ssa ), /* properties_required */ 2457 0, /* properties_provided */ 2458 0, /* properties_destroyed */ 2459 0, /* todo_flags_start */ 2460 TODO_update_address_taken, /* todo_flags_finish */ 2461 }; 2462 2463 class pass_ccp : public gimple_opt_pass 2464 { 2465 public: 2466 pass_ccp (gcc::context *ctxt) 2467 : gimple_opt_pass (pass_data_ccp, ctxt), nonzero_p (false) 2468 {} 2469 2470 /* opt_pass methods: */ 2471 opt_pass * clone () { return new pass_ccp (m_ctxt); } 2472 void set_pass_param (unsigned int n, bool param) 2473 { 2474 gcc_assert (n == 0); 2475 nonzero_p = param; 2476 } 2477 virtual bool gate (function *) { return flag_tree_ccp != 0; } 2478 virtual unsigned int execute (function *) { return do_ssa_ccp (nonzero_p); } 2479 2480 private: 2481 /* Determines whether the pass instance records nonzero bits. */ 2482 bool nonzero_p; 2483 }; // class pass_ccp 2484 2485 } // anon namespace 2486 2487 gimple_opt_pass * 2488 make_pass_ccp (gcc::context *ctxt) 2489 { 2490 return new pass_ccp (ctxt); 2491 } 2492 2493 2494 2495 /* Try to optimize out __builtin_stack_restore. Optimize it out 2496 if there is another __builtin_stack_restore in the same basic 2497 block and no calls or ASM_EXPRs are in between, or if this block's 2498 only outgoing edge is to EXIT_BLOCK and there are no calls or 2499 ASM_EXPRs after this __builtin_stack_restore. */ 2500 2501 static tree 2502 optimize_stack_restore (gimple_stmt_iterator i) 2503 { 2504 tree callee; 2505 gimple *stmt; 2506 2507 basic_block bb = gsi_bb (i); 2508 gimple *call = gsi_stmt (i); 2509 2510 if (gimple_code (call) != GIMPLE_CALL 2511 || gimple_call_num_args (call) != 1 2512 || TREE_CODE (gimple_call_arg (call, 0)) != SSA_NAME 2513 || !POINTER_TYPE_P (TREE_TYPE (gimple_call_arg (call, 0)))) 2514 return NULL_TREE; 2515 2516 for (gsi_next (&i); !gsi_end_p (i); gsi_next (&i)) 2517 { 2518 stmt = gsi_stmt (i); 2519 if (gimple_code (stmt) == GIMPLE_ASM) 2520 return NULL_TREE; 2521 if (gimple_code (stmt) != GIMPLE_CALL) 2522 continue; 2523 2524 callee = gimple_call_fndecl (stmt); 2525 if (!callee 2526 || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL 2527 /* All regular builtins are ok, just obviously not alloca. */ 2528 || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA 2529 || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA_WITH_ALIGN) 2530 return NULL_TREE; 2531 2532 if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE) 2533 goto second_stack_restore; 2534 } 2535 2536 if (!gsi_end_p (i)) 2537 return NULL_TREE; 2538 2539 /* Allow one successor of the exit block, or zero successors. */ 2540 switch (EDGE_COUNT (bb->succs)) 2541 { 2542 case 0: 2543 break; 2544 case 1: 2545 if (single_succ_edge (bb)->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) 2546 return NULL_TREE; 2547 break; 2548 default: 2549 return NULL_TREE; 2550 } 2551 second_stack_restore: 2552 2553 /* If there's exactly one use, then zap the call to __builtin_stack_save. 2554 If there are multiple uses, then the last one should remove the call. 2555 In any case, whether the call to __builtin_stack_save can be removed 2556 or not is irrelevant to removing the call to __builtin_stack_restore. */ 2557 if (has_single_use (gimple_call_arg (call, 0))) 2558 { 2559 gimple *stack_save = SSA_NAME_DEF_STMT (gimple_call_arg (call, 0)); 2560 if (is_gimple_call (stack_save)) 2561 { 2562 callee = gimple_call_fndecl (stack_save); 2563 if (callee 2564 && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL 2565 && DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_SAVE) 2566 { 2567 gimple_stmt_iterator stack_save_gsi; 2568 tree rhs; 2569 2570 stack_save_gsi = gsi_for_stmt (stack_save); 2571 rhs = build_int_cst (TREE_TYPE (gimple_call_arg (call, 0)), 0); 2572 update_call_from_tree (&stack_save_gsi, rhs); 2573 } 2574 } 2575 } 2576 2577 /* No effect, so the statement will be deleted. */ 2578 return integer_zero_node; 2579 } 2580 2581 /* If va_list type is a simple pointer and nothing special is needed, 2582 optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0), 2583 __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple 2584 pointer assignment. */ 2585 2586 static tree 2587 optimize_stdarg_builtin (gimple *call) 2588 { 2589 tree callee, lhs, rhs, cfun_va_list; 2590 bool va_list_simple_ptr; 2591 location_t loc = gimple_location (call); 2592 2593 if (gimple_code (call) != GIMPLE_CALL) 2594 return NULL_TREE; 2595 2596 callee = gimple_call_fndecl (call); 2597 2598 cfun_va_list = targetm.fn_abi_va_list (callee); 2599 va_list_simple_ptr = POINTER_TYPE_P (cfun_va_list) 2600 && (TREE_TYPE (cfun_va_list) == void_type_node 2601 || TREE_TYPE (cfun_va_list) == char_type_node); 2602 2603 switch (DECL_FUNCTION_CODE (callee)) 2604 { 2605 case BUILT_IN_VA_START: 2606 if (!va_list_simple_ptr 2607 || targetm.expand_builtin_va_start != NULL 2608 || !builtin_decl_explicit_p (BUILT_IN_NEXT_ARG)) 2609 return NULL_TREE; 2610 2611 if (gimple_call_num_args (call) != 2) 2612 return NULL_TREE; 2613 2614 lhs = gimple_call_arg (call, 0); 2615 if (!POINTER_TYPE_P (TREE_TYPE (lhs)) 2616 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) 2617 != TYPE_MAIN_VARIANT (cfun_va_list)) 2618 return NULL_TREE; 2619 2620 lhs = build_fold_indirect_ref_loc (loc, lhs); 2621 rhs = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_NEXT_ARG), 2622 1, integer_zero_node); 2623 rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); 2624 return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); 2625 2626 case BUILT_IN_VA_COPY: 2627 if (!va_list_simple_ptr) 2628 return NULL_TREE; 2629 2630 if (gimple_call_num_args (call) != 2) 2631 return NULL_TREE; 2632 2633 lhs = gimple_call_arg (call, 0); 2634 if (!POINTER_TYPE_P (TREE_TYPE (lhs)) 2635 || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs))) 2636 != TYPE_MAIN_VARIANT (cfun_va_list)) 2637 return NULL_TREE; 2638 2639 lhs = build_fold_indirect_ref_loc (loc, lhs); 2640 rhs = gimple_call_arg (call, 1); 2641 if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs)) 2642 != TYPE_MAIN_VARIANT (cfun_va_list)) 2643 return NULL_TREE; 2644 2645 rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs); 2646 return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs); 2647 2648 case BUILT_IN_VA_END: 2649 /* No effect, so the statement will be deleted. */ 2650 return integer_zero_node; 2651 2652 default: 2653 gcc_unreachable (); 2654 } 2655 } 2656 2657 /* Attemp to make the block of __builtin_unreachable I unreachable by changing 2658 the incoming jumps. Return true if at least one jump was changed. */ 2659 2660 static bool 2661 optimize_unreachable (gimple_stmt_iterator i) 2662 { 2663 basic_block bb = gsi_bb (i); 2664 gimple_stmt_iterator gsi; 2665 gimple *stmt; 2666 edge_iterator ei; 2667 edge e; 2668 bool ret; 2669 2670 if (flag_sanitize & SANITIZE_UNREACHABLE) 2671 return false; 2672 2673 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) 2674 { 2675 stmt = gsi_stmt (gsi); 2676 2677 if (is_gimple_debug (stmt)) 2678 continue; 2679 2680 if (glabel *label_stmt = dyn_cast <glabel *> (stmt)) 2681 { 2682 /* Verify we do not need to preserve the label. */ 2683 if (FORCED_LABEL (gimple_label_label (label_stmt))) 2684 return false; 2685 2686 continue; 2687 } 2688 2689 /* Only handle the case that __builtin_unreachable is the first statement 2690 in the block. We rely on DCE to remove stmts without side-effects 2691 before __builtin_unreachable. */ 2692 if (gsi_stmt (gsi) != gsi_stmt (i)) 2693 return false; 2694 } 2695 2696 ret = false; 2697 FOR_EACH_EDGE (e, ei, bb->preds) 2698 { 2699 gsi = gsi_last_bb (e->src); 2700 if (gsi_end_p (gsi)) 2701 continue; 2702 2703 stmt = gsi_stmt (gsi); 2704 if (gcond *cond_stmt = dyn_cast <gcond *> (stmt)) 2705 { 2706 if (e->flags & EDGE_TRUE_VALUE) 2707 gimple_cond_make_false (cond_stmt); 2708 else if (e->flags & EDGE_FALSE_VALUE) 2709 gimple_cond_make_true (cond_stmt); 2710 else 2711 gcc_unreachable (); 2712 update_stmt (cond_stmt); 2713 } 2714 else 2715 { 2716 /* Todo: handle other cases, f.i. switch statement. */ 2717 continue; 2718 } 2719 2720 ret = true; 2721 } 2722 2723 return ret; 2724 } 2725 2726 /* Optimize 2727 mask_2 = 1 << cnt_1; 2728 _4 = __atomic_fetch_or_* (ptr_6, mask_2, _3); 2729 _5 = _4 & mask_2; 2730 to 2731 _4 = ATOMIC_BIT_TEST_AND_SET (ptr_6, cnt_1, 0, _3); 2732 _5 = _4; 2733 If _5 is only used in _5 != 0 or _5 == 0 comparisons, 1 2734 is passed instead of 0, and the builtin just returns a zero 2735 or 1 value instead of the actual bit. 2736 Similarly for __sync_fetch_and_or_* (without the ", _3" part 2737 in there), and/or if mask_2 is a power of 2 constant. 2738 Similarly for xor instead of or, use ATOMIC_BIT_TEST_AND_COMPLEMENT 2739 in that case. And similarly for and instead of or, except that 2740 the second argument to the builtin needs to be one's complement 2741 of the mask instead of mask. */ 2742 2743 static void 2744 optimize_atomic_bit_test_and (gimple_stmt_iterator *gsip, 2745 enum internal_fn fn, bool has_model_arg, 2746 bool after) 2747 { 2748 gimple *call = gsi_stmt (*gsip); 2749 tree lhs = gimple_call_lhs (call); 2750 use_operand_p use_p; 2751 gimple *use_stmt; 2752 tree mask, bit; 2753 optab optab; 2754 2755 if (!flag_inline_atomics 2756 || optimize_debug 2757 || !gimple_call_builtin_p (call, BUILT_IN_NORMAL) 2758 || !lhs 2759 || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs) 2760 || !single_imm_use (lhs, &use_p, &use_stmt) 2761 || !is_gimple_assign (use_stmt) 2762 || gimple_assign_rhs_code (use_stmt) != BIT_AND_EXPR 2763 || !gimple_vdef (call)) 2764 return; 2765 2766 switch (fn) 2767 { 2768 case IFN_ATOMIC_BIT_TEST_AND_SET: 2769 optab = atomic_bit_test_and_set_optab; 2770 break; 2771 case IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT: 2772 optab = atomic_bit_test_and_complement_optab; 2773 break; 2774 case IFN_ATOMIC_BIT_TEST_AND_RESET: 2775 optab = atomic_bit_test_and_reset_optab; 2776 break; 2777 default: 2778 return; 2779 } 2780 2781 if (optab_handler (optab, TYPE_MODE (TREE_TYPE (lhs))) == CODE_FOR_nothing) 2782 return; 2783 2784 mask = gimple_call_arg (call, 1); 2785 tree use_lhs = gimple_assign_lhs (use_stmt); 2786 if (!use_lhs) 2787 return; 2788 2789 if (TREE_CODE (mask) == INTEGER_CST) 2790 { 2791 if (fn == IFN_ATOMIC_BIT_TEST_AND_RESET) 2792 mask = const_unop (BIT_NOT_EXPR, TREE_TYPE (mask), mask); 2793 mask = fold_convert (TREE_TYPE (lhs), mask); 2794 int ibit = tree_log2 (mask); 2795 if (ibit < 0) 2796 return; 2797 bit = build_int_cst (TREE_TYPE (lhs), ibit); 2798 } 2799 else if (TREE_CODE (mask) == SSA_NAME) 2800 { 2801 gimple *g = SSA_NAME_DEF_STMT (mask); 2802 if (fn == IFN_ATOMIC_BIT_TEST_AND_RESET) 2803 { 2804 if (!is_gimple_assign (g) 2805 || gimple_assign_rhs_code (g) != BIT_NOT_EXPR) 2806 return; 2807 mask = gimple_assign_rhs1 (g); 2808 if (TREE_CODE (mask) != SSA_NAME) 2809 return; 2810 g = SSA_NAME_DEF_STMT (mask); 2811 } 2812 if (!is_gimple_assign (g) 2813 || gimple_assign_rhs_code (g) != LSHIFT_EXPR 2814 || !integer_onep (gimple_assign_rhs1 (g))) 2815 return; 2816 bit = gimple_assign_rhs2 (g); 2817 } 2818 else 2819 return; 2820 2821 if (gimple_assign_rhs1 (use_stmt) == lhs) 2822 { 2823 if (!operand_equal_p (gimple_assign_rhs2 (use_stmt), mask, 0)) 2824 return; 2825 } 2826 else if (gimple_assign_rhs2 (use_stmt) != lhs 2827 || !operand_equal_p (gimple_assign_rhs1 (use_stmt), mask, 0)) 2828 return; 2829 2830 bool use_bool = true; 2831 bool has_debug_uses = false; 2832 imm_use_iterator iter; 2833 gimple *g; 2834 2835 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (use_lhs)) 2836 use_bool = false; 2837 FOR_EACH_IMM_USE_STMT (g, iter, use_lhs) 2838 { 2839 enum tree_code code = ERROR_MARK; 2840 tree op0 = NULL_TREE, op1 = NULL_TREE; 2841 if (is_gimple_debug (g)) 2842 { 2843 has_debug_uses = true; 2844 continue; 2845 } 2846 else if (is_gimple_assign (g)) 2847 switch (gimple_assign_rhs_code (g)) 2848 { 2849 case COND_EXPR: 2850 op1 = gimple_assign_rhs1 (g); 2851 code = TREE_CODE (op1); 2852 op0 = TREE_OPERAND (op1, 0); 2853 op1 = TREE_OPERAND (op1, 1); 2854 break; 2855 case EQ_EXPR: 2856 case NE_EXPR: 2857 code = gimple_assign_rhs_code (g); 2858 op0 = gimple_assign_rhs1 (g); 2859 op1 = gimple_assign_rhs2 (g); 2860 break; 2861 default: 2862 break; 2863 } 2864 else if (gimple_code (g) == GIMPLE_COND) 2865 { 2866 code = gimple_cond_code (g); 2867 op0 = gimple_cond_lhs (g); 2868 op1 = gimple_cond_rhs (g); 2869 } 2870 2871 if ((code == EQ_EXPR || code == NE_EXPR) 2872 && op0 == use_lhs 2873 && integer_zerop (op1)) 2874 { 2875 use_operand_p use_p; 2876 int n = 0; 2877 FOR_EACH_IMM_USE_ON_STMT (use_p, iter) 2878 n++; 2879 if (n == 1) 2880 continue; 2881 } 2882 2883 use_bool = false; 2884 BREAK_FROM_IMM_USE_STMT (iter); 2885 } 2886 2887 tree new_lhs = make_ssa_name (TREE_TYPE (lhs)); 2888 tree flag = build_int_cst (TREE_TYPE (lhs), use_bool); 2889 if (has_model_arg) 2890 g = gimple_build_call_internal (fn, 4, gimple_call_arg (call, 0), 2891 bit, flag, gimple_call_arg (call, 2)); 2892 else 2893 g = gimple_build_call_internal (fn, 3, gimple_call_arg (call, 0), 2894 bit, flag); 2895 gimple_call_set_lhs (g, new_lhs); 2896 gimple_set_location (g, gimple_location (call)); 2897 gimple_set_vuse (g, gimple_vuse (call)); 2898 gimple_set_vdef (g, gimple_vdef (call)); 2899 bool throws = stmt_can_throw_internal (call); 2900 gimple_call_set_nothrow (as_a <gcall *> (g), 2901 gimple_call_nothrow_p (as_a <gcall *> (call))); 2902 SSA_NAME_DEF_STMT (gimple_vdef (call)) = g; 2903 gimple_stmt_iterator gsi = *gsip; 2904 gsi_insert_after (&gsi, g, GSI_NEW_STMT); 2905 edge e = NULL; 2906 if (throws) 2907 { 2908 maybe_clean_or_replace_eh_stmt (call, g); 2909 if (after || (use_bool && has_debug_uses)) 2910 e = find_fallthru_edge (gsi_bb (gsi)->succs); 2911 } 2912 if (after) 2913 { 2914 /* The internal function returns the value of the specified bit 2915 before the atomic operation. If we are interested in the value 2916 of the specified bit after the atomic operation (makes only sense 2917 for xor, otherwise the bit content is compile time known), 2918 we need to invert the bit. */ 2919 g = gimple_build_assign (make_ssa_name (TREE_TYPE (lhs)), 2920 BIT_XOR_EXPR, new_lhs, 2921 use_bool ? build_int_cst (TREE_TYPE (lhs), 1) 2922 : mask); 2923 new_lhs = gimple_assign_lhs (g); 2924 if (throws) 2925 { 2926 gsi_insert_on_edge_immediate (e, g); 2927 gsi = gsi_for_stmt (g); 2928 } 2929 else 2930 gsi_insert_after (&gsi, g, GSI_NEW_STMT); 2931 } 2932 if (use_bool && has_debug_uses) 2933 { 2934 tree temp = NULL_TREE; 2935 if (!throws || after || single_pred_p (e->dest)) 2936 { 2937 temp = make_node (DEBUG_EXPR_DECL); 2938 DECL_ARTIFICIAL (temp) = 1; 2939 TREE_TYPE (temp) = TREE_TYPE (lhs); 2940 SET_DECL_MODE (temp, TYPE_MODE (TREE_TYPE (lhs))); 2941 tree t = build2 (LSHIFT_EXPR, TREE_TYPE (lhs), new_lhs, bit); 2942 g = gimple_build_debug_bind (temp, t, g); 2943 if (throws && !after) 2944 { 2945 gsi = gsi_after_labels (e->dest); 2946 gsi_insert_before (&gsi, g, GSI_SAME_STMT); 2947 } 2948 else 2949 gsi_insert_after (&gsi, g, GSI_NEW_STMT); 2950 } 2951 FOR_EACH_IMM_USE_STMT (g, iter, use_lhs) 2952 if (is_gimple_debug (g)) 2953 { 2954 use_operand_p use_p; 2955 if (temp == NULL_TREE) 2956 gimple_debug_bind_reset_value (g); 2957 else 2958 FOR_EACH_IMM_USE_ON_STMT (use_p, iter) 2959 SET_USE (use_p, temp); 2960 update_stmt (g); 2961 } 2962 } 2963 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_lhs) 2964 = SSA_NAME_OCCURS_IN_ABNORMAL_PHI (use_lhs); 2965 replace_uses_by (use_lhs, new_lhs); 2966 gsi = gsi_for_stmt (use_stmt); 2967 gsi_remove (&gsi, true); 2968 release_defs (use_stmt); 2969 gsi_remove (gsip, true); 2970 release_ssa_name (lhs); 2971 } 2972 2973 /* Optimize 2974 a = {}; 2975 b = a; 2976 into 2977 a = {}; 2978 b = {}; 2979 Similarly for memset (&a, ..., sizeof (a)); instead of a = {}; 2980 and/or memcpy (&b, &a, sizeof (a)); instead of b = a; */ 2981 2982 static void 2983 optimize_memcpy (gimple_stmt_iterator *gsip, tree dest, tree src, tree len) 2984 { 2985 gimple *stmt = gsi_stmt (*gsip); 2986 if (gimple_has_volatile_ops (stmt)) 2987 return; 2988 2989 tree vuse = gimple_vuse (stmt); 2990 if (vuse == NULL) 2991 return; 2992 2993 gimple *defstmt = SSA_NAME_DEF_STMT (vuse); 2994 tree src2 = NULL_TREE, len2 = NULL_TREE; 2995 HOST_WIDE_INT offset, offset2; 2996 tree val = integer_zero_node; 2997 if (gimple_store_p (defstmt) 2998 && gimple_assign_single_p (defstmt) 2999 && TREE_CODE (gimple_assign_rhs1 (defstmt)) == CONSTRUCTOR 3000 && !gimple_clobber_p (defstmt)) 3001 src2 = gimple_assign_lhs (defstmt); 3002 else if (gimple_call_builtin_p (defstmt, BUILT_IN_MEMSET) 3003 && TREE_CODE (gimple_call_arg (defstmt, 0)) == ADDR_EXPR 3004 && TREE_CODE (gimple_call_arg (defstmt, 1)) == INTEGER_CST) 3005 { 3006 src2 = TREE_OPERAND (gimple_call_arg (defstmt, 0), 0); 3007 len2 = gimple_call_arg (defstmt, 2); 3008 val = gimple_call_arg (defstmt, 1); 3009 /* For non-0 val, we'd have to transform stmt from assignment 3010 into memset (only if dest is addressable). */ 3011 if (!integer_zerop (val) && is_gimple_assign (stmt)) 3012 src2 = NULL_TREE; 3013 } 3014 3015 if (src2 == NULL_TREE) 3016 return; 3017 3018 if (len == NULL_TREE) 3019 len = (TREE_CODE (src) == COMPONENT_REF 3020 ? DECL_SIZE_UNIT (TREE_OPERAND (src, 1)) 3021 : TYPE_SIZE_UNIT (TREE_TYPE (src))); 3022 if (len2 == NULL_TREE) 3023 len2 = (TREE_CODE (src2) == COMPONENT_REF 3024 ? DECL_SIZE_UNIT (TREE_OPERAND (src2, 1)) 3025 : TYPE_SIZE_UNIT (TREE_TYPE (src2))); 3026 if (len == NULL_TREE 3027 || TREE_CODE (len) != INTEGER_CST 3028 || len2 == NULL_TREE 3029 || TREE_CODE (len2) != INTEGER_CST) 3030 return; 3031 3032 src = get_addr_base_and_unit_offset (src, &offset); 3033 src2 = get_addr_base_and_unit_offset (src2, &offset2); 3034 if (src == NULL_TREE 3035 || src2 == NULL_TREE 3036 || offset < offset2) 3037 return; 3038 3039 if (!operand_equal_p (src, src2, 0)) 3040 return; 3041 3042 /* [ src + offset2, src + offset2 + len2 - 1 ] is set to val. 3043 Make sure that 3044 [ src + offset, src + offset + len - 1 ] is a subset of that. */ 3045 if (wi::to_offset (len) + (offset - offset2) > wi::to_offset (len2)) 3046 return; 3047 3048 if (dump_file && (dump_flags & TDF_DETAILS)) 3049 { 3050 fprintf (dump_file, "Simplified\n "); 3051 print_gimple_stmt (dump_file, stmt, 0, dump_flags); 3052 fprintf (dump_file, "after previous\n "); 3053 print_gimple_stmt (dump_file, defstmt, 0, dump_flags); 3054 } 3055 3056 /* For simplicity, don't change the kind of the stmt, 3057 turn dest = src; into dest = {}; and memcpy (&dest, &src, len); 3058 into memset (&dest, val, len); 3059 In theory we could change dest = src into memset if dest 3060 is addressable (maybe beneficial if val is not 0), or 3061 memcpy (&dest, &src, len) into dest = {} if len is the size 3062 of dest, dest isn't volatile. */ 3063 if (is_gimple_assign (stmt)) 3064 { 3065 tree ctor = build_constructor (TREE_TYPE (dest), NULL); 3066 gimple_assign_set_rhs_from_tree (gsip, ctor); 3067 update_stmt (stmt); 3068 } 3069 else /* If stmt is memcpy, transform it into memset. */ 3070 { 3071 gcall *call = as_a <gcall *> (stmt); 3072 tree fndecl = builtin_decl_implicit (BUILT_IN_MEMSET); 3073 gimple_call_set_fndecl (call, fndecl); 3074 gimple_call_set_fntype (call, TREE_TYPE (fndecl)); 3075 gimple_call_set_arg (call, 1, val); 3076 update_stmt (stmt); 3077 } 3078 3079 if (dump_file && (dump_flags & TDF_DETAILS)) 3080 { 3081 fprintf (dump_file, "into\n "); 3082 print_gimple_stmt (dump_file, stmt, 0, dump_flags); 3083 } 3084 } 3085 3086 /* A simple pass that attempts to fold all builtin functions. This pass 3087 is run after we've propagated as many constants as we can. */ 3088 3089 namespace { 3090 3091 const pass_data pass_data_fold_builtins = 3092 { 3093 GIMPLE_PASS, /* type */ 3094 "fab", /* name */ 3095 OPTGROUP_NONE, /* optinfo_flags */ 3096 TV_NONE, /* tv_id */ 3097 ( PROP_cfg | PROP_ssa ), /* properties_required */ 3098 0, /* properties_provided */ 3099 0, /* properties_destroyed */ 3100 0, /* todo_flags_start */ 3101 TODO_update_ssa, /* todo_flags_finish */ 3102 }; 3103 3104 class pass_fold_builtins : public gimple_opt_pass 3105 { 3106 public: 3107 pass_fold_builtins (gcc::context *ctxt) 3108 : gimple_opt_pass (pass_data_fold_builtins, ctxt) 3109 {} 3110 3111 /* opt_pass methods: */ 3112 opt_pass * clone () { return new pass_fold_builtins (m_ctxt); } 3113 virtual unsigned int execute (function *); 3114 3115 }; // class pass_fold_builtins 3116 3117 unsigned int 3118 pass_fold_builtins::execute (function *fun) 3119 { 3120 bool cfg_changed = false; 3121 basic_block bb; 3122 unsigned int todoflags = 0; 3123 3124 FOR_EACH_BB_FN (bb, fun) 3125 { 3126 gimple_stmt_iterator i; 3127 for (i = gsi_start_bb (bb); !gsi_end_p (i); ) 3128 { 3129 gimple *stmt, *old_stmt; 3130 tree callee; 3131 enum built_in_function fcode; 3132 3133 stmt = gsi_stmt (i); 3134 3135 if (gimple_code (stmt) != GIMPLE_CALL) 3136 { 3137 /* Remove all *ssaname_N ={v} {CLOBBER}; stmts, 3138 after the last GIMPLE DSE they aren't needed and might 3139 unnecessarily keep the SSA_NAMEs live. */ 3140 if (gimple_clobber_p (stmt)) 3141 { 3142 tree lhs = gimple_assign_lhs (stmt); 3143 if (TREE_CODE (lhs) == MEM_REF 3144 && TREE_CODE (TREE_OPERAND (lhs, 0)) == SSA_NAME) 3145 { 3146 unlink_stmt_vdef (stmt); 3147 gsi_remove (&i, true); 3148 release_defs (stmt); 3149 continue; 3150 } 3151 } 3152 else if (gimple_assign_load_p (stmt) && gimple_store_p (stmt)) 3153 optimize_memcpy (&i, gimple_assign_lhs (stmt), 3154 gimple_assign_rhs1 (stmt), NULL_TREE); 3155 gsi_next (&i); 3156 continue; 3157 } 3158 3159 callee = gimple_call_fndecl (stmt); 3160 if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL) 3161 { 3162 gsi_next (&i); 3163 continue; 3164 } 3165 3166 fcode = DECL_FUNCTION_CODE (callee); 3167 if (fold_stmt (&i)) 3168 ; 3169 else 3170 { 3171 tree result = NULL_TREE; 3172 switch (DECL_FUNCTION_CODE (callee)) 3173 { 3174 case BUILT_IN_CONSTANT_P: 3175 /* Resolve __builtin_constant_p. If it hasn't been 3176 folded to integer_one_node by now, it's fairly 3177 certain that the value simply isn't constant. */ 3178 result = integer_zero_node; 3179 break; 3180 3181 case BUILT_IN_ASSUME_ALIGNED: 3182 /* Remove __builtin_assume_aligned. */ 3183 result = gimple_call_arg (stmt, 0); 3184 break; 3185 3186 case BUILT_IN_STACK_RESTORE: 3187 result = optimize_stack_restore (i); 3188 if (result) 3189 break; 3190 gsi_next (&i); 3191 continue; 3192 3193 case BUILT_IN_UNREACHABLE: 3194 if (optimize_unreachable (i)) 3195 cfg_changed = true; 3196 break; 3197 3198 case BUILT_IN_ATOMIC_FETCH_OR_1: 3199 case BUILT_IN_ATOMIC_FETCH_OR_2: 3200 case BUILT_IN_ATOMIC_FETCH_OR_4: 3201 case BUILT_IN_ATOMIC_FETCH_OR_8: 3202 case BUILT_IN_ATOMIC_FETCH_OR_16: 3203 optimize_atomic_bit_test_and (&i, 3204 IFN_ATOMIC_BIT_TEST_AND_SET, 3205 true, false); 3206 break; 3207 case BUILT_IN_SYNC_FETCH_AND_OR_1: 3208 case BUILT_IN_SYNC_FETCH_AND_OR_2: 3209 case BUILT_IN_SYNC_FETCH_AND_OR_4: 3210 case BUILT_IN_SYNC_FETCH_AND_OR_8: 3211 case BUILT_IN_SYNC_FETCH_AND_OR_16: 3212 optimize_atomic_bit_test_and (&i, 3213 IFN_ATOMIC_BIT_TEST_AND_SET, 3214 false, false); 3215 break; 3216 3217 case BUILT_IN_ATOMIC_FETCH_XOR_1: 3218 case BUILT_IN_ATOMIC_FETCH_XOR_2: 3219 case BUILT_IN_ATOMIC_FETCH_XOR_4: 3220 case BUILT_IN_ATOMIC_FETCH_XOR_8: 3221 case BUILT_IN_ATOMIC_FETCH_XOR_16: 3222 optimize_atomic_bit_test_and 3223 (&i, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT, true, false); 3224 break; 3225 case BUILT_IN_SYNC_FETCH_AND_XOR_1: 3226 case BUILT_IN_SYNC_FETCH_AND_XOR_2: 3227 case BUILT_IN_SYNC_FETCH_AND_XOR_4: 3228 case BUILT_IN_SYNC_FETCH_AND_XOR_8: 3229 case BUILT_IN_SYNC_FETCH_AND_XOR_16: 3230 optimize_atomic_bit_test_and 3231 (&i, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT, false, false); 3232 break; 3233 3234 case BUILT_IN_ATOMIC_XOR_FETCH_1: 3235 case BUILT_IN_ATOMIC_XOR_FETCH_2: 3236 case BUILT_IN_ATOMIC_XOR_FETCH_4: 3237 case BUILT_IN_ATOMIC_XOR_FETCH_8: 3238 case BUILT_IN_ATOMIC_XOR_FETCH_16: 3239 optimize_atomic_bit_test_and 3240 (&i, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT, true, true); 3241 break; 3242 case BUILT_IN_SYNC_XOR_AND_FETCH_1: 3243 case BUILT_IN_SYNC_XOR_AND_FETCH_2: 3244 case BUILT_IN_SYNC_XOR_AND_FETCH_4: 3245 case BUILT_IN_SYNC_XOR_AND_FETCH_8: 3246 case BUILT_IN_SYNC_XOR_AND_FETCH_16: 3247 optimize_atomic_bit_test_and 3248 (&i, IFN_ATOMIC_BIT_TEST_AND_COMPLEMENT, false, true); 3249 break; 3250 3251 case BUILT_IN_ATOMIC_FETCH_AND_1: 3252 case BUILT_IN_ATOMIC_FETCH_AND_2: 3253 case BUILT_IN_ATOMIC_FETCH_AND_4: 3254 case BUILT_IN_ATOMIC_FETCH_AND_8: 3255 case BUILT_IN_ATOMIC_FETCH_AND_16: 3256 optimize_atomic_bit_test_and (&i, 3257 IFN_ATOMIC_BIT_TEST_AND_RESET, 3258 true, false); 3259 break; 3260 case BUILT_IN_SYNC_FETCH_AND_AND_1: 3261 case BUILT_IN_SYNC_FETCH_AND_AND_2: 3262 case BUILT_IN_SYNC_FETCH_AND_AND_4: 3263 case BUILT_IN_SYNC_FETCH_AND_AND_8: 3264 case BUILT_IN_SYNC_FETCH_AND_AND_16: 3265 optimize_atomic_bit_test_and (&i, 3266 IFN_ATOMIC_BIT_TEST_AND_RESET, 3267 false, false); 3268 break; 3269 3270 case BUILT_IN_MEMCPY: 3271 if (gimple_call_builtin_p (stmt, BUILT_IN_NORMAL) 3272 && TREE_CODE (gimple_call_arg (stmt, 0)) == ADDR_EXPR 3273 && TREE_CODE (gimple_call_arg (stmt, 1)) == ADDR_EXPR 3274 && TREE_CODE (gimple_call_arg (stmt, 2)) == INTEGER_CST) 3275 { 3276 tree dest = TREE_OPERAND (gimple_call_arg (stmt, 0), 0); 3277 tree src = TREE_OPERAND (gimple_call_arg (stmt, 1), 0); 3278 tree len = gimple_call_arg (stmt, 2); 3279 optimize_memcpy (&i, dest, src, len); 3280 } 3281 break; 3282 3283 case BUILT_IN_VA_START: 3284 case BUILT_IN_VA_END: 3285 case BUILT_IN_VA_COPY: 3286 /* These shouldn't be folded before pass_stdarg. */ 3287 result = optimize_stdarg_builtin (stmt); 3288 break; 3289 3290 default:; 3291 } 3292 3293 if (!result) 3294 { 3295 gsi_next (&i); 3296 continue; 3297 } 3298 3299 if (!update_call_from_tree (&i, result)) 3300 gimplify_and_update_call_from_tree (&i, result); 3301 } 3302 3303 todoflags |= TODO_update_address_taken; 3304 3305 if (dump_file && (dump_flags & TDF_DETAILS)) 3306 { 3307 fprintf (dump_file, "Simplified\n "); 3308 print_gimple_stmt (dump_file, stmt, 0, dump_flags); 3309 } 3310 3311 old_stmt = stmt; 3312 stmt = gsi_stmt (i); 3313 update_stmt (stmt); 3314 3315 if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt) 3316 && gimple_purge_dead_eh_edges (bb)) 3317 cfg_changed = true; 3318 3319 if (dump_file && (dump_flags & TDF_DETAILS)) 3320 { 3321 fprintf (dump_file, "to\n "); 3322 print_gimple_stmt (dump_file, stmt, 0, dump_flags); 3323 fprintf (dump_file, "\n"); 3324 } 3325 3326 /* Retry the same statement if it changed into another 3327 builtin, there might be new opportunities now. */ 3328 if (gimple_code (stmt) != GIMPLE_CALL) 3329 { 3330 gsi_next (&i); 3331 continue; 3332 } 3333 callee = gimple_call_fndecl (stmt); 3334 if (!callee 3335 || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL 3336 || DECL_FUNCTION_CODE (callee) == fcode) 3337 gsi_next (&i); 3338 } 3339 } 3340 3341 /* Delete unreachable blocks. */ 3342 if (cfg_changed) 3343 todoflags |= TODO_cleanup_cfg; 3344 3345 return todoflags; 3346 } 3347 3348 } // anon namespace 3349 3350 gimple_opt_pass * 3351 make_pass_fold_builtins (gcc::context *ctxt) 3352 { 3353 return new pass_fold_builtins (ctxt); 3354 } 3355 3356 /* A simple pass that emits some warnings post IPA. */ 3357 3358 namespace { 3359 3360 const pass_data pass_data_post_ipa_warn = 3361 { 3362 GIMPLE_PASS, /* type */ 3363 "post_ipa_warn", /* name */ 3364 OPTGROUP_NONE, /* optinfo_flags */ 3365 TV_NONE, /* tv_id */ 3366 ( PROP_cfg | PROP_ssa ), /* properties_required */ 3367 0, /* properties_provided */ 3368 0, /* properties_destroyed */ 3369 0, /* todo_flags_start */ 3370 0, /* todo_flags_finish */ 3371 }; 3372 3373 class pass_post_ipa_warn : public gimple_opt_pass 3374 { 3375 public: 3376 pass_post_ipa_warn (gcc::context *ctxt) 3377 : gimple_opt_pass (pass_data_post_ipa_warn, ctxt) 3378 {} 3379 3380 /* opt_pass methods: */ 3381 opt_pass * clone () { return new pass_post_ipa_warn (m_ctxt); } 3382 virtual bool gate (function *) { return warn_nonnull != 0; } 3383 virtual unsigned int execute (function *); 3384 3385 }; // class pass_fold_builtins 3386 3387 unsigned int 3388 pass_post_ipa_warn::execute (function *fun) 3389 { 3390 basic_block bb; 3391 3392 FOR_EACH_BB_FN (bb, fun) 3393 { 3394 gimple_stmt_iterator gsi; 3395 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) 3396 { 3397 gimple *stmt = gsi_stmt (gsi); 3398 if (!is_gimple_call (stmt) || gimple_no_warning_p (stmt)) 3399 continue; 3400 3401 if (warn_nonnull) 3402 { 3403 bitmap nonnullargs 3404 = get_nonnull_args (gimple_call_fntype (stmt)); 3405 if (nonnullargs) 3406 { 3407 for (unsigned i = 0; i < gimple_call_num_args (stmt); i++) 3408 { 3409 tree arg = gimple_call_arg (stmt, i); 3410 if (TREE_CODE (TREE_TYPE (arg)) != POINTER_TYPE) 3411 continue; 3412 if (!integer_zerop (arg)) 3413 continue; 3414 if (!bitmap_empty_p (nonnullargs) 3415 && !bitmap_bit_p (nonnullargs, i)) 3416 continue; 3417 3418 location_t loc = gimple_location (stmt); 3419 if (warning_at (loc, OPT_Wnonnull, 3420 "argument %u null where non-null " 3421 "expected", i + 1)) 3422 { 3423 tree fndecl = gimple_call_fndecl (stmt); 3424 if (fndecl && DECL_IS_BUILTIN (fndecl)) 3425 inform (loc, "in a call to built-in function %qD", 3426 fndecl); 3427 else if (fndecl) 3428 inform (DECL_SOURCE_LOCATION (fndecl), 3429 "in a call to function %qD declared here", 3430 fndecl); 3431 3432 } 3433 } 3434 BITMAP_FREE (nonnullargs); 3435 } 3436 } 3437 } 3438 } 3439 return 0; 3440 } 3441 3442 } // anon namespace 3443 3444 gimple_opt_pass * 3445 make_pass_post_ipa_warn (gcc::context *ctxt) 3446 { 3447 return new pass_post_ipa_warn (ctxt); 3448 } 3449 3450 #if defined(__NetBSD__) && defined(NETBSD_NATIVE) 3451 /* 3452 * This is a big, ugly, temporary hack: 3453 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59958 3454 * To make sure we have configured all our targets correctly, mimic the 3455 * #ifdef cascade from src/lib/libc/stdlib/jemalloc.c here and compile 3456 * time assert that the value matches gcc's MALLOC_ABI_ALIGNMENT here. 3457 */ 3458 3459 #if defined(__hppa__) 3460 #define JEMALLOC_TINY_MIN_2POW 4 3461 #elif defined(__alpha__) || defined(__amd64__) || defined(__sparc64__) \ 3462 || (defined(__arm__) && defined(__ARM_EABI__)) \ 3463 || defined(__ia64__) || defined(__powerpc__) \ 3464 || defined(__aarch64__) \ 3465 || ((defined(__mips__) || defined(__riscv__)) && defined(_LP64)) 3466 #define JEMALLOC_TINY_MIN_2POW 3 3467 #endif 3468 3469 #ifndef JEMALLOC_TINY_MIN_2POW 3470 #define JEMALLOC_TINY_MIN_2POW 2 3471 #endif 3472 3473 /* make sure we test the (native) 64bit variant for targets supporting -m32 */ 3474 #undef TARGET_64BIT 3475 #ifdef _LP64 3476 #define TARGET_64BIT 1 3477 #else 3478 #ifdef __sh__ 3479 #undef UNITS_PER_WORD 3480 #define UNITS_PER_WORD 4 /* original definition varies depending on cpu */ 3481 #endif 3482 #define TARGET_64BIT 0 3483 #endif 3484 3485 /* ARM has a non-constant MALLOC_ABI_ALIGNMENT since GCC 5. */ 3486 #if !defined(__arm__) 3487 #ifdef __CTASSERT 3488 __CTASSERT((8<<JEMALLOC_TINY_MIN_2POW) == MALLOC_ABI_ALIGNMENT); 3489 #else 3490 #error compiling on an older NetBSD version? 3491 #endif 3492 #endif 3493 3494 #endif 3495