1 /* Support routines for Value Range Propagation (VRP). 2 Copyright (C) 2005-2019 Free Software Foundation, Inc. 3 Contributed by Diego Novillo <dnovillo@redhat.com>. 4 5 This file is part of GCC. 6 7 GCC is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3, or (at your option) 10 any later version. 11 12 GCC is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with GCC; see the file COPYING3. If not see 19 <http://www.gnu.org/licenses/>. */ 20 21 #include "config.h" 22 #include "system.h" 23 #include "coretypes.h" 24 #include "backend.h" 25 #include "insn-codes.h" 26 #include "rtl.h" 27 #include "tree.h" 28 #include "gimple.h" 29 #include "cfghooks.h" 30 #include "tree-pass.h" 31 #include "ssa.h" 32 #include "optabs-tree.h" 33 #include "gimple-pretty-print.h" 34 #include "diagnostic-core.h" 35 #include "flags.h" 36 #include "fold-const.h" 37 #include "stor-layout.h" 38 #include "calls.h" 39 #include "cfganal.h" 40 #include "gimple-fold.h" 41 #include "tree-eh.h" 42 #include "gimple-iterator.h" 43 #include "gimple-walk.h" 44 #include "tree-cfg.h" 45 #include "tree-dfa.h" 46 #include "tree-ssa-loop-manip.h" 47 #include "tree-ssa-loop-niter.h" 48 #include "tree-ssa-loop.h" 49 #include "tree-into-ssa.h" 50 #include "tree-ssa.h" 51 #include "intl.h" 52 #include "cfgloop.h" 53 #include "tree-scalar-evolution.h" 54 #include "tree-ssa-propagate.h" 55 #include "tree-chrec.h" 56 #include "tree-ssa-threadupdate.h" 57 #include "tree-ssa-scopedtables.h" 58 #include "tree-ssa-threadedge.h" 59 #include "omp-general.h" 60 #include "target.h" 61 #include "case-cfn-macros.h" 62 #include "params.h" 63 #include "alloc-pool.h" 64 #include "domwalk.h" 65 #include "tree-cfgcleanup.h" 66 #include "stringpool.h" 67 #include "attribs.h" 68 #include "vr-values.h" 69 #include "builtins.h" 70 #include "wide-int-range.h" 71 72 /* Set of SSA names found live during the RPO traversal of the function 73 for still active basic-blocks. */ 74 static sbitmap *live; 75 76 void 77 value_range_base::set (enum value_range_kind kind, tree min, tree max) 78 { 79 m_kind = kind; 80 m_min = min; 81 m_max = max; 82 if (flag_checking) 83 check (); 84 } 85 86 void 87 value_range::set_equiv (bitmap equiv) 88 { 89 /* Since updating the equivalence set involves deep copying the 90 bitmaps, only do it if absolutely necessary. 91 92 All equivalence bitmaps are allocated from the same obstack. So 93 we can use the obstack associated with EQUIV to allocate vr->equiv. */ 94 if (m_equiv == NULL 95 && equiv != NULL) 96 m_equiv = BITMAP_ALLOC (equiv->obstack); 97 98 if (equiv != m_equiv) 99 { 100 if (equiv && !bitmap_empty_p (equiv)) 101 bitmap_copy (m_equiv, equiv); 102 else 103 bitmap_clear (m_equiv); 104 } 105 } 106 107 /* Initialize value_range. */ 108 109 void 110 value_range::set (enum value_range_kind kind, tree min, tree max, 111 bitmap equiv) 112 { 113 value_range_base::set (kind, min, max); 114 set_equiv (equiv); 115 if (flag_checking) 116 check (); 117 } 118 119 value_range_base::value_range_base (value_range_kind kind, tree min, tree max) 120 { 121 set (kind, min, max); 122 } 123 124 value_range::value_range (value_range_kind kind, tree min, tree max, 125 bitmap equiv) 126 { 127 m_equiv = NULL; 128 set (kind, min, max, equiv); 129 } 130 131 value_range::value_range (const value_range_base &other) 132 { 133 m_equiv = NULL; 134 set (other.kind (), other.min(), other.max (), NULL); 135 } 136 137 /* Like set, but keep the equivalences in place. */ 138 139 void 140 value_range::update (value_range_kind kind, tree min, tree max) 141 { 142 set (kind, min, max, 143 (kind != VR_UNDEFINED && kind != VR_VARYING) ? m_equiv : NULL); 144 } 145 146 /* Copy value_range in FROM into THIS while avoiding bitmap sharing. 147 148 Note: The code that avoids the bitmap sharing looks at the existing 149 this->m_equiv, so this function cannot be used to initalize an 150 object. Use the constructors for initialization. */ 151 152 void 153 value_range::deep_copy (const value_range *from) 154 { 155 set (from->m_kind, from->min (), from->max (), from->m_equiv); 156 } 157 158 void 159 value_range::move (value_range *from) 160 { 161 set (from->m_kind, from->min (), from->max ()); 162 m_equiv = from->m_equiv; 163 from->m_equiv = NULL; 164 } 165 166 /* Check the validity of the range. */ 167 168 void 169 value_range_base::check () 170 { 171 switch (m_kind) 172 { 173 case VR_RANGE: 174 case VR_ANTI_RANGE: 175 { 176 int cmp; 177 178 gcc_assert (m_min && m_max); 179 180 gcc_assert (!TREE_OVERFLOW_P (m_min) && !TREE_OVERFLOW_P (m_max)); 181 182 /* Creating ~[-MIN, +MAX] is stupid because that would be 183 the empty set. */ 184 if (INTEGRAL_TYPE_P (TREE_TYPE (m_min)) && m_kind == VR_ANTI_RANGE) 185 gcc_assert (!vrp_val_is_min (m_min) || !vrp_val_is_max (m_max)); 186 187 cmp = compare_values (m_min, m_max); 188 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2); 189 break; 190 } 191 case VR_UNDEFINED: 192 case VR_VARYING: 193 gcc_assert (!min () && !max ()); 194 break; 195 default: 196 gcc_unreachable (); 197 } 198 } 199 200 void 201 value_range::check () 202 { 203 value_range_base::check (); 204 switch (m_kind) 205 { 206 case VR_UNDEFINED: 207 case VR_VARYING: 208 gcc_assert (!m_equiv || bitmap_empty_p (m_equiv)); 209 default:; 210 } 211 } 212 213 /* Equality operator. We purposely do not overload ==, to avoid 214 confusion with the equality bitmap in the derived value_range 215 class. */ 216 217 bool 218 value_range_base::equal_p (const value_range_base &other) const 219 { 220 return (m_kind == other.m_kind 221 && vrp_operand_equal_p (m_min, other.m_min) 222 && vrp_operand_equal_p (m_max, other.m_max)); 223 } 224 225 /* Returns TRUE if THIS == OTHER. Ignores the equivalence bitmap if 226 IGNORE_EQUIVS is TRUE. */ 227 228 bool 229 value_range::equal_p (const value_range &other, bool ignore_equivs) const 230 { 231 return (value_range_base::equal_p (other) 232 && (ignore_equivs 233 || vrp_bitmap_equal_p (m_equiv, other.m_equiv))); 234 } 235 236 /* Return TRUE if this is a symbolic range. */ 237 238 bool 239 value_range_base::symbolic_p () const 240 { 241 return (!varying_p () 242 && !undefined_p () 243 && (!is_gimple_min_invariant (m_min) 244 || !is_gimple_min_invariant (m_max))); 245 } 246 247 /* NOTE: This is not the inverse of symbolic_p because the range 248 could also be varying or undefined. Ideally they should be inverse 249 of each other, with varying only applying to symbolics. Varying of 250 constants would be represented as [-MIN, +MAX]. */ 251 252 bool 253 value_range_base::constant_p () const 254 { 255 return (!varying_p () 256 && !undefined_p () 257 && TREE_CODE (m_min) == INTEGER_CST 258 && TREE_CODE (m_max) == INTEGER_CST); 259 } 260 261 void 262 value_range_base::set_undefined () 263 { 264 set (VR_UNDEFINED, NULL, NULL); 265 } 266 267 void 268 value_range::set_undefined () 269 { 270 set (VR_UNDEFINED, NULL, NULL, NULL); 271 } 272 273 void 274 value_range_base::set_varying () 275 { 276 set (VR_VARYING, NULL, NULL); 277 } 278 279 void 280 value_range::set_varying () 281 { 282 set (VR_VARYING, NULL, NULL, NULL); 283 } 284 285 /* Return TRUE if it is possible that range contains VAL. */ 286 287 bool 288 value_range_base::may_contain_p (tree val) const 289 { 290 if (varying_p ()) 291 return true; 292 293 if (undefined_p ()) 294 return true; 295 296 if (m_kind == VR_ANTI_RANGE) 297 { 298 int res = value_inside_range (val, min (), max ()); 299 return res == 0 || res == -2; 300 } 301 return value_inside_range (val, min (), max ()) != 0; 302 } 303 304 void 305 value_range::equiv_clear () 306 { 307 if (m_equiv) 308 bitmap_clear (m_equiv); 309 } 310 311 /* Add VAR and VAR's equivalence set (VAR_VR) to the equivalence 312 bitmap. If no equivalence table has been created, OBSTACK is the 313 obstack to use (NULL for the default obstack). 314 315 This is the central point where equivalence processing can be 316 turned on/off. */ 317 318 void 319 value_range::equiv_add (const_tree var, 320 const value_range *var_vr, 321 bitmap_obstack *obstack) 322 { 323 if (!m_equiv) 324 m_equiv = BITMAP_ALLOC (obstack); 325 unsigned ver = SSA_NAME_VERSION (var); 326 bitmap_set_bit (m_equiv, ver); 327 if (var_vr && var_vr->m_equiv) 328 bitmap_ior_into (m_equiv, var_vr->m_equiv); 329 } 330 331 /* If range is a singleton, place it in RESULT and return TRUE. 332 Note: A singleton can be any gimple invariant, not just constants. 333 So, [&x, &x] counts as a singleton. */ 334 335 bool 336 value_range_base::singleton_p (tree *result) const 337 { 338 if (m_kind == VR_RANGE 339 && vrp_operand_equal_p (min (), max ()) 340 && is_gimple_min_invariant (min ())) 341 { 342 if (result) 343 *result = min (); 344 return true; 345 } 346 return false; 347 } 348 349 tree 350 value_range_base::type () const 351 { 352 /* Types are only valid for VR_RANGE and VR_ANTI_RANGE, which are 353 known to have non-zero min/max. */ 354 gcc_assert (min ()); 355 return TREE_TYPE (min ()); 356 } 357 358 void 359 value_range_base::dump (FILE *file) const 360 { 361 if (undefined_p ()) 362 fprintf (file, "UNDEFINED"); 363 else if (m_kind == VR_RANGE || m_kind == VR_ANTI_RANGE) 364 { 365 tree ttype = type (); 366 367 print_generic_expr (file, ttype); 368 fprintf (file, " "); 369 370 fprintf (file, "%s[", (m_kind == VR_ANTI_RANGE) ? "~" : ""); 371 372 if (INTEGRAL_TYPE_P (ttype) 373 && !TYPE_UNSIGNED (ttype) 374 && vrp_val_is_min (min ()) 375 && TYPE_PRECISION (ttype) != 1) 376 fprintf (file, "-INF"); 377 else 378 print_generic_expr (file, min ()); 379 380 fprintf (file, ", "); 381 382 if (INTEGRAL_TYPE_P (ttype) 383 && vrp_val_is_max (max ()) 384 && TYPE_PRECISION (ttype) != 1) 385 fprintf (file, "+INF"); 386 else 387 print_generic_expr (file, max ()); 388 389 fprintf (file, "]"); 390 } 391 else if (varying_p ()) 392 fprintf (file, "VARYING"); 393 else 394 gcc_unreachable (); 395 } 396 397 void 398 value_range::dump (FILE *file) const 399 { 400 value_range_base::dump (file); 401 if ((m_kind == VR_RANGE || m_kind == VR_ANTI_RANGE) 402 && m_equiv) 403 { 404 bitmap_iterator bi; 405 unsigned i, c = 0; 406 407 fprintf (file, " EQUIVALENCES: { "); 408 409 EXECUTE_IF_SET_IN_BITMAP (m_equiv, 0, i, bi) 410 { 411 print_generic_expr (file, ssa_name (i)); 412 fprintf (file, " "); 413 c++; 414 } 415 416 fprintf (file, "} (%u elements)", c); 417 } 418 } 419 420 void 421 dump_value_range (FILE *file, const value_range *vr) 422 { 423 if (!vr) 424 fprintf (file, "[]"); 425 else 426 vr->dump (file); 427 } 428 429 void 430 dump_value_range (FILE *file, const value_range_base *vr) 431 { 432 if (!vr) 433 fprintf (file, "[]"); 434 else 435 vr->dump (file); 436 } 437 438 DEBUG_FUNCTION void 439 debug (const value_range_base *vr) 440 { 441 dump_value_range (stderr, vr); 442 } 443 444 DEBUG_FUNCTION void 445 debug (const value_range_base &vr) 446 { 447 dump_value_range (stderr, &vr); 448 } 449 450 DEBUG_FUNCTION void 451 debug (const value_range *vr) 452 { 453 dump_value_range (stderr, vr); 454 } 455 456 DEBUG_FUNCTION void 457 debug (const value_range &vr) 458 { 459 dump_value_range (stderr, &vr); 460 } 461 462 /* Return true if the SSA name NAME is live on the edge E. */ 463 464 static bool 465 live_on_edge (edge e, tree name) 466 { 467 return (live[e->dest->index] 468 && bitmap_bit_p (live[e->dest->index], SSA_NAME_VERSION (name))); 469 } 470 471 /* Location information for ASSERT_EXPRs. Each instance of this 472 structure describes an ASSERT_EXPR for an SSA name. Since a single 473 SSA name may have more than one assertion associated with it, these 474 locations are kept in a linked list attached to the corresponding 475 SSA name. */ 476 struct assert_locus 477 { 478 /* Basic block where the assertion would be inserted. */ 479 basic_block bb; 480 481 /* Some assertions need to be inserted on an edge (e.g., assertions 482 generated by COND_EXPRs). In those cases, BB will be NULL. */ 483 edge e; 484 485 /* Pointer to the statement that generated this assertion. */ 486 gimple_stmt_iterator si; 487 488 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */ 489 enum tree_code comp_code; 490 491 /* Value being compared against. */ 492 tree val; 493 494 /* Expression to compare. */ 495 tree expr; 496 497 /* Next node in the linked list. */ 498 assert_locus *next; 499 }; 500 501 /* If bit I is present, it means that SSA name N_i has a list of 502 assertions that should be inserted in the IL. */ 503 static bitmap need_assert_for; 504 505 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I] 506 holds a list of ASSERT_LOCUS_T nodes that describe where 507 ASSERT_EXPRs for SSA name N_I should be inserted. */ 508 static assert_locus **asserts_for; 509 510 /* Return the maximum value for TYPE. */ 511 512 tree 513 vrp_val_max (const_tree type) 514 { 515 if (!INTEGRAL_TYPE_P (type)) 516 return NULL_TREE; 517 518 return TYPE_MAX_VALUE (type); 519 } 520 521 /* Return the minimum value for TYPE. */ 522 523 tree 524 vrp_val_min (const_tree type) 525 { 526 if (!INTEGRAL_TYPE_P (type)) 527 return NULL_TREE; 528 529 return TYPE_MIN_VALUE (type); 530 } 531 532 /* Return whether VAL is equal to the maximum value of its type. 533 We can't do a simple equality comparison with TYPE_MAX_VALUE because 534 C typedefs and Ada subtypes can produce types whose TYPE_MAX_VALUE 535 is not == to the integer constant with the same value in the type. */ 536 537 bool 538 vrp_val_is_max (const_tree val) 539 { 540 tree type_max = vrp_val_max (TREE_TYPE (val)); 541 return (val == type_max 542 || (type_max != NULL_TREE 543 && operand_equal_p (val, type_max, 0))); 544 } 545 546 /* Return whether VAL is equal to the minimum value of its type. */ 547 548 bool 549 vrp_val_is_min (const_tree val) 550 { 551 tree type_min = vrp_val_min (TREE_TYPE (val)); 552 return (val == type_min 553 || (type_min != NULL_TREE 554 && operand_equal_p (val, type_min, 0))); 555 } 556 557 /* VR_TYPE describes a range with mininum value *MIN and maximum 558 value *MAX. Restrict the range to the set of values that have 559 no bits set outside NONZERO_BITS. Update *MIN and *MAX and 560 return the new range type. 561 562 SGN gives the sign of the values described by the range. */ 563 564 enum value_range_kind 565 intersect_range_with_nonzero_bits (enum value_range_kind vr_type, 566 wide_int *min, wide_int *max, 567 const wide_int &nonzero_bits, 568 signop sgn) 569 { 570 if (vr_type == VR_ANTI_RANGE) 571 { 572 /* The VR_ANTI_RANGE is equivalent to the union of the ranges 573 A: [-INF, *MIN) and B: (*MAX, +INF]. First use NONZERO_BITS 574 to create an inclusive upper bound for A and an inclusive lower 575 bound for B. */ 576 wide_int a_max = wi::round_down_for_mask (*min - 1, nonzero_bits); 577 wide_int b_min = wi::round_up_for_mask (*max + 1, nonzero_bits); 578 579 /* If the calculation of A_MAX wrapped, A is effectively empty 580 and A_MAX is the highest value that satisfies NONZERO_BITS. 581 Likewise if the calculation of B_MIN wrapped, B is effectively 582 empty and B_MIN is the lowest value that satisfies NONZERO_BITS. */ 583 bool a_empty = wi::ge_p (a_max, *min, sgn); 584 bool b_empty = wi::le_p (b_min, *max, sgn); 585 586 /* If both A and B are empty, there are no valid values. */ 587 if (a_empty && b_empty) 588 return VR_UNDEFINED; 589 590 /* If exactly one of A or B is empty, return a VR_RANGE for the 591 other one. */ 592 if (a_empty || b_empty) 593 { 594 *min = b_min; 595 *max = a_max; 596 gcc_checking_assert (wi::le_p (*min, *max, sgn)); 597 return VR_RANGE; 598 } 599 600 /* Update the VR_ANTI_RANGE bounds. */ 601 *min = a_max + 1; 602 *max = b_min - 1; 603 gcc_checking_assert (wi::le_p (*min, *max, sgn)); 604 605 /* Now check whether the excluded range includes any values that 606 satisfy NONZERO_BITS. If not, switch to a full VR_RANGE. */ 607 if (wi::round_up_for_mask (*min, nonzero_bits) == b_min) 608 { 609 unsigned int precision = min->get_precision (); 610 *min = wi::min_value (precision, sgn); 611 *max = wi::max_value (precision, sgn); 612 vr_type = VR_RANGE; 613 } 614 } 615 if (vr_type == VR_RANGE) 616 { 617 *max = wi::round_down_for_mask (*max, nonzero_bits); 618 619 /* Check that the range contains at least one valid value. */ 620 if (wi::gt_p (*min, *max, sgn)) 621 return VR_UNDEFINED; 622 623 *min = wi::round_up_for_mask (*min, nonzero_bits); 624 gcc_checking_assert (wi::le_p (*min, *max, sgn)); 625 } 626 return vr_type; 627 } 628 629 630 /* Set value range to the canonical form of {VRTYPE, MIN, MAX, EQUIV}. 631 This means adjusting VRTYPE, MIN and MAX representing the case of a 632 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX] 633 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges. 634 In corner cases where MAX+1 or MIN-1 wraps this will fall back 635 to varying. 636 This routine exists to ease canonicalization in the case where we 637 extract ranges from var + CST op limit. */ 638 639 void 640 value_range_base::set_and_canonicalize (enum value_range_kind kind, 641 tree min, tree max) 642 { 643 /* Use the canonical setters for VR_UNDEFINED and VR_VARYING. */ 644 if (kind == VR_UNDEFINED) 645 { 646 set_undefined (); 647 return; 648 } 649 else if (kind == VR_VARYING) 650 { 651 set_varying (); 652 return; 653 } 654 655 /* Nothing to canonicalize for symbolic ranges. */ 656 if (TREE_CODE (min) != INTEGER_CST 657 || TREE_CODE (max) != INTEGER_CST) 658 { 659 set (kind, min, max); 660 return; 661 } 662 663 /* Wrong order for min and max, to swap them and the VR type we need 664 to adjust them. */ 665 if (tree_int_cst_lt (max, min)) 666 { 667 tree one, tmp; 668 669 /* For one bit precision if max < min, then the swapped 670 range covers all values, so for VR_RANGE it is varying and 671 for VR_ANTI_RANGE empty range, so drop to varying as well. */ 672 if (TYPE_PRECISION (TREE_TYPE (min)) == 1) 673 { 674 set_varying (); 675 return; 676 } 677 678 one = build_int_cst (TREE_TYPE (min), 1); 679 tmp = int_const_binop (PLUS_EXPR, max, one); 680 max = int_const_binop (MINUS_EXPR, min, one); 681 min = tmp; 682 683 /* There's one corner case, if we had [C+1, C] before we now have 684 that again. But this represents an empty value range, so drop 685 to varying in this case. */ 686 if (tree_int_cst_lt (max, min)) 687 { 688 set_varying (); 689 return; 690 } 691 692 kind = kind == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE; 693 } 694 695 /* Anti-ranges that can be represented as ranges should be so. */ 696 if (kind == VR_ANTI_RANGE) 697 { 698 /* For -fstrict-enums we may receive out-of-range ranges so consider 699 values < -INF and values > INF as -INF/INF as well. */ 700 tree type = TREE_TYPE (min); 701 bool is_min = (INTEGRAL_TYPE_P (type) 702 && tree_int_cst_compare (min, TYPE_MIN_VALUE (type)) <= 0); 703 bool is_max = (INTEGRAL_TYPE_P (type) 704 && tree_int_cst_compare (max, TYPE_MAX_VALUE (type)) >= 0); 705 706 if (is_min && is_max) 707 { 708 /* We cannot deal with empty ranges, drop to varying. 709 ??? This could be VR_UNDEFINED instead. */ 710 set_varying (); 711 return; 712 } 713 else if (TYPE_PRECISION (TREE_TYPE (min)) == 1 714 && (is_min || is_max)) 715 { 716 /* Non-empty boolean ranges can always be represented 717 as a singleton range. */ 718 if (is_min) 719 min = max = vrp_val_max (TREE_TYPE (min)); 720 else 721 min = max = vrp_val_min (TREE_TYPE (min)); 722 kind = VR_RANGE; 723 } 724 else if (is_min 725 /* As a special exception preserve non-null ranges. */ 726 && !(TYPE_UNSIGNED (TREE_TYPE (min)) 727 && integer_zerop (max))) 728 { 729 tree one = build_int_cst (TREE_TYPE (max), 1); 730 min = int_const_binop (PLUS_EXPR, max, one); 731 max = vrp_val_max (TREE_TYPE (max)); 732 kind = VR_RANGE; 733 } 734 else if (is_max) 735 { 736 tree one = build_int_cst (TREE_TYPE (min), 1); 737 max = int_const_binop (MINUS_EXPR, min, one); 738 min = vrp_val_min (TREE_TYPE (min)); 739 kind = VR_RANGE; 740 } 741 } 742 743 /* Do not drop [-INF(OVF), +INF(OVF)] to varying. (OVF) has to be sticky 744 to make sure VRP iteration terminates, otherwise we can get into 745 oscillations. */ 746 747 set (kind, min, max); 748 } 749 750 void 751 value_range::set_and_canonicalize (enum value_range_kind kind, 752 tree min, tree max, bitmap equiv) 753 { 754 value_range_base::set_and_canonicalize (kind, min, max); 755 if (this->kind () == VR_RANGE || this->kind () == VR_ANTI_RANGE) 756 set_equiv (equiv); 757 else 758 equiv_clear (); 759 } 760 761 void 762 value_range_base::set (tree val) 763 { 764 gcc_assert (TREE_CODE (val) == SSA_NAME || is_gimple_min_invariant (val)); 765 if (TREE_OVERFLOW_P (val)) 766 val = drop_tree_overflow (val); 767 set (VR_RANGE, val, val); 768 } 769 770 void 771 value_range::set (tree val) 772 { 773 gcc_assert (TREE_CODE (val) == SSA_NAME || is_gimple_min_invariant (val)); 774 if (TREE_OVERFLOW_P (val)) 775 val = drop_tree_overflow (val); 776 set (VR_RANGE, val, val, NULL); 777 } 778 779 /* Set value range VR to a non-NULL range of type TYPE. */ 780 781 void 782 value_range_base::set_nonnull (tree type) 783 { 784 tree zero = build_int_cst (type, 0); 785 set (VR_ANTI_RANGE, zero, zero); 786 } 787 788 void 789 value_range::set_nonnull (tree type) 790 { 791 tree zero = build_int_cst (type, 0); 792 set (VR_ANTI_RANGE, zero, zero, NULL); 793 } 794 795 /* Set value range VR to a NULL range of type TYPE. */ 796 797 void 798 value_range_base::set_null (tree type) 799 { 800 set (build_int_cst (type, 0)); 801 } 802 803 void 804 value_range::set_null (tree type) 805 { 806 set (build_int_cst (type, 0)); 807 } 808 809 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */ 810 811 bool 812 vrp_operand_equal_p (const_tree val1, const_tree val2) 813 { 814 if (val1 == val2) 815 return true; 816 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0)) 817 return false; 818 return true; 819 } 820 821 /* Return true, if the bitmaps B1 and B2 are equal. */ 822 823 bool 824 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2) 825 { 826 return (b1 == b2 827 || ((!b1 || bitmap_empty_p (b1)) 828 && (!b2 || bitmap_empty_p (b2))) 829 || (b1 && b2 830 && bitmap_equal_p (b1, b2))); 831 } 832 833 /* Return true if VR is [0, 0]. */ 834 835 static inline bool 836 range_is_null (const value_range_base *vr) 837 { 838 return vr->zero_p (); 839 } 840 841 static inline bool 842 range_is_nonnull (const value_range_base *vr) 843 { 844 return (vr->kind () == VR_ANTI_RANGE 845 && vr->min () == vr->max () 846 && integer_zerop (vr->min ())); 847 } 848 849 /* Return true if max and min of VR are INTEGER_CST. It's not necessary 850 a singleton. */ 851 852 bool 853 range_int_cst_p (const value_range_base *vr) 854 { 855 return (vr->kind () == VR_RANGE 856 && TREE_CODE (vr->min ()) == INTEGER_CST 857 && TREE_CODE (vr->max ()) == INTEGER_CST); 858 } 859 860 /* Return true if VR is a INTEGER_CST singleton. */ 861 862 bool 863 range_int_cst_singleton_p (const value_range_base *vr) 864 { 865 return (range_int_cst_p (vr) 866 && tree_int_cst_equal (vr->min (), vr->max ())); 867 } 868 869 /* Return the single symbol (an SSA_NAME) contained in T if any, or NULL_TREE 870 otherwise. We only handle additive operations and set NEG to true if the 871 symbol is negated and INV to the invariant part, if any. */ 872 873 tree 874 get_single_symbol (tree t, bool *neg, tree *inv) 875 { 876 bool neg_; 877 tree inv_; 878 879 *inv = NULL_TREE; 880 *neg = false; 881 882 if (TREE_CODE (t) == PLUS_EXPR 883 || TREE_CODE (t) == POINTER_PLUS_EXPR 884 || TREE_CODE (t) == MINUS_EXPR) 885 { 886 if (is_gimple_min_invariant (TREE_OPERAND (t, 0))) 887 { 888 neg_ = (TREE_CODE (t) == MINUS_EXPR); 889 inv_ = TREE_OPERAND (t, 0); 890 t = TREE_OPERAND (t, 1); 891 } 892 else if (is_gimple_min_invariant (TREE_OPERAND (t, 1))) 893 { 894 neg_ = false; 895 inv_ = TREE_OPERAND (t, 1); 896 t = TREE_OPERAND (t, 0); 897 } 898 else 899 return NULL_TREE; 900 } 901 else 902 { 903 neg_ = false; 904 inv_ = NULL_TREE; 905 } 906 907 if (TREE_CODE (t) == NEGATE_EXPR) 908 { 909 t = TREE_OPERAND (t, 0); 910 neg_ = !neg_; 911 } 912 913 if (TREE_CODE (t) != SSA_NAME) 914 return NULL_TREE; 915 916 if (inv_ && TREE_OVERFLOW_P (inv_)) 917 inv_ = drop_tree_overflow (inv_); 918 919 *neg = neg_; 920 *inv = inv_; 921 return t; 922 } 923 924 /* The reverse operation: build a symbolic expression with TYPE 925 from symbol SYM, negated according to NEG, and invariant INV. */ 926 927 static tree 928 build_symbolic_expr (tree type, tree sym, bool neg, tree inv) 929 { 930 const bool pointer_p = POINTER_TYPE_P (type); 931 tree t = sym; 932 933 if (neg) 934 t = build1 (NEGATE_EXPR, type, t); 935 936 if (integer_zerop (inv)) 937 return t; 938 939 return build2 (pointer_p ? POINTER_PLUS_EXPR : PLUS_EXPR, type, t, inv); 940 } 941 942 /* Return 943 1 if VAL < VAL2 944 0 if !(VAL < VAL2) 945 -2 if those are incomparable. */ 946 int 947 operand_less_p (tree val, tree val2) 948 { 949 /* LT is folded faster than GE and others. Inline the common case. */ 950 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST) 951 return tree_int_cst_lt (val, val2); 952 else 953 { 954 tree tcmp; 955 956 fold_defer_overflow_warnings (); 957 958 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2); 959 960 fold_undefer_and_ignore_overflow_warnings (); 961 962 if (!tcmp 963 || TREE_CODE (tcmp) != INTEGER_CST) 964 return -2; 965 966 if (!integer_zerop (tcmp)) 967 return 1; 968 } 969 970 return 0; 971 } 972 973 /* Compare two values VAL1 and VAL2. Return 974 975 -2 if VAL1 and VAL2 cannot be compared at compile-time, 976 -1 if VAL1 < VAL2, 977 0 if VAL1 == VAL2, 978 +1 if VAL1 > VAL2, and 979 +2 if VAL1 != VAL2 980 981 This is similar to tree_int_cst_compare but supports pointer values 982 and values that cannot be compared at compile time. 983 984 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to 985 true if the return value is only valid if we assume that signed 986 overflow is undefined. */ 987 988 int 989 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p) 990 { 991 if (val1 == val2) 992 return 0; 993 994 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or 995 both integers. */ 996 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1)) 997 == POINTER_TYPE_P (TREE_TYPE (val2))); 998 999 /* Convert the two values into the same type. This is needed because 1000 sizetype causes sign extension even for unsigned types. */ 1001 val2 = fold_convert (TREE_TYPE (val1), val2); 1002 STRIP_USELESS_TYPE_CONVERSION (val2); 1003 1004 const bool overflow_undefined 1005 = INTEGRAL_TYPE_P (TREE_TYPE (val1)) 1006 && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)); 1007 tree inv1, inv2; 1008 bool neg1, neg2; 1009 tree sym1 = get_single_symbol (val1, &neg1, &inv1); 1010 tree sym2 = get_single_symbol (val2, &neg2, &inv2); 1011 1012 /* If VAL1 and VAL2 are of the form '[-]NAME [+ CST]', return -1 or +1 1013 accordingly. If VAL1 and VAL2 don't use the same name, return -2. */ 1014 if (sym1 && sym2) 1015 { 1016 /* Both values must use the same name with the same sign. */ 1017 if (sym1 != sym2 || neg1 != neg2) 1018 return -2; 1019 1020 /* [-]NAME + CST == [-]NAME + CST. */ 1021 if (inv1 == inv2) 1022 return 0; 1023 1024 /* If overflow is defined we cannot simplify more. */ 1025 if (!overflow_undefined) 1026 return -2; 1027 1028 if (strict_overflow_p != NULL 1029 /* Symbolic range building sets TREE_NO_WARNING to declare 1030 that overflow doesn't happen. */ 1031 && (!inv1 || !TREE_NO_WARNING (val1)) 1032 && (!inv2 || !TREE_NO_WARNING (val2))) 1033 *strict_overflow_p = true; 1034 1035 if (!inv1) 1036 inv1 = build_int_cst (TREE_TYPE (val1), 0); 1037 if (!inv2) 1038 inv2 = build_int_cst (TREE_TYPE (val2), 0); 1039 1040 return wi::cmp (wi::to_wide (inv1), wi::to_wide (inv2), 1041 TYPE_SIGN (TREE_TYPE (val1))); 1042 } 1043 1044 const bool cst1 = is_gimple_min_invariant (val1); 1045 const bool cst2 = is_gimple_min_invariant (val2); 1046 1047 /* If one is of the form '[-]NAME + CST' and the other is constant, then 1048 it might be possible to say something depending on the constants. */ 1049 if ((sym1 && inv1 && cst2) || (sym2 && inv2 && cst1)) 1050 { 1051 if (!overflow_undefined) 1052 return -2; 1053 1054 if (strict_overflow_p != NULL 1055 /* Symbolic range building sets TREE_NO_WARNING to declare 1056 that overflow doesn't happen. */ 1057 && (!sym1 || !TREE_NO_WARNING (val1)) 1058 && (!sym2 || !TREE_NO_WARNING (val2))) 1059 *strict_overflow_p = true; 1060 1061 const signop sgn = TYPE_SIGN (TREE_TYPE (val1)); 1062 tree cst = cst1 ? val1 : val2; 1063 tree inv = cst1 ? inv2 : inv1; 1064 1065 /* Compute the difference between the constants. If it overflows or 1066 underflows, this means that we can trivially compare the NAME with 1067 it and, consequently, the two values with each other. */ 1068 wide_int diff = wi::to_wide (cst) - wi::to_wide (inv); 1069 if (wi::cmp (0, wi::to_wide (inv), sgn) 1070 != wi::cmp (diff, wi::to_wide (cst), sgn)) 1071 { 1072 const int res = wi::cmp (wi::to_wide (cst), wi::to_wide (inv), sgn); 1073 return cst1 ? res : -res; 1074 } 1075 1076 return -2; 1077 } 1078 1079 /* We cannot say anything more for non-constants. */ 1080 if (!cst1 || !cst2) 1081 return -2; 1082 1083 if (!POINTER_TYPE_P (TREE_TYPE (val1))) 1084 { 1085 /* We cannot compare overflowed values. */ 1086 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2)) 1087 return -2; 1088 1089 if (TREE_CODE (val1) == INTEGER_CST 1090 && TREE_CODE (val2) == INTEGER_CST) 1091 return tree_int_cst_compare (val1, val2); 1092 1093 if (poly_int_tree_p (val1) && poly_int_tree_p (val2)) 1094 { 1095 if (known_eq (wi::to_poly_widest (val1), 1096 wi::to_poly_widest (val2))) 1097 return 0; 1098 if (known_lt (wi::to_poly_widest (val1), 1099 wi::to_poly_widest (val2))) 1100 return -1; 1101 if (known_gt (wi::to_poly_widest (val1), 1102 wi::to_poly_widest (val2))) 1103 return 1; 1104 } 1105 1106 return -2; 1107 } 1108 else 1109 { 1110 tree t; 1111 1112 /* First see if VAL1 and VAL2 are not the same. */ 1113 if (val1 == val2 || operand_equal_p (val1, val2, 0)) 1114 return 0; 1115 1116 /* If VAL1 is a lower address than VAL2, return -1. */ 1117 if (operand_less_p (val1, val2) == 1) 1118 return -1; 1119 1120 /* If VAL1 is a higher address than VAL2, return +1. */ 1121 if (operand_less_p (val2, val1) == 1) 1122 return 1; 1123 1124 /* If VAL1 is different than VAL2, return +2. 1125 For integer constants we either have already returned -1 or 1 1126 or they are equivalent. We still might succeed in proving 1127 something about non-trivial operands. */ 1128 if (TREE_CODE (val1) != INTEGER_CST 1129 || TREE_CODE (val2) != INTEGER_CST) 1130 { 1131 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2); 1132 if (t && integer_onep (t)) 1133 return 2; 1134 } 1135 1136 return -2; 1137 } 1138 } 1139 1140 /* Compare values like compare_values_warnv. */ 1141 1142 int 1143 compare_values (tree val1, tree val2) 1144 { 1145 bool sop; 1146 return compare_values_warnv (val1, val2, &sop); 1147 } 1148 1149 1150 /* Return 1 if VAL is inside value range MIN <= VAL <= MAX, 1151 0 if VAL is not inside [MIN, MAX], 1152 -2 if we cannot tell either way. 1153 1154 Benchmark compile/20001226-1.c compilation time after changing this 1155 function. */ 1156 1157 int 1158 value_inside_range (tree val, tree min, tree max) 1159 { 1160 int cmp1, cmp2; 1161 1162 cmp1 = operand_less_p (val, min); 1163 if (cmp1 == -2) 1164 return -2; 1165 if (cmp1 == 1) 1166 return 0; 1167 1168 cmp2 = operand_less_p (max, val); 1169 if (cmp2 == -2) 1170 return -2; 1171 1172 return !cmp2; 1173 } 1174 1175 1176 /* Return TRUE if *VR includes the value X. */ 1177 1178 bool 1179 range_includes_p (const value_range_base *vr, HOST_WIDE_INT x) 1180 { 1181 if (vr->varying_p () || vr->undefined_p ()) 1182 return true; 1183 return vr->may_contain_p (build_int_cst (vr->type (), x)); 1184 } 1185 1186 /* If *VR has a value range that is a single constant value return that, 1187 otherwise return NULL_TREE. 1188 1189 ?? This actually returns TRUE for [&x, &x], so perhaps "constant" 1190 is not the best name. */ 1191 1192 tree 1193 value_range_constant_singleton (const value_range_base *vr) 1194 { 1195 tree result = NULL; 1196 if (vr->singleton_p (&result)) 1197 return result; 1198 return NULL; 1199 } 1200 1201 /* Value range wrapper for wide_int_range_set_zero_nonzero_bits. 1202 1203 Compute MAY_BE_NONZERO and MUST_BE_NONZERO bit masks for range in VR. 1204 1205 Return TRUE if VR was a constant range and we were able to compute 1206 the bit masks. */ 1207 1208 bool 1209 vrp_set_zero_nonzero_bits (const tree expr_type, 1210 const value_range_base *vr, 1211 wide_int *may_be_nonzero, 1212 wide_int *must_be_nonzero) 1213 { 1214 if (!range_int_cst_p (vr)) 1215 { 1216 *may_be_nonzero = wi::minus_one (TYPE_PRECISION (expr_type)); 1217 *must_be_nonzero = wi::zero (TYPE_PRECISION (expr_type)); 1218 return false; 1219 } 1220 wide_int_range_set_zero_nonzero_bits (TYPE_SIGN (expr_type), 1221 wi::to_wide (vr->min ()), 1222 wi::to_wide (vr->max ()), 1223 *may_be_nonzero, *must_be_nonzero); 1224 return true; 1225 } 1226 1227 /* Create two value-ranges in *VR0 and *VR1 from the anti-range *AR 1228 so that *VR0 U *VR1 == *AR. Returns true if that is possible, 1229 false otherwise. If *AR can be represented with a single range 1230 *VR1 will be VR_UNDEFINED. */ 1231 1232 static bool 1233 ranges_from_anti_range (const value_range_base *ar, 1234 value_range_base *vr0, value_range_base *vr1) 1235 { 1236 tree type = ar->type (); 1237 1238 vr0->set_undefined (); 1239 vr1->set_undefined (); 1240 1241 /* As a future improvement, we could handle ~[0, A] as: [-INF, -1] U 1242 [A+1, +INF]. Not sure if this helps in practice, though. */ 1243 1244 if (ar->kind () != VR_ANTI_RANGE 1245 || TREE_CODE (ar->min ()) != INTEGER_CST 1246 || TREE_CODE (ar->max ()) != INTEGER_CST 1247 || !vrp_val_min (type) 1248 || !vrp_val_max (type)) 1249 return false; 1250 1251 if (tree_int_cst_lt (vrp_val_min (type), ar->min ())) 1252 vr0->set (VR_RANGE, 1253 vrp_val_min (type), 1254 wide_int_to_tree (type, wi::to_wide (ar->min ()) - 1)); 1255 if (tree_int_cst_lt (ar->max (), vrp_val_max (type))) 1256 vr1->set (VR_RANGE, 1257 wide_int_to_tree (type, wi::to_wide (ar->max ()) + 1), 1258 vrp_val_max (type)); 1259 if (vr0->undefined_p ()) 1260 { 1261 *vr0 = *vr1; 1262 vr1->set_undefined (); 1263 } 1264 1265 return !vr0->undefined_p (); 1266 } 1267 1268 /* Extract the components of a value range into a pair of wide ints in 1269 [WMIN, WMAX]. 1270 1271 If the value range is anything but a VR_*RANGE of constants, the 1272 resulting wide ints are set to [-MIN, +MAX] for the type. */ 1273 1274 static void inline 1275 extract_range_into_wide_ints (const value_range_base *vr, 1276 signop sign, unsigned prec, 1277 wide_int &wmin, wide_int &wmax) 1278 { 1279 gcc_assert (vr->kind () != VR_ANTI_RANGE || vr->symbolic_p ()); 1280 if (range_int_cst_p (vr)) 1281 { 1282 wmin = wi::to_wide (vr->min ()); 1283 wmax = wi::to_wide (vr->max ()); 1284 } 1285 else 1286 { 1287 wmin = wi::min_value (prec, sign); 1288 wmax = wi::max_value (prec, sign); 1289 } 1290 } 1291 1292 /* Value range wrapper for wide_int_range_multiplicative_op: 1293 1294 *VR = *VR0 .CODE. *VR1. */ 1295 1296 static void 1297 extract_range_from_multiplicative_op (value_range_base *vr, 1298 enum tree_code code, 1299 const value_range_base *vr0, 1300 const value_range_base *vr1) 1301 { 1302 gcc_assert (code == MULT_EXPR 1303 || code == TRUNC_DIV_EXPR 1304 || code == FLOOR_DIV_EXPR 1305 || code == CEIL_DIV_EXPR 1306 || code == EXACT_DIV_EXPR 1307 || code == ROUND_DIV_EXPR 1308 || code == RSHIFT_EXPR 1309 || code == LSHIFT_EXPR); 1310 gcc_assert (vr0->kind () == VR_RANGE 1311 && vr0->kind () == vr1->kind ()); 1312 1313 tree type = vr0->type (); 1314 wide_int res_lb, res_ub; 1315 wide_int vr0_lb = wi::to_wide (vr0->min ()); 1316 wide_int vr0_ub = wi::to_wide (vr0->max ()); 1317 wide_int vr1_lb = wi::to_wide (vr1->min ()); 1318 wide_int vr1_ub = wi::to_wide (vr1->max ()); 1319 bool overflow_undefined = TYPE_OVERFLOW_UNDEFINED (type); 1320 unsigned prec = TYPE_PRECISION (type); 1321 1322 if (wide_int_range_multiplicative_op (res_lb, res_ub, 1323 code, TYPE_SIGN (type), prec, 1324 vr0_lb, vr0_ub, vr1_lb, vr1_ub, 1325 overflow_undefined)) 1326 vr->set_and_canonicalize (VR_RANGE, 1327 wide_int_to_tree (type, res_lb), 1328 wide_int_to_tree (type, res_ub)); 1329 else 1330 vr->set_varying (); 1331 } 1332 1333 /* If BOUND will include a symbolic bound, adjust it accordingly, 1334 otherwise leave it as is. 1335 1336 CODE is the original operation that combined the bounds (PLUS_EXPR 1337 or MINUS_EXPR). 1338 1339 TYPE is the type of the original operation. 1340 1341 SYM_OPn is the symbolic for OPn if it has a symbolic. 1342 1343 NEG_OPn is TRUE if the OPn was negated. */ 1344 1345 static void 1346 adjust_symbolic_bound (tree &bound, enum tree_code code, tree type, 1347 tree sym_op0, tree sym_op1, 1348 bool neg_op0, bool neg_op1) 1349 { 1350 bool minus_p = (code == MINUS_EXPR); 1351 /* If the result bound is constant, we're done; otherwise, build the 1352 symbolic lower bound. */ 1353 if (sym_op0 == sym_op1) 1354 ; 1355 else if (sym_op0) 1356 bound = build_symbolic_expr (type, sym_op0, 1357 neg_op0, bound); 1358 else if (sym_op1) 1359 { 1360 /* We may not negate if that might introduce 1361 undefined overflow. */ 1362 if (!minus_p 1363 || neg_op1 1364 || TYPE_OVERFLOW_WRAPS (type)) 1365 bound = build_symbolic_expr (type, sym_op1, 1366 neg_op1 ^ minus_p, bound); 1367 else 1368 bound = NULL_TREE; 1369 } 1370 } 1371 1372 /* Combine OP1 and OP1, which are two parts of a bound, into one wide 1373 int bound according to CODE. CODE is the operation combining the 1374 bound (either a PLUS_EXPR or a MINUS_EXPR). 1375 1376 TYPE is the type of the combine operation. 1377 1378 WI is the wide int to store the result. 1379 1380 OVF is -1 if an underflow occurred, +1 if an overflow occurred or 0 1381 if over/underflow occurred. */ 1382 1383 static void 1384 combine_bound (enum tree_code code, wide_int &wi, wi::overflow_type &ovf, 1385 tree type, tree op0, tree op1) 1386 { 1387 bool minus_p = (code == MINUS_EXPR); 1388 const signop sgn = TYPE_SIGN (type); 1389 const unsigned int prec = TYPE_PRECISION (type); 1390 1391 /* Combine the bounds, if any. */ 1392 if (op0 && op1) 1393 { 1394 if (minus_p) 1395 wi = wi::sub (wi::to_wide (op0), wi::to_wide (op1), sgn, &ovf); 1396 else 1397 wi = wi::add (wi::to_wide (op0), wi::to_wide (op1), sgn, &ovf); 1398 } 1399 else if (op0) 1400 wi = wi::to_wide (op0); 1401 else if (op1) 1402 { 1403 if (minus_p) 1404 wi = wi::neg (wi::to_wide (op1), &ovf); 1405 else 1406 wi = wi::to_wide (op1); 1407 } 1408 else 1409 wi = wi::shwi (0, prec); 1410 } 1411 1412 /* Given a range in [WMIN, WMAX], adjust it for possible overflow and 1413 put the result in VR. 1414 1415 TYPE is the type of the range. 1416 1417 MIN_OVF and MAX_OVF indicate what type of overflow, if any, 1418 occurred while originally calculating WMIN or WMAX. -1 indicates 1419 underflow. +1 indicates overflow. 0 indicates neither. */ 1420 1421 static void 1422 set_value_range_with_overflow (value_range_kind &kind, tree &min, tree &max, 1423 tree type, 1424 const wide_int &wmin, const wide_int &wmax, 1425 wi::overflow_type min_ovf, 1426 wi::overflow_type max_ovf) 1427 { 1428 const signop sgn = TYPE_SIGN (type); 1429 const unsigned int prec = TYPE_PRECISION (type); 1430 1431 /* For one bit precision if max < min, then the swapped 1432 range covers all values. */ 1433 if (prec == 1 && wi::lt_p (wmax, wmin, sgn)) 1434 { 1435 kind = VR_VARYING; 1436 return; 1437 } 1438 1439 if (TYPE_OVERFLOW_WRAPS (type)) 1440 { 1441 /* If overflow wraps, truncate the values and adjust the 1442 range kind and bounds appropriately. */ 1443 wide_int tmin = wide_int::from (wmin, prec, sgn); 1444 wide_int tmax = wide_int::from (wmax, prec, sgn); 1445 if ((min_ovf != wi::OVF_NONE) == (max_ovf != wi::OVF_NONE)) 1446 { 1447 /* If the limits are swapped, we wrapped around and cover 1448 the entire range. We have a similar check at the end of 1449 extract_range_from_binary_expr. */ 1450 if (wi::gt_p (tmin, tmax, sgn)) 1451 kind = VR_VARYING; 1452 else 1453 { 1454 kind = VR_RANGE; 1455 /* No overflow or both overflow or underflow. The 1456 range kind stays VR_RANGE. */ 1457 min = wide_int_to_tree (type, tmin); 1458 max = wide_int_to_tree (type, tmax); 1459 } 1460 return; 1461 } 1462 else if ((min_ovf == wi::OVF_UNDERFLOW && max_ovf == wi::OVF_NONE) 1463 || (max_ovf == wi::OVF_OVERFLOW && min_ovf == wi::OVF_NONE)) 1464 { 1465 /* Min underflow or max overflow. The range kind 1466 changes to VR_ANTI_RANGE. */ 1467 bool covers = false; 1468 wide_int tem = tmin; 1469 tmin = tmax + 1; 1470 if (wi::cmp (tmin, tmax, sgn) < 0) 1471 covers = true; 1472 tmax = tem - 1; 1473 if (wi::cmp (tmax, tem, sgn) > 0) 1474 covers = true; 1475 /* If the anti-range would cover nothing, drop to varying. 1476 Likewise if the anti-range bounds are outside of the 1477 types values. */ 1478 if (covers || wi::cmp (tmin, tmax, sgn) > 0) 1479 { 1480 kind = VR_VARYING; 1481 return; 1482 } 1483 kind = VR_ANTI_RANGE; 1484 min = wide_int_to_tree (type, tmin); 1485 max = wide_int_to_tree (type, tmax); 1486 return; 1487 } 1488 else 1489 { 1490 /* Other underflow and/or overflow, drop to VR_VARYING. */ 1491 kind = VR_VARYING; 1492 return; 1493 } 1494 } 1495 else 1496 { 1497 /* If overflow does not wrap, saturate to the types min/max 1498 value. */ 1499 wide_int type_min = wi::min_value (prec, sgn); 1500 wide_int type_max = wi::max_value (prec, sgn); 1501 kind = VR_RANGE; 1502 if (min_ovf == wi::OVF_UNDERFLOW) 1503 min = wide_int_to_tree (type, type_min); 1504 else if (min_ovf == wi::OVF_OVERFLOW) 1505 min = wide_int_to_tree (type, type_max); 1506 else 1507 min = wide_int_to_tree (type, wmin); 1508 1509 if (max_ovf == wi::OVF_UNDERFLOW) 1510 max = wide_int_to_tree (type, type_min); 1511 else if (max_ovf == wi::OVF_OVERFLOW) 1512 max = wide_int_to_tree (type, type_max); 1513 else 1514 max = wide_int_to_tree (type, wmax); 1515 } 1516 } 1517 1518 /* Extract range information from a binary operation CODE based on 1519 the ranges of each of its operands *VR0 and *VR1 with resulting 1520 type EXPR_TYPE. The resulting range is stored in *VR. */ 1521 1522 void 1523 extract_range_from_binary_expr (value_range_base *vr, 1524 enum tree_code code, tree expr_type, 1525 const value_range_base *vr0_, 1526 const value_range_base *vr1_) 1527 { 1528 signop sign = TYPE_SIGN (expr_type); 1529 unsigned int prec = TYPE_PRECISION (expr_type); 1530 value_range_base vr0 = *vr0_, vr1 = *vr1_; 1531 value_range_base vrtem0, vrtem1; 1532 enum value_range_kind type; 1533 tree min = NULL_TREE, max = NULL_TREE; 1534 int cmp; 1535 1536 if (!INTEGRAL_TYPE_P (expr_type) 1537 && !POINTER_TYPE_P (expr_type)) 1538 { 1539 vr->set_varying (); 1540 return; 1541 } 1542 1543 /* Not all binary expressions can be applied to ranges in a 1544 meaningful way. Handle only arithmetic operations. */ 1545 if (code != PLUS_EXPR 1546 && code != MINUS_EXPR 1547 && code != POINTER_PLUS_EXPR 1548 && code != MULT_EXPR 1549 && code != TRUNC_DIV_EXPR 1550 && code != FLOOR_DIV_EXPR 1551 && code != CEIL_DIV_EXPR 1552 && code != EXACT_DIV_EXPR 1553 && code != ROUND_DIV_EXPR 1554 && code != TRUNC_MOD_EXPR 1555 && code != RSHIFT_EXPR 1556 && code != LSHIFT_EXPR 1557 && code != MIN_EXPR 1558 && code != MAX_EXPR 1559 && code != BIT_AND_EXPR 1560 && code != BIT_IOR_EXPR 1561 && code != BIT_XOR_EXPR) 1562 { 1563 vr->set_varying (); 1564 return; 1565 } 1566 1567 /* If both ranges are UNDEFINED, so is the result. */ 1568 if (vr0.undefined_p () && vr1.undefined_p ()) 1569 { 1570 vr->set_undefined (); 1571 return; 1572 } 1573 /* If one of the ranges is UNDEFINED drop it to VARYING for the following 1574 code. At some point we may want to special-case operations that 1575 have UNDEFINED result for all or some value-ranges of the not UNDEFINED 1576 operand. */ 1577 else if (vr0.undefined_p ()) 1578 vr0.set_varying (); 1579 else if (vr1.undefined_p ()) 1580 vr1.set_varying (); 1581 1582 /* We get imprecise results from ranges_from_anti_range when 1583 code is EXACT_DIV_EXPR. We could mask out bits in the resulting 1584 range, but then we also need to hack up vrp_union. It's just 1585 easier to special case when vr0 is ~[0,0] for EXACT_DIV_EXPR. */ 1586 if (code == EXACT_DIV_EXPR && range_is_nonnull (&vr0)) 1587 { 1588 vr->set_nonnull (expr_type); 1589 return; 1590 } 1591 1592 /* Now canonicalize anti-ranges to ranges when they are not symbolic 1593 and express ~[] op X as ([]' op X) U ([]'' op X). */ 1594 if (vr0.kind () == VR_ANTI_RANGE 1595 && ranges_from_anti_range (&vr0, &vrtem0, &vrtem1)) 1596 { 1597 extract_range_from_binary_expr (vr, code, expr_type, &vrtem0, vr1_); 1598 if (!vrtem1.undefined_p ()) 1599 { 1600 value_range_base vrres; 1601 extract_range_from_binary_expr (&vrres, code, expr_type, 1602 &vrtem1, vr1_); 1603 vr->union_ (&vrres); 1604 } 1605 return; 1606 } 1607 /* Likewise for X op ~[]. */ 1608 if (vr1.kind () == VR_ANTI_RANGE 1609 && ranges_from_anti_range (&vr1, &vrtem0, &vrtem1)) 1610 { 1611 extract_range_from_binary_expr (vr, code, expr_type, vr0_, &vrtem0); 1612 if (!vrtem1.undefined_p ()) 1613 { 1614 value_range_base vrres; 1615 extract_range_from_binary_expr (&vrres, code, expr_type, 1616 vr0_, &vrtem1); 1617 vr->union_ (&vrres); 1618 } 1619 return; 1620 } 1621 1622 /* The type of the resulting value range defaults to VR0.TYPE. */ 1623 type = vr0.kind (); 1624 1625 /* Refuse to operate on VARYING ranges, ranges of different kinds 1626 and symbolic ranges. As an exception, we allow BIT_{AND,IOR} 1627 because we may be able to derive a useful range even if one of 1628 the operands is VR_VARYING or symbolic range. Similarly for 1629 divisions, MIN/MAX and PLUS/MINUS. 1630 1631 TODO, we may be able to derive anti-ranges in some cases. */ 1632 if (code != BIT_AND_EXPR 1633 && code != BIT_IOR_EXPR 1634 && code != TRUNC_DIV_EXPR 1635 && code != FLOOR_DIV_EXPR 1636 && code != CEIL_DIV_EXPR 1637 && code != EXACT_DIV_EXPR 1638 && code != ROUND_DIV_EXPR 1639 && code != TRUNC_MOD_EXPR 1640 && code != MIN_EXPR 1641 && code != MAX_EXPR 1642 && code != PLUS_EXPR 1643 && code != MINUS_EXPR 1644 && code != RSHIFT_EXPR 1645 && code != POINTER_PLUS_EXPR 1646 && (vr0.varying_p () 1647 || vr1.varying_p () 1648 || vr0.kind () != vr1.kind () 1649 || vr0.symbolic_p () 1650 || vr1.symbolic_p ())) 1651 { 1652 vr->set_varying (); 1653 return; 1654 } 1655 1656 /* Now evaluate the expression to determine the new range. */ 1657 if (POINTER_TYPE_P (expr_type)) 1658 { 1659 if (code == MIN_EXPR || code == MAX_EXPR) 1660 { 1661 /* For MIN/MAX expressions with pointers, we only care about 1662 nullness, if both are non null, then the result is nonnull. 1663 If both are null, then the result is null. Otherwise they 1664 are varying. */ 1665 if (!range_includes_zero_p (&vr0) && !range_includes_zero_p (&vr1)) 1666 vr->set_nonnull (expr_type); 1667 else if (range_is_null (&vr0) && range_is_null (&vr1)) 1668 vr->set_null (expr_type); 1669 else 1670 vr->set_varying (); 1671 } 1672 else if (code == POINTER_PLUS_EXPR) 1673 { 1674 /* For pointer types, we are really only interested in asserting 1675 whether the expression evaluates to non-NULL. 1676 With -fno-delete-null-pointer-checks we need to be more 1677 conservative. As some object might reside at address 0, 1678 then some offset could be added to it and the same offset 1679 subtracted again and the result would be NULL. 1680 E.g. 1681 static int a[12]; where &a[0] is NULL and 1682 ptr = &a[6]; 1683 ptr -= 6; 1684 ptr will be NULL here, even when there is POINTER_PLUS_EXPR 1685 where the first range doesn't include zero and the second one 1686 doesn't either. As the second operand is sizetype (unsigned), 1687 consider all ranges where the MSB could be set as possible 1688 subtractions where the result might be NULL. */ 1689 if ((!range_includes_zero_p (&vr0) 1690 || !range_includes_zero_p (&vr1)) 1691 && !TYPE_OVERFLOW_WRAPS (expr_type) 1692 && (flag_delete_null_pointer_checks 1693 || (range_int_cst_p (&vr1) 1694 && !tree_int_cst_sign_bit (vr1.max ())))) 1695 vr->set_nonnull (expr_type); 1696 else if (range_is_null (&vr0) && range_is_null (&vr1)) 1697 vr->set_null (expr_type); 1698 else 1699 vr->set_varying (); 1700 } 1701 else if (code == BIT_AND_EXPR) 1702 { 1703 /* For pointer types, we are really only interested in asserting 1704 whether the expression evaluates to non-NULL. */ 1705 if (range_is_null (&vr0) || range_is_null (&vr1)) 1706 vr->set_null (expr_type); 1707 else 1708 vr->set_varying (); 1709 } 1710 else 1711 vr->set_varying (); 1712 1713 return; 1714 } 1715 1716 /* For integer ranges, apply the operation to each end of the 1717 range and see what we end up with. */ 1718 if (code == PLUS_EXPR || code == MINUS_EXPR) 1719 { 1720 /* This will normalize things such that calculating 1721 [0,0] - VR_VARYING is not dropped to varying, but is 1722 calculated as [MIN+1, MAX]. */ 1723 if (vr0.varying_p ()) 1724 vr0.set (VR_RANGE, vrp_val_min (expr_type), vrp_val_max (expr_type)); 1725 if (vr1.varying_p ()) 1726 vr1.set (VR_RANGE, vrp_val_min (expr_type), vrp_val_max (expr_type)); 1727 1728 const bool minus_p = (code == MINUS_EXPR); 1729 tree min_op0 = vr0.min (); 1730 tree min_op1 = minus_p ? vr1.max () : vr1.min (); 1731 tree max_op0 = vr0.max (); 1732 tree max_op1 = minus_p ? vr1.min () : vr1.max (); 1733 tree sym_min_op0 = NULL_TREE; 1734 tree sym_min_op1 = NULL_TREE; 1735 tree sym_max_op0 = NULL_TREE; 1736 tree sym_max_op1 = NULL_TREE; 1737 bool neg_min_op0, neg_min_op1, neg_max_op0, neg_max_op1; 1738 1739 neg_min_op0 = neg_min_op1 = neg_max_op0 = neg_max_op1 = false; 1740 1741 /* If we have a PLUS or MINUS with two VR_RANGEs, either constant or 1742 single-symbolic ranges, try to compute the precise resulting range, 1743 but only if we know that this resulting range will also be constant 1744 or single-symbolic. */ 1745 if (vr0.kind () == VR_RANGE && vr1.kind () == VR_RANGE 1746 && (TREE_CODE (min_op0) == INTEGER_CST 1747 || (sym_min_op0 1748 = get_single_symbol (min_op0, &neg_min_op0, &min_op0))) 1749 && (TREE_CODE (min_op1) == INTEGER_CST 1750 || (sym_min_op1 1751 = get_single_symbol (min_op1, &neg_min_op1, &min_op1))) 1752 && (!(sym_min_op0 && sym_min_op1) 1753 || (sym_min_op0 == sym_min_op1 1754 && neg_min_op0 == (minus_p ? neg_min_op1 : !neg_min_op1))) 1755 && (TREE_CODE (max_op0) == INTEGER_CST 1756 || (sym_max_op0 1757 = get_single_symbol (max_op0, &neg_max_op0, &max_op0))) 1758 && (TREE_CODE (max_op1) == INTEGER_CST 1759 || (sym_max_op1 1760 = get_single_symbol (max_op1, &neg_max_op1, &max_op1))) 1761 && (!(sym_max_op0 && sym_max_op1) 1762 || (sym_max_op0 == sym_max_op1 1763 && neg_max_op0 == (minus_p ? neg_max_op1 : !neg_max_op1)))) 1764 { 1765 wide_int wmin, wmax; 1766 wi::overflow_type min_ovf = wi::OVF_NONE; 1767 wi::overflow_type max_ovf = wi::OVF_NONE; 1768 1769 /* Build the bounds. */ 1770 combine_bound (code, wmin, min_ovf, expr_type, min_op0, min_op1); 1771 combine_bound (code, wmax, max_ovf, expr_type, max_op0, max_op1); 1772 1773 /* If the resulting range will be symbolic, we need to eliminate any 1774 explicit or implicit overflow introduced in the above computation 1775 because compare_values could make an incorrect use of it. That's 1776 why we require one of the ranges to be a singleton. */ 1777 if ((sym_min_op0 != sym_min_op1 || sym_max_op0 != sym_max_op1) 1778 && ((bool)min_ovf || (bool)max_ovf 1779 || (min_op0 != max_op0 && min_op1 != max_op1))) 1780 { 1781 vr->set_varying (); 1782 return; 1783 } 1784 1785 /* Adjust the range for possible overflow. */ 1786 set_value_range_with_overflow (type, min, max, expr_type, 1787 wmin, wmax, min_ovf, max_ovf); 1788 if (type == VR_VARYING) 1789 { 1790 vr->set_varying (); 1791 return; 1792 } 1793 1794 /* Build the symbolic bounds if needed. */ 1795 adjust_symbolic_bound (min, code, expr_type, 1796 sym_min_op0, sym_min_op1, 1797 neg_min_op0, neg_min_op1); 1798 adjust_symbolic_bound (max, code, expr_type, 1799 sym_max_op0, sym_max_op1, 1800 neg_max_op0, neg_max_op1); 1801 } 1802 else 1803 { 1804 /* For other cases, for example if we have a PLUS_EXPR with two 1805 VR_ANTI_RANGEs, drop to VR_VARYING. It would take more effort 1806 to compute a precise range for such a case. 1807 ??? General even mixed range kind operations can be expressed 1808 by for example transforming ~[3, 5] + [1, 2] to range-only 1809 operations and a union primitive: 1810 [-INF, 2] + [1, 2] U [5, +INF] + [1, 2] 1811 [-INF+1, 4] U [6, +INF(OVF)] 1812 though usually the union is not exactly representable with 1813 a single range or anti-range as the above is 1814 [-INF+1, +INF(OVF)] intersected with ~[5, 5] 1815 but one could use a scheme similar to equivalences for this. */ 1816 vr->set_varying (); 1817 return; 1818 } 1819 } 1820 else if (code == MIN_EXPR 1821 || code == MAX_EXPR) 1822 { 1823 wide_int wmin, wmax; 1824 wide_int vr0_min, vr0_max; 1825 wide_int vr1_min, vr1_max; 1826 extract_range_into_wide_ints (&vr0, sign, prec, vr0_min, vr0_max); 1827 extract_range_into_wide_ints (&vr1, sign, prec, vr1_min, vr1_max); 1828 if (wide_int_range_min_max (wmin, wmax, code, sign, prec, 1829 vr0_min, vr0_max, vr1_min, vr1_max)) 1830 vr->set (VR_RANGE, wide_int_to_tree (expr_type, wmin), 1831 wide_int_to_tree (expr_type, wmax)); 1832 else 1833 vr->set_varying (); 1834 return; 1835 } 1836 else if (code == MULT_EXPR) 1837 { 1838 if (!range_int_cst_p (&vr0) 1839 || !range_int_cst_p (&vr1)) 1840 { 1841 vr->set_varying (); 1842 return; 1843 } 1844 extract_range_from_multiplicative_op (vr, code, &vr0, &vr1); 1845 return; 1846 } 1847 else if (code == RSHIFT_EXPR 1848 || code == LSHIFT_EXPR) 1849 { 1850 if (range_int_cst_p (&vr1) 1851 && !wide_int_range_shift_undefined_p 1852 (TYPE_SIGN (TREE_TYPE (vr1.min ())), 1853 prec, 1854 wi::to_wide (vr1.min ()), 1855 wi::to_wide (vr1.max ()))) 1856 { 1857 if (code == RSHIFT_EXPR) 1858 { 1859 /* Even if vr0 is VARYING or otherwise not usable, we can derive 1860 useful ranges just from the shift count. E.g. 1861 x >> 63 for signed 64-bit x is always [-1, 0]. */ 1862 if (vr0.kind () != VR_RANGE || vr0.symbolic_p ()) 1863 vr0.set (VR_RANGE, vrp_val_min (expr_type), 1864 vrp_val_max (expr_type)); 1865 extract_range_from_multiplicative_op (vr, code, &vr0, &vr1); 1866 return; 1867 } 1868 else if (code == LSHIFT_EXPR 1869 && range_int_cst_p (&vr0)) 1870 { 1871 wide_int res_lb, res_ub; 1872 if (wide_int_range_lshift (res_lb, res_ub, sign, prec, 1873 wi::to_wide (vr0.min ()), 1874 wi::to_wide (vr0.max ()), 1875 wi::to_wide (vr1.min ()), 1876 wi::to_wide (vr1.max ()), 1877 TYPE_OVERFLOW_UNDEFINED (expr_type))) 1878 { 1879 min = wide_int_to_tree (expr_type, res_lb); 1880 max = wide_int_to_tree (expr_type, res_ub); 1881 vr->set_and_canonicalize (VR_RANGE, min, max); 1882 return; 1883 } 1884 } 1885 } 1886 vr->set_varying (); 1887 return; 1888 } 1889 else if (code == TRUNC_DIV_EXPR 1890 || code == FLOOR_DIV_EXPR 1891 || code == CEIL_DIV_EXPR 1892 || code == EXACT_DIV_EXPR 1893 || code == ROUND_DIV_EXPR) 1894 { 1895 wide_int dividend_min, dividend_max, divisor_min, divisor_max; 1896 wide_int wmin, wmax, extra_min, extra_max; 1897 bool extra_range_p; 1898 1899 /* Special case explicit division by zero as undefined. */ 1900 if (range_is_null (&vr1)) 1901 { 1902 vr->set_undefined (); 1903 return; 1904 } 1905 1906 /* First, normalize ranges into constants we can handle. Note 1907 that VR_ANTI_RANGE's of constants were already normalized 1908 before arriving here. 1909 1910 NOTE: As a future improvement, we may be able to do better 1911 with mixed symbolic (anti-)ranges like [0, A]. See note in 1912 ranges_from_anti_range. */ 1913 extract_range_into_wide_ints (&vr0, sign, prec, 1914 dividend_min, dividend_max); 1915 extract_range_into_wide_ints (&vr1, sign, prec, 1916 divisor_min, divisor_max); 1917 if (!wide_int_range_div (wmin, wmax, code, sign, prec, 1918 dividend_min, dividend_max, 1919 divisor_min, divisor_max, 1920 TYPE_OVERFLOW_UNDEFINED (expr_type), 1921 extra_range_p, extra_min, extra_max)) 1922 { 1923 vr->set_varying (); 1924 return; 1925 } 1926 vr->set (VR_RANGE, wide_int_to_tree (expr_type, wmin), 1927 wide_int_to_tree (expr_type, wmax)); 1928 if (extra_range_p) 1929 { 1930 value_range_base 1931 extra_range (VR_RANGE, wide_int_to_tree (expr_type, extra_min), 1932 wide_int_to_tree (expr_type, extra_max)); 1933 vr->union_ (&extra_range); 1934 } 1935 return; 1936 } 1937 else if (code == TRUNC_MOD_EXPR) 1938 { 1939 if (range_is_null (&vr1)) 1940 { 1941 vr->set_undefined (); 1942 return; 1943 } 1944 wide_int wmin, wmax, tmp; 1945 wide_int vr0_min, vr0_max, vr1_min, vr1_max; 1946 extract_range_into_wide_ints (&vr0, sign, prec, vr0_min, vr0_max); 1947 extract_range_into_wide_ints (&vr1, sign, prec, vr1_min, vr1_max); 1948 wide_int_range_trunc_mod (wmin, wmax, sign, prec, 1949 vr0_min, vr0_max, vr1_min, vr1_max); 1950 min = wide_int_to_tree (expr_type, wmin); 1951 max = wide_int_to_tree (expr_type, wmax); 1952 vr->set (VR_RANGE, min, max); 1953 return; 1954 } 1955 else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR) 1956 { 1957 wide_int may_be_nonzero0, may_be_nonzero1; 1958 wide_int must_be_nonzero0, must_be_nonzero1; 1959 wide_int wmin, wmax; 1960 wide_int vr0_min, vr0_max, vr1_min, vr1_max; 1961 vrp_set_zero_nonzero_bits (expr_type, &vr0, 1962 &may_be_nonzero0, &must_be_nonzero0); 1963 vrp_set_zero_nonzero_bits (expr_type, &vr1, 1964 &may_be_nonzero1, &must_be_nonzero1); 1965 extract_range_into_wide_ints (&vr0, sign, prec, vr0_min, vr0_max); 1966 extract_range_into_wide_ints (&vr1, sign, prec, vr1_min, vr1_max); 1967 if (code == BIT_AND_EXPR) 1968 { 1969 if (wide_int_range_bit_and (wmin, wmax, sign, prec, 1970 vr0_min, vr0_max, 1971 vr1_min, vr1_max, 1972 must_be_nonzero0, 1973 may_be_nonzero0, 1974 must_be_nonzero1, 1975 may_be_nonzero1)) 1976 { 1977 min = wide_int_to_tree (expr_type, wmin); 1978 max = wide_int_to_tree (expr_type, wmax); 1979 vr->set (VR_RANGE, min, max); 1980 } 1981 else 1982 vr->set_varying (); 1983 return; 1984 } 1985 else if (code == BIT_IOR_EXPR) 1986 { 1987 if (wide_int_range_bit_ior (wmin, wmax, sign, 1988 vr0_min, vr0_max, 1989 vr1_min, vr1_max, 1990 must_be_nonzero0, 1991 may_be_nonzero0, 1992 must_be_nonzero1, 1993 may_be_nonzero1)) 1994 { 1995 min = wide_int_to_tree (expr_type, wmin); 1996 max = wide_int_to_tree (expr_type, wmax); 1997 vr->set (VR_RANGE, min, max); 1998 } 1999 else 2000 vr->set_varying (); 2001 return; 2002 } 2003 else if (code == BIT_XOR_EXPR) 2004 { 2005 if (wide_int_range_bit_xor (wmin, wmax, sign, prec, 2006 must_be_nonzero0, 2007 may_be_nonzero0, 2008 must_be_nonzero1, 2009 may_be_nonzero1)) 2010 { 2011 min = wide_int_to_tree (expr_type, wmin); 2012 max = wide_int_to_tree (expr_type, wmax); 2013 vr->set (VR_RANGE, min, max); 2014 } 2015 else 2016 vr->set_varying (); 2017 return; 2018 } 2019 } 2020 else 2021 gcc_unreachable (); 2022 2023 /* If either MIN or MAX overflowed, then set the resulting range to 2024 VARYING. */ 2025 if (min == NULL_TREE 2026 || TREE_OVERFLOW_P (min) 2027 || max == NULL_TREE 2028 || TREE_OVERFLOW_P (max)) 2029 { 2030 vr->set_varying (); 2031 return; 2032 } 2033 2034 /* We punt for [-INF, +INF]. 2035 We learn nothing when we have INF on both sides. 2036 Note that we do accept [-INF, -INF] and [+INF, +INF]. */ 2037 if (vrp_val_is_min (min) && vrp_val_is_max (max)) 2038 { 2039 vr->set_varying (); 2040 return; 2041 } 2042 2043 cmp = compare_values (min, max); 2044 if (cmp == -2 || cmp == 1) 2045 { 2046 /* If the new range has its limits swapped around (MIN > MAX), 2047 then the operation caused one of them to wrap around, mark 2048 the new range VARYING. */ 2049 vr->set_varying (); 2050 } 2051 else 2052 vr->set (type, min, max); 2053 } 2054 2055 /* Extract range information from a unary operation CODE based on 2056 the range of its operand *VR0 with type OP0_TYPE with resulting type TYPE. 2057 The resulting range is stored in *VR. */ 2058 2059 void 2060 extract_range_from_unary_expr (value_range_base *vr, 2061 enum tree_code code, tree type, 2062 const value_range_base *vr0_, tree op0_type) 2063 { 2064 signop sign = TYPE_SIGN (type); 2065 unsigned int prec = TYPE_PRECISION (type); 2066 value_range_base vr0 = *vr0_; 2067 value_range_base vrtem0, vrtem1; 2068 2069 /* VRP only operates on integral and pointer types. */ 2070 if (!(INTEGRAL_TYPE_P (op0_type) 2071 || POINTER_TYPE_P (op0_type)) 2072 || !(INTEGRAL_TYPE_P (type) 2073 || POINTER_TYPE_P (type))) 2074 { 2075 vr->set_varying (); 2076 return; 2077 } 2078 2079 /* If VR0 is UNDEFINED, so is the result. */ 2080 if (vr0.undefined_p ()) 2081 { 2082 vr->set_undefined (); 2083 return; 2084 } 2085 2086 /* Handle operations that we express in terms of others. */ 2087 if (code == PAREN_EXPR) 2088 { 2089 /* PAREN_EXPR and OBJ_TYPE_REF are simple copies. */ 2090 *vr = vr0; 2091 return; 2092 } 2093 else if (code == NEGATE_EXPR) 2094 { 2095 /* -X is simply 0 - X, so re-use existing code that also handles 2096 anti-ranges fine. */ 2097 value_range_base zero; 2098 zero.set (build_int_cst (type, 0)); 2099 extract_range_from_binary_expr (vr, MINUS_EXPR, type, &zero, &vr0); 2100 return; 2101 } 2102 else if (code == BIT_NOT_EXPR) 2103 { 2104 /* ~X is simply -1 - X, so re-use existing code that also handles 2105 anti-ranges fine. */ 2106 value_range_base minusone; 2107 minusone.set (build_int_cst (type, -1)); 2108 extract_range_from_binary_expr (vr, MINUS_EXPR, type, &minusone, &vr0); 2109 return; 2110 } 2111 2112 /* Now canonicalize anti-ranges to ranges when they are not symbolic 2113 and express op ~[] as (op []') U (op []''). */ 2114 if (vr0.kind () == VR_ANTI_RANGE 2115 && ranges_from_anti_range (&vr0, &vrtem0, &vrtem1)) 2116 { 2117 extract_range_from_unary_expr (vr, code, type, &vrtem0, op0_type); 2118 if (!vrtem1.undefined_p ()) 2119 { 2120 value_range_base vrres; 2121 extract_range_from_unary_expr (&vrres, code, type, 2122 &vrtem1, op0_type); 2123 vr->union_ (&vrres); 2124 } 2125 return; 2126 } 2127 2128 if (CONVERT_EXPR_CODE_P (code)) 2129 { 2130 tree inner_type = op0_type; 2131 tree outer_type = type; 2132 2133 /* If the expression involves a pointer, we are only interested in 2134 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). 2135 2136 This may lose precision when converting (char *)~[0,2] to 2137 int, because we'll forget that the pointer can also not be 1 2138 or 2. In practice we don't care, as this is some idiot 2139 storing a magic constant to a pointer. */ 2140 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (op0_type)) 2141 { 2142 if (!range_includes_zero_p (&vr0)) 2143 vr->set_nonnull (type); 2144 else if (range_is_null (&vr0)) 2145 vr->set_null (type); 2146 else 2147 vr->set_varying (); 2148 return; 2149 } 2150 2151 /* The POINTER_TYPE_P code above will have dealt with all 2152 pointer anti-ranges. Any remaining anti-ranges at this point 2153 will be integer conversions from SSA names that will be 2154 normalized into VARYING. For instance: ~[x_55, x_55]. */ 2155 gcc_assert (vr0.kind () != VR_ANTI_RANGE 2156 || TREE_CODE (vr0.min ()) != INTEGER_CST); 2157 2158 /* NOTES: Previously we were returning VARYING for all symbolics, but 2159 we can do better by treating them as [-MIN, +MAX]. For 2160 example, converting [SYM, SYM] from INT to LONG UNSIGNED, 2161 we can return: ~[0x8000000, 0xffffffff7fffffff]. 2162 2163 We were also failing to convert ~[0,0] from char* to unsigned, 2164 instead choosing to return VR_VARYING. Now we return ~[0,0]. */ 2165 wide_int vr0_min, vr0_max, wmin, wmax; 2166 signop inner_sign = TYPE_SIGN (inner_type); 2167 signop outer_sign = TYPE_SIGN (outer_type); 2168 unsigned inner_prec = TYPE_PRECISION (inner_type); 2169 unsigned outer_prec = TYPE_PRECISION (outer_type); 2170 extract_range_into_wide_ints (&vr0, inner_sign, inner_prec, 2171 vr0_min, vr0_max); 2172 if (wide_int_range_convert (wmin, wmax, 2173 inner_sign, inner_prec, 2174 outer_sign, outer_prec, 2175 vr0_min, vr0_max)) 2176 { 2177 tree min = wide_int_to_tree (outer_type, wmin); 2178 tree max = wide_int_to_tree (outer_type, wmax); 2179 vr->set_and_canonicalize (VR_RANGE, min, max); 2180 } 2181 else 2182 vr->set_varying (); 2183 return; 2184 } 2185 else if (code == ABS_EXPR) 2186 { 2187 wide_int wmin, wmax; 2188 wide_int vr0_min, vr0_max; 2189 extract_range_into_wide_ints (&vr0, sign, prec, vr0_min, vr0_max); 2190 if (wide_int_range_abs (wmin, wmax, sign, prec, vr0_min, vr0_max, 2191 TYPE_OVERFLOW_UNDEFINED (type))) 2192 vr->set (VR_RANGE, wide_int_to_tree (type, wmin), 2193 wide_int_to_tree (type, wmax)); 2194 else 2195 vr->set_varying (); 2196 return; 2197 } 2198 else if (code == ABSU_EXPR) 2199 { 2200 wide_int wmin, wmax; 2201 wide_int vr0_min, vr0_max; 2202 extract_range_into_wide_ints (&vr0, SIGNED, prec, vr0_min, vr0_max); 2203 wide_int_range_absu (wmin, wmax, prec, vr0_min, vr0_max); 2204 vr->set (VR_RANGE, wide_int_to_tree (type, wmin), 2205 wide_int_to_tree (type, wmax)); 2206 return; 2207 } 2208 2209 /* For unhandled operations fall back to varying. */ 2210 vr->set_varying (); 2211 return; 2212 } 2213 2214 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V, 2215 create a new SSA name N and return the assertion assignment 2216 'N = ASSERT_EXPR <V, V OP W>'. */ 2217 2218 static gimple * 2219 build_assert_expr_for (tree cond, tree v) 2220 { 2221 tree a; 2222 gassign *assertion; 2223 2224 gcc_assert (TREE_CODE (v) == SSA_NAME 2225 && COMPARISON_CLASS_P (cond)); 2226 2227 a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond); 2228 assertion = gimple_build_assign (NULL_TREE, a); 2229 2230 /* The new ASSERT_EXPR, creates a new SSA name that replaces the 2231 operand of the ASSERT_EXPR. Create it so the new name and the old one 2232 are registered in the replacement table so that we can fix the SSA web 2233 after adding all the ASSERT_EXPRs. */ 2234 tree new_def = create_new_def_for (v, assertion, NULL); 2235 /* Make sure we preserve abnormalness throughout an ASSERT_EXPR chain 2236 given we have to be able to fully propagate those out to re-create 2237 valid SSA when removing the asserts. */ 2238 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (v)) 2239 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_def) = 1; 2240 2241 return assertion; 2242 } 2243 2244 2245 /* Return false if EXPR is a predicate expression involving floating 2246 point values. */ 2247 2248 static inline bool 2249 fp_predicate (gimple *stmt) 2250 { 2251 GIMPLE_CHECK (stmt, GIMPLE_COND); 2252 2253 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt))); 2254 } 2255 2256 /* If the range of values taken by OP can be inferred after STMT executes, 2257 return the comparison code (COMP_CODE_P) and value (VAL_P) that 2258 describes the inferred range. Return true if a range could be 2259 inferred. */ 2260 2261 bool 2262 infer_value_range (gimple *stmt, tree op, tree_code *comp_code_p, tree *val_p) 2263 { 2264 *val_p = NULL_TREE; 2265 *comp_code_p = ERROR_MARK; 2266 2267 /* Do not attempt to infer anything in names that flow through 2268 abnormal edges. */ 2269 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op)) 2270 return false; 2271 2272 /* If STMT is the last statement of a basic block with no normal 2273 successors, there is no point inferring anything about any of its 2274 operands. We would not be able to find a proper insertion point 2275 for the assertion, anyway. */ 2276 if (stmt_ends_bb_p (stmt)) 2277 { 2278 edge_iterator ei; 2279 edge e; 2280 2281 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs) 2282 if (!(e->flags & (EDGE_ABNORMAL|EDGE_EH))) 2283 break; 2284 if (e == NULL) 2285 return false; 2286 } 2287 2288 if (infer_nonnull_range (stmt, op)) 2289 { 2290 *val_p = build_int_cst (TREE_TYPE (op), 0); 2291 *comp_code_p = NE_EXPR; 2292 return true; 2293 } 2294 2295 return false; 2296 } 2297 2298 2299 void dump_asserts_for (FILE *, tree); 2300 void debug_asserts_for (tree); 2301 void dump_all_asserts (FILE *); 2302 void debug_all_asserts (void); 2303 2304 /* Dump all the registered assertions for NAME to FILE. */ 2305 2306 void 2307 dump_asserts_for (FILE *file, tree name) 2308 { 2309 assert_locus *loc; 2310 2311 fprintf (file, "Assertions to be inserted for "); 2312 print_generic_expr (file, name); 2313 fprintf (file, "\n"); 2314 2315 loc = asserts_for[SSA_NAME_VERSION (name)]; 2316 while (loc) 2317 { 2318 fprintf (file, "\t"); 2319 print_gimple_stmt (file, gsi_stmt (loc->si), 0); 2320 fprintf (file, "\n\tBB #%d", loc->bb->index); 2321 if (loc->e) 2322 { 2323 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index, 2324 loc->e->dest->index); 2325 dump_edge_info (file, loc->e, dump_flags, 0); 2326 } 2327 fprintf (file, "\n\tPREDICATE: "); 2328 print_generic_expr (file, loc->expr); 2329 fprintf (file, " %s ", get_tree_code_name (loc->comp_code)); 2330 print_generic_expr (file, loc->val); 2331 fprintf (file, "\n\n"); 2332 loc = loc->next; 2333 } 2334 2335 fprintf (file, "\n"); 2336 } 2337 2338 2339 /* Dump all the registered assertions for NAME to stderr. */ 2340 2341 DEBUG_FUNCTION void 2342 debug_asserts_for (tree name) 2343 { 2344 dump_asserts_for (stderr, name); 2345 } 2346 2347 2348 /* Dump all the registered assertions for all the names to FILE. */ 2349 2350 void 2351 dump_all_asserts (FILE *file) 2352 { 2353 unsigned i; 2354 bitmap_iterator bi; 2355 2356 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n"); 2357 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi) 2358 dump_asserts_for (file, ssa_name (i)); 2359 fprintf (file, "\n"); 2360 } 2361 2362 2363 /* Dump all the registered assertions for all the names to stderr. */ 2364 2365 DEBUG_FUNCTION void 2366 debug_all_asserts (void) 2367 { 2368 dump_all_asserts (stderr); 2369 } 2370 2371 /* Push the assert info for NAME, EXPR, COMP_CODE and VAL to ASSERTS. */ 2372 2373 static void 2374 add_assert_info (vec<assert_info> &asserts, 2375 tree name, tree expr, enum tree_code comp_code, tree val) 2376 { 2377 assert_info info; 2378 info.comp_code = comp_code; 2379 info.name = name; 2380 if (TREE_OVERFLOW_P (val)) 2381 val = drop_tree_overflow (val); 2382 info.val = val; 2383 info.expr = expr; 2384 asserts.safe_push (info); 2385 if (dump_enabled_p ()) 2386 dump_printf (MSG_NOTE | MSG_PRIORITY_INTERNALS, 2387 "Adding assert for %T from %T %s %T\n", 2388 name, expr, op_symbol_code (comp_code), val); 2389 } 2390 2391 /* If NAME doesn't have an ASSERT_EXPR registered for asserting 2392 'EXPR COMP_CODE VAL' at a location that dominates block BB or 2393 E->DEST, then register this location as a possible insertion point 2394 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>. 2395 2396 BB, E and SI provide the exact insertion point for the new 2397 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted 2398 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on 2399 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E 2400 must not be NULL. */ 2401 2402 static void 2403 register_new_assert_for (tree name, tree expr, 2404 enum tree_code comp_code, 2405 tree val, 2406 basic_block bb, 2407 edge e, 2408 gimple_stmt_iterator si) 2409 { 2410 assert_locus *n, *loc, *last_loc; 2411 basic_block dest_bb; 2412 2413 gcc_checking_assert (bb == NULL || e == NULL); 2414 2415 if (e == NULL) 2416 gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND 2417 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH); 2418 2419 /* Never build an assert comparing against an integer constant with 2420 TREE_OVERFLOW set. This confuses our undefined overflow warning 2421 machinery. */ 2422 if (TREE_OVERFLOW_P (val)) 2423 val = drop_tree_overflow (val); 2424 2425 /* The new assertion A will be inserted at BB or E. We need to 2426 determine if the new location is dominated by a previously 2427 registered location for A. If we are doing an edge insertion, 2428 assume that A will be inserted at E->DEST. Note that this is not 2429 necessarily true. 2430 2431 If E is a critical edge, it will be split. But even if E is 2432 split, the new block will dominate the same set of blocks that 2433 E->DEST dominates. 2434 2435 The reverse, however, is not true, blocks dominated by E->DEST 2436 will not be dominated by the new block created to split E. So, 2437 if the insertion location is on a critical edge, we will not use 2438 the new location to move another assertion previously registered 2439 at a block dominated by E->DEST. */ 2440 dest_bb = (bb) ? bb : e->dest; 2441 2442 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and 2443 VAL at a block dominating DEST_BB, then we don't need to insert a new 2444 one. Similarly, if the same assertion already exists at a block 2445 dominated by DEST_BB and the new location is not on a critical 2446 edge, then update the existing location for the assertion (i.e., 2447 move the assertion up in the dominance tree). 2448 2449 Note, this is implemented as a simple linked list because there 2450 should not be more than a handful of assertions registered per 2451 name. If this becomes a performance problem, a table hashed by 2452 COMP_CODE and VAL could be implemented. */ 2453 loc = asserts_for[SSA_NAME_VERSION (name)]; 2454 last_loc = loc; 2455 while (loc) 2456 { 2457 if (loc->comp_code == comp_code 2458 && (loc->val == val 2459 || operand_equal_p (loc->val, val, 0)) 2460 && (loc->expr == expr 2461 || operand_equal_p (loc->expr, expr, 0))) 2462 { 2463 /* If E is not a critical edge and DEST_BB 2464 dominates the existing location for the assertion, move 2465 the assertion up in the dominance tree by updating its 2466 location information. */ 2467 if ((e == NULL || !EDGE_CRITICAL_P (e)) 2468 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb)) 2469 { 2470 loc->bb = dest_bb; 2471 loc->e = e; 2472 loc->si = si; 2473 return; 2474 } 2475 } 2476 2477 /* Update the last node of the list and move to the next one. */ 2478 last_loc = loc; 2479 loc = loc->next; 2480 } 2481 2482 /* If we didn't find an assertion already registered for 2483 NAME COMP_CODE VAL, add a new one at the end of the list of 2484 assertions associated with NAME. */ 2485 n = XNEW (struct assert_locus); 2486 n->bb = dest_bb; 2487 n->e = e; 2488 n->si = si; 2489 n->comp_code = comp_code; 2490 n->val = val; 2491 n->expr = expr; 2492 n->next = NULL; 2493 2494 if (last_loc) 2495 last_loc->next = n; 2496 else 2497 asserts_for[SSA_NAME_VERSION (name)] = n; 2498 2499 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name)); 2500 } 2501 2502 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME. 2503 Extract a suitable test code and value and store them into *CODE_P and 2504 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P. 2505 2506 If no extraction was possible, return FALSE, otherwise return TRUE. 2507 2508 If INVERT is true, then we invert the result stored into *CODE_P. */ 2509 2510 static bool 2511 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code, 2512 tree cond_op0, tree cond_op1, 2513 bool invert, enum tree_code *code_p, 2514 tree *val_p) 2515 { 2516 enum tree_code comp_code; 2517 tree val; 2518 2519 /* Otherwise, we have a comparison of the form NAME COMP VAL 2520 or VAL COMP NAME. */ 2521 if (name == cond_op1) 2522 { 2523 /* If the predicate is of the form VAL COMP NAME, flip 2524 COMP around because we need to register NAME as the 2525 first operand in the predicate. */ 2526 comp_code = swap_tree_comparison (cond_code); 2527 val = cond_op0; 2528 } 2529 else if (name == cond_op0) 2530 { 2531 /* The comparison is of the form NAME COMP VAL, so the 2532 comparison code remains unchanged. */ 2533 comp_code = cond_code; 2534 val = cond_op1; 2535 } 2536 else 2537 gcc_unreachable (); 2538 2539 /* Invert the comparison code as necessary. */ 2540 if (invert) 2541 comp_code = invert_tree_comparison (comp_code, 0); 2542 2543 /* VRP only handles integral and pointer types. */ 2544 if (! INTEGRAL_TYPE_P (TREE_TYPE (val)) 2545 && ! POINTER_TYPE_P (TREE_TYPE (val))) 2546 return false; 2547 2548 /* Do not register always-false predicates. 2549 FIXME: this works around a limitation in fold() when dealing with 2550 enumerations. Given 'enum { N1, N2 } x;', fold will not 2551 fold 'if (x > N2)' to 'if (0)'. */ 2552 if ((comp_code == GT_EXPR || comp_code == LT_EXPR) 2553 && INTEGRAL_TYPE_P (TREE_TYPE (val))) 2554 { 2555 tree min = TYPE_MIN_VALUE (TREE_TYPE (val)); 2556 tree max = TYPE_MAX_VALUE (TREE_TYPE (val)); 2557 2558 if (comp_code == GT_EXPR 2559 && (!max 2560 || compare_values (val, max) == 0)) 2561 return false; 2562 2563 if (comp_code == LT_EXPR 2564 && (!min 2565 || compare_values (val, min) == 0)) 2566 return false; 2567 } 2568 *code_p = comp_code; 2569 *val_p = val; 2570 return true; 2571 } 2572 2573 /* Find out smallest RES where RES > VAL && (RES & MASK) == RES, if any 2574 (otherwise return VAL). VAL and MASK must be zero-extended for 2575 precision PREC. If SGNBIT is non-zero, first xor VAL with SGNBIT 2576 (to transform signed values into unsigned) and at the end xor 2577 SGNBIT back. */ 2578 2579 static wide_int 2580 masked_increment (const wide_int &val_in, const wide_int &mask, 2581 const wide_int &sgnbit, unsigned int prec) 2582 { 2583 wide_int bit = wi::one (prec), res; 2584 unsigned int i; 2585 2586 wide_int val = val_in ^ sgnbit; 2587 for (i = 0; i < prec; i++, bit += bit) 2588 { 2589 res = mask; 2590 if ((res & bit) == 0) 2591 continue; 2592 res = bit - 1; 2593 res = wi::bit_and_not (val + bit, res); 2594 res &= mask; 2595 if (wi::gtu_p (res, val)) 2596 return res ^ sgnbit; 2597 } 2598 return val ^ sgnbit; 2599 } 2600 2601 /* Helper for overflow_comparison_p 2602 2603 OP0 CODE OP1 is a comparison. Examine the comparison and potentially 2604 OP1's defining statement to see if it ultimately has the form 2605 OP0 CODE (OP0 PLUS INTEGER_CST) 2606 2607 If so, return TRUE indicating this is an overflow test and store into 2608 *NEW_CST an updated constant that can be used in a narrowed range test. 2609 2610 REVERSED indicates if the comparison was originally: 2611 2612 OP1 CODE' OP0. 2613 2614 This affects how we build the updated constant. */ 2615 2616 static bool 2617 overflow_comparison_p_1 (enum tree_code code, tree op0, tree op1, 2618 bool follow_assert_exprs, bool reversed, tree *new_cst) 2619 { 2620 /* See if this is a relational operation between two SSA_NAMES with 2621 unsigned, overflow wrapping values. If so, check it more deeply. */ 2622 if ((code == LT_EXPR || code == LE_EXPR 2623 || code == GE_EXPR || code == GT_EXPR) 2624 && TREE_CODE (op0) == SSA_NAME 2625 && TREE_CODE (op1) == SSA_NAME 2626 && INTEGRAL_TYPE_P (TREE_TYPE (op0)) 2627 && TYPE_UNSIGNED (TREE_TYPE (op0)) 2628 && TYPE_OVERFLOW_WRAPS (TREE_TYPE (op0))) 2629 { 2630 gimple *op1_def = SSA_NAME_DEF_STMT (op1); 2631 2632 /* If requested, follow any ASSERT_EXPRs backwards for OP1. */ 2633 if (follow_assert_exprs) 2634 { 2635 while (gimple_assign_single_p (op1_def) 2636 && TREE_CODE (gimple_assign_rhs1 (op1_def)) == ASSERT_EXPR) 2637 { 2638 op1 = TREE_OPERAND (gimple_assign_rhs1 (op1_def), 0); 2639 if (TREE_CODE (op1) != SSA_NAME) 2640 break; 2641 op1_def = SSA_NAME_DEF_STMT (op1); 2642 } 2643 } 2644 2645 /* Now look at the defining statement of OP1 to see if it adds 2646 or subtracts a nonzero constant from another operand. */ 2647 if (op1_def 2648 && is_gimple_assign (op1_def) 2649 && gimple_assign_rhs_code (op1_def) == PLUS_EXPR 2650 && TREE_CODE (gimple_assign_rhs2 (op1_def)) == INTEGER_CST 2651 && !integer_zerop (gimple_assign_rhs2 (op1_def))) 2652 { 2653 tree target = gimple_assign_rhs1 (op1_def); 2654 2655 /* If requested, follow ASSERT_EXPRs backwards for op0 looking 2656 for one where TARGET appears on the RHS. */ 2657 if (follow_assert_exprs) 2658 { 2659 /* Now see if that "other operand" is op0, following the chain 2660 of ASSERT_EXPRs if necessary. */ 2661 gimple *op0_def = SSA_NAME_DEF_STMT (op0); 2662 while (op0 != target 2663 && gimple_assign_single_p (op0_def) 2664 && TREE_CODE (gimple_assign_rhs1 (op0_def)) == ASSERT_EXPR) 2665 { 2666 op0 = TREE_OPERAND (gimple_assign_rhs1 (op0_def), 0); 2667 if (TREE_CODE (op0) != SSA_NAME) 2668 break; 2669 op0_def = SSA_NAME_DEF_STMT (op0); 2670 } 2671 } 2672 2673 /* If we did not find our target SSA_NAME, then this is not 2674 an overflow test. */ 2675 if (op0 != target) 2676 return false; 2677 2678 tree type = TREE_TYPE (op0); 2679 wide_int max = wi::max_value (TYPE_PRECISION (type), UNSIGNED); 2680 tree inc = gimple_assign_rhs2 (op1_def); 2681 if (reversed) 2682 *new_cst = wide_int_to_tree (type, max + wi::to_wide (inc)); 2683 else 2684 *new_cst = wide_int_to_tree (type, max - wi::to_wide (inc)); 2685 return true; 2686 } 2687 } 2688 return false; 2689 } 2690 2691 /* OP0 CODE OP1 is a comparison. Examine the comparison and potentially 2692 OP1's defining statement to see if it ultimately has the form 2693 OP0 CODE (OP0 PLUS INTEGER_CST) 2694 2695 If so, return TRUE indicating this is an overflow test and store into 2696 *NEW_CST an updated constant that can be used in a narrowed range test. 2697 2698 These statements are left as-is in the IL to facilitate discovery of 2699 {ADD,SUB}_OVERFLOW sequences later in the optimizer pipeline. But 2700 the alternate range representation is often useful within VRP. */ 2701 2702 bool 2703 overflow_comparison_p (tree_code code, tree name, tree val, 2704 bool use_equiv_p, tree *new_cst) 2705 { 2706 if (overflow_comparison_p_1 (code, name, val, use_equiv_p, false, new_cst)) 2707 return true; 2708 return overflow_comparison_p_1 (swap_tree_comparison (code), val, name, 2709 use_equiv_p, true, new_cst); 2710 } 2711 2712 2713 /* Try to register an edge assertion for SSA name NAME on edge E for 2714 the condition COND contributing to the conditional jump pointed to by BSI. 2715 Invert the condition COND if INVERT is true. */ 2716 2717 static void 2718 register_edge_assert_for_2 (tree name, edge e, 2719 enum tree_code cond_code, 2720 tree cond_op0, tree cond_op1, bool invert, 2721 vec<assert_info> &asserts) 2722 { 2723 tree val; 2724 enum tree_code comp_code; 2725 2726 if (!extract_code_and_val_from_cond_with_ops (name, cond_code, 2727 cond_op0, 2728 cond_op1, 2729 invert, &comp_code, &val)) 2730 return; 2731 2732 /* Queue the assert. */ 2733 tree x; 2734 if (overflow_comparison_p (comp_code, name, val, false, &x)) 2735 { 2736 enum tree_code new_code = ((comp_code == GT_EXPR || comp_code == GE_EXPR) 2737 ? GT_EXPR : LE_EXPR); 2738 add_assert_info (asserts, name, name, new_code, x); 2739 } 2740 add_assert_info (asserts, name, name, comp_code, val); 2741 2742 /* In the case of NAME <= CST and NAME being defined as 2743 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2 2744 and NAME2 <= CST - CST2. We can do the same for NAME > CST. 2745 This catches range and anti-range tests. */ 2746 if ((comp_code == LE_EXPR 2747 || comp_code == GT_EXPR) 2748 && TREE_CODE (val) == INTEGER_CST 2749 && TYPE_UNSIGNED (TREE_TYPE (val))) 2750 { 2751 gimple *def_stmt = SSA_NAME_DEF_STMT (name); 2752 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE; 2753 2754 /* Extract CST2 from the (optional) addition. */ 2755 if (is_gimple_assign (def_stmt) 2756 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR) 2757 { 2758 name2 = gimple_assign_rhs1 (def_stmt); 2759 cst2 = gimple_assign_rhs2 (def_stmt); 2760 if (TREE_CODE (name2) == SSA_NAME 2761 && TREE_CODE (cst2) == INTEGER_CST) 2762 def_stmt = SSA_NAME_DEF_STMT (name2); 2763 } 2764 2765 /* Extract NAME2 from the (optional) sign-changing cast. */ 2766 if (gimple_assign_cast_p (def_stmt)) 2767 { 2768 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)) 2769 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt))) 2770 && (TYPE_PRECISION (gimple_expr_type (def_stmt)) 2771 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))) 2772 name3 = gimple_assign_rhs1 (def_stmt); 2773 } 2774 2775 /* If name3 is used later, create an ASSERT_EXPR for it. */ 2776 if (name3 != NULL_TREE 2777 && TREE_CODE (name3) == SSA_NAME 2778 && (cst2 == NULL_TREE 2779 || TREE_CODE (cst2) == INTEGER_CST) 2780 && INTEGRAL_TYPE_P (TREE_TYPE (name3))) 2781 { 2782 tree tmp; 2783 2784 /* Build an expression for the range test. */ 2785 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3); 2786 if (cst2 != NULL_TREE) 2787 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2); 2788 add_assert_info (asserts, name3, tmp, comp_code, val); 2789 } 2790 2791 /* If name2 is used later, create an ASSERT_EXPR for it. */ 2792 if (name2 != NULL_TREE 2793 && TREE_CODE (name2) == SSA_NAME 2794 && TREE_CODE (cst2) == INTEGER_CST 2795 && INTEGRAL_TYPE_P (TREE_TYPE (name2))) 2796 { 2797 tree tmp; 2798 2799 /* Build an expression for the range test. */ 2800 tmp = name2; 2801 if (TREE_TYPE (name) != TREE_TYPE (name2)) 2802 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp); 2803 if (cst2 != NULL_TREE) 2804 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2); 2805 add_assert_info (asserts, name2, tmp, comp_code, val); 2806 } 2807 } 2808 2809 /* In the case of post-in/decrement tests like if (i++) ... and uses 2810 of the in/decremented value on the edge the extra name we want to 2811 assert for is not on the def chain of the name compared. Instead 2812 it is in the set of use stmts. 2813 Similar cases happen for conversions that were simplified through 2814 fold_{sign_changed,widened}_comparison. */ 2815 if ((comp_code == NE_EXPR 2816 || comp_code == EQ_EXPR) 2817 && TREE_CODE (val) == INTEGER_CST) 2818 { 2819 imm_use_iterator ui; 2820 gimple *use_stmt; 2821 FOR_EACH_IMM_USE_STMT (use_stmt, ui, name) 2822 { 2823 if (!is_gimple_assign (use_stmt)) 2824 continue; 2825 2826 /* Cut off to use-stmts that are dominating the predecessor. */ 2827 if (!dominated_by_p (CDI_DOMINATORS, e->src, gimple_bb (use_stmt))) 2828 continue; 2829 2830 tree name2 = gimple_assign_lhs (use_stmt); 2831 if (TREE_CODE (name2) != SSA_NAME) 2832 continue; 2833 2834 enum tree_code code = gimple_assign_rhs_code (use_stmt); 2835 tree cst; 2836 if (code == PLUS_EXPR 2837 || code == MINUS_EXPR) 2838 { 2839 cst = gimple_assign_rhs2 (use_stmt); 2840 if (TREE_CODE (cst) != INTEGER_CST) 2841 continue; 2842 cst = int_const_binop (code, val, cst); 2843 } 2844 else if (CONVERT_EXPR_CODE_P (code)) 2845 { 2846 /* For truncating conversions we cannot record 2847 an inequality. */ 2848 if (comp_code == NE_EXPR 2849 && (TYPE_PRECISION (TREE_TYPE (name2)) 2850 < TYPE_PRECISION (TREE_TYPE (name)))) 2851 continue; 2852 cst = fold_convert (TREE_TYPE (name2), val); 2853 } 2854 else 2855 continue; 2856 2857 if (TREE_OVERFLOW_P (cst)) 2858 cst = drop_tree_overflow (cst); 2859 add_assert_info (asserts, name2, name2, comp_code, cst); 2860 } 2861 } 2862 2863 if (TREE_CODE_CLASS (comp_code) == tcc_comparison 2864 && TREE_CODE (val) == INTEGER_CST) 2865 { 2866 gimple *def_stmt = SSA_NAME_DEF_STMT (name); 2867 tree name2 = NULL_TREE, names[2], cst2 = NULL_TREE; 2868 tree val2 = NULL_TREE; 2869 unsigned int prec = TYPE_PRECISION (TREE_TYPE (val)); 2870 wide_int mask = wi::zero (prec); 2871 unsigned int nprec = prec; 2872 enum tree_code rhs_code = ERROR_MARK; 2873 2874 if (is_gimple_assign (def_stmt)) 2875 rhs_code = gimple_assign_rhs_code (def_stmt); 2876 2877 /* In the case of NAME != CST1 where NAME = A +- CST2 we can 2878 assert that A != CST1 -+ CST2. */ 2879 if ((comp_code == EQ_EXPR || comp_code == NE_EXPR) 2880 && (rhs_code == PLUS_EXPR || rhs_code == MINUS_EXPR)) 2881 { 2882 tree op0 = gimple_assign_rhs1 (def_stmt); 2883 tree op1 = gimple_assign_rhs2 (def_stmt); 2884 if (TREE_CODE (op0) == SSA_NAME 2885 && TREE_CODE (op1) == INTEGER_CST) 2886 { 2887 enum tree_code reverse_op = (rhs_code == PLUS_EXPR 2888 ? MINUS_EXPR : PLUS_EXPR); 2889 op1 = int_const_binop (reverse_op, val, op1); 2890 if (TREE_OVERFLOW (op1)) 2891 op1 = drop_tree_overflow (op1); 2892 add_assert_info (asserts, op0, op0, comp_code, op1); 2893 } 2894 } 2895 2896 /* Add asserts for NAME cmp CST and NAME being defined 2897 as NAME = (int) NAME2. */ 2898 if (!TYPE_UNSIGNED (TREE_TYPE (val)) 2899 && (comp_code == LE_EXPR || comp_code == LT_EXPR 2900 || comp_code == GT_EXPR || comp_code == GE_EXPR) 2901 && gimple_assign_cast_p (def_stmt)) 2902 { 2903 name2 = gimple_assign_rhs1 (def_stmt); 2904 if (CONVERT_EXPR_CODE_P (rhs_code) 2905 && TREE_CODE (name2) == SSA_NAME 2906 && INTEGRAL_TYPE_P (TREE_TYPE (name2)) 2907 && TYPE_UNSIGNED (TREE_TYPE (name2)) 2908 && prec == TYPE_PRECISION (TREE_TYPE (name2)) 2909 && (comp_code == LE_EXPR || comp_code == GT_EXPR 2910 || !tree_int_cst_equal (val, 2911 TYPE_MIN_VALUE (TREE_TYPE (val))))) 2912 { 2913 tree tmp, cst; 2914 enum tree_code new_comp_code = comp_code; 2915 2916 cst = fold_convert (TREE_TYPE (name2), 2917 TYPE_MIN_VALUE (TREE_TYPE (val))); 2918 /* Build an expression for the range test. */ 2919 tmp = build2 (PLUS_EXPR, TREE_TYPE (name2), name2, cst); 2920 cst = fold_build2 (PLUS_EXPR, TREE_TYPE (name2), cst, 2921 fold_convert (TREE_TYPE (name2), val)); 2922 if (comp_code == LT_EXPR || comp_code == GE_EXPR) 2923 { 2924 new_comp_code = comp_code == LT_EXPR ? LE_EXPR : GT_EXPR; 2925 cst = fold_build2 (MINUS_EXPR, TREE_TYPE (name2), cst, 2926 build_int_cst (TREE_TYPE (name2), 1)); 2927 } 2928 add_assert_info (asserts, name2, tmp, new_comp_code, cst); 2929 } 2930 } 2931 2932 /* Add asserts for NAME cmp CST and NAME being defined as 2933 NAME = NAME2 >> CST2. 2934 2935 Extract CST2 from the right shift. */ 2936 if (rhs_code == RSHIFT_EXPR) 2937 { 2938 name2 = gimple_assign_rhs1 (def_stmt); 2939 cst2 = gimple_assign_rhs2 (def_stmt); 2940 if (TREE_CODE (name2) == SSA_NAME 2941 && tree_fits_uhwi_p (cst2) 2942 && INTEGRAL_TYPE_P (TREE_TYPE (name2)) 2943 && IN_RANGE (tree_to_uhwi (cst2), 1, prec - 1) 2944 && type_has_mode_precision_p (TREE_TYPE (val))) 2945 { 2946 mask = wi::mask (tree_to_uhwi (cst2), false, prec); 2947 val2 = fold_binary (LSHIFT_EXPR, TREE_TYPE (val), val, cst2); 2948 } 2949 } 2950 if (val2 != NULL_TREE 2951 && TREE_CODE (val2) == INTEGER_CST 2952 && simple_cst_equal (fold_build2 (RSHIFT_EXPR, 2953 TREE_TYPE (val), 2954 val2, cst2), val)) 2955 { 2956 enum tree_code new_comp_code = comp_code; 2957 tree tmp, new_val; 2958 2959 tmp = name2; 2960 if (comp_code == EQ_EXPR || comp_code == NE_EXPR) 2961 { 2962 if (!TYPE_UNSIGNED (TREE_TYPE (val))) 2963 { 2964 tree type = build_nonstandard_integer_type (prec, 1); 2965 tmp = build1 (NOP_EXPR, type, name2); 2966 val2 = fold_convert (type, val2); 2967 } 2968 tmp = fold_build2 (MINUS_EXPR, TREE_TYPE (tmp), tmp, val2); 2969 new_val = wide_int_to_tree (TREE_TYPE (tmp), mask); 2970 new_comp_code = comp_code == EQ_EXPR ? LE_EXPR : GT_EXPR; 2971 } 2972 else if (comp_code == LT_EXPR || comp_code == GE_EXPR) 2973 { 2974 wide_int minval 2975 = wi::min_value (prec, TYPE_SIGN (TREE_TYPE (val))); 2976 new_val = val2; 2977 if (minval == wi::to_wide (new_val)) 2978 new_val = NULL_TREE; 2979 } 2980 else 2981 { 2982 wide_int maxval 2983 = wi::max_value (prec, TYPE_SIGN (TREE_TYPE (val))); 2984 mask |= wi::to_wide (val2); 2985 if (wi::eq_p (mask, maxval)) 2986 new_val = NULL_TREE; 2987 else 2988 new_val = wide_int_to_tree (TREE_TYPE (val2), mask); 2989 } 2990 2991 if (new_val) 2992 add_assert_info (asserts, name2, tmp, new_comp_code, new_val); 2993 } 2994 2995 /* If we have a conversion that doesn't change the value of the source 2996 simply register the same assert for it. */ 2997 if (CONVERT_EXPR_CODE_P (rhs_code)) 2998 { 2999 wide_int rmin, rmax; 3000 tree rhs1 = gimple_assign_rhs1 (def_stmt); 3001 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) 3002 && TREE_CODE (rhs1) == SSA_NAME 3003 /* Make sure the relation preserves the upper/lower boundary of 3004 the range conservatively. */ 3005 && (comp_code == NE_EXPR 3006 || comp_code == EQ_EXPR 3007 || (TYPE_SIGN (TREE_TYPE (name)) 3008 == TYPE_SIGN (TREE_TYPE (rhs1))) 3009 || ((comp_code == LE_EXPR 3010 || comp_code == LT_EXPR) 3011 && !TYPE_UNSIGNED (TREE_TYPE (rhs1))) 3012 || ((comp_code == GE_EXPR 3013 || comp_code == GT_EXPR) 3014 && TYPE_UNSIGNED (TREE_TYPE (rhs1)))) 3015 /* And the conversion does not alter the value we compare 3016 against and all values in rhs1 can be represented in 3017 the converted to type. */ 3018 && int_fits_type_p (val, TREE_TYPE (rhs1)) 3019 && ((TYPE_PRECISION (TREE_TYPE (name)) 3020 > TYPE_PRECISION (TREE_TYPE (rhs1))) 3021 || (get_range_info (rhs1, &rmin, &rmax) == VR_RANGE 3022 && wi::fits_to_tree_p (rmin, TREE_TYPE (name)) 3023 && wi::fits_to_tree_p (rmax, TREE_TYPE (name))))) 3024 add_assert_info (asserts, rhs1, rhs1, 3025 comp_code, fold_convert (TREE_TYPE (rhs1), val)); 3026 } 3027 3028 /* Add asserts for NAME cmp CST and NAME being defined as 3029 NAME = NAME2 & CST2. 3030 3031 Extract CST2 from the and. 3032 3033 Also handle 3034 NAME = (unsigned) NAME2; 3035 casts where NAME's type is unsigned and has smaller precision 3036 than NAME2's type as if it was NAME = NAME2 & MASK. */ 3037 names[0] = NULL_TREE; 3038 names[1] = NULL_TREE; 3039 cst2 = NULL_TREE; 3040 if (rhs_code == BIT_AND_EXPR 3041 || (CONVERT_EXPR_CODE_P (rhs_code) 3042 && INTEGRAL_TYPE_P (TREE_TYPE (val)) 3043 && TYPE_UNSIGNED (TREE_TYPE (val)) 3044 && TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt))) 3045 > prec)) 3046 { 3047 name2 = gimple_assign_rhs1 (def_stmt); 3048 if (rhs_code == BIT_AND_EXPR) 3049 cst2 = gimple_assign_rhs2 (def_stmt); 3050 else 3051 { 3052 cst2 = TYPE_MAX_VALUE (TREE_TYPE (val)); 3053 nprec = TYPE_PRECISION (TREE_TYPE (name2)); 3054 } 3055 if (TREE_CODE (name2) == SSA_NAME 3056 && INTEGRAL_TYPE_P (TREE_TYPE (name2)) 3057 && TREE_CODE (cst2) == INTEGER_CST 3058 && !integer_zerop (cst2) 3059 && (nprec > 1 3060 || TYPE_UNSIGNED (TREE_TYPE (val)))) 3061 { 3062 gimple *def_stmt2 = SSA_NAME_DEF_STMT (name2); 3063 if (gimple_assign_cast_p (def_stmt2)) 3064 { 3065 names[1] = gimple_assign_rhs1 (def_stmt2); 3066 if (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt2)) 3067 || TREE_CODE (names[1]) != SSA_NAME 3068 || !INTEGRAL_TYPE_P (TREE_TYPE (names[1])) 3069 || (TYPE_PRECISION (TREE_TYPE (name2)) 3070 != TYPE_PRECISION (TREE_TYPE (names[1])))) 3071 names[1] = NULL_TREE; 3072 } 3073 names[0] = name2; 3074 } 3075 } 3076 if (names[0] || names[1]) 3077 { 3078 wide_int minv, maxv, valv, cst2v; 3079 wide_int tem, sgnbit; 3080 bool valid_p = false, valn, cst2n; 3081 enum tree_code ccode = comp_code; 3082 3083 valv = wide_int::from (wi::to_wide (val), nprec, UNSIGNED); 3084 cst2v = wide_int::from (wi::to_wide (cst2), nprec, UNSIGNED); 3085 valn = wi::neg_p (valv, TYPE_SIGN (TREE_TYPE (val))); 3086 cst2n = wi::neg_p (cst2v, TYPE_SIGN (TREE_TYPE (val))); 3087 /* If CST2 doesn't have most significant bit set, 3088 but VAL is negative, we have comparison like 3089 if ((x & 0x123) > -4) (always true). Just give up. */ 3090 if (!cst2n && valn) 3091 ccode = ERROR_MARK; 3092 if (cst2n) 3093 sgnbit = wi::set_bit_in_zero (nprec - 1, nprec); 3094 else 3095 sgnbit = wi::zero (nprec); 3096 minv = valv & cst2v; 3097 switch (ccode) 3098 { 3099 case EQ_EXPR: 3100 /* Minimum unsigned value for equality is VAL & CST2 3101 (should be equal to VAL, otherwise we probably should 3102 have folded the comparison into false) and 3103 maximum unsigned value is VAL | ~CST2. */ 3104 maxv = valv | ~cst2v; 3105 valid_p = true; 3106 break; 3107 3108 case NE_EXPR: 3109 tem = valv | ~cst2v; 3110 /* If VAL is 0, handle (X & CST2) != 0 as (X & CST2) > 0U. */ 3111 if (valv == 0) 3112 { 3113 cst2n = false; 3114 sgnbit = wi::zero (nprec); 3115 goto gt_expr; 3116 } 3117 /* If (VAL | ~CST2) is all ones, handle it as 3118 (X & CST2) < VAL. */ 3119 if (tem == -1) 3120 { 3121 cst2n = false; 3122 valn = false; 3123 sgnbit = wi::zero (nprec); 3124 goto lt_expr; 3125 } 3126 if (!cst2n && wi::neg_p (cst2v)) 3127 sgnbit = wi::set_bit_in_zero (nprec - 1, nprec); 3128 if (sgnbit != 0) 3129 { 3130 if (valv == sgnbit) 3131 { 3132 cst2n = true; 3133 valn = true; 3134 goto gt_expr; 3135 } 3136 if (tem == wi::mask (nprec - 1, false, nprec)) 3137 { 3138 cst2n = true; 3139 goto lt_expr; 3140 } 3141 if (!cst2n) 3142 sgnbit = wi::zero (nprec); 3143 } 3144 break; 3145 3146 case GE_EXPR: 3147 /* Minimum unsigned value for >= if (VAL & CST2) == VAL 3148 is VAL and maximum unsigned value is ~0. For signed 3149 comparison, if CST2 doesn't have most significant bit 3150 set, handle it similarly. If CST2 has MSB set, 3151 the minimum is the same, and maximum is ~0U/2. */ 3152 if (minv != valv) 3153 { 3154 /* If (VAL & CST2) != VAL, X & CST2 can't be equal to 3155 VAL. */ 3156 minv = masked_increment (valv, cst2v, sgnbit, nprec); 3157 if (minv == valv) 3158 break; 3159 } 3160 maxv = wi::mask (nprec - (cst2n ? 1 : 0), false, nprec); 3161 valid_p = true; 3162 break; 3163 3164 case GT_EXPR: 3165 gt_expr: 3166 /* Find out smallest MINV where MINV > VAL 3167 && (MINV & CST2) == MINV, if any. If VAL is signed and 3168 CST2 has MSB set, compute it biased by 1 << (nprec - 1). */ 3169 minv = masked_increment (valv, cst2v, sgnbit, nprec); 3170 if (minv == valv) 3171 break; 3172 maxv = wi::mask (nprec - (cst2n ? 1 : 0), false, nprec); 3173 valid_p = true; 3174 break; 3175 3176 case LE_EXPR: 3177 /* Minimum unsigned value for <= is 0 and maximum 3178 unsigned value is VAL | ~CST2 if (VAL & CST2) == VAL. 3179 Otherwise, find smallest VAL2 where VAL2 > VAL 3180 && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2 3181 as maximum. 3182 For signed comparison, if CST2 doesn't have most 3183 significant bit set, handle it similarly. If CST2 has 3184 MSB set, the maximum is the same and minimum is INT_MIN. */ 3185 if (minv == valv) 3186 maxv = valv; 3187 else 3188 { 3189 maxv = masked_increment (valv, cst2v, sgnbit, nprec); 3190 if (maxv == valv) 3191 break; 3192 maxv -= 1; 3193 } 3194 maxv |= ~cst2v; 3195 minv = sgnbit; 3196 valid_p = true; 3197 break; 3198 3199 case LT_EXPR: 3200 lt_expr: 3201 /* Minimum unsigned value for < is 0 and maximum 3202 unsigned value is (VAL-1) | ~CST2 if (VAL & CST2) == VAL. 3203 Otherwise, find smallest VAL2 where VAL2 > VAL 3204 && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2 3205 as maximum. 3206 For signed comparison, if CST2 doesn't have most 3207 significant bit set, handle it similarly. If CST2 has 3208 MSB set, the maximum is the same and minimum is INT_MIN. */ 3209 if (minv == valv) 3210 { 3211 if (valv == sgnbit) 3212 break; 3213 maxv = valv; 3214 } 3215 else 3216 { 3217 maxv = masked_increment (valv, cst2v, sgnbit, nprec); 3218 if (maxv == valv) 3219 break; 3220 } 3221 maxv -= 1; 3222 maxv |= ~cst2v; 3223 minv = sgnbit; 3224 valid_p = true; 3225 break; 3226 3227 default: 3228 break; 3229 } 3230 if (valid_p 3231 && (maxv - minv) != -1) 3232 { 3233 tree tmp, new_val, type; 3234 int i; 3235 3236 for (i = 0; i < 2; i++) 3237 if (names[i]) 3238 { 3239 wide_int maxv2 = maxv; 3240 tmp = names[i]; 3241 type = TREE_TYPE (names[i]); 3242 if (!TYPE_UNSIGNED (type)) 3243 { 3244 type = build_nonstandard_integer_type (nprec, 1); 3245 tmp = build1 (NOP_EXPR, type, names[i]); 3246 } 3247 if (minv != 0) 3248 { 3249 tmp = build2 (PLUS_EXPR, type, tmp, 3250 wide_int_to_tree (type, -minv)); 3251 maxv2 = maxv - minv; 3252 } 3253 new_val = wide_int_to_tree (type, maxv2); 3254 add_assert_info (asserts, names[i], tmp, LE_EXPR, new_val); 3255 } 3256 } 3257 } 3258 } 3259 } 3260 3261 /* OP is an operand of a truth value expression which is known to have 3262 a particular value. Register any asserts for OP and for any 3263 operands in OP's defining statement. 3264 3265 If CODE is EQ_EXPR, then we want to register OP is zero (false), 3266 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */ 3267 3268 static void 3269 register_edge_assert_for_1 (tree op, enum tree_code code, 3270 edge e, vec<assert_info> &asserts) 3271 { 3272 gimple *op_def; 3273 tree val; 3274 enum tree_code rhs_code; 3275 3276 /* We only care about SSA_NAMEs. */ 3277 if (TREE_CODE (op) != SSA_NAME) 3278 return; 3279 3280 /* We know that OP will have a zero or nonzero value. */ 3281 val = build_int_cst (TREE_TYPE (op), 0); 3282 add_assert_info (asserts, op, op, code, val); 3283 3284 /* Now look at how OP is set. If it's set from a comparison, 3285 a truth operation or some bit operations, then we may be able 3286 to register information about the operands of that assignment. */ 3287 op_def = SSA_NAME_DEF_STMT (op); 3288 if (gimple_code (op_def) != GIMPLE_ASSIGN) 3289 return; 3290 3291 rhs_code = gimple_assign_rhs_code (op_def); 3292 3293 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison) 3294 { 3295 bool invert = (code == EQ_EXPR ? true : false); 3296 tree op0 = gimple_assign_rhs1 (op_def); 3297 tree op1 = gimple_assign_rhs2 (op_def); 3298 3299 if (TREE_CODE (op0) == SSA_NAME) 3300 register_edge_assert_for_2 (op0, e, rhs_code, op0, op1, invert, asserts); 3301 if (TREE_CODE (op1) == SSA_NAME) 3302 register_edge_assert_for_2 (op1, e, rhs_code, op0, op1, invert, asserts); 3303 } 3304 else if ((code == NE_EXPR 3305 && gimple_assign_rhs_code (op_def) == BIT_AND_EXPR) 3306 || (code == EQ_EXPR 3307 && gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)) 3308 { 3309 /* Recurse on each operand. */ 3310 tree op0 = gimple_assign_rhs1 (op_def); 3311 tree op1 = gimple_assign_rhs2 (op_def); 3312 if (TREE_CODE (op0) == SSA_NAME 3313 && has_single_use (op0)) 3314 register_edge_assert_for_1 (op0, code, e, asserts); 3315 if (TREE_CODE (op1) == SSA_NAME 3316 && has_single_use (op1)) 3317 register_edge_assert_for_1 (op1, code, e, asserts); 3318 } 3319 else if (gimple_assign_rhs_code (op_def) == BIT_NOT_EXPR 3320 && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def))) == 1) 3321 { 3322 /* Recurse, flipping CODE. */ 3323 code = invert_tree_comparison (code, false); 3324 register_edge_assert_for_1 (gimple_assign_rhs1 (op_def), code, e, asserts); 3325 } 3326 else if (gimple_assign_rhs_code (op_def) == SSA_NAME) 3327 { 3328 /* Recurse through the copy. */ 3329 register_edge_assert_for_1 (gimple_assign_rhs1 (op_def), code, e, asserts); 3330 } 3331 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def))) 3332 { 3333 /* Recurse through the type conversion, unless it is a narrowing 3334 conversion or conversion from non-integral type. */ 3335 tree rhs = gimple_assign_rhs1 (op_def); 3336 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs)) 3337 && (TYPE_PRECISION (TREE_TYPE (rhs)) 3338 <= TYPE_PRECISION (TREE_TYPE (op)))) 3339 register_edge_assert_for_1 (rhs, code, e, asserts); 3340 } 3341 } 3342 3343 /* Check if comparison 3344 NAME COND_OP INTEGER_CST 3345 has a form of 3346 (X & 11...100..0) COND_OP XX...X00...0 3347 Such comparison can yield assertions like 3348 X >= XX...X00...0 3349 X <= XX...X11...1 3350 in case of COND_OP being EQ_EXPR or 3351 X < XX...X00...0 3352 X > XX...X11...1 3353 in case of NE_EXPR. */ 3354 3355 static bool 3356 is_masked_range_test (tree name, tree valt, enum tree_code cond_code, 3357 tree *new_name, tree *low, enum tree_code *low_code, 3358 tree *high, enum tree_code *high_code) 3359 { 3360 gimple *def_stmt = SSA_NAME_DEF_STMT (name); 3361 3362 if (!is_gimple_assign (def_stmt) 3363 || gimple_assign_rhs_code (def_stmt) != BIT_AND_EXPR) 3364 return false; 3365 3366 tree t = gimple_assign_rhs1 (def_stmt); 3367 tree maskt = gimple_assign_rhs2 (def_stmt); 3368 if (TREE_CODE (t) != SSA_NAME || TREE_CODE (maskt) != INTEGER_CST) 3369 return false; 3370 3371 wi::tree_to_wide_ref mask = wi::to_wide (maskt); 3372 wide_int inv_mask = ~mask; 3373 /* Must have been removed by now so don't bother optimizing. */ 3374 if (mask == 0 || inv_mask == 0) 3375 return false; 3376 3377 /* Assume VALT is INTEGER_CST. */ 3378 wi::tree_to_wide_ref val = wi::to_wide (valt); 3379 3380 if ((inv_mask & (inv_mask + 1)) != 0 3381 || (val & mask) != val) 3382 return false; 3383 3384 bool is_range = cond_code == EQ_EXPR; 3385 3386 tree type = TREE_TYPE (t); 3387 wide_int min = wi::min_value (type), 3388 max = wi::max_value (type); 3389 3390 if (is_range) 3391 { 3392 *low_code = val == min ? ERROR_MARK : GE_EXPR; 3393 *high_code = val == max ? ERROR_MARK : LE_EXPR; 3394 } 3395 else 3396 { 3397 /* We can still generate assertion if one of alternatives 3398 is known to always be false. */ 3399 if (val == min) 3400 { 3401 *low_code = (enum tree_code) 0; 3402 *high_code = GT_EXPR; 3403 } 3404 else if ((val | inv_mask) == max) 3405 { 3406 *low_code = LT_EXPR; 3407 *high_code = (enum tree_code) 0; 3408 } 3409 else 3410 return false; 3411 } 3412 3413 *new_name = t; 3414 *low = wide_int_to_tree (type, val); 3415 *high = wide_int_to_tree (type, val | inv_mask); 3416 3417 return true; 3418 } 3419 3420 /* Try to register an edge assertion for SSA name NAME on edge E for 3421 the condition COND contributing to the conditional jump pointed to by 3422 SI. */ 3423 3424 void 3425 register_edge_assert_for (tree name, edge e, 3426 enum tree_code cond_code, tree cond_op0, 3427 tree cond_op1, vec<assert_info> &asserts) 3428 { 3429 tree val; 3430 enum tree_code comp_code; 3431 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0; 3432 3433 /* Do not attempt to infer anything in names that flow through 3434 abnormal edges. */ 3435 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name)) 3436 return; 3437 3438 if (!extract_code_and_val_from_cond_with_ops (name, cond_code, 3439 cond_op0, cond_op1, 3440 is_else_edge, 3441 &comp_code, &val)) 3442 return; 3443 3444 /* Register ASSERT_EXPRs for name. */ 3445 register_edge_assert_for_2 (name, e, cond_code, cond_op0, 3446 cond_op1, is_else_edge, asserts); 3447 3448 3449 /* If COND is effectively an equality test of an SSA_NAME against 3450 the value zero or one, then we may be able to assert values 3451 for SSA_NAMEs which flow into COND. */ 3452 3453 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining 3454 statement of NAME we can assert both operands of the BIT_AND_EXPR 3455 have nonzero value. */ 3456 if (((comp_code == EQ_EXPR && integer_onep (val)) 3457 || (comp_code == NE_EXPR && integer_zerop (val)))) 3458 { 3459 gimple *def_stmt = SSA_NAME_DEF_STMT (name); 3460 3461 if (is_gimple_assign (def_stmt) 3462 && gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR) 3463 { 3464 tree op0 = gimple_assign_rhs1 (def_stmt); 3465 tree op1 = gimple_assign_rhs2 (def_stmt); 3466 register_edge_assert_for_1 (op0, NE_EXPR, e, asserts); 3467 register_edge_assert_for_1 (op1, NE_EXPR, e, asserts); 3468 } 3469 } 3470 3471 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining 3472 statement of NAME we can assert both operands of the BIT_IOR_EXPR 3473 have zero value. */ 3474 if (((comp_code == EQ_EXPR && integer_zerop (val)) 3475 || (comp_code == NE_EXPR && integer_onep (val)))) 3476 { 3477 gimple *def_stmt = SSA_NAME_DEF_STMT (name); 3478 3479 /* For BIT_IOR_EXPR only if NAME == 0 both operands have 3480 necessarily zero value, or if type-precision is one. */ 3481 if (is_gimple_assign (def_stmt) 3482 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR 3483 && (TYPE_PRECISION (TREE_TYPE (name)) == 1 3484 || comp_code == EQ_EXPR))) 3485 { 3486 tree op0 = gimple_assign_rhs1 (def_stmt); 3487 tree op1 = gimple_assign_rhs2 (def_stmt); 3488 register_edge_assert_for_1 (op0, EQ_EXPR, e, asserts); 3489 register_edge_assert_for_1 (op1, EQ_EXPR, e, asserts); 3490 } 3491 } 3492 3493 /* Sometimes we can infer ranges from (NAME & MASK) == VALUE. */ 3494 if ((comp_code == EQ_EXPR || comp_code == NE_EXPR) 3495 && TREE_CODE (val) == INTEGER_CST) 3496 { 3497 enum tree_code low_code, high_code; 3498 tree low, high; 3499 if (is_masked_range_test (name, val, comp_code, &name, &low, 3500 &low_code, &high, &high_code)) 3501 { 3502 if (low_code != ERROR_MARK) 3503 register_edge_assert_for_2 (name, e, low_code, name, 3504 low, /*invert*/false, asserts); 3505 if (high_code != ERROR_MARK) 3506 register_edge_assert_for_2 (name, e, high_code, name, 3507 high, /*invert*/false, asserts); 3508 } 3509 } 3510 } 3511 3512 /* Finish found ASSERTS for E and register them at GSI. */ 3513 3514 static void 3515 finish_register_edge_assert_for (edge e, gimple_stmt_iterator gsi, 3516 vec<assert_info> &asserts) 3517 { 3518 for (unsigned i = 0; i < asserts.length (); ++i) 3519 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph 3520 reachable from E. */ 3521 if (live_on_edge (e, asserts[i].name)) 3522 register_new_assert_for (asserts[i].name, asserts[i].expr, 3523 asserts[i].comp_code, asserts[i].val, 3524 NULL, e, gsi); 3525 } 3526 3527 3528 3529 /* Determine whether the outgoing edges of BB should receive an 3530 ASSERT_EXPR for each of the operands of BB's LAST statement. 3531 The last statement of BB must be a COND_EXPR. 3532 3533 If any of the sub-graphs rooted at BB have an interesting use of 3534 the predicate operands, an assert location node is added to the 3535 list of assertions for the corresponding operands. */ 3536 3537 static void 3538 find_conditional_asserts (basic_block bb, gcond *last) 3539 { 3540 gimple_stmt_iterator bsi; 3541 tree op; 3542 edge_iterator ei; 3543 edge e; 3544 ssa_op_iter iter; 3545 3546 bsi = gsi_for_stmt (last); 3547 3548 /* Look for uses of the operands in each of the sub-graphs 3549 rooted at BB. We need to check each of the outgoing edges 3550 separately, so that we know what kind of ASSERT_EXPR to 3551 insert. */ 3552 FOR_EACH_EDGE (e, ei, bb->succs) 3553 { 3554 if (e->dest == bb) 3555 continue; 3556 3557 /* Register the necessary assertions for each operand in the 3558 conditional predicate. */ 3559 auto_vec<assert_info, 8> asserts; 3560 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE) 3561 register_edge_assert_for (op, e, 3562 gimple_cond_code (last), 3563 gimple_cond_lhs (last), 3564 gimple_cond_rhs (last), asserts); 3565 finish_register_edge_assert_for (e, bsi, asserts); 3566 } 3567 } 3568 3569 struct case_info 3570 { 3571 tree expr; 3572 basic_block bb; 3573 }; 3574 3575 /* Compare two case labels sorting first by the destination bb index 3576 and then by the case value. */ 3577 3578 static int 3579 compare_case_labels (const void *p1, const void *p2) 3580 { 3581 const struct case_info *ci1 = (const struct case_info *) p1; 3582 const struct case_info *ci2 = (const struct case_info *) p2; 3583 int idx1 = ci1->bb->index; 3584 int idx2 = ci2->bb->index; 3585 3586 if (idx1 < idx2) 3587 return -1; 3588 else if (idx1 == idx2) 3589 { 3590 /* Make sure the default label is first in a group. */ 3591 if (!CASE_LOW (ci1->expr)) 3592 return -1; 3593 else if (!CASE_LOW (ci2->expr)) 3594 return 1; 3595 else 3596 return tree_int_cst_compare (CASE_LOW (ci1->expr), 3597 CASE_LOW (ci2->expr)); 3598 } 3599 else 3600 return 1; 3601 } 3602 3603 /* Determine whether the outgoing edges of BB should receive an 3604 ASSERT_EXPR for each of the operands of BB's LAST statement. 3605 The last statement of BB must be a SWITCH_EXPR. 3606 3607 If any of the sub-graphs rooted at BB have an interesting use of 3608 the predicate operands, an assert location node is added to the 3609 list of assertions for the corresponding operands. */ 3610 3611 static void 3612 find_switch_asserts (basic_block bb, gswitch *last) 3613 { 3614 gimple_stmt_iterator bsi; 3615 tree op; 3616 edge e; 3617 struct case_info *ci; 3618 size_t n = gimple_switch_num_labels (last); 3619 #if GCC_VERSION >= 4000 3620 unsigned int idx; 3621 #else 3622 /* Work around GCC 3.4 bug (PR 37086). */ 3623 volatile unsigned int idx; 3624 #endif 3625 3626 bsi = gsi_for_stmt (last); 3627 op = gimple_switch_index (last); 3628 if (TREE_CODE (op) != SSA_NAME) 3629 return; 3630 3631 /* Build a vector of case labels sorted by destination label. */ 3632 ci = XNEWVEC (struct case_info, n); 3633 for (idx = 0; idx < n; ++idx) 3634 { 3635 ci[idx].expr = gimple_switch_label (last, idx); 3636 ci[idx].bb = label_to_block (cfun, CASE_LABEL (ci[idx].expr)); 3637 } 3638 edge default_edge = find_edge (bb, ci[0].bb); 3639 qsort (ci, n, sizeof (struct case_info), compare_case_labels); 3640 3641 for (idx = 0; idx < n; ++idx) 3642 { 3643 tree min, max; 3644 tree cl = ci[idx].expr; 3645 basic_block cbb = ci[idx].bb; 3646 3647 min = CASE_LOW (cl); 3648 max = CASE_HIGH (cl); 3649 3650 /* If there are multiple case labels with the same destination 3651 we need to combine them to a single value range for the edge. */ 3652 if (idx + 1 < n && cbb == ci[idx + 1].bb) 3653 { 3654 /* Skip labels until the last of the group. */ 3655 do { 3656 ++idx; 3657 } while (idx < n && cbb == ci[idx].bb); 3658 --idx; 3659 3660 /* Pick up the maximum of the case label range. */ 3661 if (CASE_HIGH (ci[idx].expr)) 3662 max = CASE_HIGH (ci[idx].expr); 3663 else 3664 max = CASE_LOW (ci[idx].expr); 3665 } 3666 3667 /* Can't extract a useful assertion out of a range that includes the 3668 default label. */ 3669 if (min == NULL_TREE) 3670 continue; 3671 3672 /* Find the edge to register the assert expr on. */ 3673 e = find_edge (bb, cbb); 3674 3675 /* Register the necessary assertions for the operand in the 3676 SWITCH_EXPR. */ 3677 auto_vec<assert_info, 8> asserts; 3678 register_edge_assert_for (op, e, 3679 max ? GE_EXPR : EQ_EXPR, 3680 op, fold_convert (TREE_TYPE (op), min), 3681 asserts); 3682 if (max) 3683 register_edge_assert_for (op, e, LE_EXPR, op, 3684 fold_convert (TREE_TYPE (op), max), 3685 asserts); 3686 finish_register_edge_assert_for (e, bsi, asserts); 3687 } 3688 3689 XDELETEVEC (ci); 3690 3691 if (!live_on_edge (default_edge, op)) 3692 return; 3693 3694 /* Now register along the default label assertions that correspond to the 3695 anti-range of each label. */ 3696 int insertion_limit = PARAM_VALUE (PARAM_MAX_VRP_SWITCH_ASSERTIONS); 3697 if (insertion_limit == 0) 3698 return; 3699 3700 /* We can't do this if the default case shares a label with another case. */ 3701 tree default_cl = gimple_switch_default_label (last); 3702 for (idx = 1; idx < n; idx++) 3703 { 3704 tree min, max; 3705 tree cl = gimple_switch_label (last, idx); 3706 if (CASE_LABEL (cl) == CASE_LABEL (default_cl)) 3707 continue; 3708 3709 min = CASE_LOW (cl); 3710 max = CASE_HIGH (cl); 3711 3712 /* Combine contiguous case ranges to reduce the number of assertions 3713 to insert. */ 3714 for (idx = idx + 1; idx < n; idx++) 3715 { 3716 tree next_min, next_max; 3717 tree next_cl = gimple_switch_label (last, idx); 3718 if (CASE_LABEL (next_cl) == CASE_LABEL (default_cl)) 3719 break; 3720 3721 next_min = CASE_LOW (next_cl); 3722 next_max = CASE_HIGH (next_cl); 3723 3724 wide_int difference = (wi::to_wide (next_min) 3725 - wi::to_wide (max ? max : min)); 3726 if (wi::eq_p (difference, 1)) 3727 max = next_max ? next_max : next_min; 3728 else 3729 break; 3730 } 3731 idx--; 3732 3733 if (max == NULL_TREE) 3734 { 3735 /* Register the assertion OP != MIN. */ 3736 auto_vec<assert_info, 8> asserts; 3737 min = fold_convert (TREE_TYPE (op), min); 3738 register_edge_assert_for (op, default_edge, NE_EXPR, op, min, 3739 asserts); 3740 finish_register_edge_assert_for (default_edge, bsi, asserts); 3741 } 3742 else 3743 { 3744 /* Register the assertion (unsigned)OP - MIN > (MAX - MIN), 3745 which will give OP the anti-range ~[MIN,MAX]. */ 3746 tree uop = fold_convert (unsigned_type_for (TREE_TYPE (op)), op); 3747 min = fold_convert (TREE_TYPE (uop), min); 3748 max = fold_convert (TREE_TYPE (uop), max); 3749 3750 tree lhs = fold_build2 (MINUS_EXPR, TREE_TYPE (uop), uop, min); 3751 tree rhs = int_const_binop (MINUS_EXPR, max, min); 3752 register_new_assert_for (op, lhs, GT_EXPR, rhs, 3753 NULL, default_edge, bsi); 3754 } 3755 3756 if (--insertion_limit == 0) 3757 break; 3758 } 3759 } 3760 3761 3762 /* Traverse all the statements in block BB looking for statements that 3763 may generate useful assertions for the SSA names in their operand. 3764 If a statement produces a useful assertion A for name N_i, then the 3765 list of assertions already generated for N_i is scanned to 3766 determine if A is actually needed. 3767 3768 If N_i already had the assertion A at a location dominating the 3769 current location, then nothing needs to be done. Otherwise, the 3770 new location for A is recorded instead. 3771 3772 1- For every statement S in BB, all the variables used by S are 3773 added to bitmap FOUND_IN_SUBGRAPH. 3774 3775 2- If statement S uses an operand N in a way that exposes a known 3776 value range for N, then if N was not already generated by an 3777 ASSERT_EXPR, create a new assert location for N. For instance, 3778 if N is a pointer and the statement dereferences it, we can 3779 assume that N is not NULL. 3780 3781 3- COND_EXPRs are a special case of #2. We can derive range 3782 information from the predicate but need to insert different 3783 ASSERT_EXPRs for each of the sub-graphs rooted at the 3784 conditional block. If the last statement of BB is a conditional 3785 expression of the form 'X op Y', then 3786 3787 a) Remove X and Y from the set FOUND_IN_SUBGRAPH. 3788 3789 b) If the conditional is the only entry point to the sub-graph 3790 corresponding to the THEN_CLAUSE, recurse into it. On 3791 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then 3792 an ASSERT_EXPR is added for the corresponding variable. 3793 3794 c) Repeat step (b) on the ELSE_CLAUSE. 3795 3796 d) Mark X and Y in FOUND_IN_SUBGRAPH. 3797 3798 For instance, 3799 3800 if (a == 9) 3801 b = a; 3802 else 3803 b = c + 1; 3804 3805 In this case, an assertion on the THEN clause is useful to 3806 determine that 'a' is always 9 on that edge. However, an assertion 3807 on the ELSE clause would be unnecessary. 3808 3809 4- If BB does not end in a conditional expression, then we recurse 3810 into BB's dominator children. 3811 3812 At the end of the recursive traversal, every SSA name will have a 3813 list of locations where ASSERT_EXPRs should be added. When a new 3814 location for name N is found, it is registered by calling 3815 register_new_assert_for. That function keeps track of all the 3816 registered assertions to prevent adding unnecessary assertions. 3817 For instance, if a pointer P_4 is dereferenced more than once in a 3818 dominator tree, only the location dominating all the dereference of 3819 P_4 will receive an ASSERT_EXPR. */ 3820 3821 static void 3822 find_assert_locations_1 (basic_block bb, sbitmap live) 3823 { 3824 gimple *last; 3825 3826 last = last_stmt (bb); 3827 3828 /* If BB's last statement is a conditional statement involving integer 3829 operands, determine if we need to add ASSERT_EXPRs. */ 3830 if (last 3831 && gimple_code (last) == GIMPLE_COND 3832 && !fp_predicate (last) 3833 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE)) 3834 find_conditional_asserts (bb, as_a <gcond *> (last)); 3835 3836 /* If BB's last statement is a switch statement involving integer 3837 operands, determine if we need to add ASSERT_EXPRs. */ 3838 if (last 3839 && gimple_code (last) == GIMPLE_SWITCH 3840 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE)) 3841 find_switch_asserts (bb, as_a <gswitch *> (last)); 3842 3843 /* Traverse all the statements in BB marking used names and looking 3844 for statements that may infer assertions for their used operands. */ 3845 for (gimple_stmt_iterator si = gsi_last_bb (bb); !gsi_end_p (si); 3846 gsi_prev (&si)) 3847 { 3848 gimple *stmt; 3849 tree op; 3850 ssa_op_iter i; 3851 3852 stmt = gsi_stmt (si); 3853 3854 if (is_gimple_debug (stmt)) 3855 continue; 3856 3857 /* See if we can derive an assertion for any of STMT's operands. */ 3858 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE) 3859 { 3860 tree value; 3861 enum tree_code comp_code; 3862 3863 /* If op is not live beyond this stmt, do not bother to insert 3864 asserts for it. */ 3865 if (!bitmap_bit_p (live, SSA_NAME_VERSION (op))) 3866 continue; 3867 3868 /* If OP is used in such a way that we can infer a value 3869 range for it, and we don't find a previous assertion for 3870 it, create a new assertion location node for OP. */ 3871 if (infer_value_range (stmt, op, &comp_code, &value)) 3872 { 3873 /* If we are able to infer a nonzero value range for OP, 3874 then walk backwards through the use-def chain to see if OP 3875 was set via a typecast. 3876 3877 If so, then we can also infer a nonzero value range 3878 for the operand of the NOP_EXPR. */ 3879 if (comp_code == NE_EXPR && integer_zerop (value)) 3880 { 3881 tree t = op; 3882 gimple *def_stmt = SSA_NAME_DEF_STMT (t); 3883 3884 while (is_gimple_assign (def_stmt) 3885 && CONVERT_EXPR_CODE_P 3886 (gimple_assign_rhs_code (def_stmt)) 3887 && TREE_CODE 3888 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME 3889 && POINTER_TYPE_P 3890 (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))) 3891 { 3892 t = gimple_assign_rhs1 (def_stmt); 3893 def_stmt = SSA_NAME_DEF_STMT (t); 3894 3895 /* Note we want to register the assert for the 3896 operand of the NOP_EXPR after SI, not after the 3897 conversion. */ 3898 if (bitmap_bit_p (live, SSA_NAME_VERSION (t))) 3899 register_new_assert_for (t, t, comp_code, value, 3900 bb, NULL, si); 3901 } 3902 } 3903 3904 register_new_assert_for (op, op, comp_code, value, bb, NULL, si); 3905 } 3906 } 3907 3908 /* Update live. */ 3909 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE) 3910 bitmap_set_bit (live, SSA_NAME_VERSION (op)); 3911 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_DEF) 3912 bitmap_clear_bit (live, SSA_NAME_VERSION (op)); 3913 } 3914 3915 /* Traverse all PHI nodes in BB, updating live. */ 3916 for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si); 3917 gsi_next (&si)) 3918 { 3919 use_operand_p arg_p; 3920 ssa_op_iter i; 3921 gphi *phi = si.phi (); 3922 tree res = gimple_phi_result (phi); 3923 3924 if (virtual_operand_p (res)) 3925 continue; 3926 3927 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE) 3928 { 3929 tree arg = USE_FROM_PTR (arg_p); 3930 if (TREE_CODE (arg) == SSA_NAME) 3931 bitmap_set_bit (live, SSA_NAME_VERSION (arg)); 3932 } 3933 3934 bitmap_clear_bit (live, SSA_NAME_VERSION (res)); 3935 } 3936 } 3937 3938 /* Do an RPO walk over the function computing SSA name liveness 3939 on-the-fly and deciding on assert expressions to insert. */ 3940 3941 static void 3942 find_assert_locations (void) 3943 { 3944 int *rpo = XNEWVEC (int, last_basic_block_for_fn (cfun)); 3945 int *bb_rpo = XNEWVEC (int, last_basic_block_for_fn (cfun)); 3946 int *last_rpo = XCNEWVEC (int, last_basic_block_for_fn (cfun)); 3947 int rpo_cnt, i; 3948 3949 live = XCNEWVEC (sbitmap, last_basic_block_for_fn (cfun)); 3950 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false); 3951 for (i = 0; i < rpo_cnt; ++i) 3952 bb_rpo[rpo[i]] = i; 3953 3954 /* Pre-seed loop latch liveness from loop header PHI nodes. Due to 3955 the order we compute liveness and insert asserts we otherwise 3956 fail to insert asserts into the loop latch. */ 3957 loop_p loop; 3958 FOR_EACH_LOOP (loop, 0) 3959 { 3960 i = loop->latch->index; 3961 unsigned int j = single_succ_edge (loop->latch)->dest_idx; 3962 for (gphi_iterator gsi = gsi_start_phis (loop->header); 3963 !gsi_end_p (gsi); gsi_next (&gsi)) 3964 { 3965 gphi *phi = gsi.phi (); 3966 if (virtual_operand_p (gimple_phi_result (phi))) 3967 continue; 3968 tree arg = gimple_phi_arg_def (phi, j); 3969 if (TREE_CODE (arg) == SSA_NAME) 3970 { 3971 if (live[i] == NULL) 3972 { 3973 live[i] = sbitmap_alloc (num_ssa_names); 3974 bitmap_clear (live[i]); 3975 } 3976 bitmap_set_bit (live[i], SSA_NAME_VERSION (arg)); 3977 } 3978 } 3979 } 3980 3981 for (i = rpo_cnt - 1; i >= 0; --i) 3982 { 3983 basic_block bb = BASIC_BLOCK_FOR_FN (cfun, rpo[i]); 3984 edge e; 3985 edge_iterator ei; 3986 3987 if (!live[rpo[i]]) 3988 { 3989 live[rpo[i]] = sbitmap_alloc (num_ssa_names); 3990 bitmap_clear (live[rpo[i]]); 3991 } 3992 3993 /* Process BB and update the live information with uses in 3994 this block. */ 3995 find_assert_locations_1 (bb, live[rpo[i]]); 3996 3997 /* Merge liveness into the predecessor blocks and free it. */ 3998 if (!bitmap_empty_p (live[rpo[i]])) 3999 { 4000 int pred_rpo = i; 4001 FOR_EACH_EDGE (e, ei, bb->preds) 4002 { 4003 int pred = e->src->index; 4004 if ((e->flags & EDGE_DFS_BACK) || pred == ENTRY_BLOCK) 4005 continue; 4006 4007 if (!live[pred]) 4008 { 4009 live[pred] = sbitmap_alloc (num_ssa_names); 4010 bitmap_clear (live[pred]); 4011 } 4012 bitmap_ior (live[pred], live[pred], live[rpo[i]]); 4013 4014 if (bb_rpo[pred] < pred_rpo) 4015 pred_rpo = bb_rpo[pred]; 4016 } 4017 4018 /* Record the RPO number of the last visited block that needs 4019 live information from this block. */ 4020 last_rpo[rpo[i]] = pred_rpo; 4021 } 4022 else 4023 { 4024 sbitmap_free (live[rpo[i]]); 4025 live[rpo[i]] = NULL; 4026 } 4027 4028 /* We can free all successors live bitmaps if all their 4029 predecessors have been visited already. */ 4030 FOR_EACH_EDGE (e, ei, bb->succs) 4031 if (last_rpo[e->dest->index] == i 4032 && live[e->dest->index]) 4033 { 4034 sbitmap_free (live[e->dest->index]); 4035 live[e->dest->index] = NULL; 4036 } 4037 } 4038 4039 XDELETEVEC (rpo); 4040 XDELETEVEC (bb_rpo); 4041 XDELETEVEC (last_rpo); 4042 for (i = 0; i < last_basic_block_for_fn (cfun); ++i) 4043 if (live[i]) 4044 sbitmap_free (live[i]); 4045 XDELETEVEC (live); 4046 } 4047 4048 /* Create an ASSERT_EXPR for NAME and insert it in the location 4049 indicated by LOC. Return true if we made any edge insertions. */ 4050 4051 static bool 4052 process_assert_insertions_for (tree name, assert_locus *loc) 4053 { 4054 /* Build the comparison expression NAME_i COMP_CODE VAL. */ 4055 gimple *stmt; 4056 tree cond; 4057 gimple *assert_stmt; 4058 edge_iterator ei; 4059 edge e; 4060 4061 /* If we have X <=> X do not insert an assert expr for that. */ 4062 if (loc->expr == loc->val) 4063 return false; 4064 4065 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val); 4066 assert_stmt = build_assert_expr_for (cond, name); 4067 if (loc->e) 4068 { 4069 /* We have been asked to insert the assertion on an edge. This 4070 is used only by COND_EXPR and SWITCH_EXPR assertions. */ 4071 gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND 4072 || (gimple_code (gsi_stmt (loc->si)) 4073 == GIMPLE_SWITCH)); 4074 4075 gsi_insert_on_edge (loc->e, assert_stmt); 4076 return true; 4077 } 4078 4079 /* If the stmt iterator points at the end then this is an insertion 4080 at the beginning of a block. */ 4081 if (gsi_end_p (loc->si)) 4082 { 4083 gimple_stmt_iterator si = gsi_after_labels (loc->bb); 4084 gsi_insert_before (&si, assert_stmt, GSI_SAME_STMT); 4085 return false; 4086 4087 } 4088 /* Otherwise, we can insert right after LOC->SI iff the 4089 statement must not be the last statement in the block. */ 4090 stmt = gsi_stmt (loc->si); 4091 if (!stmt_ends_bb_p (stmt)) 4092 { 4093 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT); 4094 return false; 4095 } 4096 4097 /* If STMT must be the last statement in BB, we can only insert new 4098 assertions on the non-abnormal edge out of BB. Note that since 4099 STMT is not control flow, there may only be one non-abnormal/eh edge 4100 out of BB. */ 4101 FOR_EACH_EDGE (e, ei, loc->bb->succs) 4102 if (!(e->flags & (EDGE_ABNORMAL|EDGE_EH))) 4103 { 4104 gsi_insert_on_edge (e, assert_stmt); 4105 return true; 4106 } 4107 4108 gcc_unreachable (); 4109 } 4110 4111 /* Qsort helper for sorting assert locations. If stable is true, don't 4112 use iterative_hash_expr because it can be unstable for -fcompare-debug, 4113 on the other side some pointers might be NULL. */ 4114 4115 template <bool stable> 4116 static int 4117 compare_assert_loc (const void *pa, const void *pb) 4118 { 4119 assert_locus * const a = *(assert_locus * const *)pa; 4120 assert_locus * const b = *(assert_locus * const *)pb; 4121 4122 /* If stable, some asserts might be optimized away already, sort 4123 them last. */ 4124 if (stable) 4125 { 4126 if (a == NULL) 4127 return b != NULL; 4128 else if (b == NULL) 4129 return -1; 4130 } 4131 4132 if (a->e == NULL && b->e != NULL) 4133 return 1; 4134 else if (a->e != NULL && b->e == NULL) 4135 return -1; 4136 4137 /* After the above checks, we know that (a->e == NULL) == (b->e == NULL), 4138 no need to test both a->e and b->e. */ 4139 4140 /* Sort after destination index. */ 4141 if (a->e == NULL) 4142 ; 4143 else if (a->e->dest->index > b->e->dest->index) 4144 return 1; 4145 else if (a->e->dest->index < b->e->dest->index) 4146 return -1; 4147 4148 /* Sort after comp_code. */ 4149 if (a->comp_code > b->comp_code) 4150 return 1; 4151 else if (a->comp_code < b->comp_code) 4152 return -1; 4153 4154 hashval_t ha, hb; 4155 4156 /* E.g. if a->val is ADDR_EXPR of a VAR_DECL, iterative_hash_expr 4157 uses DECL_UID of the VAR_DECL, so sorting might differ between 4158 -g and -g0. When doing the removal of redundant assert exprs 4159 and commonization to successors, this does not matter, but for 4160 the final sort needs to be stable. */ 4161 if (stable) 4162 { 4163 ha = 0; 4164 hb = 0; 4165 } 4166 else 4167 { 4168 ha = iterative_hash_expr (a->expr, iterative_hash_expr (a->val, 0)); 4169 hb = iterative_hash_expr (b->expr, iterative_hash_expr (b->val, 0)); 4170 } 4171 4172 /* Break the tie using hashing and source/bb index. */ 4173 if (ha == hb) 4174 return (a->e != NULL 4175 ? a->e->src->index - b->e->src->index 4176 : a->bb->index - b->bb->index); 4177 return ha > hb ? 1 : -1; 4178 } 4179 4180 /* Process all the insertions registered for every name N_i registered 4181 in NEED_ASSERT_FOR. The list of assertions to be inserted are 4182 found in ASSERTS_FOR[i]. */ 4183 4184 static void 4185 process_assert_insertions (void) 4186 { 4187 unsigned i; 4188 bitmap_iterator bi; 4189 bool update_edges_p = false; 4190 int num_asserts = 0; 4191 4192 if (dump_file && (dump_flags & TDF_DETAILS)) 4193 dump_all_asserts (dump_file); 4194 4195 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi) 4196 { 4197 assert_locus *loc = asserts_for[i]; 4198 gcc_assert (loc); 4199 4200 auto_vec<assert_locus *, 16> asserts; 4201 for (; loc; loc = loc->next) 4202 asserts.safe_push (loc); 4203 asserts.qsort (compare_assert_loc<false>); 4204 4205 /* Push down common asserts to successors and remove redundant ones. */ 4206 unsigned ecnt = 0; 4207 assert_locus *common = NULL; 4208 unsigned commonj = 0; 4209 for (unsigned j = 0; j < asserts.length (); ++j) 4210 { 4211 loc = asserts[j]; 4212 if (! loc->e) 4213 common = NULL; 4214 else if (! common 4215 || loc->e->dest != common->e->dest 4216 || loc->comp_code != common->comp_code 4217 || ! operand_equal_p (loc->val, common->val, 0) 4218 || ! operand_equal_p (loc->expr, common->expr, 0)) 4219 { 4220 commonj = j; 4221 common = loc; 4222 ecnt = 1; 4223 } 4224 else if (loc->e == asserts[j-1]->e) 4225 { 4226 /* Remove duplicate asserts. */ 4227 if (commonj == j - 1) 4228 { 4229 commonj = j; 4230 common = loc; 4231 } 4232 free (asserts[j-1]); 4233 asserts[j-1] = NULL; 4234 } 4235 else 4236 { 4237 ecnt++; 4238 if (EDGE_COUNT (common->e->dest->preds) == ecnt) 4239 { 4240 /* We have the same assertion on all incoming edges of a BB. 4241 Insert it at the beginning of that block. */ 4242 loc->bb = loc->e->dest; 4243 loc->e = NULL; 4244 loc->si = gsi_none (); 4245 common = NULL; 4246 /* Clear asserts commoned. */ 4247 for (; commonj != j; ++commonj) 4248 if (asserts[commonj]) 4249 { 4250 free (asserts[commonj]); 4251 asserts[commonj] = NULL; 4252 } 4253 } 4254 } 4255 } 4256 4257 /* The asserts vector sorting above might be unstable for 4258 -fcompare-debug, sort again to ensure a stable sort. */ 4259 asserts.qsort (compare_assert_loc<true>); 4260 for (unsigned j = 0; j < asserts.length (); ++j) 4261 { 4262 loc = asserts[j]; 4263 if (! loc) 4264 break; 4265 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc); 4266 num_asserts++; 4267 free (loc); 4268 } 4269 } 4270 4271 if (update_edges_p) 4272 gsi_commit_edge_inserts (); 4273 4274 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted", 4275 num_asserts); 4276 } 4277 4278 4279 /* Traverse the flowgraph looking for conditional jumps to insert range 4280 expressions. These range expressions are meant to provide information 4281 to optimizations that need to reason in terms of value ranges. They 4282 will not be expanded into RTL. For instance, given: 4283 4284 x = ... 4285 y = ... 4286 if (x < y) 4287 y = x - 2; 4288 else 4289 x = y + 3; 4290 4291 this pass will transform the code into: 4292 4293 x = ... 4294 y = ... 4295 if (x < y) 4296 { 4297 x = ASSERT_EXPR <x, x < y> 4298 y = x - 2 4299 } 4300 else 4301 { 4302 y = ASSERT_EXPR <y, x >= y> 4303 x = y + 3 4304 } 4305 4306 The idea is that once copy and constant propagation have run, other 4307 optimizations will be able to determine what ranges of values can 'x' 4308 take in different paths of the code, simply by checking the reaching 4309 definition of 'x'. */ 4310 4311 static void 4312 insert_range_assertions (void) 4313 { 4314 need_assert_for = BITMAP_ALLOC (NULL); 4315 asserts_for = XCNEWVEC (assert_locus *, num_ssa_names); 4316 4317 calculate_dominance_info (CDI_DOMINATORS); 4318 4319 find_assert_locations (); 4320 if (!bitmap_empty_p (need_assert_for)) 4321 { 4322 process_assert_insertions (); 4323 update_ssa (TODO_update_ssa_no_phi); 4324 } 4325 4326 if (dump_file && (dump_flags & TDF_DETAILS)) 4327 { 4328 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n"); 4329 dump_function_to_file (current_function_decl, dump_file, dump_flags); 4330 } 4331 4332 free (asserts_for); 4333 BITMAP_FREE (need_assert_for); 4334 } 4335 4336 class vrp_prop : public ssa_propagation_engine 4337 { 4338 public: 4339 enum ssa_prop_result visit_stmt (gimple *, edge *, tree *) FINAL OVERRIDE; 4340 enum ssa_prop_result visit_phi (gphi *) FINAL OVERRIDE; 4341 4342 void vrp_initialize (void); 4343 void vrp_finalize (bool); 4344 void check_all_array_refs (void); 4345 void check_array_ref (location_t, tree, bool); 4346 void check_mem_ref (location_t, tree, bool); 4347 void search_for_addr_array (tree, location_t); 4348 4349 class vr_values vr_values; 4350 /* Temporary delegator to minimize code churn. */ 4351 value_range *get_value_range (const_tree op) 4352 { return vr_values.get_value_range (op); } 4353 void set_defs_to_varying (gimple *stmt) 4354 { return vr_values.set_defs_to_varying (stmt); } 4355 void extract_range_from_stmt (gimple *stmt, edge *taken_edge_p, 4356 tree *output_p, value_range *vr) 4357 { vr_values.extract_range_from_stmt (stmt, taken_edge_p, output_p, vr); } 4358 bool update_value_range (const_tree op, value_range *vr) 4359 { return vr_values.update_value_range (op, vr); } 4360 void extract_range_basic (value_range *vr, gimple *stmt) 4361 { vr_values.extract_range_basic (vr, stmt); } 4362 void extract_range_from_phi_node (gphi *phi, value_range *vr) 4363 { vr_values.extract_range_from_phi_node (phi, vr); } 4364 }; 4365 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays 4366 and "struct" hacks. If VRP can determine that the 4367 array subscript is a constant, check if it is outside valid 4368 range. If the array subscript is a RANGE, warn if it is 4369 non-overlapping with valid range. 4370 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */ 4371 4372 void 4373 vrp_prop::check_array_ref (location_t location, tree ref, 4374 bool ignore_off_by_one) 4375 { 4376 const value_range *vr = NULL; 4377 tree low_sub, up_sub; 4378 tree low_bound, up_bound, up_bound_p1; 4379 4380 if (TREE_NO_WARNING (ref)) 4381 return; 4382 4383 low_sub = up_sub = TREE_OPERAND (ref, 1); 4384 up_bound = array_ref_up_bound (ref); 4385 4386 if (!up_bound 4387 || TREE_CODE (up_bound) != INTEGER_CST 4388 || (warn_array_bounds < 2 4389 && array_at_struct_end_p (ref))) 4390 { 4391 /* Accesses to trailing arrays via pointers may access storage 4392 beyond the types array bounds. For such arrays, or for flexible 4393 array members, as well as for other arrays of an unknown size, 4394 replace the upper bound with a more permissive one that assumes 4395 the size of the largest object is PTRDIFF_MAX. */ 4396 tree eltsize = array_ref_element_size (ref); 4397 4398 if (TREE_CODE (eltsize) != INTEGER_CST 4399 || integer_zerop (eltsize)) 4400 { 4401 up_bound = NULL_TREE; 4402 up_bound_p1 = NULL_TREE; 4403 } 4404 else 4405 { 4406 tree maxbound = TYPE_MAX_VALUE (ptrdiff_type_node); 4407 tree arg = TREE_OPERAND (ref, 0); 4408 poly_int64 off; 4409 4410 if (get_addr_base_and_unit_offset (arg, &off) && known_gt (off, 0)) 4411 maxbound = wide_int_to_tree (sizetype, 4412 wi::sub (wi::to_wide (maxbound), 4413 off)); 4414 else 4415 maxbound = fold_convert (sizetype, maxbound); 4416 4417 up_bound_p1 = int_const_binop (TRUNC_DIV_EXPR, maxbound, eltsize); 4418 4419 up_bound = int_const_binop (MINUS_EXPR, up_bound_p1, 4420 build_int_cst (ptrdiff_type_node, 1)); 4421 } 4422 } 4423 else 4424 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, 4425 build_int_cst (TREE_TYPE (up_bound), 1)); 4426 4427 low_bound = array_ref_low_bound (ref); 4428 4429 tree artype = TREE_TYPE (TREE_OPERAND (ref, 0)); 4430 4431 bool warned = false; 4432 4433 /* Empty array. */ 4434 if (up_bound && tree_int_cst_equal (low_bound, up_bound_p1)) 4435 warned = warning_at (location, OPT_Warray_bounds, 4436 "array subscript %E is above array bounds of %qT", 4437 low_bound, artype); 4438 4439 if (TREE_CODE (low_sub) == SSA_NAME) 4440 { 4441 vr = get_value_range (low_sub); 4442 if (!vr->undefined_p () && !vr->varying_p ()) 4443 { 4444 low_sub = vr->kind () == VR_RANGE ? vr->max () : vr->min (); 4445 up_sub = vr->kind () == VR_RANGE ? vr->min () : vr->max (); 4446 } 4447 } 4448 4449 if (vr && vr->kind () == VR_ANTI_RANGE) 4450 { 4451 if (up_bound 4452 && TREE_CODE (up_sub) == INTEGER_CST 4453 && (ignore_off_by_one 4454 ? tree_int_cst_lt (up_bound, up_sub) 4455 : tree_int_cst_le (up_bound, up_sub)) 4456 && TREE_CODE (low_sub) == INTEGER_CST 4457 && tree_int_cst_le (low_sub, low_bound)) 4458 warned = warning_at (location, OPT_Warray_bounds, 4459 "array subscript [%E, %E] is outside " 4460 "array bounds of %qT", 4461 low_sub, up_sub, artype); 4462 } 4463 else if (up_bound 4464 && TREE_CODE (up_sub) == INTEGER_CST 4465 && (ignore_off_by_one 4466 ? !tree_int_cst_le (up_sub, up_bound_p1) 4467 : !tree_int_cst_le (up_sub, up_bound))) 4468 { 4469 if (dump_file && (dump_flags & TDF_DETAILS)) 4470 { 4471 fprintf (dump_file, "Array bound warning for "); 4472 dump_generic_expr (MSG_NOTE, TDF_SLIM, ref); 4473 fprintf (dump_file, "\n"); 4474 } 4475 warned = warning_at (location, OPT_Warray_bounds, 4476 "array subscript %E is above array bounds of %qT", 4477 up_sub, artype); 4478 } 4479 else if (TREE_CODE (low_sub) == INTEGER_CST 4480 && tree_int_cst_lt (low_sub, low_bound)) 4481 { 4482 if (dump_file && (dump_flags & TDF_DETAILS)) 4483 { 4484 fprintf (dump_file, "Array bound warning for "); 4485 dump_generic_expr (MSG_NOTE, TDF_SLIM, ref); 4486 fprintf (dump_file, "\n"); 4487 } 4488 warned = warning_at (location, OPT_Warray_bounds, 4489 "array subscript %E is below array bounds of %qT", 4490 low_sub, artype); 4491 } 4492 4493 if (warned) 4494 { 4495 ref = TREE_OPERAND (ref, 0); 4496 4497 if (DECL_P (ref)) 4498 inform (DECL_SOURCE_LOCATION (ref), "while referencing %qD", ref); 4499 4500 TREE_NO_WARNING (ref) = 1; 4501 } 4502 } 4503 4504 /* Checks one MEM_REF in REF, located at LOCATION, for out-of-bounds 4505 references to string constants. If VRP can determine that the array 4506 subscript is a constant, check if it is outside valid range. 4507 If the array subscript is a RANGE, warn if it is non-overlapping 4508 with valid range. 4509 IGNORE_OFF_BY_ONE is true if the MEM_REF is inside an ADDR_EXPR 4510 (used to allow one-past-the-end indices for code that takes 4511 the address of the just-past-the-end element of an array). */ 4512 4513 void 4514 vrp_prop::check_mem_ref (location_t location, tree ref, 4515 bool ignore_off_by_one) 4516 { 4517 if (TREE_NO_WARNING (ref)) 4518 return; 4519 4520 tree arg = TREE_OPERAND (ref, 0); 4521 /* The constant and variable offset of the reference. */ 4522 tree cstoff = TREE_OPERAND (ref, 1); 4523 tree varoff = NULL_TREE; 4524 4525 const offset_int maxobjsize = tree_to_shwi (max_object_size ()); 4526 4527 /* The array or string constant bounds in bytes. Initially set 4528 to [-MAXOBJSIZE - 1, MAXOBJSIZE] until a tighter bound is 4529 determined. */ 4530 offset_int arrbounds[2] = { -maxobjsize - 1, maxobjsize }; 4531 4532 /* The minimum and maximum intermediate offset. For a reference 4533 to be valid, not only does the final offset/subscript must be 4534 in bounds but all intermediate offsets should be as well. 4535 GCC may be able to deal gracefully with such out-of-bounds 4536 offsets so the checking is only enbaled at -Warray-bounds=2 4537 where it may help detect bugs in uses of the intermediate 4538 offsets that could otherwise not be detectable. */ 4539 offset_int ioff = wi::to_offset (fold_convert (ptrdiff_type_node, cstoff)); 4540 offset_int extrema[2] = { 0, wi::abs (ioff) }; 4541 4542 /* The range of the byte offset into the reference. */ 4543 offset_int offrange[2] = { 0, 0 }; 4544 4545 const value_range *vr = NULL; 4546 4547 /* Determine the offsets and increment OFFRANGE for the bounds of each. 4548 The loop computes the range of the final offset for expressions such 4549 as (A + i0 + ... + iN)[CSTOFF] where i0 through iN are SSA_NAMEs in 4550 some range. */ 4551 const unsigned limit = PARAM_VALUE (PARAM_SSA_NAME_DEF_CHAIN_LIMIT); 4552 for (unsigned n = 0; TREE_CODE (arg) == SSA_NAME && n < limit; ++n) 4553 { 4554 gimple *def = SSA_NAME_DEF_STMT (arg); 4555 if (!is_gimple_assign (def)) 4556 break; 4557 4558 tree_code code = gimple_assign_rhs_code (def); 4559 if (code == POINTER_PLUS_EXPR) 4560 { 4561 arg = gimple_assign_rhs1 (def); 4562 varoff = gimple_assign_rhs2 (def); 4563 } 4564 else if (code == ASSERT_EXPR) 4565 { 4566 arg = TREE_OPERAND (gimple_assign_rhs1 (def), 0); 4567 continue; 4568 } 4569 else 4570 return; 4571 4572 /* VAROFF should always be a SSA_NAME here (and not even 4573 INTEGER_CST) but there's no point in taking chances. */ 4574 if (TREE_CODE (varoff) != SSA_NAME) 4575 break; 4576 4577 vr = get_value_range (varoff); 4578 if (!vr || vr->undefined_p () || vr->varying_p ()) 4579 break; 4580 4581 if (!vr->constant_p ()) 4582 break; 4583 4584 if (vr->kind () == VR_RANGE) 4585 { 4586 offset_int min 4587 = wi::to_offset (fold_convert (ptrdiff_type_node, vr->min ())); 4588 offset_int max 4589 = wi::to_offset (fold_convert (ptrdiff_type_node, vr->max ())); 4590 if (min < max) 4591 { 4592 offrange[0] += min; 4593 offrange[1] += max; 4594 } 4595 else 4596 { 4597 /* When MIN >= MAX, the offset is effectively in a union 4598 of two ranges: [-MAXOBJSIZE -1, MAX] and [MIN, MAXOBJSIZE]. 4599 Since there is no way to represent such a range across 4600 additions, conservatively add [-MAXOBJSIZE -1, MAXOBJSIZE] 4601 to OFFRANGE. */ 4602 offrange[0] += arrbounds[0]; 4603 offrange[1] += arrbounds[1]; 4604 } 4605 } 4606 else 4607 { 4608 /* For an anti-range, analogously to the above, conservatively 4609 add [-MAXOBJSIZE -1, MAXOBJSIZE] to OFFRANGE. */ 4610 offrange[0] += arrbounds[0]; 4611 offrange[1] += arrbounds[1]; 4612 } 4613 4614 /* Keep track of the minimum and maximum offset. */ 4615 if (offrange[1] < 0 && offrange[1] < extrema[0]) 4616 extrema[0] = offrange[1]; 4617 if (offrange[0] > 0 && offrange[0] > extrema[1]) 4618 extrema[1] = offrange[0]; 4619 4620 if (offrange[0] < arrbounds[0]) 4621 offrange[0] = arrbounds[0]; 4622 4623 if (offrange[1] > arrbounds[1]) 4624 offrange[1] = arrbounds[1]; 4625 } 4626 4627 if (TREE_CODE (arg) == ADDR_EXPR) 4628 { 4629 arg = TREE_OPERAND (arg, 0); 4630 if (TREE_CODE (arg) != STRING_CST 4631 && TREE_CODE (arg) != VAR_DECL) 4632 return; 4633 } 4634 else 4635 return; 4636 4637 /* The type of the object being referred to. It can be an array, 4638 string literal, or a non-array type when the MEM_REF represents 4639 a reference/subscript via a pointer to an object that is not 4640 an element of an array. References to members of structs and 4641 unions are excluded because MEM_REF doesn't make it possible 4642 to identify the member where the reference originated. 4643 Incomplete types are excluded as well because their size is 4644 not known. */ 4645 tree reftype = TREE_TYPE (arg); 4646 if (POINTER_TYPE_P (reftype) 4647 || !COMPLETE_TYPE_P (reftype) 4648 || TREE_CODE (TYPE_SIZE_UNIT (reftype)) != INTEGER_CST 4649 || RECORD_OR_UNION_TYPE_P (reftype)) 4650 return; 4651 4652 offset_int eltsize; 4653 if (TREE_CODE (reftype) == ARRAY_TYPE) 4654 { 4655 eltsize = wi::to_offset (TYPE_SIZE_UNIT (TREE_TYPE (reftype))); 4656 4657 if (tree dom = TYPE_DOMAIN (reftype)) 4658 { 4659 tree bnds[] = { TYPE_MIN_VALUE (dom), TYPE_MAX_VALUE (dom) }; 4660 if (array_at_struct_end_p (arg) 4661 || !bnds[0] || !bnds[1]) 4662 { 4663 arrbounds[0] = 0; 4664 arrbounds[1] = wi::lrshift (maxobjsize, wi::floor_log2 (eltsize)); 4665 } 4666 else 4667 { 4668 arrbounds[0] = wi::to_offset (bnds[0]) * eltsize; 4669 arrbounds[1] = (wi::to_offset (bnds[1]) + 1) * eltsize; 4670 } 4671 } 4672 else 4673 { 4674 arrbounds[0] = 0; 4675 arrbounds[1] = wi::lrshift (maxobjsize, wi::floor_log2 (eltsize)); 4676 } 4677 4678 if (TREE_CODE (ref) == MEM_REF) 4679 { 4680 /* For MEM_REF determine a tighter bound of the non-array 4681 element type. */ 4682 tree eltype = TREE_TYPE (reftype); 4683 while (TREE_CODE (eltype) == ARRAY_TYPE) 4684 eltype = TREE_TYPE (eltype); 4685 eltsize = wi::to_offset (TYPE_SIZE_UNIT (eltype)); 4686 } 4687 } 4688 else 4689 { 4690 eltsize = 1; 4691 arrbounds[0] = 0; 4692 arrbounds[1] = wi::to_offset (TYPE_SIZE_UNIT (reftype)); 4693 } 4694 4695 offrange[0] += ioff; 4696 offrange[1] += ioff; 4697 4698 /* Compute the more permissive upper bound when IGNORE_OFF_BY_ONE 4699 is set (when taking the address of the one-past-last element 4700 of an array) but always use the stricter bound in diagnostics. */ 4701 offset_int ubound = arrbounds[1]; 4702 if (ignore_off_by_one) 4703 ubound += 1; 4704 4705 if (offrange[0] >= ubound || offrange[1] < arrbounds[0]) 4706 { 4707 /* Treat a reference to a non-array object as one to an array 4708 of a single element. */ 4709 if (TREE_CODE (reftype) != ARRAY_TYPE) 4710 reftype = build_array_type_nelts (reftype, 1); 4711 4712 if (TREE_CODE (ref) == MEM_REF) 4713 { 4714 /* Extract the element type out of MEM_REF and use its size 4715 to compute the index to print in the diagnostic; arrays 4716 in MEM_REF don't mean anything. A type with no size like 4717 void is as good as having a size of 1. */ 4718 tree type = TREE_TYPE (ref); 4719 while (TREE_CODE (type) == ARRAY_TYPE) 4720 type = TREE_TYPE (type); 4721 if (tree size = TYPE_SIZE_UNIT (type)) 4722 { 4723 offrange[0] = offrange[0] / wi::to_offset (size); 4724 offrange[1] = offrange[1] / wi::to_offset (size); 4725 } 4726 } 4727 else 4728 { 4729 /* For anything other than MEM_REF, compute the index to 4730 print in the diagnostic as the offset over element size. */ 4731 offrange[0] = offrange[0] / eltsize; 4732 offrange[1] = offrange[1] / eltsize; 4733 } 4734 4735 bool warned; 4736 if (offrange[0] == offrange[1]) 4737 warned = warning_at (location, OPT_Warray_bounds, 4738 "array subscript %wi is outside array bounds " 4739 "of %qT", 4740 offrange[0].to_shwi (), reftype); 4741 else 4742 warned = warning_at (location, OPT_Warray_bounds, 4743 "array subscript [%wi, %wi] is outside " 4744 "array bounds of %qT", 4745 offrange[0].to_shwi (), 4746 offrange[1].to_shwi (), reftype); 4747 if (warned && DECL_P (arg)) 4748 inform (DECL_SOURCE_LOCATION (arg), "while referencing %qD", arg); 4749 4750 if (warned) 4751 TREE_NO_WARNING (ref) = 1; 4752 return; 4753 } 4754 4755 if (warn_array_bounds < 2) 4756 return; 4757 4758 /* At level 2 check also intermediate offsets. */ 4759 int i = 0; 4760 if (extrema[i] < -arrbounds[1] || extrema[i = 1] > ubound) 4761 { 4762 HOST_WIDE_INT tmpidx = extrema[i].to_shwi () / eltsize.to_shwi (); 4763 4764 if (warning_at (location, OPT_Warray_bounds, 4765 "intermediate array offset %wi is outside array bounds " 4766 "of %qT", tmpidx, reftype)) 4767 TREE_NO_WARNING (ref) = 1; 4768 } 4769 } 4770 4771 /* Searches if the expr T, located at LOCATION computes 4772 address of an ARRAY_REF, and call check_array_ref on it. */ 4773 4774 void 4775 vrp_prop::search_for_addr_array (tree t, location_t location) 4776 { 4777 /* Check each ARRAY_REF and MEM_REF in the reference chain. */ 4778 do 4779 { 4780 if (TREE_CODE (t) == ARRAY_REF) 4781 check_array_ref (location, t, true /*ignore_off_by_one*/); 4782 else if (TREE_CODE (t) == MEM_REF) 4783 check_mem_ref (location, t, true /*ignore_off_by_one*/); 4784 4785 t = TREE_OPERAND (t, 0); 4786 } 4787 while (handled_component_p (t) || TREE_CODE (t) == MEM_REF); 4788 4789 if (TREE_CODE (t) != MEM_REF 4790 || TREE_CODE (TREE_OPERAND (t, 0)) != ADDR_EXPR 4791 || TREE_NO_WARNING (t)) 4792 return; 4793 4794 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0); 4795 tree low_bound, up_bound, el_sz; 4796 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE 4797 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE 4798 || !TYPE_DOMAIN (TREE_TYPE (tem))) 4799 return; 4800 4801 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem))); 4802 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem))); 4803 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem))); 4804 if (!low_bound 4805 || TREE_CODE (low_bound) != INTEGER_CST 4806 || !up_bound 4807 || TREE_CODE (up_bound) != INTEGER_CST 4808 || !el_sz 4809 || TREE_CODE (el_sz) != INTEGER_CST) 4810 return; 4811 4812 offset_int idx; 4813 if (!mem_ref_offset (t).is_constant (&idx)) 4814 return; 4815 4816 bool warned = false; 4817 idx = wi::sdiv_trunc (idx, wi::to_offset (el_sz)); 4818 if (idx < 0) 4819 { 4820 if (dump_file && (dump_flags & TDF_DETAILS)) 4821 { 4822 fprintf (dump_file, "Array bound warning for "); 4823 dump_generic_expr (MSG_NOTE, TDF_SLIM, t); 4824 fprintf (dump_file, "\n"); 4825 } 4826 warned = warning_at (location, OPT_Warray_bounds, 4827 "array subscript %wi is below " 4828 "array bounds of %qT", 4829 idx.to_shwi (), TREE_TYPE (tem)); 4830 } 4831 else if (idx > (wi::to_offset (up_bound) 4832 - wi::to_offset (low_bound) + 1)) 4833 { 4834 if (dump_file && (dump_flags & TDF_DETAILS)) 4835 { 4836 fprintf (dump_file, "Array bound warning for "); 4837 dump_generic_expr (MSG_NOTE, TDF_SLIM, t); 4838 fprintf (dump_file, "\n"); 4839 } 4840 warned = warning_at (location, OPT_Warray_bounds, 4841 "array subscript %wu is above " 4842 "array bounds of %qT", 4843 idx.to_uhwi (), TREE_TYPE (tem)); 4844 } 4845 4846 if (warned) 4847 { 4848 if (DECL_P (t)) 4849 inform (DECL_SOURCE_LOCATION (t), "while referencing %qD", t); 4850 4851 TREE_NO_WARNING (t) = 1; 4852 } 4853 } 4854 4855 /* walk_tree() callback that checks if *TP is 4856 an ARRAY_REF inside an ADDR_EXPR (in which an array 4857 subscript one outside the valid range is allowed). Call 4858 check_array_ref for each ARRAY_REF found. The location is 4859 passed in DATA. */ 4860 4861 static tree 4862 check_array_bounds (tree *tp, int *walk_subtree, void *data) 4863 { 4864 tree t = *tp; 4865 struct walk_stmt_info *wi = (struct walk_stmt_info *) data; 4866 location_t location; 4867 4868 if (EXPR_HAS_LOCATION (t)) 4869 location = EXPR_LOCATION (t); 4870 else 4871 location = gimple_location (wi->stmt); 4872 4873 *walk_subtree = TRUE; 4874 4875 vrp_prop *vrp_prop = (class vrp_prop *)wi->info; 4876 if (TREE_CODE (t) == ARRAY_REF) 4877 vrp_prop->check_array_ref (location, t, false /*ignore_off_by_one*/); 4878 else if (TREE_CODE (t) == MEM_REF) 4879 vrp_prop->check_mem_ref (location, t, false /*ignore_off_by_one*/); 4880 else if (TREE_CODE (t) == ADDR_EXPR) 4881 { 4882 vrp_prop->search_for_addr_array (t, location); 4883 *walk_subtree = FALSE; 4884 } 4885 4886 return NULL_TREE; 4887 } 4888 4889 /* A dom_walker subclass for use by vrp_prop::check_all_array_refs, 4890 to walk over all statements of all reachable BBs and call 4891 check_array_bounds on them. */ 4892 4893 class check_array_bounds_dom_walker : public dom_walker 4894 { 4895 public: 4896 check_array_bounds_dom_walker (vrp_prop *prop) 4897 : dom_walker (CDI_DOMINATORS, 4898 /* Discover non-executable edges, preserving EDGE_EXECUTABLE 4899 flags, so that we can merge in information on 4900 non-executable edges from vrp_folder . */ 4901 REACHABLE_BLOCKS_PRESERVING_FLAGS), 4902 m_prop (prop) {} 4903 ~check_array_bounds_dom_walker () {} 4904 4905 edge before_dom_children (basic_block) FINAL OVERRIDE; 4906 4907 private: 4908 vrp_prop *m_prop; 4909 }; 4910 4911 /* Implementation of dom_walker::before_dom_children. 4912 4913 Walk over all statements of BB and call check_array_bounds on them, 4914 and determine if there's a unique successor edge. */ 4915 4916 edge 4917 check_array_bounds_dom_walker::before_dom_children (basic_block bb) 4918 { 4919 gimple_stmt_iterator si; 4920 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) 4921 { 4922 gimple *stmt = gsi_stmt (si); 4923 struct walk_stmt_info wi; 4924 if (!gimple_has_location (stmt) 4925 || is_gimple_debug (stmt)) 4926 continue; 4927 4928 memset (&wi, 0, sizeof (wi)); 4929 4930 wi.info = m_prop; 4931 4932 walk_gimple_op (stmt, check_array_bounds, &wi); 4933 } 4934 4935 /* Determine if there's a unique successor edge, and if so, return 4936 that back to dom_walker, ensuring that we don't visit blocks that 4937 became unreachable during the VRP propagation 4938 (PR tree-optimization/83312). */ 4939 return find_taken_edge (bb, NULL_TREE); 4940 } 4941 4942 /* Walk over all statements of all reachable BBs and call check_array_bounds 4943 on them. */ 4944 4945 void 4946 vrp_prop::check_all_array_refs () 4947 { 4948 check_array_bounds_dom_walker w (this); 4949 w.walk (ENTRY_BLOCK_PTR_FOR_FN (cfun)); 4950 } 4951 4952 /* Return true if all imm uses of VAR are either in STMT, or 4953 feed (optionally through a chain of single imm uses) GIMPLE_COND 4954 in basic block COND_BB. */ 4955 4956 static bool 4957 all_imm_uses_in_stmt_or_feed_cond (tree var, gimple *stmt, basic_block cond_bb) 4958 { 4959 use_operand_p use_p, use2_p; 4960 imm_use_iterator iter; 4961 4962 FOR_EACH_IMM_USE_FAST (use_p, iter, var) 4963 if (USE_STMT (use_p) != stmt) 4964 { 4965 gimple *use_stmt = USE_STMT (use_p), *use_stmt2; 4966 if (is_gimple_debug (use_stmt)) 4967 continue; 4968 while (is_gimple_assign (use_stmt) 4969 && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME 4970 && single_imm_use (gimple_assign_lhs (use_stmt), 4971 &use2_p, &use_stmt2)) 4972 use_stmt = use_stmt2; 4973 if (gimple_code (use_stmt) != GIMPLE_COND 4974 || gimple_bb (use_stmt) != cond_bb) 4975 return false; 4976 } 4977 return true; 4978 } 4979 4980 /* Handle 4981 _4 = x_3 & 31; 4982 if (_4 != 0) 4983 goto <bb 6>; 4984 else 4985 goto <bb 7>; 4986 <bb 6>: 4987 __builtin_unreachable (); 4988 <bb 7>: 4989 x_5 = ASSERT_EXPR <x_3, ...>; 4990 If x_3 has no other immediate uses (checked by caller), 4991 var is the x_3 var from ASSERT_EXPR, we can clear low 5 bits 4992 from the non-zero bitmask. */ 4993 4994 void 4995 maybe_set_nonzero_bits (edge e, tree var) 4996 { 4997 basic_block cond_bb = e->src; 4998 gimple *stmt = last_stmt (cond_bb); 4999 tree cst; 5000 5001 if (stmt == NULL 5002 || gimple_code (stmt) != GIMPLE_COND 5003 || gimple_cond_code (stmt) != ((e->flags & EDGE_TRUE_VALUE) 5004 ? EQ_EXPR : NE_EXPR) 5005 || TREE_CODE (gimple_cond_lhs (stmt)) != SSA_NAME 5006 || !integer_zerop (gimple_cond_rhs (stmt))) 5007 return; 5008 5009 stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (stmt)); 5010 if (!is_gimple_assign (stmt) 5011 || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR 5012 || TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST) 5013 return; 5014 if (gimple_assign_rhs1 (stmt) != var) 5015 { 5016 gimple *stmt2; 5017 5018 if (TREE_CODE (gimple_assign_rhs1 (stmt)) != SSA_NAME) 5019 return; 5020 stmt2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); 5021 if (!gimple_assign_cast_p (stmt2) 5022 || gimple_assign_rhs1 (stmt2) != var 5023 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt2)) 5024 || (TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt))) 5025 != TYPE_PRECISION (TREE_TYPE (var)))) 5026 return; 5027 } 5028 cst = gimple_assign_rhs2 (stmt); 5029 set_nonzero_bits (var, wi::bit_and_not (get_nonzero_bits (var), 5030 wi::to_wide (cst))); 5031 } 5032 5033 /* Convert range assertion expressions into the implied copies and 5034 copy propagate away the copies. Doing the trivial copy propagation 5035 here avoids the need to run the full copy propagation pass after 5036 VRP. 5037 5038 FIXME, this will eventually lead to copy propagation removing the 5039 names that had useful range information attached to them. For 5040 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>, 5041 then N_i will have the range [3, +INF]. 5042 5043 However, by converting the assertion into the implied copy 5044 operation N_i = N_j, we will then copy-propagate N_j into the uses 5045 of N_i and lose the range information. We may want to hold on to 5046 ASSERT_EXPRs a little while longer as the ranges could be used in 5047 things like jump threading. 5048 5049 The problem with keeping ASSERT_EXPRs around is that passes after 5050 VRP need to handle them appropriately. 5051 5052 Another approach would be to make the range information a first 5053 class property of the SSA_NAME so that it can be queried from 5054 any pass. This is made somewhat more complex by the need for 5055 multiple ranges to be associated with one SSA_NAME. */ 5056 5057 static void 5058 remove_range_assertions (void) 5059 { 5060 basic_block bb; 5061 gimple_stmt_iterator si; 5062 /* 1 if looking at ASSERT_EXPRs immediately at the beginning of 5063 a basic block preceeded by GIMPLE_COND branching to it and 5064 __builtin_trap, -1 if not yet checked, 0 otherwise. */ 5065 int is_unreachable; 5066 5067 /* Note that the BSI iterator bump happens at the bottom of the 5068 loop and no bump is necessary if we're removing the statement 5069 referenced by the current BSI. */ 5070 FOR_EACH_BB_FN (bb, cfun) 5071 for (si = gsi_after_labels (bb), is_unreachable = -1; !gsi_end_p (si);) 5072 { 5073 gimple *stmt = gsi_stmt (si); 5074 5075 if (is_gimple_assign (stmt) 5076 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR) 5077 { 5078 tree lhs = gimple_assign_lhs (stmt); 5079 tree rhs = gimple_assign_rhs1 (stmt); 5080 tree var; 5081 5082 var = ASSERT_EXPR_VAR (rhs); 5083 5084 if (TREE_CODE (var) == SSA_NAME 5085 && !POINTER_TYPE_P (TREE_TYPE (lhs)) 5086 && SSA_NAME_RANGE_INFO (lhs)) 5087 { 5088 if (is_unreachable == -1) 5089 { 5090 is_unreachable = 0; 5091 if (single_pred_p (bb) 5092 && assert_unreachable_fallthru_edge_p 5093 (single_pred_edge (bb))) 5094 is_unreachable = 1; 5095 } 5096 /* Handle 5097 if (x_7 >= 10 && x_7 < 20) 5098 __builtin_unreachable (); 5099 x_8 = ASSERT_EXPR <x_7, ...>; 5100 if the only uses of x_7 are in the ASSERT_EXPR and 5101 in the condition. In that case, we can copy the 5102 range info from x_8 computed in this pass also 5103 for x_7. */ 5104 if (is_unreachable 5105 && all_imm_uses_in_stmt_or_feed_cond (var, stmt, 5106 single_pred (bb))) 5107 { 5108 set_range_info (var, SSA_NAME_RANGE_TYPE (lhs), 5109 SSA_NAME_RANGE_INFO (lhs)->get_min (), 5110 SSA_NAME_RANGE_INFO (lhs)->get_max ()); 5111 maybe_set_nonzero_bits (single_pred_edge (bb), var); 5112 } 5113 } 5114 5115 /* Propagate the RHS into every use of the LHS. For SSA names 5116 also propagate abnormals as it merely restores the original 5117 IL in this case (an replace_uses_by would assert). */ 5118 if (TREE_CODE (var) == SSA_NAME) 5119 { 5120 imm_use_iterator iter; 5121 use_operand_p use_p; 5122 gimple *use_stmt; 5123 FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs) 5124 FOR_EACH_IMM_USE_ON_STMT (use_p, iter) 5125 SET_USE (use_p, var); 5126 } 5127 else 5128 replace_uses_by (lhs, var); 5129 5130 /* And finally, remove the copy, it is not needed. */ 5131 gsi_remove (&si, true); 5132 release_defs (stmt); 5133 } 5134 else 5135 { 5136 if (!is_gimple_debug (gsi_stmt (si))) 5137 is_unreachable = 0; 5138 gsi_next (&si); 5139 } 5140 } 5141 } 5142 5143 /* Return true if STMT is interesting for VRP. */ 5144 5145 bool 5146 stmt_interesting_for_vrp (gimple *stmt) 5147 { 5148 if (gimple_code (stmt) == GIMPLE_PHI) 5149 { 5150 tree res = gimple_phi_result (stmt); 5151 return (!virtual_operand_p (res) 5152 && (INTEGRAL_TYPE_P (TREE_TYPE (res)) 5153 || POINTER_TYPE_P (TREE_TYPE (res)))); 5154 } 5155 else if (is_gimple_assign (stmt) || is_gimple_call (stmt)) 5156 { 5157 tree lhs = gimple_get_lhs (stmt); 5158 5159 /* In general, assignments with virtual operands are not useful 5160 for deriving ranges, with the obvious exception of calls to 5161 builtin functions. */ 5162 if (lhs && TREE_CODE (lhs) == SSA_NAME 5163 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs)) 5164 || POINTER_TYPE_P (TREE_TYPE (lhs))) 5165 && (is_gimple_call (stmt) 5166 || !gimple_vuse (stmt))) 5167 return true; 5168 else if (is_gimple_call (stmt) && gimple_call_internal_p (stmt)) 5169 switch (gimple_call_internal_fn (stmt)) 5170 { 5171 case IFN_ADD_OVERFLOW: 5172 case IFN_SUB_OVERFLOW: 5173 case IFN_MUL_OVERFLOW: 5174 case IFN_ATOMIC_COMPARE_EXCHANGE: 5175 /* These internal calls return _Complex integer type, 5176 but are interesting to VRP nevertheless. */ 5177 if (lhs && TREE_CODE (lhs) == SSA_NAME) 5178 return true; 5179 break; 5180 default: 5181 break; 5182 } 5183 } 5184 else if (gimple_code (stmt) == GIMPLE_COND 5185 || gimple_code (stmt) == GIMPLE_SWITCH) 5186 return true; 5187 5188 return false; 5189 } 5190 5191 /* Initialization required by ssa_propagate engine. */ 5192 5193 void 5194 vrp_prop::vrp_initialize () 5195 { 5196 basic_block bb; 5197 5198 FOR_EACH_BB_FN (bb, cfun) 5199 { 5200 for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si); 5201 gsi_next (&si)) 5202 { 5203 gphi *phi = si.phi (); 5204 if (!stmt_interesting_for_vrp (phi)) 5205 { 5206 tree lhs = PHI_RESULT (phi); 5207 get_value_range (lhs)->set_varying (); 5208 prop_set_simulate_again (phi, false); 5209 } 5210 else 5211 prop_set_simulate_again (phi, true); 5212 } 5213 5214 for (gimple_stmt_iterator si = gsi_start_bb (bb); !gsi_end_p (si); 5215 gsi_next (&si)) 5216 { 5217 gimple *stmt = gsi_stmt (si); 5218 5219 /* If the statement is a control insn, then we do not 5220 want to avoid simulating the statement once. Failure 5221 to do so means that those edges will never get added. */ 5222 if (stmt_ends_bb_p (stmt)) 5223 prop_set_simulate_again (stmt, true); 5224 else if (!stmt_interesting_for_vrp (stmt)) 5225 { 5226 set_defs_to_varying (stmt); 5227 prop_set_simulate_again (stmt, false); 5228 } 5229 else 5230 prop_set_simulate_again (stmt, true); 5231 } 5232 } 5233 } 5234 5235 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL 5236 that includes the value VAL. The search is restricted to the range 5237 [START_IDX, n - 1] where n is the size of VEC. 5238 5239 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is 5240 returned. 5241 5242 If there is no CASE_LABEL for VAL and there is one that is larger than VAL, 5243 it is placed in IDX and false is returned. 5244 5245 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is 5246 returned. */ 5247 5248 bool 5249 find_case_label_index (gswitch *stmt, size_t start_idx, tree val, size_t *idx) 5250 { 5251 size_t n = gimple_switch_num_labels (stmt); 5252 size_t low, high; 5253 5254 /* Find case label for minimum of the value range or the next one. 5255 At each iteration we are searching in [low, high - 1]. */ 5256 5257 for (low = start_idx, high = n; high != low; ) 5258 { 5259 tree t; 5260 int cmp; 5261 /* Note that i != high, so we never ask for n. */ 5262 size_t i = (high + low) / 2; 5263 t = gimple_switch_label (stmt, i); 5264 5265 /* Cache the result of comparing CASE_LOW and val. */ 5266 cmp = tree_int_cst_compare (CASE_LOW (t), val); 5267 5268 if (cmp == 0) 5269 { 5270 /* Ranges cannot be empty. */ 5271 *idx = i; 5272 return true; 5273 } 5274 else if (cmp > 0) 5275 high = i; 5276 else 5277 { 5278 low = i + 1; 5279 if (CASE_HIGH (t) != NULL 5280 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0) 5281 { 5282 *idx = i; 5283 return true; 5284 } 5285 } 5286 } 5287 5288 *idx = high; 5289 return false; 5290 } 5291 5292 /* Searches the case label vector VEC for the range of CASE_LABELs that is used 5293 for values between MIN and MAX. The first index is placed in MIN_IDX. The 5294 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty 5295 then MAX_IDX < MIN_IDX. 5296 Returns true if the default label is not needed. */ 5297 5298 bool 5299 find_case_label_range (gswitch *stmt, tree min, tree max, size_t *min_idx, 5300 size_t *max_idx) 5301 { 5302 size_t i, j; 5303 bool min_take_default = !find_case_label_index (stmt, 1, min, &i); 5304 bool max_take_default = !find_case_label_index (stmt, i, max, &j); 5305 5306 if (i == j 5307 && min_take_default 5308 && max_take_default) 5309 { 5310 /* Only the default case label reached. 5311 Return an empty range. */ 5312 *min_idx = 1; 5313 *max_idx = 0; 5314 return false; 5315 } 5316 else 5317 { 5318 bool take_default = min_take_default || max_take_default; 5319 tree low, high; 5320 size_t k; 5321 5322 if (max_take_default) 5323 j--; 5324 5325 /* If the case label range is continuous, we do not need 5326 the default case label. Verify that. */ 5327 high = CASE_LOW (gimple_switch_label (stmt, i)); 5328 if (CASE_HIGH (gimple_switch_label (stmt, i))) 5329 high = CASE_HIGH (gimple_switch_label (stmt, i)); 5330 for (k = i + 1; k <= j; ++k) 5331 { 5332 low = CASE_LOW (gimple_switch_label (stmt, k)); 5333 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high))) 5334 { 5335 take_default = true; 5336 break; 5337 } 5338 high = low; 5339 if (CASE_HIGH (gimple_switch_label (stmt, k))) 5340 high = CASE_HIGH (gimple_switch_label (stmt, k)); 5341 } 5342 5343 *min_idx = i; 5344 *max_idx = j; 5345 return !take_default; 5346 } 5347 } 5348 5349 /* Evaluate statement STMT. If the statement produces a useful range, 5350 return SSA_PROP_INTERESTING and record the SSA name with the 5351 interesting range into *OUTPUT_P. 5352 5353 If STMT is a conditional branch and we can determine its truth 5354 value, the taken edge is recorded in *TAKEN_EDGE_P. 5355 5356 If STMT produces a varying value, return SSA_PROP_VARYING. */ 5357 5358 enum ssa_prop_result 5359 vrp_prop::visit_stmt (gimple *stmt, edge *taken_edge_p, tree *output_p) 5360 { 5361 tree lhs = gimple_get_lhs (stmt); 5362 value_range vr; 5363 extract_range_from_stmt (stmt, taken_edge_p, output_p, &vr); 5364 5365 if (*output_p) 5366 { 5367 if (update_value_range (*output_p, &vr)) 5368 { 5369 if (dump_file && (dump_flags & TDF_DETAILS)) 5370 { 5371 fprintf (dump_file, "Found new range for "); 5372 print_generic_expr (dump_file, *output_p); 5373 fprintf (dump_file, ": "); 5374 dump_value_range (dump_file, &vr); 5375 fprintf (dump_file, "\n"); 5376 } 5377 5378 if (vr.varying_p ()) 5379 return SSA_PROP_VARYING; 5380 5381 return SSA_PROP_INTERESTING; 5382 } 5383 return SSA_PROP_NOT_INTERESTING; 5384 } 5385 5386 if (is_gimple_call (stmt) && gimple_call_internal_p (stmt)) 5387 switch (gimple_call_internal_fn (stmt)) 5388 { 5389 case IFN_ADD_OVERFLOW: 5390 case IFN_SUB_OVERFLOW: 5391 case IFN_MUL_OVERFLOW: 5392 case IFN_ATOMIC_COMPARE_EXCHANGE: 5393 /* These internal calls return _Complex integer type, 5394 which VRP does not track, but the immediate uses 5395 thereof might be interesting. */ 5396 if (lhs && TREE_CODE (lhs) == SSA_NAME) 5397 { 5398 imm_use_iterator iter; 5399 use_operand_p use_p; 5400 enum ssa_prop_result res = SSA_PROP_VARYING; 5401 5402 get_value_range (lhs)->set_varying (); 5403 5404 FOR_EACH_IMM_USE_FAST (use_p, iter, lhs) 5405 { 5406 gimple *use_stmt = USE_STMT (use_p); 5407 if (!is_gimple_assign (use_stmt)) 5408 continue; 5409 enum tree_code rhs_code = gimple_assign_rhs_code (use_stmt); 5410 if (rhs_code != REALPART_EXPR && rhs_code != IMAGPART_EXPR) 5411 continue; 5412 tree rhs1 = gimple_assign_rhs1 (use_stmt); 5413 tree use_lhs = gimple_assign_lhs (use_stmt); 5414 if (TREE_CODE (rhs1) != rhs_code 5415 || TREE_OPERAND (rhs1, 0) != lhs 5416 || TREE_CODE (use_lhs) != SSA_NAME 5417 || !stmt_interesting_for_vrp (use_stmt) 5418 || (!INTEGRAL_TYPE_P (TREE_TYPE (use_lhs)) 5419 || !TYPE_MIN_VALUE (TREE_TYPE (use_lhs)) 5420 || !TYPE_MAX_VALUE (TREE_TYPE (use_lhs)))) 5421 continue; 5422 5423 /* If there is a change in the value range for any of the 5424 REALPART_EXPR/IMAGPART_EXPR immediate uses, return 5425 SSA_PROP_INTERESTING. If there are any REALPART_EXPR 5426 or IMAGPART_EXPR immediate uses, but none of them have 5427 a change in their value ranges, return 5428 SSA_PROP_NOT_INTERESTING. If there are no 5429 {REAL,IMAG}PART_EXPR uses at all, 5430 return SSA_PROP_VARYING. */ 5431 value_range new_vr; 5432 extract_range_basic (&new_vr, use_stmt); 5433 const value_range *old_vr = get_value_range (use_lhs); 5434 if (!old_vr->equal_p (new_vr, /*ignore_equivs=*/false)) 5435 res = SSA_PROP_INTERESTING; 5436 else 5437 res = SSA_PROP_NOT_INTERESTING; 5438 new_vr.equiv_clear (); 5439 if (res == SSA_PROP_INTERESTING) 5440 { 5441 *output_p = lhs; 5442 return res; 5443 } 5444 } 5445 5446 return res; 5447 } 5448 break; 5449 default: 5450 break; 5451 } 5452 5453 /* All other statements produce nothing of interest for VRP, so mark 5454 their outputs varying and prevent further simulation. */ 5455 set_defs_to_varying (stmt); 5456 5457 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING; 5458 } 5459 5460 /* Union the two value-ranges { *VR0TYPE, *VR0MIN, *VR0MAX } and 5461 { VR1TYPE, VR0MIN, VR0MAX } and store the result 5462 in { *VR0TYPE, *VR0MIN, *VR0MAX }. This may not be the smallest 5463 possible such range. The resulting range is not canonicalized. */ 5464 5465 static void 5466 union_ranges (enum value_range_kind *vr0type, 5467 tree *vr0min, tree *vr0max, 5468 enum value_range_kind vr1type, 5469 tree vr1min, tree vr1max) 5470 { 5471 bool mineq = vrp_operand_equal_p (*vr0min, vr1min); 5472 bool maxeq = vrp_operand_equal_p (*vr0max, vr1max); 5473 5474 /* [] is vr0, () is vr1 in the following classification comments. */ 5475 if (mineq && maxeq) 5476 { 5477 /* [( )] */ 5478 if (*vr0type == vr1type) 5479 /* Nothing to do for equal ranges. */ 5480 ; 5481 else if ((*vr0type == VR_RANGE 5482 && vr1type == VR_ANTI_RANGE) 5483 || (*vr0type == VR_ANTI_RANGE 5484 && vr1type == VR_RANGE)) 5485 { 5486 /* For anti-range with range union the result is varying. */ 5487 goto give_up; 5488 } 5489 else 5490 gcc_unreachable (); 5491 } 5492 else if (operand_less_p (*vr0max, vr1min) == 1 5493 || operand_less_p (vr1max, *vr0min) == 1) 5494 { 5495 /* [ ] ( ) or ( ) [ ] 5496 If the ranges have an empty intersection, result of the union 5497 operation is the anti-range or if both are anti-ranges 5498 it covers all. */ 5499 if (*vr0type == VR_ANTI_RANGE 5500 && vr1type == VR_ANTI_RANGE) 5501 goto give_up; 5502 else if (*vr0type == VR_ANTI_RANGE 5503 && vr1type == VR_RANGE) 5504 ; 5505 else if (*vr0type == VR_RANGE 5506 && vr1type == VR_ANTI_RANGE) 5507 { 5508 *vr0type = vr1type; 5509 *vr0min = vr1min; 5510 *vr0max = vr1max; 5511 } 5512 else if (*vr0type == VR_RANGE 5513 && vr1type == VR_RANGE) 5514 { 5515 /* The result is the convex hull of both ranges. */ 5516 if (operand_less_p (*vr0max, vr1min) == 1) 5517 { 5518 /* If the result can be an anti-range, create one. */ 5519 if (TREE_CODE (*vr0max) == INTEGER_CST 5520 && TREE_CODE (vr1min) == INTEGER_CST 5521 && vrp_val_is_min (*vr0min) 5522 && vrp_val_is_max (vr1max)) 5523 { 5524 tree min = int_const_binop (PLUS_EXPR, 5525 *vr0max, 5526 build_int_cst (TREE_TYPE (*vr0max), 1)); 5527 tree max = int_const_binop (MINUS_EXPR, 5528 vr1min, 5529 build_int_cst (TREE_TYPE (vr1min), 1)); 5530 if (!operand_less_p (max, min)) 5531 { 5532 *vr0type = VR_ANTI_RANGE; 5533 *vr0min = min; 5534 *vr0max = max; 5535 } 5536 else 5537 *vr0max = vr1max; 5538 } 5539 else 5540 *vr0max = vr1max; 5541 } 5542 else 5543 { 5544 /* If the result can be an anti-range, create one. */ 5545 if (TREE_CODE (vr1max) == INTEGER_CST 5546 && TREE_CODE (*vr0min) == INTEGER_CST 5547 && vrp_val_is_min (vr1min) 5548 && vrp_val_is_max (*vr0max)) 5549 { 5550 tree min = int_const_binop (PLUS_EXPR, 5551 vr1max, 5552 build_int_cst (TREE_TYPE (vr1max), 1)); 5553 tree max = int_const_binop (MINUS_EXPR, 5554 *vr0min, 5555 build_int_cst (TREE_TYPE (*vr0min), 1)); 5556 if (!operand_less_p (max, min)) 5557 { 5558 *vr0type = VR_ANTI_RANGE; 5559 *vr0min = min; 5560 *vr0max = max; 5561 } 5562 else 5563 *vr0min = vr1min; 5564 } 5565 else 5566 *vr0min = vr1min; 5567 } 5568 } 5569 else 5570 gcc_unreachable (); 5571 } 5572 else if ((maxeq || operand_less_p (vr1max, *vr0max) == 1) 5573 && (mineq || operand_less_p (*vr0min, vr1min) == 1)) 5574 { 5575 /* [ ( ) ] or [( ) ] or [ ( )] */ 5576 if (*vr0type == VR_RANGE 5577 && vr1type == VR_RANGE) 5578 ; 5579 else if (*vr0type == VR_ANTI_RANGE 5580 && vr1type == VR_ANTI_RANGE) 5581 { 5582 *vr0type = vr1type; 5583 *vr0min = vr1min; 5584 *vr0max = vr1max; 5585 } 5586 else if (*vr0type == VR_ANTI_RANGE 5587 && vr1type == VR_RANGE) 5588 { 5589 /* Arbitrarily choose the right or left gap. */ 5590 if (!mineq && TREE_CODE (vr1min) == INTEGER_CST) 5591 *vr0max = int_const_binop (MINUS_EXPR, vr1min, 5592 build_int_cst (TREE_TYPE (vr1min), 1)); 5593 else if (!maxeq && TREE_CODE (vr1max) == INTEGER_CST) 5594 *vr0min = int_const_binop (PLUS_EXPR, vr1max, 5595 build_int_cst (TREE_TYPE (vr1max), 1)); 5596 else 5597 goto give_up; 5598 } 5599 else if (*vr0type == VR_RANGE 5600 && vr1type == VR_ANTI_RANGE) 5601 /* The result covers everything. */ 5602 goto give_up; 5603 else 5604 gcc_unreachable (); 5605 } 5606 else if ((maxeq || operand_less_p (*vr0max, vr1max) == 1) 5607 && (mineq || operand_less_p (vr1min, *vr0min) == 1)) 5608 { 5609 /* ( [ ] ) or ([ ] ) or ( [ ]) */ 5610 if (*vr0type == VR_RANGE 5611 && vr1type == VR_RANGE) 5612 { 5613 *vr0type = vr1type; 5614 *vr0min = vr1min; 5615 *vr0max = vr1max; 5616 } 5617 else if (*vr0type == VR_ANTI_RANGE 5618 && vr1type == VR_ANTI_RANGE) 5619 ; 5620 else if (*vr0type == VR_RANGE 5621 && vr1type == VR_ANTI_RANGE) 5622 { 5623 *vr0type = VR_ANTI_RANGE; 5624 if (!mineq && TREE_CODE (*vr0min) == INTEGER_CST) 5625 { 5626 *vr0max = int_const_binop (MINUS_EXPR, *vr0min, 5627 build_int_cst (TREE_TYPE (*vr0min), 1)); 5628 *vr0min = vr1min; 5629 } 5630 else if (!maxeq && TREE_CODE (*vr0max) == INTEGER_CST) 5631 { 5632 *vr0min = int_const_binop (PLUS_EXPR, *vr0max, 5633 build_int_cst (TREE_TYPE (*vr0max), 1)); 5634 *vr0max = vr1max; 5635 } 5636 else 5637 goto give_up; 5638 } 5639 else if (*vr0type == VR_ANTI_RANGE 5640 && vr1type == VR_RANGE) 5641 /* The result covers everything. */ 5642 goto give_up; 5643 else 5644 gcc_unreachable (); 5645 } 5646 else if ((operand_less_p (vr1min, *vr0max) == 1 5647 || operand_equal_p (vr1min, *vr0max, 0)) 5648 && operand_less_p (*vr0min, vr1min) == 1 5649 && operand_less_p (*vr0max, vr1max) == 1) 5650 { 5651 /* [ ( ] ) or [ ]( ) */ 5652 if (*vr0type == VR_RANGE 5653 && vr1type == VR_RANGE) 5654 *vr0max = vr1max; 5655 else if (*vr0type == VR_ANTI_RANGE 5656 && vr1type == VR_ANTI_RANGE) 5657 *vr0min = vr1min; 5658 else if (*vr0type == VR_ANTI_RANGE 5659 && vr1type == VR_RANGE) 5660 { 5661 if (TREE_CODE (vr1min) == INTEGER_CST) 5662 *vr0max = int_const_binop (MINUS_EXPR, vr1min, 5663 build_int_cst (TREE_TYPE (vr1min), 1)); 5664 else 5665 goto give_up; 5666 } 5667 else if (*vr0type == VR_RANGE 5668 && vr1type == VR_ANTI_RANGE) 5669 { 5670 if (TREE_CODE (*vr0max) == INTEGER_CST) 5671 { 5672 *vr0type = vr1type; 5673 *vr0min = int_const_binop (PLUS_EXPR, *vr0max, 5674 build_int_cst (TREE_TYPE (*vr0max), 1)); 5675 *vr0max = vr1max; 5676 } 5677 else 5678 goto give_up; 5679 } 5680 else 5681 gcc_unreachable (); 5682 } 5683 else if ((operand_less_p (*vr0min, vr1max) == 1 5684 || operand_equal_p (*vr0min, vr1max, 0)) 5685 && operand_less_p (vr1min, *vr0min) == 1 5686 && operand_less_p (vr1max, *vr0max) == 1) 5687 { 5688 /* ( [ ) ] or ( )[ ] */ 5689 if (*vr0type == VR_RANGE 5690 && vr1type == VR_RANGE) 5691 *vr0min = vr1min; 5692 else if (*vr0type == VR_ANTI_RANGE 5693 && vr1type == VR_ANTI_RANGE) 5694 *vr0max = vr1max; 5695 else if (*vr0type == VR_ANTI_RANGE 5696 && vr1type == VR_RANGE) 5697 { 5698 if (TREE_CODE (vr1max) == INTEGER_CST) 5699 *vr0min = int_const_binop (PLUS_EXPR, vr1max, 5700 build_int_cst (TREE_TYPE (vr1max), 1)); 5701 else 5702 goto give_up; 5703 } 5704 else if (*vr0type == VR_RANGE 5705 && vr1type == VR_ANTI_RANGE) 5706 { 5707 if (TREE_CODE (*vr0min) == INTEGER_CST) 5708 { 5709 *vr0type = vr1type; 5710 *vr0max = int_const_binop (MINUS_EXPR, *vr0min, 5711 build_int_cst (TREE_TYPE (*vr0min), 1)); 5712 *vr0min = vr1min; 5713 } 5714 else 5715 goto give_up; 5716 } 5717 else 5718 gcc_unreachable (); 5719 } 5720 else 5721 goto give_up; 5722 5723 return; 5724 5725 give_up: 5726 *vr0type = VR_VARYING; 5727 *vr0min = NULL_TREE; 5728 *vr0max = NULL_TREE; 5729 } 5730 5731 /* Intersect the two value-ranges { *VR0TYPE, *VR0MIN, *VR0MAX } and 5732 { VR1TYPE, VR0MIN, VR0MAX } and store the result 5733 in { *VR0TYPE, *VR0MIN, *VR0MAX }. This may not be the smallest 5734 possible such range. The resulting range is not canonicalized. */ 5735 5736 static void 5737 intersect_ranges (enum value_range_kind *vr0type, 5738 tree *vr0min, tree *vr0max, 5739 enum value_range_kind vr1type, 5740 tree vr1min, tree vr1max) 5741 { 5742 bool mineq = vrp_operand_equal_p (*vr0min, vr1min); 5743 bool maxeq = vrp_operand_equal_p (*vr0max, vr1max); 5744 5745 /* [] is vr0, () is vr1 in the following classification comments. */ 5746 if (mineq && maxeq) 5747 { 5748 /* [( )] */ 5749 if (*vr0type == vr1type) 5750 /* Nothing to do for equal ranges. */ 5751 ; 5752 else if ((*vr0type == VR_RANGE 5753 && vr1type == VR_ANTI_RANGE) 5754 || (*vr0type == VR_ANTI_RANGE 5755 && vr1type == VR_RANGE)) 5756 { 5757 /* For anti-range with range intersection the result is empty. */ 5758 *vr0type = VR_UNDEFINED; 5759 *vr0min = NULL_TREE; 5760 *vr0max = NULL_TREE; 5761 } 5762 else 5763 gcc_unreachable (); 5764 } 5765 else if (operand_less_p (*vr0max, vr1min) == 1 5766 || operand_less_p (vr1max, *vr0min) == 1) 5767 { 5768 /* [ ] ( ) or ( ) [ ] 5769 If the ranges have an empty intersection, the result of the 5770 intersect operation is the range for intersecting an 5771 anti-range with a range or empty when intersecting two ranges. */ 5772 if (*vr0type == VR_RANGE 5773 && vr1type == VR_ANTI_RANGE) 5774 ; 5775 else if (*vr0type == VR_ANTI_RANGE 5776 && vr1type == VR_RANGE) 5777 { 5778 *vr0type = vr1type; 5779 *vr0min = vr1min; 5780 *vr0max = vr1max; 5781 } 5782 else if (*vr0type == VR_RANGE 5783 && vr1type == VR_RANGE) 5784 { 5785 *vr0type = VR_UNDEFINED; 5786 *vr0min = NULL_TREE; 5787 *vr0max = NULL_TREE; 5788 } 5789 else if (*vr0type == VR_ANTI_RANGE 5790 && vr1type == VR_ANTI_RANGE) 5791 { 5792 /* If the anti-ranges are adjacent to each other merge them. */ 5793 if (TREE_CODE (*vr0max) == INTEGER_CST 5794 && TREE_CODE (vr1min) == INTEGER_CST 5795 && operand_less_p (*vr0max, vr1min) == 1 5796 && integer_onep (int_const_binop (MINUS_EXPR, 5797 vr1min, *vr0max))) 5798 *vr0max = vr1max; 5799 else if (TREE_CODE (vr1max) == INTEGER_CST 5800 && TREE_CODE (*vr0min) == INTEGER_CST 5801 && operand_less_p (vr1max, *vr0min) == 1 5802 && integer_onep (int_const_binop (MINUS_EXPR, 5803 *vr0min, vr1max))) 5804 *vr0min = vr1min; 5805 /* Else arbitrarily take VR0. */ 5806 } 5807 } 5808 else if ((maxeq || operand_less_p (vr1max, *vr0max) == 1) 5809 && (mineq || operand_less_p (*vr0min, vr1min) == 1)) 5810 { 5811 /* [ ( ) ] or [( ) ] or [ ( )] */ 5812 if (*vr0type == VR_RANGE 5813 && vr1type == VR_RANGE) 5814 { 5815 /* If both are ranges the result is the inner one. */ 5816 *vr0type = vr1type; 5817 *vr0min = vr1min; 5818 *vr0max = vr1max; 5819 } 5820 else if (*vr0type == VR_RANGE 5821 && vr1type == VR_ANTI_RANGE) 5822 { 5823 /* Choose the right gap if the left one is empty. */ 5824 if (mineq) 5825 { 5826 if (TREE_CODE (vr1max) != INTEGER_CST) 5827 *vr0min = vr1max; 5828 else if (TYPE_PRECISION (TREE_TYPE (vr1max)) == 1 5829 && !TYPE_UNSIGNED (TREE_TYPE (vr1max))) 5830 *vr0min 5831 = int_const_binop (MINUS_EXPR, vr1max, 5832 build_int_cst (TREE_TYPE (vr1max), -1)); 5833 else 5834 *vr0min 5835 = int_const_binop (PLUS_EXPR, vr1max, 5836 build_int_cst (TREE_TYPE (vr1max), 1)); 5837 } 5838 /* Choose the left gap if the right one is empty. */ 5839 else if (maxeq) 5840 { 5841 if (TREE_CODE (vr1min) != INTEGER_CST) 5842 *vr0max = vr1min; 5843 else if (TYPE_PRECISION (TREE_TYPE (vr1min)) == 1 5844 && !TYPE_UNSIGNED (TREE_TYPE (vr1min))) 5845 *vr0max 5846 = int_const_binop (PLUS_EXPR, vr1min, 5847 build_int_cst (TREE_TYPE (vr1min), -1)); 5848 else 5849 *vr0max 5850 = int_const_binop (MINUS_EXPR, vr1min, 5851 build_int_cst (TREE_TYPE (vr1min), 1)); 5852 } 5853 /* Choose the anti-range if the range is effectively varying. */ 5854 else if (vrp_val_is_min (*vr0min) 5855 && vrp_val_is_max (*vr0max)) 5856 { 5857 *vr0type = vr1type; 5858 *vr0min = vr1min; 5859 *vr0max = vr1max; 5860 } 5861 /* Else choose the range. */ 5862 } 5863 else if (*vr0type == VR_ANTI_RANGE 5864 && vr1type == VR_ANTI_RANGE) 5865 /* If both are anti-ranges the result is the outer one. */ 5866 ; 5867 else if (*vr0type == VR_ANTI_RANGE 5868 && vr1type == VR_RANGE) 5869 { 5870 /* The intersection is empty. */ 5871 *vr0type = VR_UNDEFINED; 5872 *vr0min = NULL_TREE; 5873 *vr0max = NULL_TREE; 5874 } 5875 else 5876 gcc_unreachable (); 5877 } 5878 else if ((maxeq || operand_less_p (*vr0max, vr1max) == 1) 5879 && (mineq || operand_less_p (vr1min, *vr0min) == 1)) 5880 { 5881 /* ( [ ] ) or ([ ] ) or ( [ ]) */ 5882 if (*vr0type == VR_RANGE 5883 && vr1type == VR_RANGE) 5884 /* Choose the inner range. */ 5885 ; 5886 else if (*vr0type == VR_ANTI_RANGE 5887 && vr1type == VR_RANGE) 5888 { 5889 /* Choose the right gap if the left is empty. */ 5890 if (mineq) 5891 { 5892 *vr0type = VR_RANGE; 5893 if (TREE_CODE (*vr0max) != INTEGER_CST) 5894 *vr0min = *vr0max; 5895 else if (TYPE_PRECISION (TREE_TYPE (*vr0max)) == 1 5896 && !TYPE_UNSIGNED (TREE_TYPE (*vr0max))) 5897 *vr0min 5898 = int_const_binop (MINUS_EXPR, *vr0max, 5899 build_int_cst (TREE_TYPE (*vr0max), -1)); 5900 else 5901 *vr0min 5902 = int_const_binop (PLUS_EXPR, *vr0max, 5903 build_int_cst (TREE_TYPE (*vr0max), 1)); 5904 *vr0max = vr1max; 5905 } 5906 /* Choose the left gap if the right is empty. */ 5907 else if (maxeq) 5908 { 5909 *vr0type = VR_RANGE; 5910 if (TREE_CODE (*vr0min) != INTEGER_CST) 5911 *vr0max = *vr0min; 5912 else if (TYPE_PRECISION (TREE_TYPE (*vr0min)) == 1 5913 && !TYPE_UNSIGNED (TREE_TYPE (*vr0min))) 5914 *vr0max 5915 = int_const_binop (PLUS_EXPR, *vr0min, 5916 build_int_cst (TREE_TYPE (*vr0min), -1)); 5917 else 5918 *vr0max 5919 = int_const_binop (MINUS_EXPR, *vr0min, 5920 build_int_cst (TREE_TYPE (*vr0min), 1)); 5921 *vr0min = vr1min; 5922 } 5923 /* Choose the anti-range if the range is effectively varying. */ 5924 else if (vrp_val_is_min (vr1min) 5925 && vrp_val_is_max (vr1max)) 5926 ; 5927 /* Choose the anti-range if it is ~[0,0], that range is special 5928 enough to special case when vr1's range is relatively wide. 5929 At least for types bigger than int - this covers pointers 5930 and arguments to functions like ctz. */ 5931 else if (*vr0min == *vr0max 5932 && integer_zerop (*vr0min) 5933 && ((TYPE_PRECISION (TREE_TYPE (*vr0min)) 5934 >= TYPE_PRECISION (integer_type_node)) 5935 || POINTER_TYPE_P (TREE_TYPE (*vr0min))) 5936 && TREE_CODE (vr1max) == INTEGER_CST 5937 && TREE_CODE (vr1min) == INTEGER_CST 5938 && (wi::clz (wi::to_wide (vr1max) - wi::to_wide (vr1min)) 5939 < TYPE_PRECISION (TREE_TYPE (*vr0min)) / 2)) 5940 ; 5941 /* Else choose the range. */ 5942 else 5943 { 5944 *vr0type = vr1type; 5945 *vr0min = vr1min; 5946 *vr0max = vr1max; 5947 } 5948 } 5949 else if (*vr0type == VR_ANTI_RANGE 5950 && vr1type == VR_ANTI_RANGE) 5951 { 5952 /* If both are anti-ranges the result is the outer one. */ 5953 *vr0type = vr1type; 5954 *vr0min = vr1min; 5955 *vr0max = vr1max; 5956 } 5957 else if (vr1type == VR_ANTI_RANGE 5958 && *vr0type == VR_RANGE) 5959 { 5960 /* The intersection is empty. */ 5961 *vr0type = VR_UNDEFINED; 5962 *vr0min = NULL_TREE; 5963 *vr0max = NULL_TREE; 5964 } 5965 else 5966 gcc_unreachable (); 5967 } 5968 else if ((operand_less_p (vr1min, *vr0max) == 1 5969 || operand_equal_p (vr1min, *vr0max, 0)) 5970 && operand_less_p (*vr0min, vr1min) == 1) 5971 { 5972 /* [ ( ] ) or [ ]( ) */ 5973 if (*vr0type == VR_ANTI_RANGE 5974 && vr1type == VR_ANTI_RANGE) 5975 *vr0max = vr1max; 5976 else if (*vr0type == VR_RANGE 5977 && vr1type == VR_RANGE) 5978 *vr0min = vr1min; 5979 else if (*vr0type == VR_RANGE 5980 && vr1type == VR_ANTI_RANGE) 5981 { 5982 if (TREE_CODE (vr1min) == INTEGER_CST) 5983 *vr0max = int_const_binop (MINUS_EXPR, vr1min, 5984 build_int_cst (TREE_TYPE (vr1min), 1)); 5985 else 5986 *vr0max = vr1min; 5987 } 5988 else if (*vr0type == VR_ANTI_RANGE 5989 && vr1type == VR_RANGE) 5990 { 5991 *vr0type = VR_RANGE; 5992 if (TREE_CODE (*vr0max) == INTEGER_CST) 5993 *vr0min = int_const_binop (PLUS_EXPR, *vr0max, 5994 build_int_cst (TREE_TYPE (*vr0max), 1)); 5995 else 5996 *vr0min = *vr0max; 5997 *vr0max = vr1max; 5998 } 5999 else 6000 gcc_unreachable (); 6001 } 6002 else if ((operand_less_p (*vr0min, vr1max) == 1 6003 || operand_equal_p (*vr0min, vr1max, 0)) 6004 && operand_less_p (vr1min, *vr0min) == 1) 6005 { 6006 /* ( [ ) ] or ( )[ ] */ 6007 if (*vr0type == VR_ANTI_RANGE 6008 && vr1type == VR_ANTI_RANGE) 6009 *vr0min = vr1min; 6010 else if (*vr0type == VR_RANGE 6011 && vr1type == VR_RANGE) 6012 *vr0max = vr1max; 6013 else if (*vr0type == VR_RANGE 6014 && vr1type == VR_ANTI_RANGE) 6015 { 6016 if (TREE_CODE (vr1max) == INTEGER_CST) 6017 *vr0min = int_const_binop (PLUS_EXPR, vr1max, 6018 build_int_cst (TREE_TYPE (vr1max), 1)); 6019 else 6020 *vr0min = vr1max; 6021 } 6022 else if (*vr0type == VR_ANTI_RANGE 6023 && vr1type == VR_RANGE) 6024 { 6025 *vr0type = VR_RANGE; 6026 if (TREE_CODE (*vr0min) == INTEGER_CST) 6027 *vr0max = int_const_binop (MINUS_EXPR, *vr0min, 6028 build_int_cst (TREE_TYPE (*vr0min), 1)); 6029 else 6030 *vr0max = *vr0min; 6031 *vr0min = vr1min; 6032 } 6033 else 6034 gcc_unreachable (); 6035 } 6036 6037 /* As a fallback simply use { *VRTYPE, *VR0MIN, *VR0MAX } as 6038 result for the intersection. That's always a conservative 6039 correct estimate unless VR1 is a constant singleton range 6040 in which case we choose that. */ 6041 if (vr1type == VR_RANGE 6042 && is_gimple_min_invariant (vr1min) 6043 && vrp_operand_equal_p (vr1min, vr1max)) 6044 { 6045 *vr0type = vr1type; 6046 *vr0min = vr1min; 6047 *vr0max = vr1max; 6048 } 6049 } 6050 6051 6052 /* Intersect the two value-ranges *VR0 and *VR1 and store the result 6053 in *VR0. This may not be the smallest possible such range. */ 6054 6055 void 6056 value_range::intersect_helper (value_range *vr0, const value_range *vr1) 6057 { 6058 /* If either range is VR_VARYING the other one wins. */ 6059 if (vr1->varying_p ()) 6060 return; 6061 if (vr0->varying_p ()) 6062 { 6063 vr0->deep_copy (vr1); 6064 return; 6065 } 6066 6067 /* When either range is VR_UNDEFINED the resulting range is 6068 VR_UNDEFINED, too. */ 6069 if (vr0->undefined_p ()) 6070 return; 6071 if (vr1->undefined_p ()) 6072 { 6073 vr0->set_undefined (); 6074 return; 6075 } 6076 6077 value_range_kind vr0type = vr0->kind (); 6078 tree vr0min = vr0->min (); 6079 tree vr0max = vr0->max (); 6080 intersect_ranges (&vr0type, &vr0min, &vr0max, 6081 vr1->kind (), vr1->min (), vr1->max ()); 6082 /* Make sure to canonicalize the result though as the inversion of a 6083 VR_RANGE can still be a VR_RANGE. Work on a temporary so we can 6084 fall back to vr0 when this turns things to varying. */ 6085 value_range tem; 6086 tem.set_and_canonicalize (vr0type, vr0min, vr0max); 6087 /* If that failed, use the saved original VR0. */ 6088 if (tem.varying_p ()) 6089 return; 6090 vr0->update (tem.kind (), tem.min (), tem.max ()); 6091 6092 /* If the result is VR_UNDEFINED there is no need to mess with 6093 the equivalencies. */ 6094 if (vr0->undefined_p ()) 6095 return; 6096 6097 /* The resulting set of equivalences for range intersection is the union of 6098 the two sets. */ 6099 if (vr0->m_equiv && vr1->m_equiv && vr0->m_equiv != vr1->m_equiv) 6100 bitmap_ior_into (vr0->m_equiv, vr1->m_equiv); 6101 else if (vr1->m_equiv && !vr0->m_equiv) 6102 { 6103 /* All equivalence bitmaps are allocated from the same obstack. So 6104 we can use the obstack associated with VR to allocate vr0->equiv. */ 6105 vr0->m_equiv = BITMAP_ALLOC (vr1->m_equiv->obstack); 6106 bitmap_copy (m_equiv, vr1->m_equiv); 6107 } 6108 } 6109 6110 void 6111 value_range::intersect (const value_range *other) 6112 { 6113 if (dump_file && (dump_flags & TDF_DETAILS)) 6114 { 6115 fprintf (dump_file, "Intersecting\n "); 6116 dump_value_range (dump_file, this); 6117 fprintf (dump_file, "\nand\n "); 6118 dump_value_range (dump_file, other); 6119 fprintf (dump_file, "\n"); 6120 } 6121 intersect_helper (this, other); 6122 if (dump_file && (dump_flags & TDF_DETAILS)) 6123 { 6124 fprintf (dump_file, "to\n "); 6125 dump_value_range (dump_file, this); 6126 fprintf (dump_file, "\n"); 6127 } 6128 } 6129 6130 /* Helper for meet operation for value ranges. Given two value ranges VR0 and 6131 VR1, return a range that contains both VR0 and VR1. This may not be the 6132 smallest possible such range. */ 6133 6134 value_range_base 6135 value_range_base::union_helper (const value_range_base *vr0, 6136 const value_range_base *vr1) 6137 { 6138 /* VR0 has the resulting range if VR1 is undefined or VR0 is varying. */ 6139 if (vr1->undefined_p () 6140 || vr0->varying_p ()) 6141 return *vr0; 6142 6143 /* VR1 has the resulting range if VR0 is undefined or VR1 is varying. */ 6144 if (vr0->undefined_p () 6145 || vr1->varying_p ()) 6146 return *vr1; 6147 6148 value_range_kind vr0type = vr0->kind (); 6149 tree vr0min = vr0->min (); 6150 tree vr0max = vr0->max (); 6151 union_ranges (&vr0type, &vr0min, &vr0max, 6152 vr1->kind (), vr1->min (), vr1->max ()); 6153 6154 /* Work on a temporary so we can still use vr0 when union returns varying. */ 6155 value_range tem; 6156 tem.set_and_canonicalize (vr0type, vr0min, vr0max); 6157 6158 /* Failed to find an efficient meet. Before giving up and setting 6159 the result to VARYING, see if we can at least derive a useful 6160 anti-range. */ 6161 if (tem.varying_p () 6162 && range_includes_zero_p (vr0) == 0 6163 && range_includes_zero_p (vr1) == 0) 6164 { 6165 tem.set_nonnull (vr0->type ()); 6166 return tem; 6167 } 6168 6169 return tem; 6170 } 6171 6172 6173 /* Meet operation for value ranges. Given two value ranges VR0 and 6174 VR1, store in VR0 a range that contains both VR0 and VR1. This 6175 may not be the smallest possible such range. */ 6176 6177 void 6178 value_range_base::union_ (const value_range_base *other) 6179 { 6180 if (dump_file && (dump_flags & TDF_DETAILS)) 6181 { 6182 fprintf (dump_file, "Meeting\n "); 6183 dump_value_range (dump_file, this); 6184 fprintf (dump_file, "\nand\n "); 6185 dump_value_range (dump_file, other); 6186 fprintf (dump_file, "\n"); 6187 } 6188 6189 *this = union_helper (this, other); 6190 6191 if (dump_file && (dump_flags & TDF_DETAILS)) 6192 { 6193 fprintf (dump_file, "to\n "); 6194 dump_value_range (dump_file, this); 6195 fprintf (dump_file, "\n"); 6196 } 6197 } 6198 6199 void 6200 value_range::union_ (const value_range *other) 6201 { 6202 if (dump_file && (dump_flags & TDF_DETAILS)) 6203 { 6204 fprintf (dump_file, "Meeting\n "); 6205 dump_value_range (dump_file, this); 6206 fprintf (dump_file, "\nand\n "); 6207 dump_value_range (dump_file, other); 6208 fprintf (dump_file, "\n"); 6209 } 6210 6211 /* If THIS is undefined we want to pick up equivalences from OTHER. 6212 Just special-case this here rather than trying to fixup after the fact. */ 6213 if (this->undefined_p ()) 6214 this->deep_copy (other); 6215 else 6216 { 6217 value_range_base tem = union_helper (this, other); 6218 this->update (tem.kind (), tem.min (), tem.max ()); 6219 6220 /* The resulting set of equivalences is always the intersection of 6221 the two sets. */ 6222 if (this->m_equiv && other->m_equiv && this->m_equiv != other->m_equiv) 6223 bitmap_and_into (this->m_equiv, other->m_equiv); 6224 else if (this->m_equiv && !other->m_equiv) 6225 bitmap_clear (this->m_equiv); 6226 } 6227 6228 if (dump_file && (dump_flags & TDF_DETAILS)) 6229 { 6230 fprintf (dump_file, "to\n "); 6231 dump_value_range (dump_file, this); 6232 fprintf (dump_file, "\n"); 6233 } 6234 } 6235 6236 /* Visit all arguments for PHI node PHI that flow through executable 6237 edges. If a valid value range can be derived from all the incoming 6238 value ranges, set a new range for the LHS of PHI. */ 6239 6240 enum ssa_prop_result 6241 vrp_prop::visit_phi (gphi *phi) 6242 { 6243 tree lhs = PHI_RESULT (phi); 6244 value_range vr_result; 6245 extract_range_from_phi_node (phi, &vr_result); 6246 if (update_value_range (lhs, &vr_result)) 6247 { 6248 if (dump_file && (dump_flags & TDF_DETAILS)) 6249 { 6250 fprintf (dump_file, "Found new range for "); 6251 print_generic_expr (dump_file, lhs); 6252 fprintf (dump_file, ": "); 6253 dump_value_range (dump_file, &vr_result); 6254 fprintf (dump_file, "\n"); 6255 } 6256 6257 if (vr_result.varying_p ()) 6258 return SSA_PROP_VARYING; 6259 6260 return SSA_PROP_INTERESTING; 6261 } 6262 6263 /* Nothing changed, don't add outgoing edges. */ 6264 return SSA_PROP_NOT_INTERESTING; 6265 } 6266 6267 class vrp_folder : public substitute_and_fold_engine 6268 { 6269 public: 6270 tree get_value (tree) FINAL OVERRIDE; 6271 bool fold_stmt (gimple_stmt_iterator *) FINAL OVERRIDE; 6272 bool fold_predicate_in (gimple_stmt_iterator *); 6273 6274 class vr_values *vr_values; 6275 6276 /* Delegators. */ 6277 tree vrp_evaluate_conditional (tree_code code, tree op0, 6278 tree op1, gimple *stmt) 6279 { return vr_values->vrp_evaluate_conditional (code, op0, op1, stmt); } 6280 bool simplify_stmt_using_ranges (gimple_stmt_iterator *gsi) 6281 { return vr_values->simplify_stmt_using_ranges (gsi); } 6282 tree op_with_constant_singleton_value_range (tree op) 6283 { return vr_values->op_with_constant_singleton_value_range (op); } 6284 }; 6285 6286 /* If the statement pointed by SI has a predicate whose value can be 6287 computed using the value range information computed by VRP, compute 6288 its value and return true. Otherwise, return false. */ 6289 6290 bool 6291 vrp_folder::fold_predicate_in (gimple_stmt_iterator *si) 6292 { 6293 bool assignment_p = false; 6294 tree val; 6295 gimple *stmt = gsi_stmt (*si); 6296 6297 if (is_gimple_assign (stmt) 6298 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison) 6299 { 6300 assignment_p = true; 6301 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt), 6302 gimple_assign_rhs1 (stmt), 6303 gimple_assign_rhs2 (stmt), 6304 stmt); 6305 } 6306 else if (gcond *cond_stmt = dyn_cast <gcond *> (stmt)) 6307 val = vrp_evaluate_conditional (gimple_cond_code (cond_stmt), 6308 gimple_cond_lhs (cond_stmt), 6309 gimple_cond_rhs (cond_stmt), 6310 stmt); 6311 else 6312 return false; 6313 6314 if (val) 6315 { 6316 if (assignment_p) 6317 val = fold_convert (gimple_expr_type (stmt), val); 6318 6319 if (dump_file) 6320 { 6321 fprintf (dump_file, "Folding predicate "); 6322 print_gimple_expr (dump_file, stmt, 0); 6323 fprintf (dump_file, " to "); 6324 print_generic_expr (dump_file, val); 6325 fprintf (dump_file, "\n"); 6326 } 6327 6328 if (is_gimple_assign (stmt)) 6329 gimple_assign_set_rhs_from_tree (si, val); 6330 else 6331 { 6332 gcc_assert (gimple_code (stmt) == GIMPLE_COND); 6333 gcond *cond_stmt = as_a <gcond *> (stmt); 6334 if (integer_zerop (val)) 6335 gimple_cond_make_false (cond_stmt); 6336 else if (integer_onep (val)) 6337 gimple_cond_make_true (cond_stmt); 6338 else 6339 gcc_unreachable (); 6340 } 6341 6342 return true; 6343 } 6344 6345 return false; 6346 } 6347 6348 /* Callback for substitute_and_fold folding the stmt at *SI. */ 6349 6350 bool 6351 vrp_folder::fold_stmt (gimple_stmt_iterator *si) 6352 { 6353 if (fold_predicate_in (si)) 6354 return true; 6355 6356 return simplify_stmt_using_ranges (si); 6357 } 6358 6359 /* If OP has a value range with a single constant value return that, 6360 otherwise return NULL_TREE. This returns OP itself if OP is a 6361 constant. 6362 6363 Implemented as a pure wrapper right now, but this will change. */ 6364 6365 tree 6366 vrp_folder::get_value (tree op) 6367 { 6368 return op_with_constant_singleton_value_range (op); 6369 } 6370 6371 /* Return the LHS of any ASSERT_EXPR where OP appears as the first 6372 argument to the ASSERT_EXPR and in which the ASSERT_EXPR dominates 6373 BB. If no such ASSERT_EXPR is found, return OP. */ 6374 6375 static tree 6376 lhs_of_dominating_assert (tree op, basic_block bb, gimple *stmt) 6377 { 6378 imm_use_iterator imm_iter; 6379 gimple *use_stmt; 6380 use_operand_p use_p; 6381 6382 if (TREE_CODE (op) == SSA_NAME) 6383 { 6384 FOR_EACH_IMM_USE_FAST (use_p, imm_iter, op) 6385 { 6386 use_stmt = USE_STMT (use_p); 6387 if (use_stmt != stmt 6388 && gimple_assign_single_p (use_stmt) 6389 && TREE_CODE (gimple_assign_rhs1 (use_stmt)) == ASSERT_EXPR 6390 && TREE_OPERAND (gimple_assign_rhs1 (use_stmt), 0) == op 6391 && dominated_by_p (CDI_DOMINATORS, bb, gimple_bb (use_stmt))) 6392 return gimple_assign_lhs (use_stmt); 6393 } 6394 } 6395 return op; 6396 } 6397 6398 /* A hack. */ 6399 static class vr_values *x_vr_values; 6400 6401 /* A trivial wrapper so that we can present the generic jump threading 6402 code with a simple API for simplifying statements. STMT is the 6403 statement we want to simplify, WITHIN_STMT provides the location 6404 for any overflow warnings. */ 6405 6406 static tree 6407 simplify_stmt_for_jump_threading (gimple *stmt, gimple *within_stmt, 6408 class avail_exprs_stack *avail_exprs_stack ATTRIBUTE_UNUSED, 6409 basic_block bb) 6410 { 6411 /* First see if the conditional is in the hash table. */ 6412 tree cached_lhs = avail_exprs_stack->lookup_avail_expr (stmt, false, true); 6413 if (cached_lhs && is_gimple_min_invariant (cached_lhs)) 6414 return cached_lhs; 6415 6416 vr_values *vr_values = x_vr_values; 6417 if (gcond *cond_stmt = dyn_cast <gcond *> (stmt)) 6418 { 6419 tree op0 = gimple_cond_lhs (cond_stmt); 6420 op0 = lhs_of_dominating_assert (op0, bb, stmt); 6421 6422 tree op1 = gimple_cond_rhs (cond_stmt); 6423 op1 = lhs_of_dominating_assert (op1, bb, stmt); 6424 6425 return vr_values->vrp_evaluate_conditional (gimple_cond_code (cond_stmt), 6426 op0, op1, within_stmt); 6427 } 6428 6429 /* We simplify a switch statement by trying to determine which case label 6430 will be taken. If we are successful then we return the corresponding 6431 CASE_LABEL_EXPR. */ 6432 if (gswitch *switch_stmt = dyn_cast <gswitch *> (stmt)) 6433 { 6434 tree op = gimple_switch_index (switch_stmt); 6435 if (TREE_CODE (op) != SSA_NAME) 6436 return NULL_TREE; 6437 6438 op = lhs_of_dominating_assert (op, bb, stmt); 6439 6440 const value_range *vr = vr_values->get_value_range (op); 6441 if (vr->undefined_p () 6442 || vr->varying_p () 6443 || vr->symbolic_p ()) 6444 return NULL_TREE; 6445 6446 if (vr->kind () == VR_RANGE) 6447 { 6448 size_t i, j; 6449 /* Get the range of labels that contain a part of the operand's 6450 value range. */ 6451 find_case_label_range (switch_stmt, vr->min (), vr->max (), &i, &j); 6452 6453 /* Is there only one such label? */ 6454 if (i == j) 6455 { 6456 tree label = gimple_switch_label (switch_stmt, i); 6457 6458 /* The i'th label will be taken only if the value range of the 6459 operand is entirely within the bounds of this label. */ 6460 if (CASE_HIGH (label) != NULL_TREE 6461 ? (tree_int_cst_compare (CASE_LOW (label), vr->min ()) <= 0 6462 && tree_int_cst_compare (CASE_HIGH (label), 6463 vr->max ()) >= 0) 6464 : (tree_int_cst_equal (CASE_LOW (label), vr->min ()) 6465 && tree_int_cst_equal (vr->min (), vr->max ()))) 6466 return label; 6467 } 6468 6469 /* If there are no such labels then the default label will be 6470 taken. */ 6471 if (i > j) 6472 return gimple_switch_label (switch_stmt, 0); 6473 } 6474 6475 if (vr->kind () == VR_ANTI_RANGE) 6476 { 6477 unsigned n = gimple_switch_num_labels (switch_stmt); 6478 tree min_label = gimple_switch_label (switch_stmt, 1); 6479 tree max_label = gimple_switch_label (switch_stmt, n - 1); 6480 6481 /* The default label will be taken only if the anti-range of the 6482 operand is entirely outside the bounds of all the (non-default) 6483 case labels. */ 6484 if (tree_int_cst_compare (vr->min (), CASE_LOW (min_label)) <= 0 6485 && (CASE_HIGH (max_label) != NULL_TREE 6486 ? tree_int_cst_compare (vr->max (), 6487 CASE_HIGH (max_label)) >= 0 6488 : tree_int_cst_compare (vr->max (), 6489 CASE_LOW (max_label)) >= 0)) 6490 return gimple_switch_label (switch_stmt, 0); 6491 } 6492 6493 return NULL_TREE; 6494 } 6495 6496 if (gassign *assign_stmt = dyn_cast <gassign *> (stmt)) 6497 { 6498 tree lhs = gimple_assign_lhs (assign_stmt); 6499 if (TREE_CODE (lhs) == SSA_NAME 6500 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs)) 6501 || POINTER_TYPE_P (TREE_TYPE (lhs))) 6502 && stmt_interesting_for_vrp (stmt)) 6503 { 6504 edge dummy_e; 6505 tree dummy_tree; 6506 value_range new_vr; 6507 vr_values->extract_range_from_stmt (stmt, &dummy_e, 6508 &dummy_tree, &new_vr); 6509 tree singleton; 6510 if (new_vr.singleton_p (&singleton)) 6511 return singleton; 6512 } 6513 } 6514 6515 return NULL_TREE; 6516 } 6517 6518 class vrp_dom_walker : public dom_walker 6519 { 6520 public: 6521 vrp_dom_walker (cdi_direction direction, 6522 class const_and_copies *const_and_copies, 6523 class avail_exprs_stack *avail_exprs_stack) 6524 : dom_walker (direction, REACHABLE_BLOCKS), 6525 m_const_and_copies (const_and_copies), 6526 m_avail_exprs_stack (avail_exprs_stack), 6527 m_dummy_cond (NULL) {} 6528 6529 virtual edge before_dom_children (basic_block); 6530 virtual void after_dom_children (basic_block); 6531 6532 class vr_values *vr_values; 6533 6534 private: 6535 class const_and_copies *m_const_and_copies; 6536 class avail_exprs_stack *m_avail_exprs_stack; 6537 6538 gcond *m_dummy_cond; 6539 6540 }; 6541 6542 /* Called before processing dominator children of BB. We want to look 6543 at ASSERT_EXPRs and record information from them in the appropriate 6544 tables. 6545 6546 We could look at other statements here. It's not seen as likely 6547 to significantly increase the jump threads we discover. */ 6548 6549 edge 6550 vrp_dom_walker::before_dom_children (basic_block bb) 6551 { 6552 gimple_stmt_iterator gsi; 6553 6554 m_avail_exprs_stack->push_marker (); 6555 m_const_and_copies->push_marker (); 6556 for (gsi = gsi_start_nondebug_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) 6557 { 6558 gimple *stmt = gsi_stmt (gsi); 6559 if (gimple_assign_single_p (stmt) 6560 && TREE_CODE (gimple_assign_rhs1 (stmt)) == ASSERT_EXPR) 6561 { 6562 tree rhs1 = gimple_assign_rhs1 (stmt); 6563 tree cond = TREE_OPERAND (rhs1, 1); 6564 tree inverted = invert_truthvalue (cond); 6565 vec<cond_equivalence> p; 6566 p.create (3); 6567 record_conditions (&p, cond, inverted); 6568 for (unsigned int i = 0; i < p.length (); i++) 6569 m_avail_exprs_stack->record_cond (&p[i]); 6570 6571 tree lhs = gimple_assign_lhs (stmt); 6572 m_const_and_copies->record_const_or_copy (lhs, 6573 TREE_OPERAND (rhs1, 0)); 6574 p.release (); 6575 continue; 6576 } 6577 break; 6578 } 6579 return NULL; 6580 } 6581 6582 /* Called after processing dominator children of BB. This is where we 6583 actually call into the threader. */ 6584 void 6585 vrp_dom_walker::after_dom_children (basic_block bb) 6586 { 6587 if (!m_dummy_cond) 6588 m_dummy_cond = gimple_build_cond (NE_EXPR, 6589 integer_zero_node, integer_zero_node, 6590 NULL, NULL); 6591 6592 x_vr_values = vr_values; 6593 thread_outgoing_edges (bb, m_dummy_cond, m_const_and_copies, 6594 m_avail_exprs_stack, NULL, 6595 simplify_stmt_for_jump_threading); 6596 x_vr_values = NULL; 6597 6598 m_avail_exprs_stack->pop_to_marker (); 6599 m_const_and_copies->pop_to_marker (); 6600 } 6601 6602 /* Blocks which have more than one predecessor and more than 6603 one successor present jump threading opportunities, i.e., 6604 when the block is reached from a specific predecessor, we 6605 may be able to determine which of the outgoing edges will 6606 be traversed. When this optimization applies, we are able 6607 to avoid conditionals at runtime and we may expose secondary 6608 optimization opportunities. 6609 6610 This routine is effectively a driver for the generic jump 6611 threading code. It basically just presents the generic code 6612 with edges that may be suitable for jump threading. 6613 6614 Unlike DOM, we do not iterate VRP if jump threading was successful. 6615 While iterating may expose new opportunities for VRP, it is expected 6616 those opportunities would be very limited and the compile time cost 6617 to expose those opportunities would be significant. 6618 6619 As jump threading opportunities are discovered, they are registered 6620 for later realization. */ 6621 6622 static void 6623 identify_jump_threads (class vr_values *vr_values) 6624 { 6625 /* Ugh. When substituting values earlier in this pass we can 6626 wipe the dominance information. So rebuild the dominator 6627 information as we need it within the jump threading code. */ 6628 calculate_dominance_info (CDI_DOMINATORS); 6629 6630 /* We do not allow VRP information to be used for jump threading 6631 across a back edge in the CFG. Otherwise it becomes too 6632 difficult to avoid eliminating loop exit tests. Of course 6633 EDGE_DFS_BACK is not accurate at this time so we have to 6634 recompute it. */ 6635 mark_dfs_back_edges (); 6636 6637 /* Allocate our unwinder stack to unwind any temporary equivalences 6638 that might be recorded. */ 6639 const_and_copies *equiv_stack = new const_and_copies (); 6640 6641 hash_table<expr_elt_hasher> *avail_exprs 6642 = new hash_table<expr_elt_hasher> (1024); 6643 avail_exprs_stack *avail_exprs_stack 6644 = new class avail_exprs_stack (avail_exprs); 6645 6646 vrp_dom_walker walker (CDI_DOMINATORS, equiv_stack, avail_exprs_stack); 6647 walker.vr_values = vr_values; 6648 walker.walk (cfun->cfg->x_entry_block_ptr); 6649 6650 /* We do not actually update the CFG or SSA graphs at this point as 6651 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet 6652 handle ASSERT_EXPRs gracefully. */ 6653 delete equiv_stack; 6654 delete avail_exprs; 6655 delete avail_exprs_stack; 6656 } 6657 6658 /* Traverse all the blocks folding conditionals with known ranges. */ 6659 6660 void 6661 vrp_prop::vrp_finalize (bool warn_array_bounds_p) 6662 { 6663 size_t i; 6664 6665 /* We have completed propagating through the lattice. */ 6666 vr_values.set_lattice_propagation_complete (); 6667 6668 if (dump_file) 6669 { 6670 fprintf (dump_file, "\nValue ranges after VRP:\n\n"); 6671 vr_values.dump_all_value_ranges (dump_file); 6672 fprintf (dump_file, "\n"); 6673 } 6674 6675 /* Set value range to non pointer SSA_NAMEs. */ 6676 for (i = 0; i < num_ssa_names; i++) 6677 { 6678 tree name = ssa_name (i); 6679 if (!name) 6680 continue; 6681 6682 const value_range *vr = get_value_range (name); 6683 if (!name || !vr->constant_p ()) 6684 continue; 6685 6686 if (POINTER_TYPE_P (TREE_TYPE (name)) 6687 && range_includes_zero_p (vr) == 0) 6688 set_ptr_nonnull (name); 6689 else if (!POINTER_TYPE_P (TREE_TYPE (name))) 6690 set_range_info (name, *vr); 6691 } 6692 6693 /* If we're checking array refs, we want to merge information on 6694 the executability of each edge between vrp_folder and the 6695 check_array_bounds_dom_walker: each can clear the 6696 EDGE_EXECUTABLE flag on edges, in different ways. 6697 6698 Hence, if we're going to call check_all_array_refs, set 6699 the flag on every edge now, rather than in 6700 check_array_bounds_dom_walker's ctor; vrp_folder may clear 6701 it from some edges. */ 6702 if (warn_array_bounds && warn_array_bounds_p) 6703 set_all_edges_as_executable (cfun); 6704 6705 class vrp_folder vrp_folder; 6706 vrp_folder.vr_values = &vr_values; 6707 vrp_folder.substitute_and_fold (); 6708 6709 if (warn_array_bounds && warn_array_bounds_p) 6710 check_all_array_refs (); 6711 } 6712 6713 /* Main entry point to VRP (Value Range Propagation). This pass is 6714 loosely based on J. R. C. Patterson, ``Accurate Static Branch 6715 Prediction by Value Range Propagation,'' in SIGPLAN Conference on 6716 Programming Language Design and Implementation, pp. 67-78, 1995. 6717 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html 6718 6719 This is essentially an SSA-CCP pass modified to deal with ranges 6720 instead of constants. 6721 6722 While propagating ranges, we may find that two or more SSA name 6723 have equivalent, though distinct ranges. For instance, 6724 6725 1 x_9 = p_3->a; 6726 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0> 6727 3 if (p_4 == q_2) 6728 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>; 6729 5 endif 6730 6 if (q_2) 6731 6732 In the code above, pointer p_5 has range [q_2, q_2], but from the 6733 code we can also determine that p_5 cannot be NULL and, if q_2 had 6734 a non-varying range, p_5's range should also be compatible with it. 6735 6736 These equivalences are created by two expressions: ASSERT_EXPR and 6737 copy operations. Since p_5 is an assertion on p_4, and p_4 was the 6738 result of another assertion, then we can use the fact that p_5 and 6739 p_4 are equivalent when evaluating p_5's range. 6740 6741 Together with value ranges, we also propagate these equivalences 6742 between names so that we can take advantage of information from 6743 multiple ranges when doing final replacement. Note that this 6744 equivalency relation is transitive but not symmetric. 6745 6746 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we 6747 cannot assert that q_2 is equivalent to p_5 because q_2 may be used 6748 in contexts where that assertion does not hold (e.g., in line 6). 6749 6750 TODO, the main difference between this pass and Patterson's is that 6751 we do not propagate edge probabilities. We only compute whether 6752 edges can be taken or not. That is, instead of having a spectrum 6753 of jump probabilities between 0 and 1, we only deal with 0, 1 and 6754 DON'T KNOW. In the future, it may be worthwhile to propagate 6755 probabilities to aid branch prediction. */ 6756 6757 static unsigned int 6758 execute_vrp (bool warn_array_bounds_p) 6759 { 6760 6761 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS); 6762 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa); 6763 scev_initialize (); 6764 6765 /* ??? This ends up using stale EDGE_DFS_BACK for liveness computation. 6766 Inserting assertions may split edges which will invalidate 6767 EDGE_DFS_BACK. */ 6768 insert_range_assertions (); 6769 6770 threadedge_initialize_values (); 6771 6772 /* For visiting PHI nodes we need EDGE_DFS_BACK computed. */ 6773 mark_dfs_back_edges (); 6774 6775 class vrp_prop vrp_prop; 6776 vrp_prop.vrp_initialize (); 6777 vrp_prop.ssa_propagate (); 6778 vrp_prop.vrp_finalize (warn_array_bounds_p); 6779 6780 /* We must identify jump threading opportunities before we release 6781 the datastructures built by VRP. */ 6782 identify_jump_threads (&vrp_prop.vr_values); 6783 6784 /* A comparison of an SSA_NAME against a constant where the SSA_NAME 6785 was set by a type conversion can often be rewritten to use the 6786 RHS of the type conversion. 6787 6788 However, doing so inhibits jump threading through the comparison. 6789 So that transformation is not performed until after jump threading 6790 is complete. */ 6791 basic_block bb; 6792 FOR_EACH_BB_FN (bb, cfun) 6793 { 6794 gimple *last = last_stmt (bb); 6795 if (last && gimple_code (last) == GIMPLE_COND) 6796 vrp_prop.vr_values.simplify_cond_using_ranges_2 (as_a <gcond *> (last)); 6797 } 6798 6799 free_numbers_of_iterations_estimates (cfun); 6800 6801 /* ASSERT_EXPRs must be removed before finalizing jump threads 6802 as finalizing jump threads calls the CFG cleanup code which 6803 does not properly handle ASSERT_EXPRs. */ 6804 remove_range_assertions (); 6805 6806 /* If we exposed any new variables, go ahead and put them into 6807 SSA form now, before we handle jump threading. This simplifies 6808 interactions between rewriting of _DECL nodes into SSA form 6809 and rewriting SSA_NAME nodes into SSA form after block 6810 duplication and CFG manipulation. */ 6811 update_ssa (TODO_update_ssa); 6812 6813 /* We identified all the jump threading opportunities earlier, but could 6814 not transform the CFG at that time. This routine transforms the 6815 CFG and arranges for the dominator tree to be rebuilt if necessary. 6816 6817 Note the SSA graph update will occur during the normal TODO 6818 processing by the pass manager. */ 6819 thread_through_all_blocks (false); 6820 6821 vrp_prop.vr_values.cleanup_edges_and_switches (); 6822 threadedge_finalize_values (); 6823 6824 scev_finalize (); 6825 loop_optimizer_finalize (); 6826 return 0; 6827 } 6828 6829 namespace { 6830 6831 const pass_data pass_data_vrp = 6832 { 6833 GIMPLE_PASS, /* type */ 6834 "vrp", /* name */ 6835 OPTGROUP_NONE, /* optinfo_flags */ 6836 TV_TREE_VRP, /* tv_id */ 6837 PROP_ssa, /* properties_required */ 6838 0, /* properties_provided */ 6839 0, /* properties_destroyed */ 6840 0, /* todo_flags_start */ 6841 ( TODO_cleanup_cfg | TODO_update_ssa ), /* todo_flags_finish */ 6842 }; 6843 6844 class pass_vrp : public gimple_opt_pass 6845 { 6846 public: 6847 pass_vrp (gcc::context *ctxt) 6848 : gimple_opt_pass (pass_data_vrp, ctxt), warn_array_bounds_p (false) 6849 {} 6850 6851 /* opt_pass methods: */ 6852 opt_pass * clone () { return new pass_vrp (m_ctxt); } 6853 void set_pass_param (unsigned int n, bool param) 6854 { 6855 gcc_assert (n == 0); 6856 warn_array_bounds_p = param; 6857 } 6858 virtual bool gate (function *) { return flag_tree_vrp != 0; } 6859 virtual unsigned int execute (function *) 6860 { return execute_vrp (warn_array_bounds_p); } 6861 6862 private: 6863 bool warn_array_bounds_p; 6864 }; // class pass_vrp 6865 6866 } // anon namespace 6867 6868 gimple_opt_pass * 6869 make_pass_vrp (gcc::context *ctxt) 6870 { 6871 return new pass_vrp (ctxt); 6872 } 6873 6874 6875 /* Worker for determine_value_range. */ 6876 6877 static void 6878 determine_value_range_1 (value_range_base *vr, tree expr) 6879 { 6880 if (BINARY_CLASS_P (expr)) 6881 { 6882 value_range_base vr0, vr1; 6883 determine_value_range_1 (&vr0, TREE_OPERAND (expr, 0)); 6884 determine_value_range_1 (&vr1, TREE_OPERAND (expr, 1)); 6885 extract_range_from_binary_expr (vr, TREE_CODE (expr), TREE_TYPE (expr), 6886 &vr0, &vr1); 6887 } 6888 else if (UNARY_CLASS_P (expr)) 6889 { 6890 value_range_base vr0; 6891 determine_value_range_1 (&vr0, TREE_OPERAND (expr, 0)); 6892 extract_range_from_unary_expr (vr, TREE_CODE (expr), TREE_TYPE (expr), 6893 &vr0, TREE_TYPE (TREE_OPERAND (expr, 0))); 6894 } 6895 else if (TREE_CODE (expr) == INTEGER_CST) 6896 vr->set (expr); 6897 else 6898 { 6899 value_range_kind kind; 6900 wide_int min, max; 6901 /* For SSA names try to extract range info computed by VRP. Otherwise 6902 fall back to varying. */ 6903 if (TREE_CODE (expr) == SSA_NAME 6904 && INTEGRAL_TYPE_P (TREE_TYPE (expr)) 6905 && (kind = get_range_info (expr, &min, &max)) != VR_VARYING) 6906 vr->set (kind, wide_int_to_tree (TREE_TYPE (expr), min), 6907 wide_int_to_tree (TREE_TYPE (expr), max)); 6908 else 6909 vr->set_varying (); 6910 } 6911 } 6912 6913 /* Compute a value-range for EXPR and set it in *MIN and *MAX. Return 6914 the determined range type. */ 6915 6916 value_range_kind 6917 determine_value_range (tree expr, wide_int *min, wide_int *max) 6918 { 6919 value_range_base vr; 6920 determine_value_range_1 (&vr, expr); 6921 if (vr.constant_p ()) 6922 { 6923 *min = wi::to_wide (vr.min ()); 6924 *max = wi::to_wide (vr.max ()); 6925 return vr.kind (); 6926 } 6927 6928 return VR_VARYING; 6929 } 6930