1 /* Support routines for Value Range Propagation (VRP). 2 Copyright (C) 2005-2016 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-ssa-loop-manip.h" 46 #include "tree-ssa-loop-niter.h" 47 #include "tree-ssa-loop.h" 48 #include "tree-into-ssa.h" 49 #include "tree-ssa.h" 50 #include "intl.h" 51 #include "cfgloop.h" 52 #include "tree-scalar-evolution.h" 53 #include "tree-ssa-propagate.h" 54 #include "tree-chrec.h" 55 #include "tree-ssa-threadupdate.h" 56 #include "tree-ssa-scopedtables.h" 57 #include "tree-ssa-threadedge.h" 58 #include "omp-low.h" 59 #include "target.h" 60 #include "case-cfn-macros.h" 61 62 /* Range of values that can be associated with an SSA_NAME after VRP 63 has executed. */ 64 struct value_range 65 { 66 /* Lattice value represented by this range. */ 67 enum value_range_type type; 68 69 /* Minimum and maximum values represented by this range. These 70 values should be interpreted as follows: 71 72 - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must 73 be NULL. 74 75 - If TYPE == VR_RANGE then MIN holds the minimum value and 76 MAX holds the maximum value of the range [MIN, MAX]. 77 78 - If TYPE == ANTI_RANGE the variable is known to NOT 79 take any values in the range [MIN, MAX]. */ 80 tree min; 81 tree max; 82 83 /* Set of SSA names whose value ranges are equivalent to this one. 84 This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */ 85 bitmap equiv; 86 }; 87 88 #define VR_INITIALIZER { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL } 89 90 /* Set of SSA names found live during the RPO traversal of the function 91 for still active basic-blocks. */ 92 static sbitmap *live; 93 94 /* Return true if the SSA name NAME is live on the edge E. */ 95 96 static bool 97 live_on_edge (edge e, tree name) 98 { 99 return (live[e->dest->index] 100 && bitmap_bit_p (live[e->dest->index], SSA_NAME_VERSION (name))); 101 } 102 103 /* Local functions. */ 104 static int compare_values (tree val1, tree val2); 105 static int compare_values_warnv (tree val1, tree val2, bool *); 106 static void vrp_meet (value_range *, value_range *); 107 static void vrp_intersect_ranges (value_range *, value_range *); 108 static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code, 109 tree, tree, bool, bool *, 110 bool *); 111 112 /* Location information for ASSERT_EXPRs. Each instance of this 113 structure describes an ASSERT_EXPR for an SSA name. Since a single 114 SSA name may have more than one assertion associated with it, these 115 locations are kept in a linked list attached to the corresponding 116 SSA name. */ 117 struct assert_locus 118 { 119 /* Basic block where the assertion would be inserted. */ 120 basic_block bb; 121 122 /* Some assertions need to be inserted on an edge (e.g., assertions 123 generated by COND_EXPRs). In those cases, BB will be NULL. */ 124 edge e; 125 126 /* Pointer to the statement that generated this assertion. */ 127 gimple_stmt_iterator si; 128 129 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */ 130 enum tree_code comp_code; 131 132 /* Value being compared against. */ 133 tree val; 134 135 /* Expression to compare. */ 136 tree expr; 137 138 /* Next node in the linked list. */ 139 assert_locus *next; 140 }; 141 142 /* If bit I is present, it means that SSA name N_i has a list of 143 assertions that should be inserted in the IL. */ 144 static bitmap need_assert_for; 145 146 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I] 147 holds a list of ASSERT_LOCUS_T nodes that describe where 148 ASSERT_EXPRs for SSA name N_I should be inserted. */ 149 static assert_locus **asserts_for; 150 151 /* Value range array. After propagation, VR_VALUE[I] holds the range 152 of values that SSA name N_I may take. */ 153 static unsigned num_vr_values; 154 static value_range **vr_value; 155 static bool values_propagated; 156 157 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the 158 number of executable edges we saw the last time we visited the 159 node. */ 160 static int *vr_phi_edge_counts; 161 162 struct switch_update { 163 gswitch *stmt; 164 tree vec; 165 }; 166 167 static vec<edge> to_remove_edges; 168 static vec<switch_update> to_update_switch_stmts; 169 170 171 /* Return the maximum value for TYPE. */ 172 173 static inline tree 174 vrp_val_max (const_tree type) 175 { 176 if (!INTEGRAL_TYPE_P (type)) 177 return NULL_TREE; 178 179 return TYPE_MAX_VALUE (type); 180 } 181 182 /* Return the minimum value for TYPE. */ 183 184 static inline tree 185 vrp_val_min (const_tree type) 186 { 187 if (!INTEGRAL_TYPE_P (type)) 188 return NULL_TREE; 189 190 return TYPE_MIN_VALUE (type); 191 } 192 193 /* Return whether VAL is equal to the maximum value of its type. This 194 will be true for a positive overflow infinity. We can't do a 195 simple equality comparison with TYPE_MAX_VALUE because C typedefs 196 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not == 197 to the integer constant with the same value in the type. */ 198 199 static inline bool 200 vrp_val_is_max (const_tree val) 201 { 202 tree type_max = vrp_val_max (TREE_TYPE (val)); 203 return (val == type_max 204 || (type_max != NULL_TREE 205 && operand_equal_p (val, type_max, 0))); 206 } 207 208 /* Return whether VAL is equal to the minimum value of its type. This 209 will be true for a negative overflow infinity. */ 210 211 static inline bool 212 vrp_val_is_min (const_tree val) 213 { 214 tree type_min = vrp_val_min (TREE_TYPE (val)); 215 return (val == type_min 216 || (type_min != NULL_TREE 217 && operand_equal_p (val, type_min, 0))); 218 } 219 220 221 /* Return whether TYPE should use an overflow infinity distinct from 222 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to 223 represent a signed overflow during VRP computations. An infinity 224 is distinct from a half-range, which will go from some number to 225 TYPE_{MIN,MAX}_VALUE. */ 226 227 static inline bool 228 needs_overflow_infinity (const_tree type) 229 { 230 return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type); 231 } 232 233 /* Return whether TYPE can support our overflow infinity 234 representation: we use the TREE_OVERFLOW flag, which only exists 235 for constants. If TYPE doesn't support this, we don't optimize 236 cases which would require signed overflow--we drop them to 237 VARYING. */ 238 239 static inline bool 240 supports_overflow_infinity (const_tree type) 241 { 242 tree min = vrp_val_min (type), max = vrp_val_max (type); 243 gcc_checking_assert (needs_overflow_infinity (type)); 244 return (min != NULL_TREE 245 && CONSTANT_CLASS_P (min) 246 && max != NULL_TREE 247 && CONSTANT_CLASS_P (max)); 248 } 249 250 /* VAL is the maximum or minimum value of a type. Return a 251 corresponding overflow infinity. */ 252 253 static inline tree 254 make_overflow_infinity (tree val) 255 { 256 gcc_checking_assert (val != NULL_TREE && CONSTANT_CLASS_P (val)); 257 val = copy_node (val); 258 TREE_OVERFLOW (val) = 1; 259 return val; 260 } 261 262 /* Return a negative overflow infinity for TYPE. */ 263 264 static inline tree 265 negative_overflow_infinity (tree type) 266 { 267 gcc_checking_assert (supports_overflow_infinity (type)); 268 return make_overflow_infinity (vrp_val_min (type)); 269 } 270 271 /* Return a positive overflow infinity for TYPE. */ 272 273 static inline tree 274 positive_overflow_infinity (tree type) 275 { 276 gcc_checking_assert (supports_overflow_infinity (type)); 277 return make_overflow_infinity (vrp_val_max (type)); 278 } 279 280 /* Return whether VAL is a negative overflow infinity. */ 281 282 static inline bool 283 is_negative_overflow_infinity (const_tree val) 284 { 285 return (TREE_OVERFLOW_P (val) 286 && needs_overflow_infinity (TREE_TYPE (val)) 287 && vrp_val_is_min (val)); 288 } 289 290 /* Return whether VAL is a positive overflow infinity. */ 291 292 static inline bool 293 is_positive_overflow_infinity (const_tree val) 294 { 295 return (TREE_OVERFLOW_P (val) 296 && needs_overflow_infinity (TREE_TYPE (val)) 297 && vrp_val_is_max (val)); 298 } 299 300 /* Return whether VAL is a positive or negative overflow infinity. */ 301 302 static inline bool 303 is_overflow_infinity (const_tree val) 304 { 305 return (TREE_OVERFLOW_P (val) 306 && needs_overflow_infinity (TREE_TYPE (val)) 307 && (vrp_val_is_min (val) || vrp_val_is_max (val))); 308 } 309 310 /* Return whether STMT has a constant rhs that is_overflow_infinity. */ 311 312 static inline bool 313 stmt_overflow_infinity (gimple *stmt) 314 { 315 if (is_gimple_assign (stmt) 316 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) == 317 GIMPLE_SINGLE_RHS) 318 return is_overflow_infinity (gimple_assign_rhs1 (stmt)); 319 return false; 320 } 321 322 /* If VAL is now an overflow infinity, return VAL. Otherwise, return 323 the same value with TREE_OVERFLOW clear. This can be used to avoid 324 confusing a regular value with an overflow value. */ 325 326 static inline tree 327 avoid_overflow_infinity (tree val) 328 { 329 if (!is_overflow_infinity (val)) 330 return val; 331 332 if (vrp_val_is_max (val)) 333 return vrp_val_max (TREE_TYPE (val)); 334 else 335 { 336 gcc_checking_assert (vrp_val_is_min (val)); 337 return vrp_val_min (TREE_TYPE (val)); 338 } 339 } 340 341 342 /* Set value range VR to VR_UNDEFINED. */ 343 344 static inline void 345 set_value_range_to_undefined (value_range *vr) 346 { 347 vr->type = VR_UNDEFINED; 348 vr->min = vr->max = NULL_TREE; 349 if (vr->equiv) 350 bitmap_clear (vr->equiv); 351 } 352 353 354 /* Set value range VR to VR_VARYING. */ 355 356 static inline void 357 set_value_range_to_varying (value_range *vr) 358 { 359 vr->type = VR_VARYING; 360 vr->min = vr->max = NULL_TREE; 361 if (vr->equiv) 362 bitmap_clear (vr->equiv); 363 } 364 365 366 /* Set value range VR to {T, MIN, MAX, EQUIV}. */ 367 368 static void 369 set_value_range (value_range *vr, enum value_range_type t, tree min, 370 tree max, bitmap equiv) 371 { 372 /* Check the validity of the range. */ 373 if (flag_checking 374 && (t == VR_RANGE || t == VR_ANTI_RANGE)) 375 { 376 int cmp; 377 378 gcc_assert (min && max); 379 380 gcc_assert ((!TREE_OVERFLOW_P (min) || is_overflow_infinity (min)) 381 && (!TREE_OVERFLOW_P (max) || is_overflow_infinity (max))); 382 383 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE) 384 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max)); 385 386 cmp = compare_values (min, max); 387 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2); 388 389 if (needs_overflow_infinity (TREE_TYPE (min))) 390 gcc_assert (!is_overflow_infinity (min) 391 || !is_overflow_infinity (max)); 392 } 393 394 if (flag_checking 395 && (t == VR_UNDEFINED || t == VR_VARYING)) 396 { 397 gcc_assert (min == NULL_TREE && max == NULL_TREE); 398 gcc_assert (equiv == NULL || bitmap_empty_p (equiv)); 399 } 400 401 vr->type = t; 402 vr->min = min; 403 vr->max = max; 404 405 /* Since updating the equivalence set involves deep copying the 406 bitmaps, only do it if absolutely necessary. */ 407 if (vr->equiv == NULL 408 && equiv != NULL) 409 vr->equiv = BITMAP_ALLOC (NULL); 410 411 if (equiv != vr->equiv) 412 { 413 if (equiv && !bitmap_empty_p (equiv)) 414 bitmap_copy (vr->equiv, equiv); 415 else 416 bitmap_clear (vr->equiv); 417 } 418 } 419 420 421 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}. 422 This means adjusting T, MIN and MAX representing the case of a 423 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX] 424 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges. 425 In corner cases where MAX+1 or MIN-1 wraps this will fall back 426 to varying. 427 This routine exists to ease canonicalization in the case where we 428 extract ranges from var + CST op limit. */ 429 430 static void 431 set_and_canonicalize_value_range (value_range *vr, enum value_range_type t, 432 tree min, tree max, bitmap equiv) 433 { 434 /* Use the canonical setters for VR_UNDEFINED and VR_VARYING. */ 435 if (t == VR_UNDEFINED) 436 { 437 set_value_range_to_undefined (vr); 438 return; 439 } 440 else if (t == VR_VARYING) 441 { 442 set_value_range_to_varying (vr); 443 return; 444 } 445 446 /* Nothing to canonicalize for symbolic ranges. */ 447 if (TREE_CODE (min) != INTEGER_CST 448 || TREE_CODE (max) != INTEGER_CST) 449 { 450 set_value_range (vr, t, min, max, equiv); 451 return; 452 } 453 454 /* Wrong order for min and max, to swap them and the VR type we need 455 to adjust them. */ 456 if (tree_int_cst_lt (max, min)) 457 { 458 tree one, tmp; 459 460 /* For one bit precision if max < min, then the swapped 461 range covers all values, so for VR_RANGE it is varying and 462 for VR_ANTI_RANGE empty range, so drop to varying as well. */ 463 if (TYPE_PRECISION (TREE_TYPE (min)) == 1) 464 { 465 set_value_range_to_varying (vr); 466 return; 467 } 468 469 one = build_int_cst (TREE_TYPE (min), 1); 470 tmp = int_const_binop (PLUS_EXPR, max, one); 471 max = int_const_binop (MINUS_EXPR, min, one); 472 min = tmp; 473 474 /* There's one corner case, if we had [C+1, C] before we now have 475 that again. But this represents an empty value range, so drop 476 to varying in this case. */ 477 if (tree_int_cst_lt (max, min)) 478 { 479 set_value_range_to_varying (vr); 480 return; 481 } 482 483 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE; 484 } 485 486 /* Anti-ranges that can be represented as ranges should be so. */ 487 if (t == VR_ANTI_RANGE) 488 { 489 bool is_min = vrp_val_is_min (min); 490 bool is_max = vrp_val_is_max (max); 491 492 if (is_min && is_max) 493 { 494 /* We cannot deal with empty ranges, drop to varying. 495 ??? This could be VR_UNDEFINED instead. */ 496 set_value_range_to_varying (vr); 497 return; 498 } 499 else if (TYPE_PRECISION (TREE_TYPE (min)) == 1 500 && (is_min || is_max)) 501 { 502 /* Non-empty boolean ranges can always be represented 503 as a singleton range. */ 504 if (is_min) 505 min = max = vrp_val_max (TREE_TYPE (min)); 506 else 507 min = max = vrp_val_min (TREE_TYPE (min)); 508 t = VR_RANGE; 509 } 510 else if (is_min 511 /* As a special exception preserve non-null ranges. */ 512 && !(TYPE_UNSIGNED (TREE_TYPE (min)) 513 && integer_zerop (max))) 514 { 515 tree one = build_int_cst (TREE_TYPE (max), 1); 516 min = int_const_binop (PLUS_EXPR, max, one); 517 max = vrp_val_max (TREE_TYPE (max)); 518 t = VR_RANGE; 519 } 520 else if (is_max) 521 { 522 tree one = build_int_cst (TREE_TYPE (min), 1); 523 max = int_const_binop (MINUS_EXPR, min, one); 524 min = vrp_val_min (TREE_TYPE (min)); 525 t = VR_RANGE; 526 } 527 } 528 529 /* Drop [-INF(OVF), +INF(OVF)] to varying. */ 530 if (needs_overflow_infinity (TREE_TYPE (min)) 531 && is_overflow_infinity (min) 532 && is_overflow_infinity (max)) 533 { 534 set_value_range_to_varying (vr); 535 return; 536 } 537 538 set_value_range (vr, t, min, max, equiv); 539 } 540 541 /* Copy value range FROM into value range TO. */ 542 543 static inline void 544 copy_value_range (value_range *to, value_range *from) 545 { 546 set_value_range (to, from->type, from->min, from->max, from->equiv); 547 } 548 549 /* Set value range VR to a single value. This function is only called 550 with values we get from statements, and exists to clear the 551 TREE_OVERFLOW flag so that we don't think we have an overflow 552 infinity when we shouldn't. */ 553 554 static inline void 555 set_value_range_to_value (value_range *vr, tree val, bitmap equiv) 556 { 557 gcc_assert (is_gimple_min_invariant (val)); 558 if (TREE_OVERFLOW_P (val)) 559 val = drop_tree_overflow (val); 560 set_value_range (vr, VR_RANGE, val, val, equiv); 561 } 562 563 /* Set value range VR to a non-negative range of type TYPE. 564 OVERFLOW_INFINITY indicates whether to use an overflow infinity 565 rather than TYPE_MAX_VALUE; this should be true if we determine 566 that the range is nonnegative based on the assumption that signed 567 overflow does not occur. */ 568 569 static inline void 570 set_value_range_to_nonnegative (value_range *vr, tree type, 571 bool overflow_infinity) 572 { 573 tree zero; 574 575 if (overflow_infinity && !supports_overflow_infinity (type)) 576 { 577 set_value_range_to_varying (vr); 578 return; 579 } 580 581 zero = build_int_cst (type, 0); 582 set_value_range (vr, VR_RANGE, zero, 583 (overflow_infinity 584 ? positive_overflow_infinity (type) 585 : TYPE_MAX_VALUE (type)), 586 vr->equiv); 587 } 588 589 /* Set value range VR to a non-NULL range of type TYPE. */ 590 591 static inline void 592 set_value_range_to_nonnull (value_range *vr, tree type) 593 { 594 tree zero = build_int_cst (type, 0); 595 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv); 596 } 597 598 599 /* Set value range VR to a NULL range of type TYPE. */ 600 601 static inline void 602 set_value_range_to_null (value_range *vr, tree type) 603 { 604 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv); 605 } 606 607 608 /* Set value range VR to a range of a truthvalue of type TYPE. */ 609 610 static inline void 611 set_value_range_to_truthvalue (value_range *vr, tree type) 612 { 613 if (TYPE_PRECISION (type) == 1) 614 set_value_range_to_varying (vr); 615 else 616 set_value_range (vr, VR_RANGE, 617 build_int_cst (type, 0), build_int_cst (type, 1), 618 vr->equiv); 619 } 620 621 622 /* If abs (min) < abs (max), set VR to [-max, max], if 623 abs (min) >= abs (max), set VR to [-min, min]. */ 624 625 static void 626 abs_extent_range (value_range *vr, tree min, tree max) 627 { 628 int cmp; 629 630 gcc_assert (TREE_CODE (min) == INTEGER_CST); 631 gcc_assert (TREE_CODE (max) == INTEGER_CST); 632 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min))); 633 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min))); 634 min = fold_unary (ABS_EXPR, TREE_TYPE (min), min); 635 max = fold_unary (ABS_EXPR, TREE_TYPE (max), max); 636 if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max)) 637 { 638 set_value_range_to_varying (vr); 639 return; 640 } 641 cmp = compare_values (min, max); 642 if (cmp == -1) 643 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max); 644 else if (cmp == 0 || cmp == 1) 645 { 646 max = min; 647 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min); 648 } 649 else 650 { 651 set_value_range_to_varying (vr); 652 return; 653 } 654 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL); 655 } 656 657 658 /* Return value range information for VAR. 659 660 If we have no values ranges recorded (ie, VRP is not running), then 661 return NULL. Otherwise create an empty range if none existed for VAR. */ 662 663 static value_range * 664 get_value_range (const_tree var) 665 { 666 static const value_range vr_const_varying 667 = { VR_VARYING, NULL_TREE, NULL_TREE, NULL }; 668 value_range *vr; 669 tree sym; 670 unsigned ver = SSA_NAME_VERSION (var); 671 672 /* If we have no recorded ranges, then return NULL. */ 673 if (! vr_value) 674 return NULL; 675 676 /* If we query the range for a new SSA name return an unmodifiable VARYING. 677 We should get here at most from the substitute-and-fold stage which 678 will never try to change values. */ 679 if (ver >= num_vr_values) 680 return CONST_CAST (value_range *, &vr_const_varying); 681 682 vr = vr_value[ver]; 683 if (vr) 684 return vr; 685 686 /* After propagation finished do not allocate new value-ranges. */ 687 if (values_propagated) 688 return CONST_CAST (value_range *, &vr_const_varying); 689 690 /* Create a default value range. */ 691 vr_value[ver] = vr = XCNEW (value_range); 692 693 /* Defer allocating the equivalence set. */ 694 vr->equiv = NULL; 695 696 /* If VAR is a default definition of a parameter, the variable can 697 take any value in VAR's type. */ 698 if (SSA_NAME_IS_DEFAULT_DEF (var)) 699 { 700 sym = SSA_NAME_VAR (var); 701 if (TREE_CODE (sym) == PARM_DECL) 702 { 703 /* Try to use the "nonnull" attribute to create ~[0, 0] 704 anti-ranges for pointers. Note that this is only valid with 705 default definitions of PARM_DECLs. */ 706 if (POINTER_TYPE_P (TREE_TYPE (sym)) 707 && nonnull_arg_p (sym)) 708 set_value_range_to_nonnull (vr, TREE_TYPE (sym)); 709 else 710 set_value_range_to_varying (vr); 711 } 712 else if (TREE_CODE (sym) == RESULT_DECL 713 && DECL_BY_REFERENCE (sym)) 714 set_value_range_to_nonnull (vr, TREE_TYPE (sym)); 715 } 716 717 return vr; 718 } 719 720 /* Set value-ranges of all SSA names defined by STMT to varying. */ 721 722 static void 723 set_defs_to_varying (gimple *stmt) 724 { 725 ssa_op_iter i; 726 tree def; 727 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF) 728 { 729 value_range *vr = get_value_range (def); 730 /* Avoid writing to vr_const_varying get_value_range may return. */ 731 if (vr->type != VR_VARYING) 732 set_value_range_to_varying (vr); 733 } 734 } 735 736 737 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */ 738 739 static inline bool 740 vrp_operand_equal_p (const_tree val1, const_tree val2) 741 { 742 if (val1 == val2) 743 return true; 744 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0)) 745 return false; 746 return is_overflow_infinity (val1) == is_overflow_infinity (val2); 747 } 748 749 /* Return true, if the bitmaps B1 and B2 are equal. */ 750 751 static inline bool 752 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2) 753 { 754 return (b1 == b2 755 || ((!b1 || bitmap_empty_p (b1)) 756 && (!b2 || bitmap_empty_p (b2))) 757 || (b1 && b2 758 && bitmap_equal_p (b1, b2))); 759 } 760 761 /* Update the value range and equivalence set for variable VAR to 762 NEW_VR. Return true if NEW_VR is different from VAR's previous 763 value. 764 765 NOTE: This function assumes that NEW_VR is a temporary value range 766 object created for the sole purpose of updating VAR's range. The 767 storage used by the equivalence set from NEW_VR will be freed by 768 this function. Do not call update_value_range when NEW_VR 769 is the range object associated with another SSA name. */ 770 771 static inline bool 772 update_value_range (const_tree var, value_range *new_vr) 773 { 774 value_range *old_vr; 775 bool is_new; 776 777 /* If there is a value-range on the SSA name from earlier analysis 778 factor that in. */ 779 if (INTEGRAL_TYPE_P (TREE_TYPE (var))) 780 { 781 wide_int min, max; 782 value_range_type rtype = get_range_info (var, &min, &max); 783 if (rtype == VR_RANGE || rtype == VR_ANTI_RANGE) 784 { 785 value_range nr; 786 nr.type = rtype; 787 /* Range info on SSA names doesn't carry overflow information 788 so make sure to preserve the overflow bit on the lattice. */ 789 if (new_vr->type == VR_RANGE 790 && is_negative_overflow_infinity (new_vr->min) 791 && wi::eq_p (new_vr->min, min)) 792 nr.min = new_vr->min; 793 else 794 nr.min = wide_int_to_tree (TREE_TYPE (var), min); 795 if (new_vr->type == VR_RANGE 796 && is_positive_overflow_infinity (new_vr->max) 797 && wi::eq_p (new_vr->max, max)) 798 nr.max = new_vr->max; 799 else 800 nr.max = wide_int_to_tree (TREE_TYPE (var), max); 801 nr.equiv = NULL; 802 vrp_intersect_ranges (new_vr, &nr); 803 } 804 } 805 806 /* Update the value range, if necessary. */ 807 old_vr = get_value_range (var); 808 is_new = old_vr->type != new_vr->type 809 || !vrp_operand_equal_p (old_vr->min, new_vr->min) 810 || !vrp_operand_equal_p (old_vr->max, new_vr->max) 811 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv); 812 813 if (is_new) 814 { 815 /* Do not allow transitions up the lattice. The following 816 is slightly more awkward than just new_vr->type < old_vr->type 817 because VR_RANGE and VR_ANTI_RANGE need to be considered 818 the same. We may not have is_new when transitioning to 819 UNDEFINED. If old_vr->type is VARYING, we shouldn't be 820 called. */ 821 if (new_vr->type == VR_UNDEFINED) 822 { 823 BITMAP_FREE (new_vr->equiv); 824 set_value_range_to_varying (old_vr); 825 set_value_range_to_varying (new_vr); 826 return true; 827 } 828 else 829 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max, 830 new_vr->equiv); 831 } 832 833 BITMAP_FREE (new_vr->equiv); 834 835 return is_new; 836 } 837 838 839 /* Add VAR and VAR's equivalence set to EQUIV. This is the central 840 point where equivalence processing can be turned on/off. */ 841 842 static void 843 add_equivalence (bitmap *equiv, const_tree var) 844 { 845 unsigned ver = SSA_NAME_VERSION (var); 846 value_range *vr = vr_value[ver]; 847 848 if (*equiv == NULL) 849 *equiv = BITMAP_ALLOC (NULL); 850 bitmap_set_bit (*equiv, ver); 851 if (vr && vr->equiv) 852 bitmap_ior_into (*equiv, vr->equiv); 853 } 854 855 856 /* Return true if VR is ~[0, 0]. */ 857 858 static inline bool 859 range_is_nonnull (value_range *vr) 860 { 861 return vr->type == VR_ANTI_RANGE 862 && integer_zerop (vr->min) 863 && integer_zerop (vr->max); 864 } 865 866 867 /* Return true if VR is [0, 0]. */ 868 869 static inline bool 870 range_is_null (value_range *vr) 871 { 872 return vr->type == VR_RANGE 873 && integer_zerop (vr->min) 874 && integer_zerop (vr->max); 875 } 876 877 /* Return true if max and min of VR are INTEGER_CST. It's not necessary 878 a singleton. */ 879 880 static inline bool 881 range_int_cst_p (value_range *vr) 882 { 883 return (vr->type == VR_RANGE 884 && TREE_CODE (vr->max) == INTEGER_CST 885 && TREE_CODE (vr->min) == INTEGER_CST); 886 } 887 888 /* Return true if VR is a INTEGER_CST singleton. */ 889 890 static inline bool 891 range_int_cst_singleton_p (value_range *vr) 892 { 893 return (range_int_cst_p (vr) 894 && !is_overflow_infinity (vr->min) 895 && !is_overflow_infinity (vr->max) 896 && tree_int_cst_equal (vr->min, vr->max)); 897 } 898 899 /* Return true if value range VR involves at least one symbol. */ 900 901 static inline bool 902 symbolic_range_p (value_range *vr) 903 { 904 return (!is_gimple_min_invariant (vr->min) 905 || !is_gimple_min_invariant (vr->max)); 906 } 907 908 /* Return the single symbol (an SSA_NAME) contained in T if any, or NULL_TREE 909 otherwise. We only handle additive operations and set NEG to true if the 910 symbol is negated and INV to the invariant part, if any. */ 911 912 static tree 913 get_single_symbol (tree t, bool *neg, tree *inv) 914 { 915 bool neg_; 916 tree inv_; 917 918 if (TREE_CODE (t) == PLUS_EXPR 919 || TREE_CODE (t) == POINTER_PLUS_EXPR 920 || TREE_CODE (t) == MINUS_EXPR) 921 { 922 if (is_gimple_min_invariant (TREE_OPERAND (t, 0))) 923 { 924 neg_ = (TREE_CODE (t) == MINUS_EXPR); 925 inv_ = TREE_OPERAND (t, 0); 926 t = TREE_OPERAND (t, 1); 927 } 928 else if (is_gimple_min_invariant (TREE_OPERAND (t, 1))) 929 { 930 neg_ = false; 931 inv_ = TREE_OPERAND (t, 1); 932 t = TREE_OPERAND (t, 0); 933 } 934 else 935 return NULL_TREE; 936 } 937 else 938 { 939 neg_ = false; 940 inv_ = NULL_TREE; 941 } 942 943 if (TREE_CODE (t) == NEGATE_EXPR) 944 { 945 t = TREE_OPERAND (t, 0); 946 neg_ = !neg_; 947 } 948 949 if (TREE_CODE (t) != SSA_NAME) 950 return NULL_TREE; 951 952 *neg = neg_; 953 *inv = inv_; 954 return t; 955 } 956 957 /* The reverse operation: build a symbolic expression with TYPE 958 from symbol SYM, negated according to NEG, and invariant INV. */ 959 960 static tree 961 build_symbolic_expr (tree type, tree sym, bool neg, tree inv) 962 { 963 const bool pointer_p = POINTER_TYPE_P (type); 964 tree t = sym; 965 966 if (neg) 967 t = build1 (NEGATE_EXPR, type, t); 968 969 if (integer_zerop (inv)) 970 return t; 971 972 return build2 (pointer_p ? POINTER_PLUS_EXPR : PLUS_EXPR, type, t, inv); 973 } 974 975 /* Return true if value range VR involves exactly one symbol SYM. */ 976 977 static bool 978 symbolic_range_based_on_p (value_range *vr, const_tree sym) 979 { 980 bool neg, min_has_symbol, max_has_symbol; 981 tree inv; 982 983 if (is_gimple_min_invariant (vr->min)) 984 min_has_symbol = false; 985 else if (get_single_symbol (vr->min, &neg, &inv) == sym) 986 min_has_symbol = true; 987 else 988 return false; 989 990 if (is_gimple_min_invariant (vr->max)) 991 max_has_symbol = false; 992 else if (get_single_symbol (vr->max, &neg, &inv) == sym) 993 max_has_symbol = true; 994 else 995 return false; 996 997 return (min_has_symbol || max_has_symbol); 998 } 999 1000 /* Return true if value range VR uses an overflow infinity. */ 1001 1002 static inline bool 1003 overflow_infinity_range_p (value_range *vr) 1004 { 1005 return (vr->type == VR_RANGE 1006 && (is_overflow_infinity (vr->min) 1007 || is_overflow_infinity (vr->max))); 1008 } 1009 1010 /* Return false if we can not make a valid comparison based on VR; 1011 this will be the case if it uses an overflow infinity and overflow 1012 is not undefined (i.e., -fno-strict-overflow is in effect). 1013 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR 1014 uses an overflow infinity. */ 1015 1016 static bool 1017 usable_range_p (value_range *vr, bool *strict_overflow_p) 1018 { 1019 gcc_assert (vr->type == VR_RANGE); 1020 if (is_overflow_infinity (vr->min)) 1021 { 1022 *strict_overflow_p = true; 1023 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min))) 1024 return false; 1025 } 1026 if (is_overflow_infinity (vr->max)) 1027 { 1028 *strict_overflow_p = true; 1029 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max))) 1030 return false; 1031 } 1032 return true; 1033 } 1034 1035 /* Return true if the result of assignment STMT is know to be non-zero. 1036 If the return value is based on the assumption that signed overflow is 1037 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change 1038 *STRICT_OVERFLOW_P.*/ 1039 1040 static bool 1041 gimple_assign_nonzero_warnv_p (gimple *stmt, bool *strict_overflow_p) 1042 { 1043 enum tree_code code = gimple_assign_rhs_code (stmt); 1044 switch (get_gimple_rhs_class (code)) 1045 { 1046 case GIMPLE_UNARY_RHS: 1047 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt), 1048 gimple_expr_type (stmt), 1049 gimple_assign_rhs1 (stmt), 1050 strict_overflow_p); 1051 case GIMPLE_BINARY_RHS: 1052 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt), 1053 gimple_expr_type (stmt), 1054 gimple_assign_rhs1 (stmt), 1055 gimple_assign_rhs2 (stmt), 1056 strict_overflow_p); 1057 case GIMPLE_TERNARY_RHS: 1058 return false; 1059 case GIMPLE_SINGLE_RHS: 1060 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt), 1061 strict_overflow_p); 1062 case GIMPLE_INVALID_RHS: 1063 gcc_unreachable (); 1064 default: 1065 gcc_unreachable (); 1066 } 1067 } 1068 1069 /* Return true if STMT is known to compute a non-zero value. 1070 If the return value is based on the assumption that signed overflow is 1071 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change 1072 *STRICT_OVERFLOW_P.*/ 1073 1074 static bool 1075 gimple_stmt_nonzero_warnv_p (gimple *stmt, bool *strict_overflow_p) 1076 { 1077 switch (gimple_code (stmt)) 1078 { 1079 case GIMPLE_ASSIGN: 1080 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p); 1081 case GIMPLE_CALL: 1082 { 1083 tree fndecl = gimple_call_fndecl (stmt); 1084 if (!fndecl) return false; 1085 if (flag_delete_null_pointer_checks && !flag_check_new 1086 && DECL_IS_OPERATOR_NEW (fndecl) 1087 && !TREE_NOTHROW (fndecl)) 1088 return true; 1089 /* References are always non-NULL. */ 1090 if (flag_delete_null_pointer_checks 1091 && TREE_CODE (TREE_TYPE (fndecl)) == REFERENCE_TYPE) 1092 return true; 1093 if (flag_delete_null_pointer_checks && 1094 lookup_attribute ("returns_nonnull", 1095 TYPE_ATTRIBUTES (gimple_call_fntype (stmt)))) 1096 return true; 1097 return gimple_alloca_call_p (stmt); 1098 } 1099 default: 1100 gcc_unreachable (); 1101 } 1102 } 1103 1104 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges 1105 obtained so far. */ 1106 1107 static bool 1108 vrp_stmt_computes_nonzero (gimple *stmt, bool *strict_overflow_p) 1109 { 1110 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p)) 1111 return true; 1112 1113 /* If we have an expression of the form &X->a, then the expression 1114 is nonnull if X is nonnull. */ 1115 if (is_gimple_assign (stmt) 1116 && gimple_assign_rhs_code (stmt) == ADDR_EXPR) 1117 { 1118 tree expr = gimple_assign_rhs1 (stmt); 1119 tree base = get_base_address (TREE_OPERAND (expr, 0)); 1120 1121 if (base != NULL_TREE 1122 && TREE_CODE (base) == MEM_REF 1123 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) 1124 { 1125 value_range *vr = get_value_range (TREE_OPERAND (base, 0)); 1126 if (range_is_nonnull (vr)) 1127 return true; 1128 } 1129 } 1130 1131 return false; 1132 } 1133 1134 /* Returns true if EXPR is a valid value (as expected by compare_values) -- 1135 a gimple invariant, or SSA_NAME +- CST. */ 1136 1137 static bool 1138 valid_value_p (tree expr) 1139 { 1140 if (TREE_CODE (expr) == SSA_NAME) 1141 return true; 1142 1143 if (TREE_CODE (expr) == PLUS_EXPR 1144 || TREE_CODE (expr) == MINUS_EXPR) 1145 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME 1146 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST); 1147 1148 return is_gimple_min_invariant (expr); 1149 } 1150 1151 /* Return 1152 1 if VAL < VAL2 1153 0 if !(VAL < VAL2) 1154 -2 if those are incomparable. */ 1155 static inline int 1156 operand_less_p (tree val, tree val2) 1157 { 1158 /* LT is folded faster than GE and others. Inline the common case. */ 1159 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST) 1160 { 1161 if (! is_positive_overflow_infinity (val2)) 1162 return tree_int_cst_lt (val, val2); 1163 } 1164 else 1165 { 1166 tree tcmp; 1167 1168 fold_defer_overflow_warnings (); 1169 1170 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2); 1171 1172 fold_undefer_and_ignore_overflow_warnings (); 1173 1174 if (!tcmp 1175 || TREE_CODE (tcmp) != INTEGER_CST) 1176 return -2; 1177 1178 if (!integer_zerop (tcmp)) 1179 return 1; 1180 } 1181 1182 /* val >= val2, not considering overflow infinity. */ 1183 if (is_negative_overflow_infinity (val)) 1184 return is_negative_overflow_infinity (val2) ? 0 : 1; 1185 else if (is_positive_overflow_infinity (val2)) 1186 return is_positive_overflow_infinity (val) ? 0 : 1; 1187 1188 return 0; 1189 } 1190 1191 /* Compare two values VAL1 and VAL2. Return 1192 1193 -2 if VAL1 and VAL2 cannot be compared at compile-time, 1194 -1 if VAL1 < VAL2, 1195 0 if VAL1 == VAL2, 1196 +1 if VAL1 > VAL2, and 1197 +2 if VAL1 != VAL2 1198 1199 This is similar to tree_int_cst_compare but supports pointer values 1200 and values that cannot be compared at compile time. 1201 1202 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to 1203 true if the return value is only valid if we assume that signed 1204 overflow is undefined. */ 1205 1206 static int 1207 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p) 1208 { 1209 if (val1 == val2) 1210 return 0; 1211 1212 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or 1213 both integers. */ 1214 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1)) 1215 == POINTER_TYPE_P (TREE_TYPE (val2))); 1216 1217 /* Convert the two values into the same type. This is needed because 1218 sizetype causes sign extension even for unsigned types. */ 1219 val2 = fold_convert (TREE_TYPE (val1), val2); 1220 STRIP_USELESS_TYPE_CONVERSION (val2); 1221 1222 if ((TREE_CODE (val1) == SSA_NAME 1223 || (TREE_CODE (val1) == NEGATE_EXPR 1224 && TREE_CODE (TREE_OPERAND (val1, 0)) == SSA_NAME) 1225 || TREE_CODE (val1) == PLUS_EXPR 1226 || TREE_CODE (val1) == MINUS_EXPR) 1227 && (TREE_CODE (val2) == SSA_NAME 1228 || (TREE_CODE (val2) == NEGATE_EXPR 1229 && TREE_CODE (TREE_OPERAND (val2, 0)) == SSA_NAME) 1230 || TREE_CODE (val2) == PLUS_EXPR 1231 || TREE_CODE (val2) == MINUS_EXPR)) 1232 { 1233 tree n1, c1, n2, c2; 1234 enum tree_code code1, code2; 1235 1236 /* If VAL1 and VAL2 are of the form '[-]NAME [+-] CST' or 'NAME', 1237 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the 1238 same name, return -2. */ 1239 if (TREE_CODE (val1) == SSA_NAME || TREE_CODE (val1) == NEGATE_EXPR) 1240 { 1241 code1 = SSA_NAME; 1242 n1 = val1; 1243 c1 = NULL_TREE; 1244 } 1245 else 1246 { 1247 code1 = TREE_CODE (val1); 1248 n1 = TREE_OPERAND (val1, 0); 1249 c1 = TREE_OPERAND (val1, 1); 1250 if (tree_int_cst_sgn (c1) == -1) 1251 { 1252 if (is_negative_overflow_infinity (c1)) 1253 return -2; 1254 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1); 1255 if (!c1) 1256 return -2; 1257 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR; 1258 } 1259 } 1260 1261 if (TREE_CODE (val2) == SSA_NAME || TREE_CODE (val2) == NEGATE_EXPR) 1262 { 1263 code2 = SSA_NAME; 1264 n2 = val2; 1265 c2 = NULL_TREE; 1266 } 1267 else 1268 { 1269 code2 = TREE_CODE (val2); 1270 n2 = TREE_OPERAND (val2, 0); 1271 c2 = TREE_OPERAND (val2, 1); 1272 if (tree_int_cst_sgn (c2) == -1) 1273 { 1274 if (is_negative_overflow_infinity (c2)) 1275 return -2; 1276 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2); 1277 if (!c2) 1278 return -2; 1279 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR; 1280 } 1281 } 1282 1283 /* Both values must use the same name. */ 1284 if (TREE_CODE (n1) == NEGATE_EXPR && TREE_CODE (n2) == NEGATE_EXPR) 1285 { 1286 n1 = TREE_OPERAND (n1, 0); 1287 n2 = TREE_OPERAND (n2, 0); 1288 } 1289 if (n1 != n2) 1290 return -2; 1291 1292 if (code1 == SSA_NAME && code2 == SSA_NAME) 1293 /* NAME == NAME */ 1294 return 0; 1295 1296 /* If overflow is defined we cannot simplify more. */ 1297 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1))) 1298 return -2; 1299 1300 if (strict_overflow_p != NULL 1301 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1)) 1302 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2))) 1303 *strict_overflow_p = true; 1304 1305 if (code1 == SSA_NAME) 1306 { 1307 if (code2 == PLUS_EXPR) 1308 /* NAME < NAME + CST */ 1309 return -1; 1310 else if (code2 == MINUS_EXPR) 1311 /* NAME > NAME - CST */ 1312 return 1; 1313 } 1314 else if (code1 == PLUS_EXPR) 1315 { 1316 if (code2 == SSA_NAME) 1317 /* NAME + CST > NAME */ 1318 return 1; 1319 else if (code2 == PLUS_EXPR) 1320 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */ 1321 return compare_values_warnv (c1, c2, strict_overflow_p); 1322 else if (code2 == MINUS_EXPR) 1323 /* NAME + CST1 > NAME - CST2 */ 1324 return 1; 1325 } 1326 else if (code1 == MINUS_EXPR) 1327 { 1328 if (code2 == SSA_NAME) 1329 /* NAME - CST < NAME */ 1330 return -1; 1331 else if (code2 == PLUS_EXPR) 1332 /* NAME - CST1 < NAME + CST2 */ 1333 return -1; 1334 else if (code2 == MINUS_EXPR) 1335 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that 1336 C1 and C2 are swapped in the call to compare_values. */ 1337 return compare_values_warnv (c2, c1, strict_overflow_p); 1338 } 1339 1340 gcc_unreachable (); 1341 } 1342 1343 /* We cannot compare non-constants. */ 1344 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)) 1345 return -2; 1346 1347 if (!POINTER_TYPE_P (TREE_TYPE (val1))) 1348 { 1349 /* We cannot compare overflowed values, except for overflow 1350 infinities. */ 1351 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2)) 1352 { 1353 if (strict_overflow_p != NULL) 1354 *strict_overflow_p = true; 1355 if (is_negative_overflow_infinity (val1)) 1356 return is_negative_overflow_infinity (val2) ? 0 : -1; 1357 else if (is_negative_overflow_infinity (val2)) 1358 return 1; 1359 else if (is_positive_overflow_infinity (val1)) 1360 return is_positive_overflow_infinity (val2) ? 0 : 1; 1361 else if (is_positive_overflow_infinity (val2)) 1362 return -1; 1363 return -2; 1364 } 1365 1366 return tree_int_cst_compare (val1, val2); 1367 } 1368 else 1369 { 1370 tree t; 1371 1372 /* First see if VAL1 and VAL2 are not the same. */ 1373 if (val1 == val2 || operand_equal_p (val1, val2, 0)) 1374 return 0; 1375 1376 /* If VAL1 is a lower address than VAL2, return -1. */ 1377 if (operand_less_p (val1, val2) == 1) 1378 return -1; 1379 1380 /* If VAL1 is a higher address than VAL2, return +1. */ 1381 if (operand_less_p (val2, val1) == 1) 1382 return 1; 1383 1384 /* If VAL1 is different than VAL2, return +2. 1385 For integer constants we either have already returned -1 or 1 1386 or they are equivalent. We still might succeed in proving 1387 something about non-trivial operands. */ 1388 if (TREE_CODE (val1) != INTEGER_CST 1389 || TREE_CODE (val2) != INTEGER_CST) 1390 { 1391 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2); 1392 if (t && integer_onep (t)) 1393 return 2; 1394 } 1395 1396 return -2; 1397 } 1398 } 1399 1400 /* Compare values like compare_values_warnv, but treat comparisons of 1401 nonconstants which rely on undefined overflow as incomparable. */ 1402 1403 static int 1404 compare_values (tree val1, tree val2) 1405 { 1406 bool sop; 1407 int ret; 1408 1409 sop = false; 1410 ret = compare_values_warnv (val1, val2, &sop); 1411 if (sop 1412 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))) 1413 ret = -2; 1414 return ret; 1415 } 1416 1417 1418 /* Return 1 if VAL is inside value range MIN <= VAL <= MAX, 1419 0 if VAL is not inside [MIN, MAX], 1420 -2 if we cannot tell either way. 1421 1422 Benchmark compile/20001226-1.c compilation time after changing this 1423 function. */ 1424 1425 static inline int 1426 value_inside_range (tree val, tree min, tree max) 1427 { 1428 int cmp1, cmp2; 1429 1430 cmp1 = operand_less_p (val, min); 1431 if (cmp1 == -2) 1432 return -2; 1433 if (cmp1 == 1) 1434 return 0; 1435 1436 cmp2 = operand_less_p (max, val); 1437 if (cmp2 == -2) 1438 return -2; 1439 1440 return !cmp2; 1441 } 1442 1443 1444 /* Return true if value ranges VR0 and VR1 have a non-empty 1445 intersection. 1446 1447 Benchmark compile/20001226-1.c compilation time after changing this 1448 function. 1449 */ 1450 1451 static inline bool 1452 value_ranges_intersect_p (value_range *vr0, value_range *vr1) 1453 { 1454 /* The value ranges do not intersect if the maximum of the first range is 1455 less than the minimum of the second range or vice versa. 1456 When those relations are unknown, we can't do any better. */ 1457 if (operand_less_p (vr0->max, vr1->min) != 0) 1458 return false; 1459 if (operand_less_p (vr1->max, vr0->min) != 0) 1460 return false; 1461 return true; 1462 } 1463 1464 1465 /* Return 1 if [MIN, MAX] includes the value zero, 0 if it does not 1466 include the value zero, -2 if we cannot tell. */ 1467 1468 static inline int 1469 range_includes_zero_p (tree min, tree max) 1470 { 1471 tree zero = build_int_cst (TREE_TYPE (min), 0); 1472 return value_inside_range (zero, min, max); 1473 } 1474 1475 /* Return true if *VR is know to only contain nonnegative values. */ 1476 1477 static inline bool 1478 value_range_nonnegative_p (value_range *vr) 1479 { 1480 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range 1481 which would return a useful value should be encoded as a 1482 VR_RANGE. */ 1483 if (vr->type == VR_RANGE) 1484 { 1485 int result = compare_values (vr->min, integer_zero_node); 1486 return (result == 0 || result == 1); 1487 } 1488 1489 return false; 1490 } 1491 1492 /* If *VR has a value rante that is a single constant value return that, 1493 otherwise return NULL_TREE. */ 1494 1495 static tree 1496 value_range_constant_singleton (value_range *vr) 1497 { 1498 if (vr->type == VR_RANGE 1499 && vrp_operand_equal_p (vr->min, vr->max) 1500 && is_gimple_min_invariant (vr->min)) 1501 return vr->min; 1502 1503 return NULL_TREE; 1504 } 1505 1506 /* If OP has a value range with a single constant value return that, 1507 otherwise return NULL_TREE. This returns OP itself if OP is a 1508 constant. */ 1509 1510 static tree 1511 op_with_constant_singleton_value_range (tree op) 1512 { 1513 if (is_gimple_min_invariant (op)) 1514 return op; 1515 1516 if (TREE_CODE (op) != SSA_NAME) 1517 return NULL_TREE; 1518 1519 return value_range_constant_singleton (get_value_range (op)); 1520 } 1521 1522 /* Return true if op is in a boolean [0, 1] value-range. */ 1523 1524 static bool 1525 op_with_boolean_value_range_p (tree op) 1526 { 1527 value_range *vr; 1528 1529 if (TYPE_PRECISION (TREE_TYPE (op)) == 1) 1530 return true; 1531 1532 if (integer_zerop (op) 1533 || integer_onep (op)) 1534 return true; 1535 1536 if (TREE_CODE (op) != SSA_NAME) 1537 return false; 1538 1539 vr = get_value_range (op); 1540 return (vr->type == VR_RANGE 1541 && integer_zerop (vr->min) 1542 && integer_onep (vr->max)); 1543 } 1544 1545 /* Extract value range information from an ASSERT_EXPR EXPR and store 1546 it in *VR_P. */ 1547 1548 static void 1549 extract_range_from_assert (value_range *vr_p, tree expr) 1550 { 1551 tree var, cond, limit, min, max, type; 1552 value_range *limit_vr; 1553 enum tree_code cond_code; 1554 1555 var = ASSERT_EXPR_VAR (expr); 1556 cond = ASSERT_EXPR_COND (expr); 1557 1558 gcc_assert (COMPARISON_CLASS_P (cond)); 1559 1560 /* Find VAR in the ASSERT_EXPR conditional. */ 1561 if (var == TREE_OPERAND (cond, 0) 1562 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR 1563 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR) 1564 { 1565 /* If the predicate is of the form VAR COMP LIMIT, then we just 1566 take LIMIT from the RHS and use the same comparison code. */ 1567 cond_code = TREE_CODE (cond); 1568 limit = TREE_OPERAND (cond, 1); 1569 cond = TREE_OPERAND (cond, 0); 1570 } 1571 else 1572 { 1573 /* If the predicate is of the form LIMIT COMP VAR, then we need 1574 to flip around the comparison code to create the proper range 1575 for VAR. */ 1576 cond_code = swap_tree_comparison (TREE_CODE (cond)); 1577 limit = TREE_OPERAND (cond, 0); 1578 cond = TREE_OPERAND (cond, 1); 1579 } 1580 1581 limit = avoid_overflow_infinity (limit); 1582 1583 type = TREE_TYPE (var); 1584 gcc_assert (limit != var); 1585 1586 /* For pointer arithmetic, we only keep track of pointer equality 1587 and inequality. */ 1588 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR) 1589 { 1590 set_value_range_to_varying (vr_p); 1591 return; 1592 } 1593 1594 /* If LIMIT is another SSA name and LIMIT has a range of its own, 1595 try to use LIMIT's range to avoid creating symbolic ranges 1596 unnecessarily. */ 1597 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL; 1598 1599 /* LIMIT's range is only interesting if it has any useful information. */ 1600 if (limit_vr 1601 && (limit_vr->type == VR_UNDEFINED 1602 || limit_vr->type == VR_VARYING 1603 || symbolic_range_p (limit_vr))) 1604 limit_vr = NULL; 1605 1606 /* Initially, the new range has the same set of equivalences of 1607 VAR's range. This will be revised before returning the final 1608 value. Since assertions may be chained via mutually exclusive 1609 predicates, we will need to trim the set of equivalences before 1610 we are done. */ 1611 gcc_assert (vr_p->equiv == NULL); 1612 add_equivalence (&vr_p->equiv, var); 1613 1614 /* Extract a new range based on the asserted comparison for VAR and 1615 LIMIT's value range. Notice that if LIMIT has an anti-range, we 1616 will only use it for equality comparisons (EQ_EXPR). For any 1617 other kind of assertion, we cannot derive a range from LIMIT's 1618 anti-range that can be used to describe the new range. For 1619 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10], 1620 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is 1621 no single range for x_2 that could describe LE_EXPR, so we might 1622 as well build the range [b_4, +INF] for it. 1623 One special case we handle is extracting a range from a 1624 range test encoded as (unsigned)var + CST <= limit. */ 1625 if (TREE_CODE (cond) == NOP_EXPR 1626 || TREE_CODE (cond) == PLUS_EXPR) 1627 { 1628 if (TREE_CODE (cond) == PLUS_EXPR) 1629 { 1630 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)), 1631 TREE_OPERAND (cond, 1)); 1632 max = int_const_binop (PLUS_EXPR, limit, min); 1633 cond = TREE_OPERAND (cond, 0); 1634 } 1635 else 1636 { 1637 min = build_int_cst (TREE_TYPE (var), 0); 1638 max = limit; 1639 } 1640 1641 /* Make sure to not set TREE_OVERFLOW on the final type 1642 conversion. We are willingly interpreting large positive 1643 unsigned values as negative signed values here. */ 1644 min = force_fit_type (TREE_TYPE (var), wi::to_widest (min), 0, false); 1645 max = force_fit_type (TREE_TYPE (var), wi::to_widest (max), 0, false); 1646 1647 /* We can transform a max, min range to an anti-range or 1648 vice-versa. Use set_and_canonicalize_value_range which does 1649 this for us. */ 1650 if (cond_code == LE_EXPR) 1651 set_and_canonicalize_value_range (vr_p, VR_RANGE, 1652 min, max, vr_p->equiv); 1653 else if (cond_code == GT_EXPR) 1654 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE, 1655 min, max, vr_p->equiv); 1656 else 1657 gcc_unreachable (); 1658 } 1659 else if (cond_code == EQ_EXPR) 1660 { 1661 enum value_range_type range_type; 1662 1663 if (limit_vr) 1664 { 1665 range_type = limit_vr->type; 1666 min = limit_vr->min; 1667 max = limit_vr->max; 1668 } 1669 else 1670 { 1671 range_type = VR_RANGE; 1672 min = limit; 1673 max = limit; 1674 } 1675 1676 set_value_range (vr_p, range_type, min, max, vr_p->equiv); 1677 1678 /* When asserting the equality VAR == LIMIT and LIMIT is another 1679 SSA name, the new range will also inherit the equivalence set 1680 from LIMIT. */ 1681 if (TREE_CODE (limit) == SSA_NAME) 1682 add_equivalence (&vr_p->equiv, limit); 1683 } 1684 else if (cond_code == NE_EXPR) 1685 { 1686 /* As described above, when LIMIT's range is an anti-range and 1687 this assertion is an inequality (NE_EXPR), then we cannot 1688 derive anything from the anti-range. For instance, if 1689 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does 1690 not imply that VAR's range is [0, 0]. So, in the case of 1691 anti-ranges, we just assert the inequality using LIMIT and 1692 not its anti-range. 1693 1694 If LIMIT_VR is a range, we can only use it to build a new 1695 anti-range if LIMIT_VR is a single-valued range. For 1696 instance, if LIMIT_VR is [0, 1], the predicate 1697 VAR != [0, 1] does not mean that VAR's range is ~[0, 1]. 1698 Rather, it means that for value 0 VAR should be ~[0, 0] 1699 and for value 1, VAR should be ~[1, 1]. We cannot 1700 represent these ranges. 1701 1702 The only situation in which we can build a valid 1703 anti-range is when LIMIT_VR is a single-valued range 1704 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case, 1705 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */ 1706 if (limit_vr 1707 && limit_vr->type == VR_RANGE 1708 && compare_values (limit_vr->min, limit_vr->max) == 0) 1709 { 1710 min = limit_vr->min; 1711 max = limit_vr->max; 1712 } 1713 else 1714 { 1715 /* In any other case, we cannot use LIMIT's range to build a 1716 valid anti-range. */ 1717 min = max = limit; 1718 } 1719 1720 /* If MIN and MAX cover the whole range for their type, then 1721 just use the original LIMIT. */ 1722 if (INTEGRAL_TYPE_P (type) 1723 && vrp_val_is_min (min) 1724 && vrp_val_is_max (max)) 1725 min = max = limit; 1726 1727 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE, 1728 min, max, vr_p->equiv); 1729 } 1730 else if (cond_code == LE_EXPR || cond_code == LT_EXPR) 1731 { 1732 min = TYPE_MIN_VALUE (type); 1733 1734 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE) 1735 max = limit; 1736 else 1737 { 1738 /* If LIMIT_VR is of the form [N1, N2], we need to build the 1739 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for 1740 LT_EXPR. */ 1741 max = limit_vr->max; 1742 } 1743 1744 /* If the maximum value forces us to be out of bounds, simply punt. 1745 It would be pointless to try and do anything more since this 1746 all should be optimized away above us. */ 1747 if ((cond_code == LT_EXPR 1748 && compare_values (max, min) == 0) 1749 || is_overflow_infinity (max)) 1750 set_value_range_to_varying (vr_p); 1751 else 1752 { 1753 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */ 1754 if (cond_code == LT_EXPR) 1755 { 1756 if (TYPE_PRECISION (TREE_TYPE (max)) == 1 1757 && !TYPE_UNSIGNED (TREE_TYPE (max))) 1758 max = fold_build2 (PLUS_EXPR, TREE_TYPE (max), max, 1759 build_int_cst (TREE_TYPE (max), -1)); 1760 else 1761 max = fold_build2 (MINUS_EXPR, TREE_TYPE (max), max, 1762 build_int_cst (TREE_TYPE (max), 1)); 1763 if (EXPR_P (max)) 1764 TREE_NO_WARNING (max) = 1; 1765 } 1766 1767 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv); 1768 } 1769 } 1770 else if (cond_code == GE_EXPR || cond_code == GT_EXPR) 1771 { 1772 max = TYPE_MAX_VALUE (type); 1773 1774 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE) 1775 min = limit; 1776 else 1777 { 1778 /* If LIMIT_VR is of the form [N1, N2], we need to build the 1779 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for 1780 GT_EXPR. */ 1781 min = limit_vr->min; 1782 } 1783 1784 /* If the minimum value forces us to be out of bounds, simply punt. 1785 It would be pointless to try and do anything more since this 1786 all should be optimized away above us. */ 1787 if ((cond_code == GT_EXPR 1788 && compare_values (min, max) == 0) 1789 || is_overflow_infinity (min)) 1790 set_value_range_to_varying (vr_p); 1791 else 1792 { 1793 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */ 1794 if (cond_code == GT_EXPR) 1795 { 1796 if (TYPE_PRECISION (TREE_TYPE (min)) == 1 1797 && !TYPE_UNSIGNED (TREE_TYPE (min))) 1798 min = fold_build2 (MINUS_EXPR, TREE_TYPE (min), min, 1799 build_int_cst (TREE_TYPE (min), -1)); 1800 else 1801 min = fold_build2 (PLUS_EXPR, TREE_TYPE (min), min, 1802 build_int_cst (TREE_TYPE (min), 1)); 1803 if (EXPR_P (min)) 1804 TREE_NO_WARNING (min) = 1; 1805 } 1806 1807 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv); 1808 } 1809 } 1810 else 1811 gcc_unreachable (); 1812 1813 /* Finally intersect the new range with what we already know about var. */ 1814 vrp_intersect_ranges (vr_p, get_value_range (var)); 1815 } 1816 1817 1818 /* Extract range information from SSA name VAR and store it in VR. If 1819 VAR has an interesting range, use it. Otherwise, create the 1820 range [VAR, VAR] and return it. This is useful in situations where 1821 we may have conditionals testing values of VARYING names. For 1822 instance, 1823 1824 x_3 = y_5; 1825 if (x_3 > y_5) 1826 ... 1827 1828 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is 1829 always false. */ 1830 1831 static void 1832 extract_range_from_ssa_name (value_range *vr, tree var) 1833 { 1834 value_range *var_vr = get_value_range (var); 1835 1836 if (var_vr->type != VR_VARYING) 1837 copy_value_range (vr, var_vr); 1838 else 1839 set_value_range (vr, VR_RANGE, var, var, NULL); 1840 1841 add_equivalence (&vr->equiv, var); 1842 } 1843 1844 1845 /* Wrapper around int_const_binop. If the operation overflows and we 1846 are not using wrapping arithmetic, then adjust the result to be 1847 -INF or +INF depending on CODE, VAL1 and VAL2. This can return 1848 NULL_TREE if we need to use an overflow infinity representation but 1849 the type does not support it. */ 1850 1851 static tree 1852 vrp_int_const_binop (enum tree_code code, tree val1, tree val2) 1853 { 1854 tree res; 1855 1856 res = int_const_binop (code, val1, val2); 1857 1858 /* If we are using unsigned arithmetic, operate symbolically 1859 on -INF and +INF as int_const_binop only handles signed overflow. */ 1860 if (TYPE_UNSIGNED (TREE_TYPE (val1))) 1861 { 1862 int checkz = compare_values (res, val1); 1863 bool overflow = false; 1864 1865 /* Ensure that res = val1 [+*] val2 >= val1 1866 or that res = val1 - val2 <= val1. */ 1867 if ((code == PLUS_EXPR 1868 && !(checkz == 1 || checkz == 0)) 1869 || (code == MINUS_EXPR 1870 && !(checkz == 0 || checkz == -1))) 1871 { 1872 overflow = true; 1873 } 1874 /* Checking for multiplication overflow is done by dividing the 1875 output of the multiplication by the first input of the 1876 multiplication. If the result of that division operation is 1877 not equal to the second input of the multiplication, then the 1878 multiplication overflowed. */ 1879 else if (code == MULT_EXPR && !integer_zerop (val1)) 1880 { 1881 tree tmp = int_const_binop (TRUNC_DIV_EXPR, 1882 res, 1883 val1); 1884 int check = compare_values (tmp, val2); 1885 1886 if (check != 0) 1887 overflow = true; 1888 } 1889 1890 if (overflow) 1891 { 1892 res = copy_node (res); 1893 TREE_OVERFLOW (res) = 1; 1894 } 1895 1896 } 1897 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1))) 1898 /* If the singed operation wraps then int_const_binop has done 1899 everything we want. */ 1900 ; 1901 /* Signed division of -1/0 overflows and by the time it gets here 1902 returns NULL_TREE. */ 1903 else if (!res) 1904 return NULL_TREE; 1905 else if ((TREE_OVERFLOW (res) 1906 && !TREE_OVERFLOW (val1) 1907 && !TREE_OVERFLOW (val2)) 1908 || is_overflow_infinity (val1) 1909 || is_overflow_infinity (val2)) 1910 { 1911 /* If the operation overflowed but neither VAL1 nor VAL2 are 1912 overflown, return -INF or +INF depending on the operation 1913 and the combination of signs of the operands. */ 1914 int sgn1 = tree_int_cst_sgn (val1); 1915 int sgn2 = tree_int_cst_sgn (val2); 1916 1917 if (needs_overflow_infinity (TREE_TYPE (res)) 1918 && !supports_overflow_infinity (TREE_TYPE (res))) 1919 return NULL_TREE; 1920 1921 /* We have to punt on adding infinities of different signs, 1922 since we can't tell what the sign of the result should be. 1923 Likewise for subtracting infinities of the same sign. */ 1924 if (((code == PLUS_EXPR && sgn1 != sgn2) 1925 || (code == MINUS_EXPR && sgn1 == sgn2)) 1926 && is_overflow_infinity (val1) 1927 && is_overflow_infinity (val2)) 1928 return NULL_TREE; 1929 1930 /* Don't try to handle division or shifting of infinities. */ 1931 if ((code == TRUNC_DIV_EXPR 1932 || code == FLOOR_DIV_EXPR 1933 || code == CEIL_DIV_EXPR 1934 || code == EXACT_DIV_EXPR 1935 || code == ROUND_DIV_EXPR 1936 || code == RSHIFT_EXPR) 1937 && (is_overflow_infinity (val1) 1938 || is_overflow_infinity (val2))) 1939 return NULL_TREE; 1940 1941 /* Notice that we only need to handle the restricted set of 1942 operations handled by extract_range_from_binary_expr. 1943 Among them, only multiplication, addition and subtraction 1944 can yield overflow without overflown operands because we 1945 are working with integral types only... except in the 1946 case VAL1 = -INF and VAL2 = -1 which overflows to +INF 1947 for division too. */ 1948 1949 /* For multiplication, the sign of the overflow is given 1950 by the comparison of the signs of the operands. */ 1951 if ((code == MULT_EXPR && sgn1 == sgn2) 1952 /* For addition, the operands must be of the same sign 1953 to yield an overflow. Its sign is therefore that 1954 of one of the operands, for example the first. For 1955 infinite operands X + -INF is negative, not positive. */ 1956 || (code == PLUS_EXPR 1957 && (sgn1 >= 0 1958 ? !is_negative_overflow_infinity (val2) 1959 : is_positive_overflow_infinity (val2))) 1960 /* For subtraction, non-infinite operands must be of 1961 different signs to yield an overflow. Its sign is 1962 therefore that of the first operand or the opposite of 1963 that of the second operand. A first operand of 0 counts 1964 as positive here, for the corner case 0 - (-INF), which 1965 overflows, but must yield +INF. For infinite operands 0 1966 - INF is negative, not positive. */ 1967 || (code == MINUS_EXPR 1968 && (sgn1 >= 0 1969 ? !is_positive_overflow_infinity (val2) 1970 : is_negative_overflow_infinity (val2))) 1971 /* We only get in here with positive shift count, so the 1972 overflow direction is the same as the sign of val1. 1973 Actually rshift does not overflow at all, but we only 1974 handle the case of shifting overflowed -INF and +INF. */ 1975 || (code == RSHIFT_EXPR 1976 && sgn1 >= 0) 1977 /* For division, the only case is -INF / -1 = +INF. */ 1978 || code == TRUNC_DIV_EXPR 1979 || code == FLOOR_DIV_EXPR 1980 || code == CEIL_DIV_EXPR 1981 || code == EXACT_DIV_EXPR 1982 || code == ROUND_DIV_EXPR) 1983 return (needs_overflow_infinity (TREE_TYPE (res)) 1984 ? positive_overflow_infinity (TREE_TYPE (res)) 1985 : TYPE_MAX_VALUE (TREE_TYPE (res))); 1986 else 1987 return (needs_overflow_infinity (TREE_TYPE (res)) 1988 ? negative_overflow_infinity (TREE_TYPE (res)) 1989 : TYPE_MIN_VALUE (TREE_TYPE (res))); 1990 } 1991 1992 return res; 1993 } 1994 1995 1996 /* For range VR compute two wide_int bitmasks. In *MAY_BE_NONZERO 1997 bitmask if some bit is unset, it means for all numbers in the range 1998 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO 1999 bitmask if some bit is set, it means for all numbers in the range 2000 the bit is 1, otherwise it might be 0 or 1. */ 2001 2002 static bool 2003 zero_nonzero_bits_from_vr (const tree expr_type, 2004 value_range *vr, 2005 wide_int *may_be_nonzero, 2006 wide_int *must_be_nonzero) 2007 { 2008 *may_be_nonzero = wi::minus_one (TYPE_PRECISION (expr_type)); 2009 *must_be_nonzero = wi::zero (TYPE_PRECISION (expr_type)); 2010 if (!range_int_cst_p (vr) 2011 || is_overflow_infinity (vr->min) 2012 || is_overflow_infinity (vr->max)) 2013 return false; 2014 2015 if (range_int_cst_singleton_p (vr)) 2016 { 2017 *may_be_nonzero = vr->min; 2018 *must_be_nonzero = *may_be_nonzero; 2019 } 2020 else if (tree_int_cst_sgn (vr->min) >= 0 2021 || tree_int_cst_sgn (vr->max) < 0) 2022 { 2023 wide_int xor_mask = wi::bit_xor (vr->min, vr->max); 2024 *may_be_nonzero = wi::bit_or (vr->min, vr->max); 2025 *must_be_nonzero = wi::bit_and (vr->min, vr->max); 2026 if (xor_mask != 0) 2027 { 2028 wide_int mask = wi::mask (wi::floor_log2 (xor_mask), false, 2029 may_be_nonzero->get_precision ()); 2030 *may_be_nonzero = *may_be_nonzero | mask; 2031 *must_be_nonzero = must_be_nonzero->and_not (mask); 2032 } 2033 } 2034 2035 return true; 2036 } 2037 2038 /* Create two value-ranges in *VR0 and *VR1 from the anti-range *AR 2039 so that *VR0 U *VR1 == *AR. Returns true if that is possible, 2040 false otherwise. If *AR can be represented with a single range 2041 *VR1 will be VR_UNDEFINED. */ 2042 2043 static bool 2044 ranges_from_anti_range (value_range *ar, 2045 value_range *vr0, value_range *vr1) 2046 { 2047 tree type = TREE_TYPE (ar->min); 2048 2049 vr0->type = VR_UNDEFINED; 2050 vr1->type = VR_UNDEFINED; 2051 2052 if (ar->type != VR_ANTI_RANGE 2053 || TREE_CODE (ar->min) != INTEGER_CST 2054 || TREE_CODE (ar->max) != INTEGER_CST 2055 || !vrp_val_min (type) 2056 || !vrp_val_max (type)) 2057 return false; 2058 2059 if (!vrp_val_is_min (ar->min)) 2060 { 2061 vr0->type = VR_RANGE; 2062 vr0->min = vrp_val_min (type); 2063 vr0->max = wide_int_to_tree (type, wi::sub (ar->min, 1)); 2064 } 2065 if (!vrp_val_is_max (ar->max)) 2066 { 2067 vr1->type = VR_RANGE; 2068 vr1->min = wide_int_to_tree (type, wi::add (ar->max, 1)); 2069 vr1->max = vrp_val_max (type); 2070 } 2071 if (vr0->type == VR_UNDEFINED) 2072 { 2073 *vr0 = *vr1; 2074 vr1->type = VR_UNDEFINED; 2075 } 2076 2077 return vr0->type != VR_UNDEFINED; 2078 } 2079 2080 /* Helper to extract a value-range *VR for a multiplicative operation 2081 *VR0 CODE *VR1. */ 2082 2083 static void 2084 extract_range_from_multiplicative_op_1 (value_range *vr, 2085 enum tree_code code, 2086 value_range *vr0, value_range *vr1) 2087 { 2088 enum value_range_type type; 2089 tree val[4]; 2090 size_t i; 2091 tree min, max; 2092 bool sop; 2093 int cmp; 2094 2095 /* Multiplications, divisions and shifts are a bit tricky to handle, 2096 depending on the mix of signs we have in the two ranges, we 2097 need to operate on different values to get the minimum and 2098 maximum values for the new range. One approach is to figure 2099 out all the variations of range combinations and do the 2100 operations. 2101 2102 However, this involves several calls to compare_values and it 2103 is pretty convoluted. It's simpler to do the 4 operations 2104 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP 2105 MAX1) and then figure the smallest and largest values to form 2106 the new range. */ 2107 gcc_assert (code == MULT_EXPR 2108 || code == TRUNC_DIV_EXPR 2109 || code == FLOOR_DIV_EXPR 2110 || code == CEIL_DIV_EXPR 2111 || code == EXACT_DIV_EXPR 2112 || code == ROUND_DIV_EXPR 2113 || code == RSHIFT_EXPR 2114 || code == LSHIFT_EXPR); 2115 gcc_assert ((vr0->type == VR_RANGE 2116 || (code == MULT_EXPR && vr0->type == VR_ANTI_RANGE)) 2117 && vr0->type == vr1->type); 2118 2119 type = vr0->type; 2120 2121 /* Compute the 4 cross operations. */ 2122 sop = false; 2123 val[0] = vrp_int_const_binop (code, vr0->min, vr1->min); 2124 if (val[0] == NULL_TREE) 2125 sop = true; 2126 2127 if (vr1->max == vr1->min) 2128 val[1] = NULL_TREE; 2129 else 2130 { 2131 val[1] = vrp_int_const_binop (code, vr0->min, vr1->max); 2132 if (val[1] == NULL_TREE) 2133 sop = true; 2134 } 2135 2136 if (vr0->max == vr0->min) 2137 val[2] = NULL_TREE; 2138 else 2139 { 2140 val[2] = vrp_int_const_binop (code, vr0->max, vr1->min); 2141 if (val[2] == NULL_TREE) 2142 sop = true; 2143 } 2144 2145 if (vr0->min == vr0->max || vr1->min == vr1->max) 2146 val[3] = NULL_TREE; 2147 else 2148 { 2149 val[3] = vrp_int_const_binop (code, vr0->max, vr1->max); 2150 if (val[3] == NULL_TREE) 2151 sop = true; 2152 } 2153 2154 if (sop) 2155 { 2156 set_value_range_to_varying (vr); 2157 return; 2158 } 2159 2160 /* Set MIN to the minimum of VAL[i] and MAX to the maximum 2161 of VAL[i]. */ 2162 min = val[0]; 2163 max = val[0]; 2164 for (i = 1; i < 4; i++) 2165 { 2166 if (!is_gimple_min_invariant (min) 2167 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min)) 2168 || !is_gimple_min_invariant (max) 2169 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max))) 2170 break; 2171 2172 if (val[i]) 2173 { 2174 if (!is_gimple_min_invariant (val[i]) 2175 || (TREE_OVERFLOW (val[i]) 2176 && !is_overflow_infinity (val[i]))) 2177 { 2178 /* If we found an overflowed value, set MIN and MAX 2179 to it so that we set the resulting range to 2180 VARYING. */ 2181 min = max = val[i]; 2182 break; 2183 } 2184 2185 if (compare_values (val[i], min) == -1) 2186 min = val[i]; 2187 2188 if (compare_values (val[i], max) == 1) 2189 max = val[i]; 2190 } 2191 } 2192 2193 /* If either MIN or MAX overflowed, then set the resulting range to 2194 VARYING. But we do accept an overflow infinity 2195 representation. */ 2196 if (min == NULL_TREE 2197 || !is_gimple_min_invariant (min) 2198 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min)) 2199 || max == NULL_TREE 2200 || !is_gimple_min_invariant (max) 2201 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max))) 2202 { 2203 set_value_range_to_varying (vr); 2204 return; 2205 } 2206 2207 /* We punt if: 2208 1) [-INF, +INF] 2209 2) [-INF, +-INF(OVF)] 2210 3) [+-INF(OVF), +INF] 2211 4) [+-INF(OVF), +-INF(OVF)] 2212 We learn nothing when we have INF and INF(OVF) on both sides. 2213 Note that we do accept [-INF, -INF] and [+INF, +INF] without 2214 overflow. */ 2215 if ((vrp_val_is_min (min) || is_overflow_infinity (min)) 2216 && (vrp_val_is_max (max) || is_overflow_infinity (max))) 2217 { 2218 set_value_range_to_varying (vr); 2219 return; 2220 } 2221 2222 cmp = compare_values (min, max); 2223 if (cmp == -2 || cmp == 1) 2224 { 2225 /* If the new range has its limits swapped around (MIN > MAX), 2226 then the operation caused one of them to wrap around, mark 2227 the new range VARYING. */ 2228 set_value_range_to_varying (vr); 2229 } 2230 else 2231 set_value_range (vr, type, min, max, NULL); 2232 } 2233 2234 /* Extract range information from a binary operation CODE based on 2235 the ranges of each of its operands *VR0 and *VR1 with resulting 2236 type EXPR_TYPE. The resulting range is stored in *VR. */ 2237 2238 static void 2239 extract_range_from_binary_expr_1 (value_range *vr, 2240 enum tree_code code, tree expr_type, 2241 value_range *vr0_, value_range *vr1_) 2242 { 2243 value_range vr0 = *vr0_, vr1 = *vr1_; 2244 value_range vrtem0 = VR_INITIALIZER, vrtem1 = VR_INITIALIZER; 2245 enum value_range_type type; 2246 tree min = NULL_TREE, max = NULL_TREE; 2247 int cmp; 2248 2249 if (!INTEGRAL_TYPE_P (expr_type) 2250 && !POINTER_TYPE_P (expr_type)) 2251 { 2252 set_value_range_to_varying (vr); 2253 return; 2254 } 2255 2256 /* Not all binary expressions can be applied to ranges in a 2257 meaningful way. Handle only arithmetic operations. */ 2258 if (code != PLUS_EXPR 2259 && code != MINUS_EXPR 2260 && code != POINTER_PLUS_EXPR 2261 && code != MULT_EXPR 2262 && code != TRUNC_DIV_EXPR 2263 && code != FLOOR_DIV_EXPR 2264 && code != CEIL_DIV_EXPR 2265 && code != EXACT_DIV_EXPR 2266 && code != ROUND_DIV_EXPR 2267 && code != TRUNC_MOD_EXPR 2268 && code != RSHIFT_EXPR 2269 && code != LSHIFT_EXPR 2270 && code != MIN_EXPR 2271 && code != MAX_EXPR 2272 && code != BIT_AND_EXPR 2273 && code != BIT_IOR_EXPR 2274 && code != BIT_XOR_EXPR) 2275 { 2276 set_value_range_to_varying (vr); 2277 return; 2278 } 2279 2280 /* If both ranges are UNDEFINED, so is the result. */ 2281 if (vr0.type == VR_UNDEFINED && vr1.type == VR_UNDEFINED) 2282 { 2283 set_value_range_to_undefined (vr); 2284 return; 2285 } 2286 /* If one of the ranges is UNDEFINED drop it to VARYING for the following 2287 code. At some point we may want to special-case operations that 2288 have UNDEFINED result for all or some value-ranges of the not UNDEFINED 2289 operand. */ 2290 else if (vr0.type == VR_UNDEFINED) 2291 set_value_range_to_varying (&vr0); 2292 else if (vr1.type == VR_UNDEFINED) 2293 set_value_range_to_varying (&vr1); 2294 2295 /* Now canonicalize anti-ranges to ranges when they are not symbolic 2296 and express ~[] op X as ([]' op X) U ([]'' op X). */ 2297 if (vr0.type == VR_ANTI_RANGE 2298 && ranges_from_anti_range (&vr0, &vrtem0, &vrtem1)) 2299 { 2300 extract_range_from_binary_expr_1 (vr, code, expr_type, &vrtem0, vr1_); 2301 if (vrtem1.type != VR_UNDEFINED) 2302 { 2303 value_range vrres = VR_INITIALIZER; 2304 extract_range_from_binary_expr_1 (&vrres, code, expr_type, 2305 &vrtem1, vr1_); 2306 vrp_meet (vr, &vrres); 2307 } 2308 return; 2309 } 2310 /* Likewise for X op ~[]. */ 2311 if (vr1.type == VR_ANTI_RANGE 2312 && ranges_from_anti_range (&vr1, &vrtem0, &vrtem1)) 2313 { 2314 extract_range_from_binary_expr_1 (vr, code, expr_type, vr0_, &vrtem0); 2315 if (vrtem1.type != VR_UNDEFINED) 2316 { 2317 value_range vrres = VR_INITIALIZER; 2318 extract_range_from_binary_expr_1 (&vrres, code, expr_type, 2319 vr0_, &vrtem1); 2320 vrp_meet (vr, &vrres); 2321 } 2322 return; 2323 } 2324 2325 /* The type of the resulting value range defaults to VR0.TYPE. */ 2326 type = vr0.type; 2327 2328 /* Refuse to operate on VARYING ranges, ranges of different kinds 2329 and symbolic ranges. As an exception, we allow BIT_{AND,IOR} 2330 because we may be able to derive a useful range even if one of 2331 the operands is VR_VARYING or symbolic range. Similarly for 2332 divisions, MIN/MAX and PLUS/MINUS. 2333 2334 TODO, we may be able to derive anti-ranges in some cases. */ 2335 if (code != BIT_AND_EXPR 2336 && code != BIT_IOR_EXPR 2337 && code != TRUNC_DIV_EXPR 2338 && code != FLOOR_DIV_EXPR 2339 && code != CEIL_DIV_EXPR 2340 && code != EXACT_DIV_EXPR 2341 && code != ROUND_DIV_EXPR 2342 && code != TRUNC_MOD_EXPR 2343 && code != MIN_EXPR 2344 && code != MAX_EXPR 2345 && code != PLUS_EXPR 2346 && code != MINUS_EXPR 2347 && code != RSHIFT_EXPR 2348 && (vr0.type == VR_VARYING 2349 || vr1.type == VR_VARYING 2350 || vr0.type != vr1.type 2351 || symbolic_range_p (&vr0) 2352 || symbolic_range_p (&vr1))) 2353 { 2354 set_value_range_to_varying (vr); 2355 return; 2356 } 2357 2358 /* Now evaluate the expression to determine the new range. */ 2359 if (POINTER_TYPE_P (expr_type)) 2360 { 2361 if (code == MIN_EXPR || code == MAX_EXPR) 2362 { 2363 /* For MIN/MAX expressions with pointers, we only care about 2364 nullness, if both are non null, then the result is nonnull. 2365 If both are null, then the result is null. Otherwise they 2366 are varying. */ 2367 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1)) 2368 set_value_range_to_nonnull (vr, expr_type); 2369 else if (range_is_null (&vr0) && range_is_null (&vr1)) 2370 set_value_range_to_null (vr, expr_type); 2371 else 2372 set_value_range_to_varying (vr); 2373 } 2374 else if (code == POINTER_PLUS_EXPR) 2375 { 2376 /* For pointer types, we are really only interested in asserting 2377 whether the expression evaluates to non-NULL. */ 2378 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1)) 2379 set_value_range_to_nonnull (vr, expr_type); 2380 else if (range_is_null (&vr0) && range_is_null (&vr1)) 2381 set_value_range_to_null (vr, expr_type); 2382 else 2383 set_value_range_to_varying (vr); 2384 } 2385 else if (code == BIT_AND_EXPR) 2386 { 2387 /* For pointer types, we are really only interested in asserting 2388 whether the expression evaluates to non-NULL. */ 2389 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1)) 2390 set_value_range_to_nonnull (vr, expr_type); 2391 else if (range_is_null (&vr0) || range_is_null (&vr1)) 2392 set_value_range_to_null (vr, expr_type); 2393 else 2394 set_value_range_to_varying (vr); 2395 } 2396 else 2397 set_value_range_to_varying (vr); 2398 2399 return; 2400 } 2401 2402 /* For integer ranges, apply the operation to each end of the 2403 range and see what we end up with. */ 2404 if (code == PLUS_EXPR || code == MINUS_EXPR) 2405 { 2406 const bool minus_p = (code == MINUS_EXPR); 2407 tree min_op0 = vr0.min; 2408 tree min_op1 = minus_p ? vr1.max : vr1.min; 2409 tree max_op0 = vr0.max; 2410 tree max_op1 = minus_p ? vr1.min : vr1.max; 2411 tree sym_min_op0 = NULL_TREE; 2412 tree sym_min_op1 = NULL_TREE; 2413 tree sym_max_op0 = NULL_TREE; 2414 tree sym_max_op1 = NULL_TREE; 2415 bool neg_min_op0, neg_min_op1, neg_max_op0, neg_max_op1; 2416 2417 /* If we have a PLUS or MINUS with two VR_RANGEs, either constant or 2418 single-symbolic ranges, try to compute the precise resulting range, 2419 but only if we know that this resulting range will also be constant 2420 or single-symbolic. */ 2421 if (vr0.type == VR_RANGE && vr1.type == VR_RANGE 2422 && (TREE_CODE (min_op0) == INTEGER_CST 2423 || (sym_min_op0 2424 = get_single_symbol (min_op0, &neg_min_op0, &min_op0))) 2425 && (TREE_CODE (min_op1) == INTEGER_CST 2426 || (sym_min_op1 2427 = get_single_symbol (min_op1, &neg_min_op1, &min_op1))) 2428 && (!(sym_min_op0 && sym_min_op1) 2429 || (sym_min_op0 == sym_min_op1 2430 && neg_min_op0 == (minus_p ? neg_min_op1 : !neg_min_op1))) 2431 && (TREE_CODE (max_op0) == INTEGER_CST 2432 || (sym_max_op0 2433 = get_single_symbol (max_op0, &neg_max_op0, &max_op0))) 2434 && (TREE_CODE (max_op1) == INTEGER_CST 2435 || (sym_max_op1 2436 = get_single_symbol (max_op1, &neg_max_op1, &max_op1))) 2437 && (!(sym_max_op0 && sym_max_op1) 2438 || (sym_max_op0 == sym_max_op1 2439 && neg_max_op0 == (minus_p ? neg_max_op1 : !neg_max_op1)))) 2440 { 2441 const signop sgn = TYPE_SIGN (expr_type); 2442 const unsigned int prec = TYPE_PRECISION (expr_type); 2443 wide_int type_min, type_max, wmin, wmax; 2444 int min_ovf = 0; 2445 int max_ovf = 0; 2446 2447 /* Get the lower and upper bounds of the type. */ 2448 if (TYPE_OVERFLOW_WRAPS (expr_type)) 2449 { 2450 type_min = wi::min_value (prec, sgn); 2451 type_max = wi::max_value (prec, sgn); 2452 } 2453 else 2454 { 2455 type_min = vrp_val_min (expr_type); 2456 type_max = vrp_val_max (expr_type); 2457 } 2458 2459 /* Combine the lower bounds, if any. */ 2460 if (min_op0 && min_op1) 2461 { 2462 if (minus_p) 2463 { 2464 wmin = wi::sub (min_op0, min_op1); 2465 2466 /* Check for overflow. */ 2467 if (wi::cmp (0, min_op1, sgn) 2468 != wi::cmp (wmin, min_op0, sgn)) 2469 min_ovf = wi::cmp (min_op0, min_op1, sgn); 2470 } 2471 else 2472 { 2473 wmin = wi::add (min_op0, min_op1); 2474 2475 /* Check for overflow. */ 2476 if (wi::cmp (min_op1, 0, sgn) 2477 != wi::cmp (wmin, min_op0, sgn)) 2478 min_ovf = wi::cmp (min_op0, wmin, sgn); 2479 } 2480 } 2481 else if (min_op0) 2482 wmin = min_op0; 2483 else if (min_op1) 2484 { 2485 if (minus_p) 2486 { 2487 wmin = wi::neg (min_op1); 2488 2489 /* Check for overflow. */ 2490 if (sgn == SIGNED && wi::neg_p (min_op1) && wi::neg_p (wmin)) 2491 min_ovf = 1; 2492 else if (sgn == UNSIGNED && wi::ne_p (min_op1, 0)) 2493 min_ovf = -1; 2494 } 2495 else 2496 wmin = min_op1; 2497 } 2498 else 2499 wmin = wi::shwi (0, prec); 2500 2501 /* Combine the upper bounds, if any. */ 2502 if (max_op0 && max_op1) 2503 { 2504 if (minus_p) 2505 { 2506 wmax = wi::sub (max_op0, max_op1); 2507 2508 /* Check for overflow. */ 2509 if (wi::cmp (0, max_op1, sgn) 2510 != wi::cmp (wmax, max_op0, sgn)) 2511 max_ovf = wi::cmp (max_op0, max_op1, sgn); 2512 } 2513 else 2514 { 2515 wmax = wi::add (max_op0, max_op1); 2516 2517 if (wi::cmp (max_op1, 0, sgn) 2518 != wi::cmp (wmax, max_op0, sgn)) 2519 max_ovf = wi::cmp (max_op0, wmax, sgn); 2520 } 2521 } 2522 else if (max_op0) 2523 wmax = max_op0; 2524 else if (max_op1) 2525 { 2526 if (minus_p) 2527 { 2528 wmax = wi::neg (max_op1); 2529 2530 /* Check for overflow. */ 2531 if (sgn == SIGNED && wi::neg_p (max_op1) && wi::neg_p (wmax)) 2532 max_ovf = 1; 2533 else if (sgn == UNSIGNED && wi::ne_p (max_op1, 0)) 2534 max_ovf = -1; 2535 } 2536 else 2537 wmax = max_op1; 2538 } 2539 else 2540 wmax = wi::shwi (0, prec); 2541 2542 /* Check for type overflow. */ 2543 if (min_ovf == 0) 2544 { 2545 if (wi::cmp (wmin, type_min, sgn) == -1) 2546 min_ovf = -1; 2547 else if (wi::cmp (wmin, type_max, sgn) == 1) 2548 min_ovf = 1; 2549 } 2550 if (max_ovf == 0) 2551 { 2552 if (wi::cmp (wmax, type_min, sgn) == -1) 2553 max_ovf = -1; 2554 else if (wi::cmp (wmax, type_max, sgn) == 1) 2555 max_ovf = 1; 2556 } 2557 2558 /* If we have overflow for the constant part and the resulting 2559 range will be symbolic, drop to VR_VARYING. */ 2560 if ((min_ovf && sym_min_op0 != sym_min_op1) 2561 || (max_ovf && sym_max_op0 != sym_max_op1)) 2562 { 2563 set_value_range_to_varying (vr); 2564 return; 2565 } 2566 2567 if (TYPE_OVERFLOW_WRAPS (expr_type)) 2568 { 2569 /* If overflow wraps, truncate the values and adjust the 2570 range kind and bounds appropriately. */ 2571 wide_int tmin = wide_int::from (wmin, prec, sgn); 2572 wide_int tmax = wide_int::from (wmax, prec, sgn); 2573 if (min_ovf == max_ovf) 2574 { 2575 /* No overflow or both overflow or underflow. The 2576 range kind stays VR_RANGE. */ 2577 min = wide_int_to_tree (expr_type, tmin); 2578 max = wide_int_to_tree (expr_type, tmax); 2579 } 2580 else if ((min_ovf == -1 && max_ovf == 0) 2581 || (max_ovf == 1 && min_ovf == 0)) 2582 { 2583 /* Min underflow or max overflow. The range kind 2584 changes to VR_ANTI_RANGE. */ 2585 bool covers = false; 2586 wide_int tem = tmin; 2587 type = VR_ANTI_RANGE; 2588 tmin = tmax + 1; 2589 if (wi::cmp (tmin, tmax, sgn) < 0) 2590 covers = true; 2591 tmax = tem - 1; 2592 if (wi::cmp (tmax, tem, sgn) > 0) 2593 covers = true; 2594 /* If the anti-range would cover nothing, drop to varying. 2595 Likewise if the anti-range bounds are outside of the 2596 types values. */ 2597 if (covers || wi::cmp (tmin, tmax, sgn) > 0) 2598 { 2599 set_value_range_to_varying (vr); 2600 return; 2601 } 2602 min = wide_int_to_tree (expr_type, tmin); 2603 max = wide_int_to_tree (expr_type, tmax); 2604 } 2605 else 2606 { 2607 /* Other underflow and/or overflow, drop to VR_VARYING. */ 2608 set_value_range_to_varying (vr); 2609 return; 2610 } 2611 } 2612 else 2613 { 2614 /* If overflow does not wrap, saturate to the types min/max 2615 value. */ 2616 if (min_ovf == -1) 2617 { 2618 if (needs_overflow_infinity (expr_type) 2619 && supports_overflow_infinity (expr_type)) 2620 min = negative_overflow_infinity (expr_type); 2621 else 2622 min = wide_int_to_tree (expr_type, type_min); 2623 } 2624 else if (min_ovf == 1) 2625 { 2626 if (needs_overflow_infinity (expr_type) 2627 && supports_overflow_infinity (expr_type)) 2628 min = positive_overflow_infinity (expr_type); 2629 else 2630 min = wide_int_to_tree (expr_type, type_max); 2631 } 2632 else 2633 min = wide_int_to_tree (expr_type, wmin); 2634 2635 if (max_ovf == -1) 2636 { 2637 if (needs_overflow_infinity (expr_type) 2638 && supports_overflow_infinity (expr_type)) 2639 max = negative_overflow_infinity (expr_type); 2640 else 2641 max = wide_int_to_tree (expr_type, type_min); 2642 } 2643 else if (max_ovf == 1) 2644 { 2645 if (needs_overflow_infinity (expr_type) 2646 && supports_overflow_infinity (expr_type)) 2647 max = positive_overflow_infinity (expr_type); 2648 else 2649 max = wide_int_to_tree (expr_type, type_max); 2650 } 2651 else 2652 max = wide_int_to_tree (expr_type, wmax); 2653 } 2654 2655 if (needs_overflow_infinity (expr_type) 2656 && supports_overflow_infinity (expr_type)) 2657 { 2658 if ((min_op0 && is_negative_overflow_infinity (min_op0)) 2659 || (min_op1 2660 && (minus_p 2661 ? is_positive_overflow_infinity (min_op1) 2662 : is_negative_overflow_infinity (min_op1)))) 2663 min = negative_overflow_infinity (expr_type); 2664 if ((max_op0 && is_positive_overflow_infinity (max_op0)) 2665 || (max_op1 2666 && (minus_p 2667 ? is_negative_overflow_infinity (max_op1) 2668 : is_positive_overflow_infinity (max_op1)))) 2669 max = positive_overflow_infinity (expr_type); 2670 } 2671 2672 /* If the result lower bound is constant, we're done; 2673 otherwise, build the symbolic lower bound. */ 2674 if (sym_min_op0 == sym_min_op1) 2675 ; 2676 else if (sym_min_op0) 2677 min = build_symbolic_expr (expr_type, sym_min_op0, 2678 neg_min_op0, min); 2679 else if (sym_min_op1) 2680 { 2681 /* We may not negate if that might introduce 2682 undefined overflow. */ 2683 if (! minus_p 2684 || neg_min_op1 2685 || TYPE_OVERFLOW_WRAPS (expr_type)) 2686 min = build_symbolic_expr (expr_type, sym_min_op1, 2687 neg_min_op1 ^ minus_p, min); 2688 else 2689 min = NULL_TREE; 2690 } 2691 2692 /* Likewise for the upper bound. */ 2693 if (sym_max_op0 == sym_max_op1) 2694 ; 2695 else if (sym_max_op0) 2696 max = build_symbolic_expr (expr_type, sym_max_op0, 2697 neg_max_op0, max); 2698 else if (sym_max_op1) 2699 { 2700 /* We may not negate if that might introduce 2701 undefined overflow. */ 2702 if (! minus_p 2703 || neg_max_op1 2704 || TYPE_OVERFLOW_WRAPS (expr_type)) 2705 max = build_symbolic_expr (expr_type, sym_max_op1, 2706 neg_max_op1 ^ minus_p, max); 2707 else 2708 max = NULL_TREE; 2709 } 2710 } 2711 else 2712 { 2713 /* For other cases, for example if we have a PLUS_EXPR with two 2714 VR_ANTI_RANGEs, drop to VR_VARYING. It would take more effort 2715 to compute a precise range for such a case. 2716 ??? General even mixed range kind operations can be expressed 2717 by for example transforming ~[3, 5] + [1, 2] to range-only 2718 operations and a union primitive: 2719 [-INF, 2] + [1, 2] U [5, +INF] + [1, 2] 2720 [-INF+1, 4] U [6, +INF(OVF)] 2721 though usually the union is not exactly representable with 2722 a single range or anti-range as the above is 2723 [-INF+1, +INF(OVF)] intersected with ~[5, 5] 2724 but one could use a scheme similar to equivalences for this. */ 2725 set_value_range_to_varying (vr); 2726 return; 2727 } 2728 } 2729 else if (code == MIN_EXPR 2730 || code == MAX_EXPR) 2731 { 2732 if (vr0.type == VR_RANGE 2733 && !symbolic_range_p (&vr0)) 2734 { 2735 type = VR_RANGE; 2736 if (vr1.type == VR_RANGE 2737 && !symbolic_range_p (&vr1)) 2738 { 2739 /* For operations that make the resulting range directly 2740 proportional to the original ranges, apply the operation to 2741 the same end of each range. */ 2742 min = vrp_int_const_binop (code, vr0.min, vr1.min); 2743 max = vrp_int_const_binop (code, vr0.max, vr1.max); 2744 } 2745 else if (code == MIN_EXPR) 2746 { 2747 min = vrp_val_min (expr_type); 2748 max = vr0.max; 2749 } 2750 else if (code == MAX_EXPR) 2751 { 2752 min = vr0.min; 2753 max = vrp_val_max (expr_type); 2754 } 2755 } 2756 else if (vr1.type == VR_RANGE 2757 && !symbolic_range_p (&vr1)) 2758 { 2759 type = VR_RANGE; 2760 if (code == MIN_EXPR) 2761 { 2762 min = vrp_val_min (expr_type); 2763 max = vr1.max; 2764 } 2765 else if (code == MAX_EXPR) 2766 { 2767 min = vr1.min; 2768 max = vrp_val_max (expr_type); 2769 } 2770 } 2771 else 2772 { 2773 set_value_range_to_varying (vr); 2774 return; 2775 } 2776 } 2777 else if (code == MULT_EXPR) 2778 { 2779 /* Fancy code so that with unsigned, [-3,-1]*[-3,-1] does not 2780 drop to varying. This test requires 2*prec bits if both 2781 operands are signed and 2*prec + 2 bits if either is not. */ 2782 2783 signop sign = TYPE_SIGN (expr_type); 2784 unsigned int prec = TYPE_PRECISION (expr_type); 2785 2786 if (range_int_cst_p (&vr0) 2787 && range_int_cst_p (&vr1) 2788 && TYPE_OVERFLOW_WRAPS (expr_type)) 2789 { 2790 typedef FIXED_WIDE_INT (WIDE_INT_MAX_PRECISION * 2) vrp_int; 2791 typedef generic_wide_int 2792 <wi::extended_tree <WIDE_INT_MAX_PRECISION * 2> > vrp_int_cst; 2793 vrp_int sizem1 = wi::mask <vrp_int> (prec, false); 2794 vrp_int size = sizem1 + 1; 2795 2796 /* Extend the values using the sign of the result to PREC2. 2797 From here on out, everthing is just signed math no matter 2798 what the input types were. */ 2799 vrp_int min0 = vrp_int_cst (vr0.min); 2800 vrp_int max0 = vrp_int_cst (vr0.max); 2801 vrp_int min1 = vrp_int_cst (vr1.min); 2802 vrp_int max1 = vrp_int_cst (vr1.max); 2803 /* Canonicalize the intervals. */ 2804 if (sign == UNSIGNED) 2805 { 2806 if (wi::ltu_p (size, min0 + max0)) 2807 { 2808 min0 -= size; 2809 max0 -= size; 2810 } 2811 2812 if (wi::ltu_p (size, min1 + max1)) 2813 { 2814 min1 -= size; 2815 max1 -= size; 2816 } 2817 } 2818 2819 vrp_int prod0 = min0 * min1; 2820 vrp_int prod1 = min0 * max1; 2821 vrp_int prod2 = max0 * min1; 2822 vrp_int prod3 = max0 * max1; 2823 2824 /* Sort the 4 products so that min is in prod0 and max is in 2825 prod3. */ 2826 /* min0min1 > max0max1 */ 2827 if (wi::gts_p (prod0, prod3)) 2828 std::swap (prod0, prod3); 2829 2830 /* min0max1 > max0min1 */ 2831 if (wi::gts_p (prod1, prod2)) 2832 std::swap (prod1, prod2); 2833 2834 if (wi::gts_p (prod0, prod1)) 2835 std::swap (prod0, prod1); 2836 2837 if (wi::gts_p (prod2, prod3)) 2838 std::swap (prod2, prod3); 2839 2840 /* diff = max - min. */ 2841 prod2 = prod3 - prod0; 2842 if (wi::geu_p (prod2, sizem1)) 2843 { 2844 /* the range covers all values. */ 2845 set_value_range_to_varying (vr); 2846 return; 2847 } 2848 2849 /* The following should handle the wrapping and selecting 2850 VR_ANTI_RANGE for us. */ 2851 min = wide_int_to_tree (expr_type, prod0); 2852 max = wide_int_to_tree (expr_type, prod3); 2853 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL); 2854 return; 2855 } 2856 2857 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs, 2858 drop to VR_VARYING. It would take more effort to compute a 2859 precise range for such a case. For example, if we have 2860 op0 == 65536 and op1 == 65536 with their ranges both being 2861 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so 2862 we cannot claim that the product is in ~[0,0]. Note that we 2863 are guaranteed to have vr0.type == vr1.type at this 2864 point. */ 2865 if (vr0.type == VR_ANTI_RANGE 2866 && !TYPE_OVERFLOW_UNDEFINED (expr_type)) 2867 { 2868 set_value_range_to_varying (vr); 2869 return; 2870 } 2871 2872 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1); 2873 return; 2874 } 2875 else if (code == RSHIFT_EXPR 2876 || code == LSHIFT_EXPR) 2877 { 2878 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1], 2879 then drop to VR_VARYING. Outside of this range we get undefined 2880 behavior from the shift operation. We cannot even trust 2881 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl 2882 shifts, and the operation at the tree level may be widened. */ 2883 if (range_int_cst_p (&vr1) 2884 && compare_tree_int (vr1.min, 0) >= 0 2885 && compare_tree_int (vr1.max, TYPE_PRECISION (expr_type)) == -1) 2886 { 2887 if (code == RSHIFT_EXPR) 2888 { 2889 /* Even if vr0 is VARYING or otherwise not usable, we can derive 2890 useful ranges just from the shift count. E.g. 2891 x >> 63 for signed 64-bit x is always [-1, 0]. */ 2892 if (vr0.type != VR_RANGE || symbolic_range_p (&vr0)) 2893 { 2894 vr0.type = type = VR_RANGE; 2895 vr0.min = vrp_val_min (expr_type); 2896 vr0.max = vrp_val_max (expr_type); 2897 } 2898 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1); 2899 return; 2900 } 2901 /* We can map lshifts by constants to MULT_EXPR handling. */ 2902 else if (code == LSHIFT_EXPR 2903 && range_int_cst_singleton_p (&vr1)) 2904 { 2905 bool saved_flag_wrapv; 2906 value_range vr1p = VR_INITIALIZER; 2907 vr1p.type = VR_RANGE; 2908 vr1p.min = (wide_int_to_tree 2909 (expr_type, 2910 wi::set_bit_in_zero (tree_to_shwi (vr1.min), 2911 TYPE_PRECISION (expr_type)))); 2912 vr1p.max = vr1p.min; 2913 /* We have to use a wrapping multiply though as signed overflow 2914 on lshifts is implementation defined in C89. */ 2915 saved_flag_wrapv = flag_wrapv; 2916 flag_wrapv = 1; 2917 extract_range_from_binary_expr_1 (vr, MULT_EXPR, expr_type, 2918 &vr0, &vr1p); 2919 flag_wrapv = saved_flag_wrapv; 2920 return; 2921 } 2922 else if (code == LSHIFT_EXPR 2923 && range_int_cst_p (&vr0)) 2924 { 2925 int prec = TYPE_PRECISION (expr_type); 2926 int overflow_pos = prec; 2927 int bound_shift; 2928 wide_int low_bound, high_bound; 2929 bool uns = TYPE_UNSIGNED (expr_type); 2930 bool in_bounds = false; 2931 2932 if (!uns) 2933 overflow_pos -= 1; 2934 2935 bound_shift = overflow_pos - tree_to_shwi (vr1.max); 2936 /* If bound_shift == HOST_BITS_PER_WIDE_INT, the llshift can 2937 overflow. However, for that to happen, vr1.max needs to be 2938 zero, which means vr1 is a singleton range of zero, which 2939 means it should be handled by the previous LSHIFT_EXPR 2940 if-clause. */ 2941 wide_int bound = wi::set_bit_in_zero (bound_shift, prec); 2942 wide_int complement = ~(bound - 1); 2943 2944 if (uns) 2945 { 2946 low_bound = bound; 2947 high_bound = complement; 2948 if (wi::ltu_p (vr0.max, low_bound)) 2949 { 2950 /* [5, 6] << [1, 2] == [10, 24]. */ 2951 /* We're shifting out only zeroes, the value increases 2952 monotonically. */ 2953 in_bounds = true; 2954 } 2955 else if (wi::ltu_p (high_bound, vr0.min)) 2956 { 2957 /* [0xffffff00, 0xffffffff] << [1, 2] 2958 == [0xfffffc00, 0xfffffffe]. */ 2959 /* We're shifting out only ones, the value decreases 2960 monotonically. */ 2961 in_bounds = true; 2962 } 2963 } 2964 else 2965 { 2966 /* [-1, 1] << [1, 2] == [-4, 4]. */ 2967 low_bound = complement; 2968 high_bound = bound; 2969 if (wi::lts_p (vr0.max, high_bound) 2970 && wi::lts_p (low_bound, vr0.min)) 2971 { 2972 /* For non-negative numbers, we're shifting out only 2973 zeroes, the value increases monotonically. 2974 For negative numbers, we're shifting out only ones, the 2975 value decreases monotomically. */ 2976 in_bounds = true; 2977 } 2978 } 2979 2980 if (in_bounds) 2981 { 2982 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1); 2983 return; 2984 } 2985 } 2986 } 2987 set_value_range_to_varying (vr); 2988 return; 2989 } 2990 else if (code == TRUNC_DIV_EXPR 2991 || code == FLOOR_DIV_EXPR 2992 || code == CEIL_DIV_EXPR 2993 || code == EXACT_DIV_EXPR 2994 || code == ROUND_DIV_EXPR) 2995 { 2996 if (vr0.type != VR_RANGE || symbolic_range_p (&vr0)) 2997 { 2998 /* For division, if op1 has VR_RANGE but op0 does not, something 2999 can be deduced just from that range. Say [min, max] / [4, max] 3000 gives [min / 4, max / 4] range. */ 3001 if (vr1.type == VR_RANGE 3002 && !symbolic_range_p (&vr1) 3003 && range_includes_zero_p (vr1.min, vr1.max) == 0) 3004 { 3005 vr0.type = type = VR_RANGE; 3006 vr0.min = vrp_val_min (expr_type); 3007 vr0.max = vrp_val_max (expr_type); 3008 } 3009 else 3010 { 3011 set_value_range_to_varying (vr); 3012 return; 3013 } 3014 } 3015 3016 /* For divisions, if flag_non_call_exceptions is true, we must 3017 not eliminate a division by zero. */ 3018 if (cfun->can_throw_non_call_exceptions 3019 && (vr1.type != VR_RANGE 3020 || range_includes_zero_p (vr1.min, vr1.max) != 0)) 3021 { 3022 set_value_range_to_varying (vr); 3023 return; 3024 } 3025 3026 /* For divisions, if op0 is VR_RANGE, we can deduce a range 3027 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can 3028 include 0. */ 3029 if (vr0.type == VR_RANGE 3030 && (vr1.type != VR_RANGE 3031 || range_includes_zero_p (vr1.min, vr1.max) != 0)) 3032 { 3033 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0); 3034 int cmp; 3035 3036 min = NULL_TREE; 3037 max = NULL_TREE; 3038 if (TYPE_UNSIGNED (expr_type) 3039 || value_range_nonnegative_p (&vr1)) 3040 { 3041 /* For unsigned division or when divisor is known 3042 to be non-negative, the range has to cover 3043 all numbers from 0 to max for positive max 3044 and all numbers from min to 0 for negative min. */ 3045 cmp = compare_values (vr0.max, zero); 3046 if (cmp == -1) 3047 { 3048 /* When vr0.max < 0, vr1.min != 0 and value 3049 ranges for dividend and divisor are available. */ 3050 if (vr1.type == VR_RANGE 3051 && !symbolic_range_p (&vr0) 3052 && !symbolic_range_p (&vr1) 3053 && compare_values (vr1.min, zero) != 0) 3054 max = int_const_binop (code, vr0.max, vr1.min); 3055 else 3056 max = zero; 3057 } 3058 else if (cmp == 0 || cmp == 1) 3059 max = vr0.max; 3060 else 3061 type = VR_VARYING; 3062 cmp = compare_values (vr0.min, zero); 3063 if (cmp == 1) 3064 { 3065 /* For unsigned division when value ranges for dividend 3066 and divisor are available. */ 3067 if (vr1.type == VR_RANGE 3068 && !symbolic_range_p (&vr0) 3069 && !symbolic_range_p (&vr1) 3070 && compare_values (vr1.max, zero) != 0) 3071 min = int_const_binop (code, vr0.min, vr1.max); 3072 else 3073 min = zero; 3074 } 3075 else if (cmp == 0 || cmp == -1) 3076 min = vr0.min; 3077 else 3078 type = VR_VARYING; 3079 } 3080 else 3081 { 3082 /* Otherwise the range is -max .. max or min .. -min 3083 depending on which bound is bigger in absolute value, 3084 as the division can change the sign. */ 3085 abs_extent_range (vr, vr0.min, vr0.max); 3086 return; 3087 } 3088 if (type == VR_VARYING) 3089 { 3090 set_value_range_to_varying (vr); 3091 return; 3092 } 3093 } 3094 else if (!symbolic_range_p (&vr0) && !symbolic_range_p (&vr1)) 3095 { 3096 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1); 3097 return; 3098 } 3099 } 3100 else if (code == TRUNC_MOD_EXPR) 3101 { 3102 if (range_is_null (&vr1)) 3103 { 3104 set_value_range_to_undefined (vr); 3105 return; 3106 } 3107 /* ABS (A % B) < ABS (B) and either 3108 0 <= A % B <= A or A <= A % B <= 0. */ 3109 type = VR_RANGE; 3110 signop sgn = TYPE_SIGN (expr_type); 3111 unsigned int prec = TYPE_PRECISION (expr_type); 3112 wide_int wmin, wmax, tmp; 3113 wide_int zero = wi::zero (prec); 3114 wide_int one = wi::one (prec); 3115 if (vr1.type == VR_RANGE && !symbolic_range_p (&vr1)) 3116 { 3117 wmax = wi::sub (vr1.max, one); 3118 if (sgn == SIGNED) 3119 { 3120 tmp = wi::sub (wi::minus_one (prec), vr1.min); 3121 wmax = wi::smax (wmax, tmp); 3122 } 3123 } 3124 else 3125 { 3126 wmax = wi::max_value (prec, sgn); 3127 /* X % INT_MIN may be INT_MAX. */ 3128 if (sgn == UNSIGNED) 3129 wmax = wmax - one; 3130 } 3131 3132 if (sgn == UNSIGNED) 3133 wmin = zero; 3134 else 3135 { 3136 wmin = -wmax; 3137 if (vr0.type == VR_RANGE && TREE_CODE (vr0.min) == INTEGER_CST) 3138 { 3139 tmp = vr0.min; 3140 if (wi::gts_p (tmp, zero)) 3141 tmp = zero; 3142 wmin = wi::smax (wmin, tmp); 3143 } 3144 } 3145 3146 if (vr0.type == VR_RANGE && TREE_CODE (vr0.max) == INTEGER_CST) 3147 { 3148 tmp = vr0.max; 3149 if (sgn == SIGNED && wi::neg_p (tmp)) 3150 tmp = zero; 3151 wmax = wi::min (wmax, tmp, sgn); 3152 } 3153 3154 min = wide_int_to_tree (expr_type, wmin); 3155 max = wide_int_to_tree (expr_type, wmax); 3156 } 3157 else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR) 3158 { 3159 bool int_cst_range0, int_cst_range1; 3160 wide_int may_be_nonzero0, may_be_nonzero1; 3161 wide_int must_be_nonzero0, must_be_nonzero1; 3162 3163 int_cst_range0 = zero_nonzero_bits_from_vr (expr_type, &vr0, 3164 &may_be_nonzero0, 3165 &must_be_nonzero0); 3166 int_cst_range1 = zero_nonzero_bits_from_vr (expr_type, &vr1, 3167 &may_be_nonzero1, 3168 &must_be_nonzero1); 3169 3170 type = VR_RANGE; 3171 if (code == BIT_AND_EXPR) 3172 { 3173 min = wide_int_to_tree (expr_type, 3174 must_be_nonzero0 & must_be_nonzero1); 3175 wide_int wmax = may_be_nonzero0 & may_be_nonzero1; 3176 /* If both input ranges contain only negative values we can 3177 truncate the result range maximum to the minimum of the 3178 input range maxima. */ 3179 if (int_cst_range0 && int_cst_range1 3180 && tree_int_cst_sgn (vr0.max) < 0 3181 && tree_int_cst_sgn (vr1.max) < 0) 3182 { 3183 wmax = wi::min (wmax, vr0.max, TYPE_SIGN (expr_type)); 3184 wmax = wi::min (wmax, vr1.max, TYPE_SIGN (expr_type)); 3185 } 3186 /* If either input range contains only non-negative values 3187 we can truncate the result range maximum to the respective 3188 maximum of the input range. */ 3189 if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0) 3190 wmax = wi::min (wmax, vr0.max, TYPE_SIGN (expr_type)); 3191 if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0) 3192 wmax = wi::min (wmax, vr1.max, TYPE_SIGN (expr_type)); 3193 max = wide_int_to_tree (expr_type, wmax); 3194 } 3195 else if (code == BIT_IOR_EXPR) 3196 { 3197 max = wide_int_to_tree (expr_type, 3198 may_be_nonzero0 | may_be_nonzero1); 3199 wide_int wmin = must_be_nonzero0 | must_be_nonzero1; 3200 /* If the input ranges contain only positive values we can 3201 truncate the minimum of the result range to the maximum 3202 of the input range minima. */ 3203 if (int_cst_range0 && int_cst_range1 3204 && tree_int_cst_sgn (vr0.min) >= 0 3205 && tree_int_cst_sgn (vr1.min) >= 0) 3206 { 3207 wmin = wi::max (wmin, vr0.min, TYPE_SIGN (expr_type)); 3208 wmin = wi::max (wmin, vr1.min, TYPE_SIGN (expr_type)); 3209 } 3210 /* If either input range contains only negative values 3211 we can truncate the minimum of the result range to the 3212 respective minimum range. */ 3213 if (int_cst_range0 && tree_int_cst_sgn (vr0.max) < 0) 3214 wmin = wi::max (wmin, vr0.min, TYPE_SIGN (expr_type)); 3215 if (int_cst_range1 && tree_int_cst_sgn (vr1.max) < 0) 3216 wmin = wi::max (wmin, vr1.min, TYPE_SIGN (expr_type)); 3217 min = wide_int_to_tree (expr_type, wmin); 3218 } 3219 else if (code == BIT_XOR_EXPR) 3220 { 3221 wide_int result_zero_bits = ((must_be_nonzero0 & must_be_nonzero1) 3222 | ~(may_be_nonzero0 | may_be_nonzero1)); 3223 wide_int result_one_bits 3224 = (must_be_nonzero0.and_not (may_be_nonzero1) 3225 | must_be_nonzero1.and_not (may_be_nonzero0)); 3226 max = wide_int_to_tree (expr_type, ~result_zero_bits); 3227 min = wide_int_to_tree (expr_type, result_one_bits); 3228 /* If the range has all positive or all negative values the 3229 result is better than VARYING. */ 3230 if (tree_int_cst_sgn (min) < 0 3231 || tree_int_cst_sgn (max) >= 0) 3232 ; 3233 else 3234 max = min = NULL_TREE; 3235 } 3236 } 3237 else 3238 gcc_unreachable (); 3239 3240 /* If either MIN or MAX overflowed, then set the resulting range to 3241 VARYING. But we do accept an overflow infinity representation. */ 3242 if (min == NULL_TREE 3243 || (TREE_OVERFLOW_P (min) && !is_overflow_infinity (min)) 3244 || max == NULL_TREE 3245 || (TREE_OVERFLOW_P (max) && !is_overflow_infinity (max))) 3246 { 3247 set_value_range_to_varying (vr); 3248 return; 3249 } 3250 3251 /* We punt if: 3252 1) [-INF, +INF] 3253 2) [-INF, +-INF(OVF)] 3254 3) [+-INF(OVF), +INF] 3255 4) [+-INF(OVF), +-INF(OVF)] 3256 We learn nothing when we have INF and INF(OVF) on both sides. 3257 Note that we do accept [-INF, -INF] and [+INF, +INF] without 3258 overflow. */ 3259 if ((vrp_val_is_min (min) || is_overflow_infinity (min)) 3260 && (vrp_val_is_max (max) || is_overflow_infinity (max))) 3261 { 3262 set_value_range_to_varying (vr); 3263 return; 3264 } 3265 3266 cmp = compare_values (min, max); 3267 if (cmp == -2 || cmp == 1) 3268 { 3269 /* If the new range has its limits swapped around (MIN > MAX), 3270 then the operation caused one of them to wrap around, mark 3271 the new range VARYING. */ 3272 set_value_range_to_varying (vr); 3273 } 3274 else 3275 set_value_range (vr, type, min, max, NULL); 3276 } 3277 3278 /* Extract range information from a binary expression OP0 CODE OP1 based on 3279 the ranges of each of its operands with resulting type EXPR_TYPE. 3280 The resulting range is stored in *VR. */ 3281 3282 static void 3283 extract_range_from_binary_expr (value_range *vr, 3284 enum tree_code code, 3285 tree expr_type, tree op0, tree op1) 3286 { 3287 value_range vr0 = VR_INITIALIZER; 3288 value_range vr1 = VR_INITIALIZER; 3289 3290 /* Get value ranges for each operand. For constant operands, create 3291 a new value range with the operand to simplify processing. */ 3292 if (TREE_CODE (op0) == SSA_NAME) 3293 vr0 = *(get_value_range (op0)); 3294 else if (is_gimple_min_invariant (op0)) 3295 set_value_range_to_value (&vr0, op0, NULL); 3296 else 3297 set_value_range_to_varying (&vr0); 3298 3299 if (TREE_CODE (op1) == SSA_NAME) 3300 vr1 = *(get_value_range (op1)); 3301 else if (is_gimple_min_invariant (op1)) 3302 set_value_range_to_value (&vr1, op1, NULL); 3303 else 3304 set_value_range_to_varying (&vr1); 3305 3306 extract_range_from_binary_expr_1 (vr, code, expr_type, &vr0, &vr1); 3307 3308 /* Try harder for PLUS and MINUS if the range of one operand is symbolic 3309 and based on the other operand, for example if it was deduced from a 3310 symbolic comparison. When a bound of the range of the first operand 3311 is invariant, we set the corresponding bound of the new range to INF 3312 in order to avoid recursing on the range of the second operand. */ 3313 if (vr->type == VR_VARYING 3314 && (code == PLUS_EXPR || code == MINUS_EXPR) 3315 && TREE_CODE (op1) == SSA_NAME 3316 && vr0.type == VR_RANGE 3317 && symbolic_range_based_on_p (&vr0, op1)) 3318 { 3319 const bool minus_p = (code == MINUS_EXPR); 3320 value_range n_vr1 = VR_INITIALIZER; 3321 3322 /* Try with VR0 and [-INF, OP1]. */ 3323 if (is_gimple_min_invariant (minus_p ? vr0.max : vr0.min)) 3324 set_value_range (&n_vr1, VR_RANGE, vrp_val_min (expr_type), op1, NULL); 3325 3326 /* Try with VR0 and [OP1, +INF]. */ 3327 else if (is_gimple_min_invariant (minus_p ? vr0.min : vr0.max)) 3328 set_value_range (&n_vr1, VR_RANGE, op1, vrp_val_max (expr_type), NULL); 3329 3330 /* Try with VR0 and [OP1, OP1]. */ 3331 else 3332 set_value_range (&n_vr1, VR_RANGE, op1, op1, NULL); 3333 3334 extract_range_from_binary_expr_1 (vr, code, expr_type, &vr0, &n_vr1); 3335 } 3336 3337 if (vr->type == VR_VARYING 3338 && (code == PLUS_EXPR || code == MINUS_EXPR) 3339 && TREE_CODE (op0) == SSA_NAME 3340 && vr1.type == VR_RANGE 3341 && symbolic_range_based_on_p (&vr1, op0)) 3342 { 3343 const bool minus_p = (code == MINUS_EXPR); 3344 value_range n_vr0 = VR_INITIALIZER; 3345 3346 /* Try with [-INF, OP0] and VR1. */ 3347 if (is_gimple_min_invariant (minus_p ? vr1.max : vr1.min)) 3348 set_value_range (&n_vr0, VR_RANGE, vrp_val_min (expr_type), op0, NULL); 3349 3350 /* Try with [OP0, +INF] and VR1. */ 3351 else if (is_gimple_min_invariant (minus_p ? vr1.min : vr1.max)) 3352 set_value_range (&n_vr0, VR_RANGE, op0, vrp_val_max (expr_type), NULL); 3353 3354 /* Try with [OP0, OP0] and VR1. */ 3355 else 3356 set_value_range (&n_vr0, VR_RANGE, op0, op0, NULL); 3357 3358 extract_range_from_binary_expr_1 (vr, code, expr_type, &n_vr0, &vr1); 3359 } 3360 } 3361 3362 /* Extract range information from a unary operation CODE based on 3363 the range of its operand *VR0 with type OP0_TYPE with resulting type TYPE. 3364 The resulting range is stored in *VR. */ 3365 3366 static void 3367 extract_range_from_unary_expr_1 (value_range *vr, 3368 enum tree_code code, tree type, 3369 value_range *vr0_, tree op0_type) 3370 { 3371 value_range vr0 = *vr0_, vrtem0 = VR_INITIALIZER, vrtem1 = VR_INITIALIZER; 3372 3373 /* VRP only operates on integral and pointer types. */ 3374 if (!(INTEGRAL_TYPE_P (op0_type) 3375 || POINTER_TYPE_P (op0_type)) 3376 || !(INTEGRAL_TYPE_P (type) 3377 || POINTER_TYPE_P (type))) 3378 { 3379 set_value_range_to_varying (vr); 3380 return; 3381 } 3382 3383 /* If VR0 is UNDEFINED, so is the result. */ 3384 if (vr0.type == VR_UNDEFINED) 3385 { 3386 set_value_range_to_undefined (vr); 3387 return; 3388 } 3389 3390 /* Handle operations that we express in terms of others. */ 3391 if (code == PAREN_EXPR || code == OBJ_TYPE_REF) 3392 { 3393 /* PAREN_EXPR and OBJ_TYPE_REF are simple copies. */ 3394 copy_value_range (vr, &vr0); 3395 return; 3396 } 3397 else if (code == NEGATE_EXPR) 3398 { 3399 /* -X is simply 0 - X, so re-use existing code that also handles 3400 anti-ranges fine. */ 3401 value_range zero = VR_INITIALIZER; 3402 set_value_range_to_value (&zero, build_int_cst (type, 0), NULL); 3403 extract_range_from_binary_expr_1 (vr, MINUS_EXPR, type, &zero, &vr0); 3404 return; 3405 } 3406 else if (code == BIT_NOT_EXPR) 3407 { 3408 /* ~X is simply -1 - X, so re-use existing code that also handles 3409 anti-ranges fine. */ 3410 value_range minusone = VR_INITIALIZER; 3411 set_value_range_to_value (&minusone, build_int_cst (type, -1), NULL); 3412 extract_range_from_binary_expr_1 (vr, MINUS_EXPR, 3413 type, &minusone, &vr0); 3414 return; 3415 } 3416 3417 /* Now canonicalize anti-ranges to ranges when they are not symbolic 3418 and express op ~[] as (op []') U (op []''). */ 3419 if (vr0.type == VR_ANTI_RANGE 3420 && ranges_from_anti_range (&vr0, &vrtem0, &vrtem1)) 3421 { 3422 extract_range_from_unary_expr_1 (vr, code, type, &vrtem0, op0_type); 3423 if (vrtem1.type != VR_UNDEFINED) 3424 { 3425 value_range vrres = VR_INITIALIZER; 3426 extract_range_from_unary_expr_1 (&vrres, code, type, 3427 &vrtem1, op0_type); 3428 vrp_meet (vr, &vrres); 3429 } 3430 return; 3431 } 3432 3433 if (CONVERT_EXPR_CODE_P (code)) 3434 { 3435 tree inner_type = op0_type; 3436 tree outer_type = type; 3437 3438 /* If the expression evaluates to a pointer, we are only interested in 3439 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */ 3440 if (POINTER_TYPE_P (type)) 3441 { 3442 if (range_is_nonnull (&vr0)) 3443 set_value_range_to_nonnull (vr, type); 3444 else if (range_is_null (&vr0)) 3445 set_value_range_to_null (vr, type); 3446 else 3447 set_value_range_to_varying (vr); 3448 return; 3449 } 3450 3451 /* If VR0 is varying and we increase the type precision, assume 3452 a full range for the following transformation. */ 3453 if (vr0.type == VR_VARYING 3454 && INTEGRAL_TYPE_P (inner_type) 3455 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type)) 3456 { 3457 vr0.type = VR_RANGE; 3458 vr0.min = TYPE_MIN_VALUE (inner_type); 3459 vr0.max = TYPE_MAX_VALUE (inner_type); 3460 } 3461 3462 /* If VR0 is a constant range or anti-range and the conversion is 3463 not truncating we can convert the min and max values and 3464 canonicalize the resulting range. Otherwise we can do the 3465 conversion if the size of the range is less than what the 3466 precision of the target type can represent and the range is 3467 not an anti-range. */ 3468 if ((vr0.type == VR_RANGE 3469 || vr0.type == VR_ANTI_RANGE) 3470 && TREE_CODE (vr0.min) == INTEGER_CST 3471 && TREE_CODE (vr0.max) == INTEGER_CST 3472 && (!is_overflow_infinity (vr0.min) 3473 || (vr0.type == VR_RANGE 3474 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type) 3475 && needs_overflow_infinity (outer_type) 3476 && supports_overflow_infinity (outer_type))) 3477 && (!is_overflow_infinity (vr0.max) 3478 || (vr0.type == VR_RANGE 3479 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type) 3480 && needs_overflow_infinity (outer_type) 3481 && supports_overflow_infinity (outer_type))) 3482 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type) 3483 || (vr0.type == VR_RANGE 3484 && integer_zerop (int_const_binop (RSHIFT_EXPR, 3485 int_const_binop (MINUS_EXPR, vr0.max, vr0.min), 3486 size_int (TYPE_PRECISION (outer_type))))))) 3487 { 3488 tree new_min, new_max; 3489 if (is_overflow_infinity (vr0.min)) 3490 new_min = negative_overflow_infinity (outer_type); 3491 else 3492 new_min = force_fit_type (outer_type, wi::to_widest (vr0.min), 3493 0, false); 3494 if (is_overflow_infinity (vr0.max)) 3495 new_max = positive_overflow_infinity (outer_type); 3496 else 3497 new_max = force_fit_type (outer_type, wi::to_widest (vr0.max), 3498 0, false); 3499 set_and_canonicalize_value_range (vr, vr0.type, 3500 new_min, new_max, NULL); 3501 return; 3502 } 3503 3504 set_value_range_to_varying (vr); 3505 return; 3506 } 3507 else if (code == ABS_EXPR) 3508 { 3509 tree min, max; 3510 int cmp; 3511 3512 /* Pass through vr0 in the easy cases. */ 3513 if (TYPE_UNSIGNED (type) 3514 || value_range_nonnegative_p (&vr0)) 3515 { 3516 copy_value_range (vr, &vr0); 3517 return; 3518 } 3519 3520 /* For the remaining varying or symbolic ranges we can't do anything 3521 useful. */ 3522 if (vr0.type == VR_VARYING 3523 || symbolic_range_p (&vr0)) 3524 { 3525 set_value_range_to_varying (vr); 3526 return; 3527 } 3528 3529 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a 3530 useful range. */ 3531 if (!TYPE_OVERFLOW_UNDEFINED (type) 3532 && ((vr0.type == VR_RANGE 3533 && vrp_val_is_min (vr0.min)) 3534 || (vr0.type == VR_ANTI_RANGE 3535 && !vrp_val_is_min (vr0.min)))) 3536 { 3537 set_value_range_to_varying (vr); 3538 return; 3539 } 3540 3541 /* ABS_EXPR may flip the range around, if the original range 3542 included negative values. */ 3543 if (is_overflow_infinity (vr0.min)) 3544 min = positive_overflow_infinity (type); 3545 else if (!vrp_val_is_min (vr0.min)) 3546 min = fold_unary_to_constant (code, type, vr0.min); 3547 else if (!needs_overflow_infinity (type)) 3548 min = TYPE_MAX_VALUE (type); 3549 else if (supports_overflow_infinity (type)) 3550 min = positive_overflow_infinity (type); 3551 else 3552 { 3553 set_value_range_to_varying (vr); 3554 return; 3555 } 3556 3557 if (is_overflow_infinity (vr0.max)) 3558 max = positive_overflow_infinity (type); 3559 else if (!vrp_val_is_min (vr0.max)) 3560 max = fold_unary_to_constant (code, type, vr0.max); 3561 else if (!needs_overflow_infinity (type)) 3562 max = TYPE_MAX_VALUE (type); 3563 else if (supports_overflow_infinity (type) 3564 /* We shouldn't generate [+INF, +INF] as set_value_range 3565 doesn't like this and ICEs. */ 3566 && !is_positive_overflow_infinity (min)) 3567 max = positive_overflow_infinity (type); 3568 else 3569 { 3570 set_value_range_to_varying (vr); 3571 return; 3572 } 3573 3574 cmp = compare_values (min, max); 3575 3576 /* If a VR_ANTI_RANGEs contains zero, then we have 3577 ~[-INF, min(MIN, MAX)]. */ 3578 if (vr0.type == VR_ANTI_RANGE) 3579 { 3580 if (range_includes_zero_p (vr0.min, vr0.max) == 1) 3581 { 3582 /* Take the lower of the two values. */ 3583 if (cmp != 1) 3584 max = min; 3585 3586 /* Create ~[-INF, min (abs(MIN), abs(MAX))] 3587 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when 3588 flag_wrapv is set and the original anti-range doesn't include 3589 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */ 3590 if (TYPE_OVERFLOW_WRAPS (type)) 3591 { 3592 tree type_min_value = TYPE_MIN_VALUE (type); 3593 3594 min = (vr0.min != type_min_value 3595 ? int_const_binop (PLUS_EXPR, type_min_value, 3596 build_int_cst (TREE_TYPE (type_min_value), 1)) 3597 : type_min_value); 3598 } 3599 else 3600 { 3601 if (overflow_infinity_range_p (&vr0)) 3602 min = negative_overflow_infinity (type); 3603 else 3604 min = TYPE_MIN_VALUE (type); 3605 } 3606 } 3607 else 3608 { 3609 /* All else has failed, so create the range [0, INF], even for 3610 flag_wrapv since TYPE_MIN_VALUE is in the original 3611 anti-range. */ 3612 vr0.type = VR_RANGE; 3613 min = build_int_cst (type, 0); 3614 if (needs_overflow_infinity (type)) 3615 { 3616 if (supports_overflow_infinity (type)) 3617 max = positive_overflow_infinity (type); 3618 else 3619 { 3620 set_value_range_to_varying (vr); 3621 return; 3622 } 3623 } 3624 else 3625 max = TYPE_MAX_VALUE (type); 3626 } 3627 } 3628 3629 /* If the range contains zero then we know that the minimum value in the 3630 range will be zero. */ 3631 else if (range_includes_zero_p (vr0.min, vr0.max) == 1) 3632 { 3633 if (cmp == 1) 3634 max = min; 3635 min = build_int_cst (type, 0); 3636 } 3637 else 3638 { 3639 /* If the range was reversed, swap MIN and MAX. */ 3640 if (cmp == 1) 3641 std::swap (min, max); 3642 } 3643 3644 cmp = compare_values (min, max); 3645 if (cmp == -2 || cmp == 1) 3646 { 3647 /* If the new range has its limits swapped around (MIN > MAX), 3648 then the operation caused one of them to wrap around, mark 3649 the new range VARYING. */ 3650 set_value_range_to_varying (vr); 3651 } 3652 else 3653 set_value_range (vr, vr0.type, min, max, NULL); 3654 return; 3655 } 3656 3657 /* For unhandled operations fall back to varying. */ 3658 set_value_range_to_varying (vr); 3659 return; 3660 } 3661 3662 3663 /* Extract range information from a unary expression CODE OP0 based on 3664 the range of its operand with resulting type TYPE. 3665 The resulting range is stored in *VR. */ 3666 3667 static void 3668 extract_range_from_unary_expr (value_range *vr, enum tree_code code, 3669 tree type, tree op0) 3670 { 3671 value_range vr0 = VR_INITIALIZER; 3672 3673 /* Get value ranges for the operand. For constant operands, create 3674 a new value range with the operand to simplify processing. */ 3675 if (TREE_CODE (op0) == SSA_NAME) 3676 vr0 = *(get_value_range (op0)); 3677 else if (is_gimple_min_invariant (op0)) 3678 set_value_range_to_value (&vr0, op0, NULL); 3679 else 3680 set_value_range_to_varying (&vr0); 3681 3682 extract_range_from_unary_expr_1 (vr, code, type, &vr0, TREE_TYPE (op0)); 3683 } 3684 3685 3686 /* Extract range information from a conditional expression STMT based on 3687 the ranges of each of its operands and the expression code. */ 3688 3689 static void 3690 extract_range_from_cond_expr (value_range *vr, gassign *stmt) 3691 { 3692 tree op0, op1; 3693 value_range vr0 = VR_INITIALIZER; 3694 value_range vr1 = VR_INITIALIZER; 3695 3696 /* Get value ranges for each operand. For constant operands, create 3697 a new value range with the operand to simplify processing. */ 3698 op0 = gimple_assign_rhs2 (stmt); 3699 if (TREE_CODE (op0) == SSA_NAME) 3700 vr0 = *(get_value_range (op0)); 3701 else if (is_gimple_min_invariant (op0)) 3702 set_value_range_to_value (&vr0, op0, NULL); 3703 else 3704 set_value_range_to_varying (&vr0); 3705 3706 op1 = gimple_assign_rhs3 (stmt); 3707 if (TREE_CODE (op1) == SSA_NAME) 3708 vr1 = *(get_value_range (op1)); 3709 else if (is_gimple_min_invariant (op1)) 3710 set_value_range_to_value (&vr1, op1, NULL); 3711 else 3712 set_value_range_to_varying (&vr1); 3713 3714 /* The resulting value range is the union of the operand ranges */ 3715 copy_value_range (vr, &vr0); 3716 vrp_meet (vr, &vr1); 3717 } 3718 3719 3720 /* Extract range information from a comparison expression EXPR based 3721 on the range of its operand and the expression code. */ 3722 3723 static void 3724 extract_range_from_comparison (value_range *vr, enum tree_code code, 3725 tree type, tree op0, tree op1) 3726 { 3727 bool sop = false; 3728 tree val; 3729 3730 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop, 3731 NULL); 3732 3733 /* A disadvantage of using a special infinity as an overflow 3734 representation is that we lose the ability to record overflow 3735 when we don't have an infinity. So we have to ignore a result 3736 which relies on overflow. */ 3737 3738 if (val && !is_overflow_infinity (val) && !sop) 3739 { 3740 /* Since this expression was found on the RHS of an assignment, 3741 its type may be different from _Bool. Convert VAL to EXPR's 3742 type. */ 3743 val = fold_convert (type, val); 3744 if (is_gimple_min_invariant (val)) 3745 set_value_range_to_value (vr, val, vr->equiv); 3746 else 3747 set_value_range (vr, VR_RANGE, val, val, vr->equiv); 3748 } 3749 else 3750 /* The result of a comparison is always true or false. */ 3751 set_value_range_to_truthvalue (vr, type); 3752 } 3753 3754 /* Helper function for simplify_internal_call_using_ranges and 3755 extract_range_basic. Return true if OP0 SUBCODE OP1 for 3756 SUBCODE {PLUS,MINUS,MULT}_EXPR is known to never overflow or 3757 always overflow. Set *OVF to true if it is known to always 3758 overflow. */ 3759 3760 static bool 3761 check_for_binary_op_overflow (enum tree_code subcode, tree type, 3762 tree op0, tree op1, bool *ovf) 3763 { 3764 value_range vr0 = VR_INITIALIZER; 3765 value_range vr1 = VR_INITIALIZER; 3766 if (TREE_CODE (op0) == SSA_NAME) 3767 vr0 = *get_value_range (op0); 3768 else if (TREE_CODE (op0) == INTEGER_CST) 3769 set_value_range_to_value (&vr0, op0, NULL); 3770 else 3771 set_value_range_to_varying (&vr0); 3772 3773 if (TREE_CODE (op1) == SSA_NAME) 3774 vr1 = *get_value_range (op1); 3775 else if (TREE_CODE (op1) == INTEGER_CST) 3776 set_value_range_to_value (&vr1, op1, NULL); 3777 else 3778 set_value_range_to_varying (&vr1); 3779 3780 if (!range_int_cst_p (&vr0) 3781 || TREE_OVERFLOW (vr0.min) 3782 || TREE_OVERFLOW (vr0.max)) 3783 { 3784 vr0.min = vrp_val_min (TREE_TYPE (op0)); 3785 vr0.max = vrp_val_max (TREE_TYPE (op0)); 3786 } 3787 if (!range_int_cst_p (&vr1) 3788 || TREE_OVERFLOW (vr1.min) 3789 || TREE_OVERFLOW (vr1.max)) 3790 { 3791 vr1.min = vrp_val_min (TREE_TYPE (op1)); 3792 vr1.max = vrp_val_max (TREE_TYPE (op1)); 3793 } 3794 *ovf = arith_overflowed_p (subcode, type, vr0.min, 3795 subcode == MINUS_EXPR ? vr1.max : vr1.min); 3796 if (arith_overflowed_p (subcode, type, vr0.max, 3797 subcode == MINUS_EXPR ? vr1.min : vr1.max) != *ovf) 3798 return false; 3799 if (subcode == MULT_EXPR) 3800 { 3801 if (arith_overflowed_p (subcode, type, vr0.min, vr1.max) != *ovf 3802 || arith_overflowed_p (subcode, type, vr0.max, vr1.min) != *ovf) 3803 return false; 3804 } 3805 if (*ovf) 3806 { 3807 /* So far we found that there is an overflow on the boundaries. 3808 That doesn't prove that there is an overflow even for all values 3809 in between the boundaries. For that compute widest_int range 3810 of the result and see if it doesn't overlap the range of 3811 type. */ 3812 widest_int wmin, wmax; 3813 widest_int w[4]; 3814 int i; 3815 w[0] = wi::to_widest (vr0.min); 3816 w[1] = wi::to_widest (vr0.max); 3817 w[2] = wi::to_widest (vr1.min); 3818 w[3] = wi::to_widest (vr1.max); 3819 for (i = 0; i < 4; i++) 3820 { 3821 widest_int wt; 3822 switch (subcode) 3823 { 3824 case PLUS_EXPR: 3825 wt = wi::add (w[i & 1], w[2 + (i & 2) / 2]); 3826 break; 3827 case MINUS_EXPR: 3828 wt = wi::sub (w[i & 1], w[2 + (i & 2) / 2]); 3829 break; 3830 case MULT_EXPR: 3831 wt = wi::mul (w[i & 1], w[2 + (i & 2) / 2]); 3832 break; 3833 default: 3834 gcc_unreachable (); 3835 } 3836 if (i == 0) 3837 { 3838 wmin = wt; 3839 wmax = wt; 3840 } 3841 else 3842 { 3843 wmin = wi::smin (wmin, wt); 3844 wmax = wi::smax (wmax, wt); 3845 } 3846 } 3847 /* The result of op0 CODE op1 is known to be in range 3848 [wmin, wmax]. */ 3849 widest_int wtmin = wi::to_widest (vrp_val_min (type)); 3850 widest_int wtmax = wi::to_widest (vrp_val_max (type)); 3851 /* If all values in [wmin, wmax] are smaller than 3852 [wtmin, wtmax] or all are larger than [wtmin, wtmax], 3853 the arithmetic operation will always overflow. */ 3854 if (wi::lts_p (wmax, wtmin) || wi::gts_p (wmin, wtmax)) 3855 return true; 3856 return false; 3857 } 3858 return true; 3859 } 3860 3861 /* Try to derive a nonnegative or nonzero range out of STMT relying 3862 primarily on generic routines in fold in conjunction with range data. 3863 Store the result in *VR */ 3864 3865 static void 3866 extract_range_basic (value_range *vr, gimple *stmt) 3867 { 3868 bool sop = false; 3869 tree type = gimple_expr_type (stmt); 3870 3871 if (is_gimple_call (stmt)) 3872 { 3873 tree arg; 3874 int mini, maxi, zerov = 0, prec; 3875 enum tree_code subcode = ERROR_MARK; 3876 combined_fn cfn = gimple_call_combined_fn (stmt); 3877 3878 switch (cfn) 3879 { 3880 case CFN_BUILT_IN_CONSTANT_P: 3881 /* If the call is __builtin_constant_p and the argument is a 3882 function parameter resolve it to false. This avoids bogus 3883 array bound warnings. 3884 ??? We could do this as early as inlining is finished. */ 3885 arg = gimple_call_arg (stmt, 0); 3886 if (TREE_CODE (arg) == SSA_NAME 3887 && SSA_NAME_IS_DEFAULT_DEF (arg) 3888 && TREE_CODE (SSA_NAME_VAR (arg)) == PARM_DECL) 3889 { 3890 set_value_range_to_null (vr, type); 3891 return; 3892 } 3893 break; 3894 /* Both __builtin_ffs* and __builtin_popcount return 3895 [0, prec]. */ 3896 CASE_CFN_FFS: 3897 CASE_CFN_POPCOUNT: 3898 arg = gimple_call_arg (stmt, 0); 3899 prec = TYPE_PRECISION (TREE_TYPE (arg)); 3900 mini = 0; 3901 maxi = prec; 3902 if (TREE_CODE (arg) == SSA_NAME) 3903 { 3904 value_range *vr0 = get_value_range (arg); 3905 /* If arg is non-zero, then ffs or popcount 3906 are non-zero. */ 3907 if (((vr0->type == VR_RANGE 3908 && range_includes_zero_p (vr0->min, vr0->max) == 0) 3909 || (vr0->type == VR_ANTI_RANGE 3910 && range_includes_zero_p (vr0->min, vr0->max) == 1)) 3911 && !is_overflow_infinity (vr0->min) 3912 && !is_overflow_infinity (vr0->max)) 3913 mini = 1; 3914 /* If some high bits are known to be zero, 3915 we can decrease the maximum. */ 3916 if (vr0->type == VR_RANGE 3917 && TREE_CODE (vr0->max) == INTEGER_CST 3918 && !operand_less_p (vr0->min, 3919 build_zero_cst (TREE_TYPE (vr0->min))) 3920 && !is_overflow_infinity (vr0->max)) 3921 maxi = tree_floor_log2 (vr0->max) + 1; 3922 } 3923 goto bitop_builtin; 3924 /* __builtin_parity* returns [0, 1]. */ 3925 CASE_CFN_PARITY: 3926 mini = 0; 3927 maxi = 1; 3928 goto bitop_builtin; 3929 /* __builtin_c[lt]z* return [0, prec-1], except for 3930 when the argument is 0, but that is undefined behavior. 3931 On many targets where the CLZ RTL or optab value is defined 3932 for 0 the value is prec, so include that in the range 3933 by default. */ 3934 CASE_CFN_CLZ: 3935 arg = gimple_call_arg (stmt, 0); 3936 prec = TYPE_PRECISION (TREE_TYPE (arg)); 3937 mini = 0; 3938 maxi = prec; 3939 if (optab_handler (clz_optab, TYPE_MODE (TREE_TYPE (arg))) 3940 != CODE_FOR_nothing 3941 && CLZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (TREE_TYPE (arg)), 3942 zerov) 3943 /* Handle only the single common value. */ 3944 && zerov != prec) 3945 /* Magic value to give up, unless vr0 proves 3946 arg is non-zero. */ 3947 mini = -2; 3948 if (TREE_CODE (arg) == SSA_NAME) 3949 { 3950 value_range *vr0 = get_value_range (arg); 3951 /* From clz of VR_RANGE minimum we can compute 3952 result maximum. */ 3953 if (vr0->type == VR_RANGE 3954 && TREE_CODE (vr0->min) == INTEGER_CST 3955 && !is_overflow_infinity (vr0->min)) 3956 { 3957 maxi = prec - 1 - tree_floor_log2 (vr0->min); 3958 if (maxi != prec) 3959 mini = 0; 3960 } 3961 else if (vr0->type == VR_ANTI_RANGE 3962 && integer_zerop (vr0->min) 3963 && !is_overflow_infinity (vr0->min)) 3964 { 3965 maxi = prec - 1; 3966 mini = 0; 3967 } 3968 if (mini == -2) 3969 break; 3970 /* From clz of VR_RANGE maximum we can compute 3971 result minimum. */ 3972 if (vr0->type == VR_RANGE 3973 && TREE_CODE (vr0->max) == INTEGER_CST 3974 && !is_overflow_infinity (vr0->max)) 3975 { 3976 mini = prec - 1 - tree_floor_log2 (vr0->max); 3977 if (mini == prec) 3978 break; 3979 } 3980 } 3981 if (mini == -2) 3982 break; 3983 goto bitop_builtin; 3984 /* __builtin_ctz* return [0, prec-1], except for 3985 when the argument is 0, but that is undefined behavior. 3986 If there is a ctz optab for this mode and 3987 CTZ_DEFINED_VALUE_AT_ZERO, include that in the range, 3988 otherwise just assume 0 won't be seen. */ 3989 CASE_CFN_CTZ: 3990 arg = gimple_call_arg (stmt, 0); 3991 prec = TYPE_PRECISION (TREE_TYPE (arg)); 3992 mini = 0; 3993 maxi = prec - 1; 3994 if (optab_handler (ctz_optab, TYPE_MODE (TREE_TYPE (arg))) 3995 != CODE_FOR_nothing 3996 && CTZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (TREE_TYPE (arg)), 3997 zerov)) 3998 { 3999 /* Handle only the two common values. */ 4000 if (zerov == -1) 4001 mini = -1; 4002 else if (zerov == prec) 4003 maxi = prec; 4004 else 4005 /* Magic value to give up, unless vr0 proves 4006 arg is non-zero. */ 4007 mini = -2; 4008 } 4009 if (TREE_CODE (arg) == SSA_NAME) 4010 { 4011 value_range *vr0 = get_value_range (arg); 4012 /* If arg is non-zero, then use [0, prec - 1]. */ 4013 if (((vr0->type == VR_RANGE 4014 && integer_nonzerop (vr0->min)) 4015 || (vr0->type == VR_ANTI_RANGE 4016 && integer_zerop (vr0->min))) 4017 && !is_overflow_infinity (vr0->min)) 4018 { 4019 mini = 0; 4020 maxi = prec - 1; 4021 } 4022 /* If some high bits are known to be zero, 4023 we can decrease the result maximum. */ 4024 if (vr0->type == VR_RANGE 4025 && TREE_CODE (vr0->max) == INTEGER_CST 4026 && !is_overflow_infinity (vr0->max)) 4027 { 4028 maxi = tree_floor_log2 (vr0->max); 4029 /* For vr0 [0, 0] give up. */ 4030 if (maxi == -1) 4031 break; 4032 } 4033 } 4034 if (mini == -2) 4035 break; 4036 goto bitop_builtin; 4037 /* __builtin_clrsb* returns [0, prec-1]. */ 4038 CASE_CFN_CLRSB: 4039 arg = gimple_call_arg (stmt, 0); 4040 prec = TYPE_PRECISION (TREE_TYPE (arg)); 4041 mini = 0; 4042 maxi = prec - 1; 4043 goto bitop_builtin; 4044 bitop_builtin: 4045 set_value_range (vr, VR_RANGE, build_int_cst (type, mini), 4046 build_int_cst (type, maxi), NULL); 4047 return; 4048 case CFN_UBSAN_CHECK_ADD: 4049 subcode = PLUS_EXPR; 4050 break; 4051 case CFN_UBSAN_CHECK_SUB: 4052 subcode = MINUS_EXPR; 4053 break; 4054 case CFN_UBSAN_CHECK_MUL: 4055 subcode = MULT_EXPR; 4056 break; 4057 case CFN_GOACC_DIM_SIZE: 4058 case CFN_GOACC_DIM_POS: 4059 /* Optimizing these two internal functions helps the loop 4060 optimizer eliminate outer comparisons. Size is [1,N] 4061 and pos is [0,N-1]. */ 4062 { 4063 bool is_pos = cfn == CFN_GOACC_DIM_POS; 4064 int axis = get_oacc_ifn_dim_arg (stmt); 4065 int size = get_oacc_fn_dim_size (current_function_decl, axis); 4066 4067 if (!size) 4068 /* If it's dynamic, the backend might know a hardware 4069 limitation. */ 4070 size = targetm.goacc.dim_limit (axis); 4071 4072 tree type = TREE_TYPE (gimple_call_lhs (stmt)); 4073 set_value_range (vr, VR_RANGE, 4074 build_int_cst (type, is_pos ? 0 : 1), 4075 size ? build_int_cst (type, size - is_pos) 4076 : vrp_val_max (type), NULL); 4077 } 4078 return; 4079 default: 4080 break; 4081 } 4082 if (subcode != ERROR_MARK) 4083 { 4084 bool saved_flag_wrapv = flag_wrapv; 4085 /* Pretend the arithmetics is wrapping. If there is 4086 any overflow, we'll complain, but will actually do 4087 wrapping operation. */ 4088 flag_wrapv = 1; 4089 extract_range_from_binary_expr (vr, subcode, type, 4090 gimple_call_arg (stmt, 0), 4091 gimple_call_arg (stmt, 1)); 4092 flag_wrapv = saved_flag_wrapv; 4093 4094 /* If for both arguments vrp_valueize returned non-NULL, 4095 this should have been already folded and if not, it 4096 wasn't folded because of overflow. Avoid removing the 4097 UBSAN_CHECK_* calls in that case. */ 4098 if (vr->type == VR_RANGE 4099 && (vr->min == vr->max 4100 || operand_equal_p (vr->min, vr->max, 0))) 4101 set_value_range_to_varying (vr); 4102 return; 4103 } 4104 } 4105 /* Handle extraction of the two results (result of arithmetics and 4106 a flag whether arithmetics overflowed) from {ADD,SUB,MUL}_OVERFLOW 4107 internal function. */ 4108 else if (is_gimple_assign (stmt) 4109 && (gimple_assign_rhs_code (stmt) == REALPART_EXPR 4110 || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR) 4111 && INTEGRAL_TYPE_P (type)) 4112 { 4113 enum tree_code code = gimple_assign_rhs_code (stmt); 4114 tree op = gimple_assign_rhs1 (stmt); 4115 if (TREE_CODE (op) == code && TREE_CODE (TREE_OPERAND (op, 0)) == SSA_NAME) 4116 { 4117 gimple *g = SSA_NAME_DEF_STMT (TREE_OPERAND (op, 0)); 4118 if (is_gimple_call (g) && gimple_call_internal_p (g)) 4119 { 4120 enum tree_code subcode = ERROR_MARK; 4121 switch (gimple_call_internal_fn (g)) 4122 { 4123 case IFN_ADD_OVERFLOW: 4124 subcode = PLUS_EXPR; 4125 break; 4126 case IFN_SUB_OVERFLOW: 4127 subcode = MINUS_EXPR; 4128 break; 4129 case IFN_MUL_OVERFLOW: 4130 subcode = MULT_EXPR; 4131 break; 4132 default: 4133 break; 4134 } 4135 if (subcode != ERROR_MARK) 4136 { 4137 tree op0 = gimple_call_arg (g, 0); 4138 tree op1 = gimple_call_arg (g, 1); 4139 if (code == IMAGPART_EXPR) 4140 { 4141 bool ovf = false; 4142 if (check_for_binary_op_overflow (subcode, type, 4143 op0, op1, &ovf)) 4144 set_value_range_to_value (vr, 4145 build_int_cst (type, ovf), 4146 NULL); 4147 else 4148 set_value_range (vr, VR_RANGE, build_int_cst (type, 0), 4149 build_int_cst (type, 1), NULL); 4150 } 4151 else if (types_compatible_p (type, TREE_TYPE (op0)) 4152 && types_compatible_p (type, TREE_TYPE (op1))) 4153 { 4154 bool saved_flag_wrapv = flag_wrapv; 4155 /* Pretend the arithmetics is wrapping. If there is 4156 any overflow, IMAGPART_EXPR will be set. */ 4157 flag_wrapv = 1; 4158 extract_range_from_binary_expr (vr, subcode, type, 4159 op0, op1); 4160 flag_wrapv = saved_flag_wrapv; 4161 } 4162 else 4163 { 4164 value_range vr0 = VR_INITIALIZER; 4165 value_range vr1 = VR_INITIALIZER; 4166 bool saved_flag_wrapv = flag_wrapv; 4167 /* Pretend the arithmetics is wrapping. If there is 4168 any overflow, IMAGPART_EXPR will be set. */ 4169 flag_wrapv = 1; 4170 extract_range_from_unary_expr (&vr0, NOP_EXPR, 4171 type, op0); 4172 extract_range_from_unary_expr (&vr1, NOP_EXPR, 4173 type, op1); 4174 extract_range_from_binary_expr_1 (vr, subcode, type, 4175 &vr0, &vr1); 4176 flag_wrapv = saved_flag_wrapv; 4177 } 4178 return; 4179 } 4180 } 4181 } 4182 } 4183 if (INTEGRAL_TYPE_P (type) 4184 && gimple_stmt_nonnegative_warnv_p (stmt, &sop)) 4185 set_value_range_to_nonnegative (vr, type, 4186 sop || stmt_overflow_infinity (stmt)); 4187 else if (vrp_stmt_computes_nonzero (stmt, &sop) 4188 && !sop) 4189 set_value_range_to_nonnull (vr, type); 4190 else 4191 set_value_range_to_varying (vr); 4192 } 4193 4194 4195 /* Try to compute a useful range out of assignment STMT and store it 4196 in *VR. */ 4197 4198 static void 4199 extract_range_from_assignment (value_range *vr, gassign *stmt) 4200 { 4201 enum tree_code code = gimple_assign_rhs_code (stmt); 4202 4203 if (code == ASSERT_EXPR) 4204 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt)); 4205 else if (code == SSA_NAME) 4206 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt)); 4207 else if (TREE_CODE_CLASS (code) == tcc_binary) 4208 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt), 4209 gimple_expr_type (stmt), 4210 gimple_assign_rhs1 (stmt), 4211 gimple_assign_rhs2 (stmt)); 4212 else if (TREE_CODE_CLASS (code) == tcc_unary) 4213 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt), 4214 gimple_expr_type (stmt), 4215 gimple_assign_rhs1 (stmt)); 4216 else if (code == COND_EXPR) 4217 extract_range_from_cond_expr (vr, stmt); 4218 else if (TREE_CODE_CLASS (code) == tcc_comparison) 4219 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt), 4220 gimple_expr_type (stmt), 4221 gimple_assign_rhs1 (stmt), 4222 gimple_assign_rhs2 (stmt)); 4223 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS 4224 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt))) 4225 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL); 4226 else 4227 set_value_range_to_varying (vr); 4228 4229 if (vr->type == VR_VARYING) 4230 extract_range_basic (vr, stmt); 4231 } 4232 4233 /* Given a range VR, a LOOP and a variable VAR, determine whether it 4234 would be profitable to adjust VR using scalar evolution information 4235 for VAR. If so, update VR with the new limits. */ 4236 4237 static void 4238 adjust_range_with_scev (value_range *vr, struct loop *loop, 4239 gimple *stmt, tree var) 4240 { 4241 tree init, step, chrec, tmin, tmax, min, max, type, tem; 4242 enum ev_direction dir; 4243 4244 /* TODO. Don't adjust anti-ranges. An anti-range may provide 4245 better opportunities than a regular range, but I'm not sure. */ 4246 if (vr->type == VR_ANTI_RANGE) 4247 return; 4248 4249 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var)); 4250 4251 /* Like in PR19590, scev can return a constant function. */ 4252 if (is_gimple_min_invariant (chrec)) 4253 { 4254 set_value_range_to_value (vr, chrec, vr->equiv); 4255 return; 4256 } 4257 4258 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC) 4259 return; 4260 4261 init = initial_condition_in_loop_num (chrec, loop->num); 4262 tem = op_with_constant_singleton_value_range (init); 4263 if (tem) 4264 init = tem; 4265 step = evolution_part_in_loop_num (chrec, loop->num); 4266 tem = op_with_constant_singleton_value_range (step); 4267 if (tem) 4268 step = tem; 4269 4270 /* If STEP is symbolic, we can't know whether INIT will be the 4271 minimum or maximum value in the range. Also, unless INIT is 4272 a simple expression, compare_values and possibly other functions 4273 in tree-vrp won't be able to handle it. */ 4274 if (step == NULL_TREE 4275 || !is_gimple_min_invariant (step) 4276 || !valid_value_p (init)) 4277 return; 4278 4279 dir = scev_direction (chrec); 4280 if (/* Do not adjust ranges if we do not know whether the iv increases 4281 or decreases, ... */ 4282 dir == EV_DIR_UNKNOWN 4283 /* ... or if it may wrap. */ 4284 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec), 4285 true)) 4286 return; 4287 4288 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of 4289 negative_overflow_infinity and positive_overflow_infinity, 4290 because we have concluded that the loop probably does not 4291 wrap. */ 4292 4293 type = TREE_TYPE (var); 4294 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type)) 4295 tmin = lower_bound_in_type (type, type); 4296 else 4297 tmin = TYPE_MIN_VALUE (type); 4298 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type)) 4299 tmax = upper_bound_in_type (type, type); 4300 else 4301 tmax = TYPE_MAX_VALUE (type); 4302 4303 /* Try to use estimated number of iterations for the loop to constrain the 4304 final value in the evolution. */ 4305 if (TREE_CODE (step) == INTEGER_CST 4306 && is_gimple_val (init) 4307 && (TREE_CODE (init) != SSA_NAME 4308 || get_value_range (init)->type == VR_RANGE)) 4309 { 4310 widest_int nit; 4311 4312 /* We are only entering here for loop header PHI nodes, so using 4313 the number of latch executions is the correct thing to use. */ 4314 if (max_loop_iterations (loop, &nit)) 4315 { 4316 value_range maxvr = VR_INITIALIZER; 4317 signop sgn = TYPE_SIGN (TREE_TYPE (step)); 4318 bool overflow; 4319 4320 widest_int wtmp = wi::mul (wi::to_widest (step), nit, sgn, 4321 &overflow); 4322 /* If the multiplication overflowed we can't do a meaningful 4323 adjustment. Likewise if the result doesn't fit in the type 4324 of the induction variable. For a signed type we have to 4325 check whether the result has the expected signedness which 4326 is that of the step as number of iterations is unsigned. */ 4327 if (!overflow 4328 && wi::fits_to_tree_p (wtmp, TREE_TYPE (init)) 4329 && (sgn == UNSIGNED 4330 || wi::gts_p (wtmp, 0) == wi::gts_p (step, 0))) 4331 { 4332 tem = wide_int_to_tree (TREE_TYPE (init), wtmp); 4333 extract_range_from_binary_expr (&maxvr, PLUS_EXPR, 4334 TREE_TYPE (init), init, tem); 4335 /* Likewise if the addition did. */ 4336 if (maxvr.type == VR_RANGE) 4337 { 4338 value_range initvr = VR_INITIALIZER; 4339 4340 if (TREE_CODE (init) == SSA_NAME) 4341 initvr = *(get_value_range (init)); 4342 else if (is_gimple_min_invariant (init)) 4343 set_value_range_to_value (&initvr, init, NULL); 4344 else 4345 return; 4346 4347 /* Check if init + nit * step overflows. Though we checked 4348 scev {init, step}_loop doesn't wrap, it is not enough 4349 because the loop may exit immediately. Overflow could 4350 happen in the plus expression in this case. */ 4351 if ((dir == EV_DIR_DECREASES 4352 && (is_negative_overflow_infinity (maxvr.min) 4353 || compare_values (maxvr.min, initvr.min) != -1)) 4354 || (dir == EV_DIR_GROWS 4355 && (is_positive_overflow_infinity (maxvr.max) 4356 || compare_values (maxvr.max, initvr.max) != 1))) 4357 return; 4358 4359 tmin = maxvr.min; 4360 tmax = maxvr.max; 4361 } 4362 } 4363 } 4364 } 4365 4366 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED) 4367 { 4368 min = tmin; 4369 max = tmax; 4370 4371 /* For VARYING or UNDEFINED ranges, just about anything we get 4372 from scalar evolutions should be better. */ 4373 4374 if (dir == EV_DIR_DECREASES) 4375 max = init; 4376 else 4377 min = init; 4378 } 4379 else if (vr->type == VR_RANGE) 4380 { 4381 min = vr->min; 4382 max = vr->max; 4383 4384 if (dir == EV_DIR_DECREASES) 4385 { 4386 /* INIT is the maximum value. If INIT is lower than VR->MAX 4387 but no smaller than VR->MIN, set VR->MAX to INIT. */ 4388 if (compare_values (init, max) == -1) 4389 max = init; 4390 4391 /* According to the loop information, the variable does not 4392 overflow. If we think it does, probably because of an 4393 overflow due to arithmetic on a different INF value, 4394 reset now. */ 4395 if (is_negative_overflow_infinity (min) 4396 || compare_values (min, tmin) == -1) 4397 min = tmin; 4398 4399 } 4400 else 4401 { 4402 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */ 4403 if (compare_values (init, min) == 1) 4404 min = init; 4405 4406 if (is_positive_overflow_infinity (max) 4407 || compare_values (tmax, max) == -1) 4408 max = tmax; 4409 } 4410 } 4411 else 4412 return; 4413 4414 /* If we just created an invalid range with the minimum 4415 greater than the maximum, we fail conservatively. 4416 This should happen only in unreachable 4417 parts of code, or for invalid programs. */ 4418 if (compare_values (min, max) == 1 4419 || (is_negative_overflow_infinity (min) 4420 && is_positive_overflow_infinity (max))) 4421 return; 4422 4423 /* Even for valid range info, sometimes overflow flag will leak in. 4424 As GIMPLE IL should have no constants with TREE_OVERFLOW set, we 4425 drop them except for +-overflow_infinity which still need special 4426 handling in vrp pass. */ 4427 if (TREE_OVERFLOW_P (min) 4428 && ! is_negative_overflow_infinity (min)) 4429 min = drop_tree_overflow (min); 4430 if (TREE_OVERFLOW_P (max) 4431 && ! is_positive_overflow_infinity (max)) 4432 max = drop_tree_overflow (max); 4433 4434 set_value_range (vr, VR_RANGE, min, max, vr->equiv); 4435 } 4436 4437 4438 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP: 4439 4440 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for 4441 all the values in the ranges. 4442 4443 - Return BOOLEAN_FALSE_NODE if the comparison always returns false. 4444 4445 - Return NULL_TREE if it is not always possible to determine the 4446 value of the comparison. 4447 4448 Also set *STRICT_OVERFLOW_P to indicate whether a range with an 4449 overflow infinity was used in the test. */ 4450 4451 4452 static tree 4453 compare_ranges (enum tree_code comp, value_range *vr0, value_range *vr1, 4454 bool *strict_overflow_p) 4455 { 4456 /* VARYING or UNDEFINED ranges cannot be compared. */ 4457 if (vr0->type == VR_VARYING 4458 || vr0->type == VR_UNDEFINED 4459 || vr1->type == VR_VARYING 4460 || vr1->type == VR_UNDEFINED) 4461 return NULL_TREE; 4462 4463 /* Anti-ranges need to be handled separately. */ 4464 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE) 4465 { 4466 /* If both are anti-ranges, then we cannot compute any 4467 comparison. */ 4468 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE) 4469 return NULL_TREE; 4470 4471 /* These comparisons are never statically computable. */ 4472 if (comp == GT_EXPR 4473 || comp == GE_EXPR 4474 || comp == LT_EXPR 4475 || comp == LE_EXPR) 4476 return NULL_TREE; 4477 4478 /* Equality can be computed only between a range and an 4479 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */ 4480 if (vr0->type == VR_RANGE) 4481 { 4482 /* To simplify processing, make VR0 the anti-range. */ 4483 value_range *tmp = vr0; 4484 vr0 = vr1; 4485 vr1 = tmp; 4486 } 4487 4488 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR); 4489 4490 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0 4491 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0) 4492 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node; 4493 4494 return NULL_TREE; 4495 } 4496 4497 if (!usable_range_p (vr0, strict_overflow_p) 4498 || !usable_range_p (vr1, strict_overflow_p)) 4499 return NULL_TREE; 4500 4501 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the 4502 operands around and change the comparison code. */ 4503 if (comp == GT_EXPR || comp == GE_EXPR) 4504 { 4505 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR; 4506 std::swap (vr0, vr1); 4507 } 4508 4509 if (comp == EQ_EXPR) 4510 { 4511 /* Equality may only be computed if both ranges represent 4512 exactly one value. */ 4513 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0 4514 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0) 4515 { 4516 int cmp_min = compare_values_warnv (vr0->min, vr1->min, 4517 strict_overflow_p); 4518 int cmp_max = compare_values_warnv (vr0->max, vr1->max, 4519 strict_overflow_p); 4520 if (cmp_min == 0 && cmp_max == 0) 4521 return boolean_true_node; 4522 else if (cmp_min != -2 && cmp_max != -2) 4523 return boolean_false_node; 4524 } 4525 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */ 4526 else if (compare_values_warnv (vr0->min, vr1->max, 4527 strict_overflow_p) == 1 4528 || compare_values_warnv (vr1->min, vr0->max, 4529 strict_overflow_p) == 1) 4530 return boolean_false_node; 4531 4532 return NULL_TREE; 4533 } 4534 else if (comp == NE_EXPR) 4535 { 4536 int cmp1, cmp2; 4537 4538 /* If VR0 is completely to the left or completely to the right 4539 of VR1, they are always different. Notice that we need to 4540 make sure that both comparisons yield similar results to 4541 avoid comparing values that cannot be compared at 4542 compile-time. */ 4543 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p); 4544 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p); 4545 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1)) 4546 return boolean_true_node; 4547 4548 /* If VR0 and VR1 represent a single value and are identical, 4549 return false. */ 4550 else if (compare_values_warnv (vr0->min, vr0->max, 4551 strict_overflow_p) == 0 4552 && compare_values_warnv (vr1->min, vr1->max, 4553 strict_overflow_p) == 0 4554 && compare_values_warnv (vr0->min, vr1->min, 4555 strict_overflow_p) == 0 4556 && compare_values_warnv (vr0->max, vr1->max, 4557 strict_overflow_p) == 0) 4558 return boolean_false_node; 4559 4560 /* Otherwise, they may or may not be different. */ 4561 else 4562 return NULL_TREE; 4563 } 4564 else if (comp == LT_EXPR || comp == LE_EXPR) 4565 { 4566 int tst; 4567 4568 /* If VR0 is to the left of VR1, return true. */ 4569 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p); 4570 if ((comp == LT_EXPR && tst == -1) 4571 || (comp == LE_EXPR && (tst == -1 || tst == 0))) 4572 { 4573 if (overflow_infinity_range_p (vr0) 4574 || overflow_infinity_range_p (vr1)) 4575 *strict_overflow_p = true; 4576 return boolean_true_node; 4577 } 4578 4579 /* If VR0 is to the right of VR1, return false. */ 4580 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p); 4581 if ((comp == LT_EXPR && (tst == 0 || tst == 1)) 4582 || (comp == LE_EXPR && tst == 1)) 4583 { 4584 if (overflow_infinity_range_p (vr0) 4585 || overflow_infinity_range_p (vr1)) 4586 *strict_overflow_p = true; 4587 return boolean_false_node; 4588 } 4589 4590 /* Otherwise, we don't know. */ 4591 return NULL_TREE; 4592 } 4593 4594 gcc_unreachable (); 4595 } 4596 4597 4598 /* Given a value range VR, a value VAL and a comparison code COMP, return 4599 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the 4600 values in VR. Return BOOLEAN_FALSE_NODE if the comparison 4601 always returns false. Return NULL_TREE if it is not always 4602 possible to determine the value of the comparison. Also set 4603 *STRICT_OVERFLOW_P to indicate whether a range with an overflow 4604 infinity was used in the test. */ 4605 4606 static tree 4607 compare_range_with_value (enum tree_code comp, value_range *vr, tree val, 4608 bool *strict_overflow_p) 4609 { 4610 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED) 4611 return NULL_TREE; 4612 4613 /* Anti-ranges need to be handled separately. */ 4614 if (vr->type == VR_ANTI_RANGE) 4615 { 4616 /* For anti-ranges, the only predicates that we can compute at 4617 compile time are equality and inequality. */ 4618 if (comp == GT_EXPR 4619 || comp == GE_EXPR 4620 || comp == LT_EXPR 4621 || comp == LE_EXPR) 4622 return NULL_TREE; 4623 4624 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */ 4625 if (value_inside_range (val, vr->min, vr->max) == 1) 4626 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node; 4627 4628 return NULL_TREE; 4629 } 4630 4631 if (!usable_range_p (vr, strict_overflow_p)) 4632 return NULL_TREE; 4633 4634 if (comp == EQ_EXPR) 4635 { 4636 /* EQ_EXPR may only be computed if VR represents exactly 4637 one value. */ 4638 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0) 4639 { 4640 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p); 4641 if (cmp == 0) 4642 return boolean_true_node; 4643 else if (cmp == -1 || cmp == 1 || cmp == 2) 4644 return boolean_false_node; 4645 } 4646 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1 4647 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1) 4648 return boolean_false_node; 4649 4650 return NULL_TREE; 4651 } 4652 else if (comp == NE_EXPR) 4653 { 4654 /* If VAL is not inside VR, then they are always different. */ 4655 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1 4656 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1) 4657 return boolean_true_node; 4658 4659 /* If VR represents exactly one value equal to VAL, then return 4660 false. */ 4661 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0 4662 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0) 4663 return boolean_false_node; 4664 4665 /* Otherwise, they may or may not be different. */ 4666 return NULL_TREE; 4667 } 4668 else if (comp == LT_EXPR || comp == LE_EXPR) 4669 { 4670 int tst; 4671 4672 /* If VR is to the left of VAL, return true. */ 4673 tst = compare_values_warnv (vr->max, val, strict_overflow_p); 4674 if ((comp == LT_EXPR && tst == -1) 4675 || (comp == LE_EXPR && (tst == -1 || tst == 0))) 4676 { 4677 if (overflow_infinity_range_p (vr)) 4678 *strict_overflow_p = true; 4679 return boolean_true_node; 4680 } 4681 4682 /* If VR is to the right of VAL, return false. */ 4683 tst = compare_values_warnv (vr->min, val, strict_overflow_p); 4684 if ((comp == LT_EXPR && (tst == 0 || tst == 1)) 4685 || (comp == LE_EXPR && tst == 1)) 4686 { 4687 if (overflow_infinity_range_p (vr)) 4688 *strict_overflow_p = true; 4689 return boolean_false_node; 4690 } 4691 4692 /* Otherwise, we don't know. */ 4693 return NULL_TREE; 4694 } 4695 else if (comp == GT_EXPR || comp == GE_EXPR) 4696 { 4697 int tst; 4698 4699 /* If VR is to the right of VAL, return true. */ 4700 tst = compare_values_warnv (vr->min, val, strict_overflow_p); 4701 if ((comp == GT_EXPR && tst == 1) 4702 || (comp == GE_EXPR && (tst == 0 || tst == 1))) 4703 { 4704 if (overflow_infinity_range_p (vr)) 4705 *strict_overflow_p = true; 4706 return boolean_true_node; 4707 } 4708 4709 /* If VR is to the left of VAL, return false. */ 4710 tst = compare_values_warnv (vr->max, val, strict_overflow_p); 4711 if ((comp == GT_EXPR && (tst == -1 || tst == 0)) 4712 || (comp == GE_EXPR && tst == -1)) 4713 { 4714 if (overflow_infinity_range_p (vr)) 4715 *strict_overflow_p = true; 4716 return boolean_false_node; 4717 } 4718 4719 /* Otherwise, we don't know. */ 4720 return NULL_TREE; 4721 } 4722 4723 gcc_unreachable (); 4724 } 4725 4726 4727 /* Debugging dumps. */ 4728 4729 void dump_value_range (FILE *, value_range *); 4730 void debug_value_range (value_range *); 4731 void dump_all_value_ranges (FILE *); 4732 void debug_all_value_ranges (void); 4733 void dump_vr_equiv (FILE *, bitmap); 4734 void debug_vr_equiv (bitmap); 4735 4736 4737 /* Dump value range VR to FILE. */ 4738 4739 void 4740 dump_value_range (FILE *file, value_range *vr) 4741 { 4742 if (vr == NULL) 4743 fprintf (file, "[]"); 4744 else if (vr->type == VR_UNDEFINED) 4745 fprintf (file, "UNDEFINED"); 4746 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE) 4747 { 4748 tree type = TREE_TYPE (vr->min); 4749 4750 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : ""); 4751 4752 if (is_negative_overflow_infinity (vr->min)) 4753 fprintf (file, "-INF(OVF)"); 4754 else if (INTEGRAL_TYPE_P (type) 4755 && !TYPE_UNSIGNED (type) 4756 && vrp_val_is_min (vr->min)) 4757 fprintf (file, "-INF"); 4758 else 4759 print_generic_expr (file, vr->min, 0); 4760 4761 fprintf (file, ", "); 4762 4763 if (is_positive_overflow_infinity (vr->max)) 4764 fprintf (file, "+INF(OVF)"); 4765 else if (INTEGRAL_TYPE_P (type) 4766 && vrp_val_is_max (vr->max)) 4767 fprintf (file, "+INF"); 4768 else 4769 print_generic_expr (file, vr->max, 0); 4770 4771 fprintf (file, "]"); 4772 4773 if (vr->equiv) 4774 { 4775 bitmap_iterator bi; 4776 unsigned i, c = 0; 4777 4778 fprintf (file, " EQUIVALENCES: { "); 4779 4780 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi) 4781 { 4782 print_generic_expr (file, ssa_name (i), 0); 4783 fprintf (file, " "); 4784 c++; 4785 } 4786 4787 fprintf (file, "} (%u elements)", c); 4788 } 4789 } 4790 else if (vr->type == VR_VARYING) 4791 fprintf (file, "VARYING"); 4792 else 4793 fprintf (file, "INVALID RANGE"); 4794 } 4795 4796 4797 /* Dump value range VR to stderr. */ 4798 4799 DEBUG_FUNCTION void 4800 debug_value_range (value_range *vr) 4801 { 4802 dump_value_range (stderr, vr); 4803 fprintf (stderr, "\n"); 4804 } 4805 4806 4807 /* Dump value ranges of all SSA_NAMEs to FILE. */ 4808 4809 void 4810 dump_all_value_ranges (FILE *file) 4811 { 4812 size_t i; 4813 4814 for (i = 0; i < num_vr_values; i++) 4815 { 4816 if (vr_value[i]) 4817 { 4818 print_generic_expr (file, ssa_name (i), 0); 4819 fprintf (file, ": "); 4820 dump_value_range (file, vr_value[i]); 4821 fprintf (file, "\n"); 4822 } 4823 } 4824 4825 fprintf (file, "\n"); 4826 } 4827 4828 4829 /* Dump all value ranges to stderr. */ 4830 4831 DEBUG_FUNCTION void 4832 debug_all_value_ranges (void) 4833 { 4834 dump_all_value_ranges (stderr); 4835 } 4836 4837 4838 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V, 4839 create a new SSA name N and return the assertion assignment 4840 'N = ASSERT_EXPR <V, V OP W>'. */ 4841 4842 static gimple * 4843 build_assert_expr_for (tree cond, tree v) 4844 { 4845 tree a; 4846 gassign *assertion; 4847 4848 gcc_assert (TREE_CODE (v) == SSA_NAME 4849 && COMPARISON_CLASS_P (cond)); 4850 4851 a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond); 4852 assertion = gimple_build_assign (NULL_TREE, a); 4853 4854 /* The new ASSERT_EXPR, creates a new SSA name that replaces the 4855 operand of the ASSERT_EXPR. Create it so the new name and the old one 4856 are registered in the replacement table so that we can fix the SSA web 4857 after adding all the ASSERT_EXPRs. */ 4858 create_new_def_for (v, assertion, NULL); 4859 4860 return assertion; 4861 } 4862 4863 4864 /* Return false if EXPR is a predicate expression involving floating 4865 point values. */ 4866 4867 static inline bool 4868 fp_predicate (gimple *stmt) 4869 { 4870 GIMPLE_CHECK (stmt, GIMPLE_COND); 4871 4872 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt))); 4873 } 4874 4875 /* If the range of values taken by OP can be inferred after STMT executes, 4876 return the comparison code (COMP_CODE_P) and value (VAL_P) that 4877 describes the inferred range. Return true if a range could be 4878 inferred. */ 4879 4880 static bool 4881 infer_value_range (gimple *stmt, tree op, tree_code *comp_code_p, tree *val_p) 4882 { 4883 *val_p = NULL_TREE; 4884 *comp_code_p = ERROR_MARK; 4885 4886 /* Do not attempt to infer anything in names that flow through 4887 abnormal edges. */ 4888 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op)) 4889 return false; 4890 4891 /* Similarly, don't infer anything from statements that may throw 4892 exceptions. ??? Relax this requirement? */ 4893 if (stmt_could_throw_p (stmt)) 4894 return false; 4895 4896 /* If STMT is the last statement of a basic block with no normal 4897 successors, there is no point inferring anything about any of its 4898 operands. We would not be able to find a proper insertion point 4899 for the assertion, anyway. */ 4900 if (stmt_ends_bb_p (stmt)) 4901 { 4902 edge_iterator ei; 4903 edge e; 4904 4905 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs) 4906 if (!(e->flags & EDGE_ABNORMAL)) 4907 break; 4908 if (e == NULL) 4909 return false; 4910 } 4911 4912 if (infer_nonnull_range (stmt, op)) 4913 { 4914 *val_p = build_int_cst (TREE_TYPE (op), 0); 4915 *comp_code_p = NE_EXPR; 4916 return true; 4917 } 4918 4919 return false; 4920 } 4921 4922 4923 void dump_asserts_for (FILE *, tree); 4924 void debug_asserts_for (tree); 4925 void dump_all_asserts (FILE *); 4926 void debug_all_asserts (void); 4927 4928 /* Dump all the registered assertions for NAME to FILE. */ 4929 4930 void 4931 dump_asserts_for (FILE *file, tree name) 4932 { 4933 assert_locus *loc; 4934 4935 fprintf (file, "Assertions to be inserted for "); 4936 print_generic_expr (file, name, 0); 4937 fprintf (file, "\n"); 4938 4939 loc = asserts_for[SSA_NAME_VERSION (name)]; 4940 while (loc) 4941 { 4942 fprintf (file, "\t"); 4943 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0); 4944 fprintf (file, "\n\tBB #%d", loc->bb->index); 4945 if (loc->e) 4946 { 4947 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index, 4948 loc->e->dest->index); 4949 dump_edge_info (file, loc->e, dump_flags, 0); 4950 } 4951 fprintf (file, "\n\tPREDICATE: "); 4952 print_generic_expr (file, name, 0); 4953 fprintf (file, " %s ", get_tree_code_name (loc->comp_code)); 4954 print_generic_expr (file, loc->val, 0); 4955 fprintf (file, "\n\n"); 4956 loc = loc->next; 4957 } 4958 4959 fprintf (file, "\n"); 4960 } 4961 4962 4963 /* Dump all the registered assertions for NAME to stderr. */ 4964 4965 DEBUG_FUNCTION void 4966 debug_asserts_for (tree name) 4967 { 4968 dump_asserts_for (stderr, name); 4969 } 4970 4971 4972 /* Dump all the registered assertions for all the names to FILE. */ 4973 4974 void 4975 dump_all_asserts (FILE *file) 4976 { 4977 unsigned i; 4978 bitmap_iterator bi; 4979 4980 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n"); 4981 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi) 4982 dump_asserts_for (file, ssa_name (i)); 4983 fprintf (file, "\n"); 4984 } 4985 4986 4987 /* Dump all the registered assertions for all the names to stderr. */ 4988 4989 DEBUG_FUNCTION void 4990 debug_all_asserts (void) 4991 { 4992 dump_all_asserts (stderr); 4993 } 4994 4995 4996 /* If NAME doesn't have an ASSERT_EXPR registered for asserting 4997 'EXPR COMP_CODE VAL' at a location that dominates block BB or 4998 E->DEST, then register this location as a possible insertion point 4999 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>. 5000 5001 BB, E and SI provide the exact insertion point for the new 5002 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted 5003 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on 5004 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E 5005 must not be NULL. */ 5006 5007 static void 5008 register_new_assert_for (tree name, tree expr, 5009 enum tree_code comp_code, 5010 tree val, 5011 basic_block bb, 5012 edge e, 5013 gimple_stmt_iterator si) 5014 { 5015 assert_locus *n, *loc, *last_loc; 5016 basic_block dest_bb; 5017 5018 gcc_checking_assert (bb == NULL || e == NULL); 5019 5020 if (e == NULL) 5021 gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND 5022 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH); 5023 5024 /* Never build an assert comparing against an integer constant with 5025 TREE_OVERFLOW set. This confuses our undefined overflow warning 5026 machinery. */ 5027 if (TREE_OVERFLOW_P (val)) 5028 val = drop_tree_overflow (val); 5029 5030 /* The new assertion A will be inserted at BB or E. We need to 5031 determine if the new location is dominated by a previously 5032 registered location for A. If we are doing an edge insertion, 5033 assume that A will be inserted at E->DEST. Note that this is not 5034 necessarily true. 5035 5036 If E is a critical edge, it will be split. But even if E is 5037 split, the new block will dominate the same set of blocks that 5038 E->DEST dominates. 5039 5040 The reverse, however, is not true, blocks dominated by E->DEST 5041 will not be dominated by the new block created to split E. So, 5042 if the insertion location is on a critical edge, we will not use 5043 the new location to move another assertion previously registered 5044 at a block dominated by E->DEST. */ 5045 dest_bb = (bb) ? bb : e->dest; 5046 5047 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and 5048 VAL at a block dominating DEST_BB, then we don't need to insert a new 5049 one. Similarly, if the same assertion already exists at a block 5050 dominated by DEST_BB and the new location is not on a critical 5051 edge, then update the existing location for the assertion (i.e., 5052 move the assertion up in the dominance tree). 5053 5054 Note, this is implemented as a simple linked list because there 5055 should not be more than a handful of assertions registered per 5056 name. If this becomes a performance problem, a table hashed by 5057 COMP_CODE and VAL could be implemented. */ 5058 loc = asserts_for[SSA_NAME_VERSION (name)]; 5059 last_loc = loc; 5060 while (loc) 5061 { 5062 if (loc->comp_code == comp_code 5063 && (loc->val == val 5064 || operand_equal_p (loc->val, val, 0)) 5065 && (loc->expr == expr 5066 || operand_equal_p (loc->expr, expr, 0))) 5067 { 5068 /* If E is not a critical edge and DEST_BB 5069 dominates the existing location for the assertion, move 5070 the assertion up in the dominance tree by updating its 5071 location information. */ 5072 if ((e == NULL || !EDGE_CRITICAL_P (e)) 5073 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb)) 5074 { 5075 loc->bb = dest_bb; 5076 loc->e = e; 5077 loc->si = si; 5078 return; 5079 } 5080 } 5081 5082 /* Update the last node of the list and move to the next one. */ 5083 last_loc = loc; 5084 loc = loc->next; 5085 } 5086 5087 /* If we didn't find an assertion already registered for 5088 NAME COMP_CODE VAL, add a new one at the end of the list of 5089 assertions associated with NAME. */ 5090 n = XNEW (struct assert_locus); 5091 n->bb = dest_bb; 5092 n->e = e; 5093 n->si = si; 5094 n->comp_code = comp_code; 5095 n->val = val; 5096 n->expr = expr; 5097 n->next = NULL; 5098 5099 if (last_loc) 5100 last_loc->next = n; 5101 else 5102 asserts_for[SSA_NAME_VERSION (name)] = n; 5103 5104 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name)); 5105 } 5106 5107 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME. 5108 Extract a suitable test code and value and store them into *CODE_P and 5109 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P. 5110 5111 If no extraction was possible, return FALSE, otherwise return TRUE. 5112 5113 If INVERT is true, then we invert the result stored into *CODE_P. */ 5114 5115 static bool 5116 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code, 5117 tree cond_op0, tree cond_op1, 5118 bool invert, enum tree_code *code_p, 5119 tree *val_p) 5120 { 5121 enum tree_code comp_code; 5122 tree val; 5123 5124 /* Otherwise, we have a comparison of the form NAME COMP VAL 5125 or VAL COMP NAME. */ 5126 if (name == cond_op1) 5127 { 5128 /* If the predicate is of the form VAL COMP NAME, flip 5129 COMP around because we need to register NAME as the 5130 first operand in the predicate. */ 5131 comp_code = swap_tree_comparison (cond_code); 5132 val = cond_op0; 5133 } 5134 else 5135 { 5136 /* The comparison is of the form NAME COMP VAL, so the 5137 comparison code remains unchanged. */ 5138 comp_code = cond_code; 5139 val = cond_op1; 5140 } 5141 5142 /* Invert the comparison code as necessary. */ 5143 if (invert) 5144 comp_code = invert_tree_comparison (comp_code, 0); 5145 5146 /* VRP only handles integral and pointer types. */ 5147 if (! INTEGRAL_TYPE_P (TREE_TYPE (val)) 5148 && ! POINTER_TYPE_P (TREE_TYPE (val))) 5149 return false; 5150 5151 /* Do not register always-false predicates. 5152 FIXME: this works around a limitation in fold() when dealing with 5153 enumerations. Given 'enum { N1, N2 } x;', fold will not 5154 fold 'if (x > N2)' to 'if (0)'. */ 5155 if ((comp_code == GT_EXPR || comp_code == LT_EXPR) 5156 && INTEGRAL_TYPE_P (TREE_TYPE (val))) 5157 { 5158 tree min = TYPE_MIN_VALUE (TREE_TYPE (val)); 5159 tree max = TYPE_MAX_VALUE (TREE_TYPE (val)); 5160 5161 if (comp_code == GT_EXPR 5162 && (!max 5163 || compare_values (val, max) == 0)) 5164 return false; 5165 5166 if (comp_code == LT_EXPR 5167 && (!min 5168 || compare_values (val, min) == 0)) 5169 return false; 5170 } 5171 *code_p = comp_code; 5172 *val_p = val; 5173 return true; 5174 } 5175 5176 /* Find out smallest RES where RES > VAL && (RES & MASK) == RES, if any 5177 (otherwise return VAL). VAL and MASK must be zero-extended for 5178 precision PREC. If SGNBIT is non-zero, first xor VAL with SGNBIT 5179 (to transform signed values into unsigned) and at the end xor 5180 SGNBIT back. */ 5181 5182 static wide_int 5183 masked_increment (const wide_int &val_in, const wide_int &mask, 5184 const wide_int &sgnbit, unsigned int prec) 5185 { 5186 wide_int bit = wi::one (prec), res; 5187 unsigned int i; 5188 5189 wide_int val = val_in ^ sgnbit; 5190 for (i = 0; i < prec; i++, bit += bit) 5191 { 5192 res = mask; 5193 if ((res & bit) == 0) 5194 continue; 5195 res = bit - 1; 5196 res = (val + bit).and_not (res); 5197 res &= mask; 5198 if (wi::gtu_p (res, val)) 5199 return res ^ sgnbit; 5200 } 5201 return val ^ sgnbit; 5202 } 5203 5204 /* Try to register an edge assertion for SSA name NAME on edge E for 5205 the condition COND contributing to the conditional jump pointed to by BSI. 5206 Invert the condition COND if INVERT is true. */ 5207 5208 static void 5209 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi, 5210 enum tree_code cond_code, 5211 tree cond_op0, tree cond_op1, bool invert) 5212 { 5213 tree val; 5214 enum tree_code comp_code; 5215 5216 if (!extract_code_and_val_from_cond_with_ops (name, cond_code, 5217 cond_op0, 5218 cond_op1, 5219 invert, &comp_code, &val)) 5220 return; 5221 5222 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph 5223 reachable from E. */ 5224 if (live_on_edge (e, name) 5225 && !has_single_use (name)) 5226 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi); 5227 5228 /* In the case of NAME <= CST and NAME being defined as 5229 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2 5230 and NAME2 <= CST - CST2. We can do the same for NAME > CST. 5231 This catches range and anti-range tests. */ 5232 if ((comp_code == LE_EXPR 5233 || comp_code == GT_EXPR) 5234 && TREE_CODE (val) == INTEGER_CST 5235 && TYPE_UNSIGNED (TREE_TYPE (val))) 5236 { 5237 gimple *def_stmt = SSA_NAME_DEF_STMT (name); 5238 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE; 5239 5240 /* Extract CST2 from the (optional) addition. */ 5241 if (is_gimple_assign (def_stmt) 5242 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR) 5243 { 5244 name2 = gimple_assign_rhs1 (def_stmt); 5245 cst2 = gimple_assign_rhs2 (def_stmt); 5246 if (TREE_CODE (name2) == SSA_NAME 5247 && TREE_CODE (cst2) == INTEGER_CST) 5248 def_stmt = SSA_NAME_DEF_STMT (name2); 5249 } 5250 5251 /* Extract NAME2 from the (optional) sign-changing cast. */ 5252 if (gimple_assign_cast_p (def_stmt)) 5253 { 5254 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)) 5255 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt))) 5256 && (TYPE_PRECISION (gimple_expr_type (def_stmt)) 5257 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))) 5258 name3 = gimple_assign_rhs1 (def_stmt); 5259 } 5260 5261 /* If name3 is used later, create an ASSERT_EXPR for it. */ 5262 if (name3 != NULL_TREE 5263 && TREE_CODE (name3) == SSA_NAME 5264 && (cst2 == NULL_TREE 5265 || TREE_CODE (cst2) == INTEGER_CST) 5266 && INTEGRAL_TYPE_P (TREE_TYPE (name3)) 5267 && live_on_edge (e, name3) 5268 && !has_single_use (name3)) 5269 { 5270 tree tmp; 5271 5272 /* Build an expression for the range test. */ 5273 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3); 5274 if (cst2 != NULL_TREE) 5275 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2); 5276 5277 if (dump_file) 5278 { 5279 fprintf (dump_file, "Adding assert for "); 5280 print_generic_expr (dump_file, name3, 0); 5281 fprintf (dump_file, " from "); 5282 print_generic_expr (dump_file, tmp, 0); 5283 fprintf (dump_file, "\n"); 5284 } 5285 5286 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi); 5287 } 5288 5289 /* If name2 is used later, create an ASSERT_EXPR for it. */ 5290 if (name2 != NULL_TREE 5291 && TREE_CODE (name2) == SSA_NAME 5292 && TREE_CODE (cst2) == INTEGER_CST 5293 && INTEGRAL_TYPE_P (TREE_TYPE (name2)) 5294 && live_on_edge (e, name2) 5295 && !has_single_use (name2)) 5296 { 5297 tree tmp; 5298 5299 /* Build an expression for the range test. */ 5300 tmp = name2; 5301 if (TREE_TYPE (name) != TREE_TYPE (name2)) 5302 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp); 5303 if (cst2 != NULL_TREE) 5304 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2); 5305 5306 if (dump_file) 5307 { 5308 fprintf (dump_file, "Adding assert for "); 5309 print_generic_expr (dump_file, name2, 0); 5310 fprintf (dump_file, " from "); 5311 print_generic_expr (dump_file, tmp, 0); 5312 fprintf (dump_file, "\n"); 5313 } 5314 5315 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi); 5316 } 5317 } 5318 5319 /* In the case of post-in/decrement tests like if (i++) ... and uses 5320 of the in/decremented value on the edge the extra name we want to 5321 assert for is not on the def chain of the name compared. Instead 5322 it is in the set of use stmts. 5323 Similar cases happen for conversions that were simplified through 5324 fold_{sign_changed,widened}_comparison. */ 5325 if ((comp_code == NE_EXPR 5326 || comp_code == EQ_EXPR) 5327 && TREE_CODE (val) == INTEGER_CST) 5328 { 5329 imm_use_iterator ui; 5330 gimple *use_stmt; 5331 FOR_EACH_IMM_USE_STMT (use_stmt, ui, name) 5332 { 5333 if (!is_gimple_assign (use_stmt)) 5334 continue; 5335 5336 /* Cut off to use-stmts that are dominating the predecessor. */ 5337 if (!dominated_by_p (CDI_DOMINATORS, e->src, gimple_bb (use_stmt))) 5338 continue; 5339 5340 tree name2 = gimple_assign_lhs (use_stmt); 5341 if (TREE_CODE (name2) != SSA_NAME 5342 || !live_on_edge (e, name2)) 5343 continue; 5344 5345 enum tree_code code = gimple_assign_rhs_code (use_stmt); 5346 tree cst; 5347 if (code == PLUS_EXPR 5348 || code == MINUS_EXPR) 5349 { 5350 cst = gimple_assign_rhs2 (use_stmt); 5351 if (TREE_CODE (cst) != INTEGER_CST) 5352 continue; 5353 cst = int_const_binop (code, val, cst); 5354 } 5355 else if (CONVERT_EXPR_CODE_P (code)) 5356 { 5357 /* For truncating conversions we cannot record 5358 an inequality. */ 5359 if (comp_code == NE_EXPR 5360 && (TYPE_PRECISION (TREE_TYPE (name2)) 5361 < TYPE_PRECISION (TREE_TYPE (name)))) 5362 continue; 5363 cst = fold_convert (TREE_TYPE (name2), val); 5364 } 5365 else 5366 continue; 5367 5368 if (TREE_OVERFLOW_P (cst)) 5369 cst = drop_tree_overflow (cst); 5370 register_new_assert_for (name2, name2, comp_code, cst, 5371 NULL, e, bsi); 5372 } 5373 } 5374 5375 if (TREE_CODE_CLASS (comp_code) == tcc_comparison 5376 && TREE_CODE (val) == INTEGER_CST) 5377 { 5378 gimple *def_stmt = SSA_NAME_DEF_STMT (name); 5379 tree name2 = NULL_TREE, names[2], cst2 = NULL_TREE; 5380 tree val2 = NULL_TREE; 5381 unsigned int prec = TYPE_PRECISION (TREE_TYPE (val)); 5382 wide_int mask = wi::zero (prec); 5383 unsigned int nprec = prec; 5384 enum tree_code rhs_code = ERROR_MARK; 5385 5386 if (is_gimple_assign (def_stmt)) 5387 rhs_code = gimple_assign_rhs_code (def_stmt); 5388 5389 /* In the case of NAME != CST1 where NAME = A +- CST2 we can 5390 assert that A != CST1 -+ CST2. */ 5391 if ((comp_code == EQ_EXPR || comp_code == NE_EXPR) 5392 && (rhs_code == PLUS_EXPR || rhs_code == MINUS_EXPR)) 5393 { 5394 tree op0 = gimple_assign_rhs1 (def_stmt); 5395 tree op1 = gimple_assign_rhs2 (def_stmt); 5396 if (TREE_CODE (op0) == SSA_NAME 5397 && TREE_CODE (op1) == INTEGER_CST 5398 && live_on_edge (e, op0) 5399 && !has_single_use (op0)) 5400 { 5401 enum tree_code reverse_op = (rhs_code == PLUS_EXPR 5402 ? MINUS_EXPR : PLUS_EXPR); 5403 op1 = int_const_binop (reverse_op, val, op1); 5404 if (TREE_OVERFLOW (op1)) 5405 op1 = drop_tree_overflow (op1); 5406 register_new_assert_for (op0, op0, comp_code, op1, NULL, e, bsi); 5407 } 5408 } 5409 5410 /* Add asserts for NAME cmp CST and NAME being defined 5411 as NAME = (int) NAME2. */ 5412 if (!TYPE_UNSIGNED (TREE_TYPE (val)) 5413 && (comp_code == LE_EXPR || comp_code == LT_EXPR 5414 || comp_code == GT_EXPR || comp_code == GE_EXPR) 5415 && gimple_assign_cast_p (def_stmt)) 5416 { 5417 name2 = gimple_assign_rhs1 (def_stmt); 5418 if (CONVERT_EXPR_CODE_P (rhs_code) 5419 && INTEGRAL_TYPE_P (TREE_TYPE (name2)) 5420 && TYPE_UNSIGNED (TREE_TYPE (name2)) 5421 && prec == TYPE_PRECISION (TREE_TYPE (name2)) 5422 && (comp_code == LE_EXPR || comp_code == GT_EXPR 5423 || !tree_int_cst_equal (val, 5424 TYPE_MIN_VALUE (TREE_TYPE (val)))) 5425 && live_on_edge (e, name2) 5426 && !has_single_use (name2)) 5427 { 5428 tree tmp, cst; 5429 enum tree_code new_comp_code = comp_code; 5430 5431 cst = fold_convert (TREE_TYPE (name2), 5432 TYPE_MIN_VALUE (TREE_TYPE (val))); 5433 /* Build an expression for the range test. */ 5434 tmp = build2 (PLUS_EXPR, TREE_TYPE (name2), name2, cst); 5435 cst = fold_build2 (PLUS_EXPR, TREE_TYPE (name2), cst, 5436 fold_convert (TREE_TYPE (name2), val)); 5437 if (comp_code == LT_EXPR || comp_code == GE_EXPR) 5438 { 5439 new_comp_code = comp_code == LT_EXPR ? LE_EXPR : GT_EXPR; 5440 cst = fold_build2 (MINUS_EXPR, TREE_TYPE (name2), cst, 5441 build_int_cst (TREE_TYPE (name2), 1)); 5442 } 5443 5444 if (dump_file) 5445 { 5446 fprintf (dump_file, "Adding assert for "); 5447 print_generic_expr (dump_file, name2, 0); 5448 fprintf (dump_file, " from "); 5449 print_generic_expr (dump_file, tmp, 0); 5450 fprintf (dump_file, "\n"); 5451 } 5452 5453 register_new_assert_for (name2, tmp, new_comp_code, cst, NULL, 5454 e, bsi); 5455 } 5456 } 5457 5458 /* Add asserts for NAME cmp CST and NAME being defined as 5459 NAME = NAME2 >> CST2. 5460 5461 Extract CST2 from the right shift. */ 5462 if (rhs_code == RSHIFT_EXPR) 5463 { 5464 name2 = gimple_assign_rhs1 (def_stmt); 5465 cst2 = gimple_assign_rhs2 (def_stmt); 5466 if (TREE_CODE (name2) == SSA_NAME 5467 && tree_fits_uhwi_p (cst2) 5468 && INTEGRAL_TYPE_P (TREE_TYPE (name2)) 5469 && IN_RANGE (tree_to_uhwi (cst2), 1, prec - 1) 5470 && prec == GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (val))) 5471 && live_on_edge (e, name2) 5472 && !has_single_use (name2)) 5473 { 5474 mask = wi::mask (tree_to_uhwi (cst2), false, prec); 5475 val2 = fold_binary (LSHIFT_EXPR, TREE_TYPE (val), val, cst2); 5476 } 5477 } 5478 if (val2 != NULL_TREE 5479 && TREE_CODE (val2) == INTEGER_CST 5480 && simple_cst_equal (fold_build2 (RSHIFT_EXPR, 5481 TREE_TYPE (val), 5482 val2, cst2), val)) 5483 { 5484 enum tree_code new_comp_code = comp_code; 5485 tree tmp, new_val; 5486 5487 tmp = name2; 5488 if (comp_code == EQ_EXPR || comp_code == NE_EXPR) 5489 { 5490 if (!TYPE_UNSIGNED (TREE_TYPE (val))) 5491 { 5492 tree type = build_nonstandard_integer_type (prec, 1); 5493 tmp = build1 (NOP_EXPR, type, name2); 5494 val2 = fold_convert (type, val2); 5495 } 5496 tmp = fold_build2 (MINUS_EXPR, TREE_TYPE (tmp), tmp, val2); 5497 new_val = wide_int_to_tree (TREE_TYPE (tmp), mask); 5498 new_comp_code = comp_code == EQ_EXPR ? LE_EXPR : GT_EXPR; 5499 } 5500 else if (comp_code == LT_EXPR || comp_code == GE_EXPR) 5501 { 5502 wide_int minval 5503 = wi::min_value (prec, TYPE_SIGN (TREE_TYPE (val))); 5504 new_val = val2; 5505 if (minval == new_val) 5506 new_val = NULL_TREE; 5507 } 5508 else 5509 { 5510 wide_int maxval 5511 = wi::max_value (prec, TYPE_SIGN (TREE_TYPE (val))); 5512 mask |= val2; 5513 if (mask == maxval) 5514 new_val = NULL_TREE; 5515 else 5516 new_val = wide_int_to_tree (TREE_TYPE (val2), mask); 5517 } 5518 5519 if (new_val) 5520 { 5521 if (dump_file) 5522 { 5523 fprintf (dump_file, "Adding assert for "); 5524 print_generic_expr (dump_file, name2, 0); 5525 fprintf (dump_file, " from "); 5526 print_generic_expr (dump_file, tmp, 0); 5527 fprintf (dump_file, "\n"); 5528 } 5529 5530 register_new_assert_for (name2, tmp, new_comp_code, new_val, 5531 NULL, e, bsi); 5532 } 5533 } 5534 5535 /* Add asserts for NAME cmp CST and NAME being defined as 5536 NAME = NAME2 & CST2. 5537 5538 Extract CST2 from the and. 5539 5540 Also handle 5541 NAME = (unsigned) NAME2; 5542 casts where NAME's type is unsigned and has smaller precision 5543 than NAME2's type as if it was NAME = NAME2 & MASK. */ 5544 names[0] = NULL_TREE; 5545 names[1] = NULL_TREE; 5546 cst2 = NULL_TREE; 5547 if (rhs_code == BIT_AND_EXPR 5548 || (CONVERT_EXPR_CODE_P (rhs_code) 5549 && INTEGRAL_TYPE_P (TREE_TYPE (val)) 5550 && TYPE_UNSIGNED (TREE_TYPE (val)) 5551 && TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt))) 5552 > prec)) 5553 { 5554 name2 = gimple_assign_rhs1 (def_stmt); 5555 if (rhs_code == BIT_AND_EXPR) 5556 cst2 = gimple_assign_rhs2 (def_stmt); 5557 else 5558 { 5559 cst2 = TYPE_MAX_VALUE (TREE_TYPE (val)); 5560 nprec = TYPE_PRECISION (TREE_TYPE (name2)); 5561 } 5562 if (TREE_CODE (name2) == SSA_NAME 5563 && INTEGRAL_TYPE_P (TREE_TYPE (name2)) 5564 && TREE_CODE (cst2) == INTEGER_CST 5565 && !integer_zerop (cst2) 5566 && (nprec > 1 5567 || TYPE_UNSIGNED (TREE_TYPE (val)))) 5568 { 5569 gimple *def_stmt2 = SSA_NAME_DEF_STMT (name2); 5570 if (gimple_assign_cast_p (def_stmt2)) 5571 { 5572 names[1] = gimple_assign_rhs1 (def_stmt2); 5573 if (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt2)) 5574 || !INTEGRAL_TYPE_P (TREE_TYPE (names[1])) 5575 || (TYPE_PRECISION (TREE_TYPE (name2)) 5576 != TYPE_PRECISION (TREE_TYPE (names[1]))) 5577 || !live_on_edge (e, names[1]) 5578 || has_single_use (names[1])) 5579 names[1] = NULL_TREE; 5580 } 5581 if (live_on_edge (e, name2) 5582 && !has_single_use (name2)) 5583 names[0] = name2; 5584 } 5585 } 5586 if (names[0] || names[1]) 5587 { 5588 wide_int minv, maxv, valv, cst2v; 5589 wide_int tem, sgnbit; 5590 bool valid_p = false, valn, cst2n; 5591 enum tree_code ccode = comp_code; 5592 5593 valv = wide_int::from (val, nprec, UNSIGNED); 5594 cst2v = wide_int::from (cst2, nprec, UNSIGNED); 5595 valn = wi::neg_p (valv, TYPE_SIGN (TREE_TYPE (val))); 5596 cst2n = wi::neg_p (cst2v, TYPE_SIGN (TREE_TYPE (val))); 5597 /* If CST2 doesn't have most significant bit set, 5598 but VAL is negative, we have comparison like 5599 if ((x & 0x123) > -4) (always true). Just give up. */ 5600 if (!cst2n && valn) 5601 ccode = ERROR_MARK; 5602 if (cst2n) 5603 sgnbit = wi::set_bit_in_zero (nprec - 1, nprec); 5604 else 5605 sgnbit = wi::zero (nprec); 5606 minv = valv & cst2v; 5607 switch (ccode) 5608 { 5609 case EQ_EXPR: 5610 /* Minimum unsigned value for equality is VAL & CST2 5611 (should be equal to VAL, otherwise we probably should 5612 have folded the comparison into false) and 5613 maximum unsigned value is VAL | ~CST2. */ 5614 maxv = valv | ~cst2v; 5615 valid_p = true; 5616 break; 5617 5618 case NE_EXPR: 5619 tem = valv | ~cst2v; 5620 /* If VAL is 0, handle (X & CST2) != 0 as (X & CST2) > 0U. */ 5621 if (valv == 0) 5622 { 5623 cst2n = false; 5624 sgnbit = wi::zero (nprec); 5625 goto gt_expr; 5626 } 5627 /* If (VAL | ~CST2) is all ones, handle it as 5628 (X & CST2) < VAL. */ 5629 if (tem == -1) 5630 { 5631 cst2n = false; 5632 valn = false; 5633 sgnbit = wi::zero (nprec); 5634 goto lt_expr; 5635 } 5636 if (!cst2n && wi::neg_p (cst2v)) 5637 sgnbit = wi::set_bit_in_zero (nprec - 1, nprec); 5638 if (sgnbit != 0) 5639 { 5640 if (valv == sgnbit) 5641 { 5642 cst2n = true; 5643 valn = true; 5644 goto gt_expr; 5645 } 5646 if (tem == wi::mask (nprec - 1, false, nprec)) 5647 { 5648 cst2n = true; 5649 goto lt_expr; 5650 } 5651 if (!cst2n) 5652 sgnbit = wi::zero (nprec); 5653 } 5654 break; 5655 5656 case GE_EXPR: 5657 /* Minimum unsigned value for >= if (VAL & CST2) == VAL 5658 is VAL and maximum unsigned value is ~0. For signed 5659 comparison, if CST2 doesn't have most significant bit 5660 set, handle it similarly. If CST2 has MSB set, 5661 the minimum is the same, and maximum is ~0U/2. */ 5662 if (minv != valv) 5663 { 5664 /* If (VAL & CST2) != VAL, X & CST2 can't be equal to 5665 VAL. */ 5666 minv = masked_increment (valv, cst2v, sgnbit, nprec); 5667 if (minv == valv) 5668 break; 5669 } 5670 maxv = wi::mask (nprec - (cst2n ? 1 : 0), false, nprec); 5671 valid_p = true; 5672 break; 5673 5674 case GT_EXPR: 5675 gt_expr: 5676 /* Find out smallest MINV where MINV > VAL 5677 && (MINV & CST2) == MINV, if any. If VAL is signed and 5678 CST2 has MSB set, compute it biased by 1 << (nprec - 1). */ 5679 minv = masked_increment (valv, cst2v, sgnbit, nprec); 5680 if (minv == valv) 5681 break; 5682 maxv = wi::mask (nprec - (cst2n ? 1 : 0), false, nprec); 5683 valid_p = true; 5684 break; 5685 5686 case LE_EXPR: 5687 /* Minimum unsigned value for <= is 0 and maximum 5688 unsigned value is VAL | ~CST2 if (VAL & CST2) == VAL. 5689 Otherwise, find smallest VAL2 where VAL2 > VAL 5690 && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2 5691 as maximum. 5692 For signed comparison, if CST2 doesn't have most 5693 significant bit set, handle it similarly. If CST2 has 5694 MSB set, the maximum is the same and minimum is INT_MIN. */ 5695 if (minv == valv) 5696 maxv = valv; 5697 else 5698 { 5699 maxv = masked_increment (valv, cst2v, sgnbit, nprec); 5700 if (maxv == valv) 5701 break; 5702 maxv -= 1; 5703 } 5704 maxv |= ~cst2v; 5705 minv = sgnbit; 5706 valid_p = true; 5707 break; 5708 5709 case LT_EXPR: 5710 lt_expr: 5711 /* Minimum unsigned value for < is 0 and maximum 5712 unsigned value is (VAL-1) | ~CST2 if (VAL & CST2) == VAL. 5713 Otherwise, find smallest VAL2 where VAL2 > VAL 5714 && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2 5715 as maximum. 5716 For signed comparison, if CST2 doesn't have most 5717 significant bit set, handle it similarly. If CST2 has 5718 MSB set, the maximum is the same and minimum is INT_MIN. */ 5719 if (minv == valv) 5720 { 5721 if (valv == sgnbit) 5722 break; 5723 maxv = valv; 5724 } 5725 else 5726 { 5727 maxv = masked_increment (valv, cst2v, sgnbit, nprec); 5728 if (maxv == valv) 5729 break; 5730 } 5731 maxv -= 1; 5732 maxv |= ~cst2v; 5733 minv = sgnbit; 5734 valid_p = true; 5735 break; 5736 5737 default: 5738 break; 5739 } 5740 if (valid_p 5741 && (maxv - minv) != -1) 5742 { 5743 tree tmp, new_val, type; 5744 int i; 5745 5746 for (i = 0; i < 2; i++) 5747 if (names[i]) 5748 { 5749 wide_int maxv2 = maxv; 5750 tmp = names[i]; 5751 type = TREE_TYPE (names[i]); 5752 if (!TYPE_UNSIGNED (type)) 5753 { 5754 type = build_nonstandard_integer_type (nprec, 1); 5755 tmp = build1 (NOP_EXPR, type, names[i]); 5756 } 5757 if (minv != 0) 5758 { 5759 tmp = build2 (PLUS_EXPR, type, tmp, 5760 wide_int_to_tree (type, -minv)); 5761 maxv2 = maxv - minv; 5762 } 5763 new_val = wide_int_to_tree (type, maxv2); 5764 5765 if (dump_file) 5766 { 5767 fprintf (dump_file, "Adding assert for "); 5768 print_generic_expr (dump_file, names[i], 0); 5769 fprintf (dump_file, " from "); 5770 print_generic_expr (dump_file, tmp, 0); 5771 fprintf (dump_file, "\n"); 5772 } 5773 5774 register_new_assert_for (names[i], tmp, LE_EXPR, 5775 new_val, NULL, e, bsi); 5776 } 5777 } 5778 } 5779 } 5780 } 5781 5782 /* OP is an operand of a truth value expression which is known to have 5783 a particular value. Register any asserts for OP and for any 5784 operands in OP's defining statement. 5785 5786 If CODE is EQ_EXPR, then we want to register OP is zero (false), 5787 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */ 5788 5789 static void 5790 register_edge_assert_for_1 (tree op, enum tree_code code, 5791 edge e, gimple_stmt_iterator bsi) 5792 { 5793 gimple *op_def; 5794 tree val; 5795 enum tree_code rhs_code; 5796 5797 /* We only care about SSA_NAMEs. */ 5798 if (TREE_CODE (op) != SSA_NAME) 5799 return; 5800 5801 /* We know that OP will have a zero or nonzero value. If OP is used 5802 more than once go ahead and register an assert for OP. */ 5803 if (live_on_edge (e, op) 5804 && !has_single_use (op)) 5805 { 5806 val = build_int_cst (TREE_TYPE (op), 0); 5807 register_new_assert_for (op, op, code, val, NULL, e, bsi); 5808 } 5809 5810 /* Now look at how OP is set. If it's set from a comparison, 5811 a truth operation or some bit operations, then we may be able 5812 to register information about the operands of that assignment. */ 5813 op_def = SSA_NAME_DEF_STMT (op); 5814 if (gimple_code (op_def) != GIMPLE_ASSIGN) 5815 return; 5816 5817 rhs_code = gimple_assign_rhs_code (op_def); 5818 5819 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison) 5820 { 5821 bool invert = (code == EQ_EXPR ? true : false); 5822 tree op0 = gimple_assign_rhs1 (op_def); 5823 tree op1 = gimple_assign_rhs2 (op_def); 5824 5825 if (TREE_CODE (op0) == SSA_NAME) 5826 register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1, invert); 5827 if (TREE_CODE (op1) == SSA_NAME) 5828 register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1, invert); 5829 } 5830 else if ((code == NE_EXPR 5831 && gimple_assign_rhs_code (op_def) == BIT_AND_EXPR) 5832 || (code == EQ_EXPR 5833 && gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)) 5834 { 5835 /* Recurse on each operand. */ 5836 tree op0 = gimple_assign_rhs1 (op_def); 5837 tree op1 = gimple_assign_rhs2 (op_def); 5838 if (TREE_CODE (op0) == SSA_NAME 5839 && has_single_use (op0)) 5840 register_edge_assert_for_1 (op0, code, e, bsi); 5841 if (TREE_CODE (op1) == SSA_NAME 5842 && has_single_use (op1)) 5843 register_edge_assert_for_1 (op1, code, e, bsi); 5844 } 5845 else if (gimple_assign_rhs_code (op_def) == BIT_NOT_EXPR 5846 && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def))) == 1) 5847 { 5848 /* Recurse, flipping CODE. */ 5849 code = invert_tree_comparison (code, false); 5850 register_edge_assert_for_1 (gimple_assign_rhs1 (op_def), code, e, bsi); 5851 } 5852 else if (gimple_assign_rhs_code (op_def) == SSA_NAME) 5853 { 5854 /* Recurse through the copy. */ 5855 register_edge_assert_for_1 (gimple_assign_rhs1 (op_def), code, e, bsi); 5856 } 5857 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def))) 5858 { 5859 /* Recurse through the type conversion, unless it is a narrowing 5860 conversion or conversion from non-integral type. */ 5861 tree rhs = gimple_assign_rhs1 (op_def); 5862 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs)) 5863 && (TYPE_PRECISION (TREE_TYPE (rhs)) 5864 <= TYPE_PRECISION (TREE_TYPE (op)))) 5865 register_edge_assert_for_1 (rhs, code, e, bsi); 5866 } 5867 } 5868 5869 /* Try to register an edge assertion for SSA name NAME on edge E for 5870 the condition COND contributing to the conditional jump pointed to by 5871 SI. */ 5872 5873 static void 5874 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si, 5875 enum tree_code cond_code, tree cond_op0, 5876 tree cond_op1) 5877 { 5878 tree val; 5879 enum tree_code comp_code; 5880 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0; 5881 5882 /* Do not attempt to infer anything in names that flow through 5883 abnormal edges. */ 5884 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name)) 5885 return; 5886 5887 if (!extract_code_and_val_from_cond_with_ops (name, cond_code, 5888 cond_op0, cond_op1, 5889 is_else_edge, 5890 &comp_code, &val)) 5891 return; 5892 5893 /* Register ASSERT_EXPRs for name. */ 5894 register_edge_assert_for_2 (name, e, si, cond_code, cond_op0, 5895 cond_op1, is_else_edge); 5896 5897 5898 /* If COND is effectively an equality test of an SSA_NAME against 5899 the value zero or one, then we may be able to assert values 5900 for SSA_NAMEs which flow into COND. */ 5901 5902 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining 5903 statement of NAME we can assert both operands of the BIT_AND_EXPR 5904 have nonzero value. */ 5905 if (((comp_code == EQ_EXPR && integer_onep (val)) 5906 || (comp_code == NE_EXPR && integer_zerop (val)))) 5907 { 5908 gimple *def_stmt = SSA_NAME_DEF_STMT (name); 5909 5910 if (is_gimple_assign (def_stmt) 5911 && gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR) 5912 { 5913 tree op0 = gimple_assign_rhs1 (def_stmt); 5914 tree op1 = gimple_assign_rhs2 (def_stmt); 5915 register_edge_assert_for_1 (op0, NE_EXPR, e, si); 5916 register_edge_assert_for_1 (op1, NE_EXPR, e, si); 5917 } 5918 } 5919 5920 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining 5921 statement of NAME we can assert both operands of the BIT_IOR_EXPR 5922 have zero value. */ 5923 if (((comp_code == EQ_EXPR && integer_zerop (val)) 5924 || (comp_code == NE_EXPR && integer_onep (val)))) 5925 { 5926 gimple *def_stmt = SSA_NAME_DEF_STMT (name); 5927 5928 /* For BIT_IOR_EXPR only if NAME == 0 both operands have 5929 necessarily zero value, or if type-precision is one. */ 5930 if (is_gimple_assign (def_stmt) 5931 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR 5932 && (TYPE_PRECISION (TREE_TYPE (name)) == 1 5933 || comp_code == EQ_EXPR))) 5934 { 5935 tree op0 = gimple_assign_rhs1 (def_stmt); 5936 tree op1 = gimple_assign_rhs2 (def_stmt); 5937 register_edge_assert_for_1 (op0, EQ_EXPR, e, si); 5938 register_edge_assert_for_1 (op1, EQ_EXPR, e, si); 5939 } 5940 } 5941 } 5942 5943 5944 /* Determine whether the outgoing edges of BB should receive an 5945 ASSERT_EXPR for each of the operands of BB's LAST statement. 5946 The last statement of BB must be a COND_EXPR. 5947 5948 If any of the sub-graphs rooted at BB have an interesting use of 5949 the predicate operands, an assert location node is added to the 5950 list of assertions for the corresponding operands. */ 5951 5952 static void 5953 find_conditional_asserts (basic_block bb, gcond *last) 5954 { 5955 gimple_stmt_iterator bsi; 5956 tree op; 5957 edge_iterator ei; 5958 edge e; 5959 ssa_op_iter iter; 5960 5961 bsi = gsi_for_stmt (last); 5962 5963 /* Look for uses of the operands in each of the sub-graphs 5964 rooted at BB. We need to check each of the outgoing edges 5965 separately, so that we know what kind of ASSERT_EXPR to 5966 insert. */ 5967 FOR_EACH_EDGE (e, ei, bb->succs) 5968 { 5969 if (e->dest == bb) 5970 continue; 5971 5972 /* Register the necessary assertions for each operand in the 5973 conditional predicate. */ 5974 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE) 5975 register_edge_assert_for (op, e, bsi, 5976 gimple_cond_code (last), 5977 gimple_cond_lhs (last), 5978 gimple_cond_rhs (last)); 5979 } 5980 } 5981 5982 struct case_info 5983 { 5984 tree expr; 5985 basic_block bb; 5986 }; 5987 5988 /* Compare two case labels sorting first by the destination bb index 5989 and then by the case value. */ 5990 5991 static int 5992 compare_case_labels (const void *p1, const void *p2) 5993 { 5994 const struct case_info *ci1 = (const struct case_info *) p1; 5995 const struct case_info *ci2 = (const struct case_info *) p2; 5996 int idx1 = ci1->bb->index; 5997 int idx2 = ci2->bb->index; 5998 5999 if (idx1 < idx2) 6000 return -1; 6001 else if (idx1 == idx2) 6002 { 6003 /* Make sure the default label is first in a group. */ 6004 if (!CASE_LOW (ci1->expr)) 6005 return -1; 6006 else if (!CASE_LOW (ci2->expr)) 6007 return 1; 6008 else 6009 return tree_int_cst_compare (CASE_LOW (ci1->expr), 6010 CASE_LOW (ci2->expr)); 6011 } 6012 else 6013 return 1; 6014 } 6015 6016 /* Determine whether the outgoing edges of BB should receive an 6017 ASSERT_EXPR for each of the operands of BB's LAST statement. 6018 The last statement of BB must be a SWITCH_EXPR. 6019 6020 If any of the sub-graphs rooted at BB have an interesting use of 6021 the predicate operands, an assert location node is added to the 6022 list of assertions for the corresponding operands. */ 6023 6024 static void 6025 find_switch_asserts (basic_block bb, gswitch *last) 6026 { 6027 gimple_stmt_iterator bsi; 6028 tree op; 6029 edge e; 6030 struct case_info *ci; 6031 size_t n = gimple_switch_num_labels (last); 6032 #if GCC_VERSION >= 4000 6033 unsigned int idx; 6034 #else 6035 /* Work around GCC 3.4 bug (PR 37086). */ 6036 volatile unsigned int idx; 6037 #endif 6038 6039 bsi = gsi_for_stmt (last); 6040 op = gimple_switch_index (last); 6041 if (TREE_CODE (op) != SSA_NAME) 6042 return; 6043 6044 /* Build a vector of case labels sorted by destination label. */ 6045 ci = XNEWVEC (struct case_info, n); 6046 for (idx = 0; idx < n; ++idx) 6047 { 6048 ci[idx].expr = gimple_switch_label (last, idx); 6049 ci[idx].bb = label_to_block (CASE_LABEL (ci[idx].expr)); 6050 } 6051 qsort (ci, n, sizeof (struct case_info), compare_case_labels); 6052 6053 for (idx = 0; idx < n; ++idx) 6054 { 6055 tree min, max; 6056 tree cl = ci[idx].expr; 6057 basic_block cbb = ci[idx].bb; 6058 6059 min = CASE_LOW (cl); 6060 max = CASE_HIGH (cl); 6061 6062 /* If there are multiple case labels with the same destination 6063 we need to combine them to a single value range for the edge. */ 6064 if (idx + 1 < n && cbb == ci[idx + 1].bb) 6065 { 6066 /* Skip labels until the last of the group. */ 6067 do { 6068 ++idx; 6069 } while (idx < n && cbb == ci[idx].bb); 6070 --idx; 6071 6072 /* Pick up the maximum of the case label range. */ 6073 if (CASE_HIGH (ci[idx].expr)) 6074 max = CASE_HIGH (ci[idx].expr); 6075 else 6076 max = CASE_LOW (ci[idx].expr); 6077 } 6078 6079 /* Nothing to do if the range includes the default label until we 6080 can register anti-ranges. */ 6081 if (min == NULL_TREE) 6082 continue; 6083 6084 /* Find the edge to register the assert expr on. */ 6085 e = find_edge (bb, cbb); 6086 6087 /* Register the necessary assertions for the operand in the 6088 SWITCH_EXPR. */ 6089 register_edge_assert_for (op, e, bsi, 6090 max ? GE_EXPR : EQ_EXPR, 6091 op, fold_convert (TREE_TYPE (op), min)); 6092 if (max) 6093 register_edge_assert_for (op, e, bsi, LE_EXPR, op, 6094 fold_convert (TREE_TYPE (op), max)); 6095 } 6096 6097 XDELETEVEC (ci); 6098 } 6099 6100 6101 /* Traverse all the statements in block BB looking for statements that 6102 may generate useful assertions for the SSA names in their operand. 6103 If a statement produces a useful assertion A for name N_i, then the 6104 list of assertions already generated for N_i is scanned to 6105 determine if A is actually needed. 6106 6107 If N_i already had the assertion A at a location dominating the 6108 current location, then nothing needs to be done. Otherwise, the 6109 new location for A is recorded instead. 6110 6111 1- For every statement S in BB, all the variables used by S are 6112 added to bitmap FOUND_IN_SUBGRAPH. 6113 6114 2- If statement S uses an operand N in a way that exposes a known 6115 value range for N, then if N was not already generated by an 6116 ASSERT_EXPR, create a new assert location for N. For instance, 6117 if N is a pointer and the statement dereferences it, we can 6118 assume that N is not NULL. 6119 6120 3- COND_EXPRs are a special case of #2. We can derive range 6121 information from the predicate but need to insert different 6122 ASSERT_EXPRs for each of the sub-graphs rooted at the 6123 conditional block. If the last statement of BB is a conditional 6124 expression of the form 'X op Y', then 6125 6126 a) Remove X and Y from the set FOUND_IN_SUBGRAPH. 6127 6128 b) If the conditional is the only entry point to the sub-graph 6129 corresponding to the THEN_CLAUSE, recurse into it. On 6130 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then 6131 an ASSERT_EXPR is added for the corresponding variable. 6132 6133 c) Repeat step (b) on the ELSE_CLAUSE. 6134 6135 d) Mark X and Y in FOUND_IN_SUBGRAPH. 6136 6137 For instance, 6138 6139 if (a == 9) 6140 b = a; 6141 else 6142 b = c + 1; 6143 6144 In this case, an assertion on the THEN clause is useful to 6145 determine that 'a' is always 9 on that edge. However, an assertion 6146 on the ELSE clause would be unnecessary. 6147 6148 4- If BB does not end in a conditional expression, then we recurse 6149 into BB's dominator children. 6150 6151 At the end of the recursive traversal, every SSA name will have a 6152 list of locations where ASSERT_EXPRs should be added. When a new 6153 location for name N is found, it is registered by calling 6154 register_new_assert_for. That function keeps track of all the 6155 registered assertions to prevent adding unnecessary assertions. 6156 For instance, if a pointer P_4 is dereferenced more than once in a 6157 dominator tree, only the location dominating all the dereference of 6158 P_4 will receive an ASSERT_EXPR. */ 6159 6160 static void 6161 find_assert_locations_1 (basic_block bb, sbitmap live) 6162 { 6163 gimple *last; 6164 6165 last = last_stmt (bb); 6166 6167 /* If BB's last statement is a conditional statement involving integer 6168 operands, determine if we need to add ASSERT_EXPRs. */ 6169 if (last 6170 && gimple_code (last) == GIMPLE_COND 6171 && !fp_predicate (last) 6172 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE)) 6173 find_conditional_asserts (bb, as_a <gcond *> (last)); 6174 6175 /* If BB's last statement is a switch statement involving integer 6176 operands, determine if we need to add ASSERT_EXPRs. */ 6177 if (last 6178 && gimple_code (last) == GIMPLE_SWITCH 6179 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE)) 6180 find_switch_asserts (bb, as_a <gswitch *> (last)); 6181 6182 /* Traverse all the statements in BB marking used names and looking 6183 for statements that may infer assertions for their used operands. */ 6184 for (gimple_stmt_iterator si = gsi_last_bb (bb); !gsi_end_p (si); 6185 gsi_prev (&si)) 6186 { 6187 gimple *stmt; 6188 tree op; 6189 ssa_op_iter i; 6190 6191 stmt = gsi_stmt (si); 6192 6193 if (is_gimple_debug (stmt)) 6194 continue; 6195 6196 /* See if we can derive an assertion for any of STMT's operands. */ 6197 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE) 6198 { 6199 tree value; 6200 enum tree_code comp_code; 6201 6202 /* If op is not live beyond this stmt, do not bother to insert 6203 asserts for it. */ 6204 if (!bitmap_bit_p (live, SSA_NAME_VERSION (op))) 6205 continue; 6206 6207 /* If OP is used in such a way that we can infer a value 6208 range for it, and we don't find a previous assertion for 6209 it, create a new assertion location node for OP. */ 6210 if (infer_value_range (stmt, op, &comp_code, &value)) 6211 { 6212 /* If we are able to infer a nonzero value range for OP, 6213 then walk backwards through the use-def chain to see if OP 6214 was set via a typecast. 6215 6216 If so, then we can also infer a nonzero value range 6217 for the operand of the NOP_EXPR. */ 6218 if (comp_code == NE_EXPR && integer_zerop (value)) 6219 { 6220 tree t = op; 6221 gimple *def_stmt = SSA_NAME_DEF_STMT (t); 6222 6223 while (is_gimple_assign (def_stmt) 6224 && CONVERT_EXPR_CODE_P 6225 (gimple_assign_rhs_code (def_stmt)) 6226 && TREE_CODE 6227 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME 6228 && POINTER_TYPE_P 6229 (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))) 6230 { 6231 t = gimple_assign_rhs1 (def_stmt); 6232 def_stmt = SSA_NAME_DEF_STMT (t); 6233 6234 /* Note we want to register the assert for the 6235 operand of the NOP_EXPR after SI, not after the 6236 conversion. */ 6237 if (! has_single_use (t)) 6238 register_new_assert_for (t, t, comp_code, value, 6239 bb, NULL, si); 6240 } 6241 } 6242 6243 register_new_assert_for (op, op, comp_code, value, bb, NULL, si); 6244 } 6245 } 6246 6247 /* Update live. */ 6248 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE) 6249 bitmap_set_bit (live, SSA_NAME_VERSION (op)); 6250 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_DEF) 6251 bitmap_clear_bit (live, SSA_NAME_VERSION (op)); 6252 } 6253 6254 /* Traverse all PHI nodes in BB, updating live. */ 6255 for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si); 6256 gsi_next (&si)) 6257 { 6258 use_operand_p arg_p; 6259 ssa_op_iter i; 6260 gphi *phi = si.phi (); 6261 tree res = gimple_phi_result (phi); 6262 6263 if (virtual_operand_p (res)) 6264 continue; 6265 6266 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE) 6267 { 6268 tree arg = USE_FROM_PTR (arg_p); 6269 if (TREE_CODE (arg) == SSA_NAME) 6270 bitmap_set_bit (live, SSA_NAME_VERSION (arg)); 6271 } 6272 6273 bitmap_clear_bit (live, SSA_NAME_VERSION (res)); 6274 } 6275 } 6276 6277 /* Do an RPO walk over the function computing SSA name liveness 6278 on-the-fly and deciding on assert expressions to insert. */ 6279 6280 static void 6281 find_assert_locations (void) 6282 { 6283 int *rpo = XNEWVEC (int, last_basic_block_for_fn (cfun)); 6284 int *bb_rpo = XNEWVEC (int, last_basic_block_for_fn (cfun)); 6285 int *last_rpo = XCNEWVEC (int, last_basic_block_for_fn (cfun)); 6286 int rpo_cnt, i; 6287 6288 live = XCNEWVEC (sbitmap, last_basic_block_for_fn (cfun)); 6289 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false); 6290 for (i = 0; i < rpo_cnt; ++i) 6291 bb_rpo[rpo[i]] = i; 6292 6293 /* Pre-seed loop latch liveness from loop header PHI nodes. Due to 6294 the order we compute liveness and insert asserts we otherwise 6295 fail to insert asserts into the loop latch. */ 6296 loop_p loop; 6297 FOR_EACH_LOOP (loop, 0) 6298 { 6299 i = loop->latch->index; 6300 unsigned int j = single_succ_edge (loop->latch)->dest_idx; 6301 for (gphi_iterator gsi = gsi_start_phis (loop->header); 6302 !gsi_end_p (gsi); gsi_next (&gsi)) 6303 { 6304 gphi *phi = gsi.phi (); 6305 if (virtual_operand_p (gimple_phi_result (phi))) 6306 continue; 6307 tree arg = gimple_phi_arg_def (phi, j); 6308 if (TREE_CODE (arg) == SSA_NAME) 6309 { 6310 if (live[i] == NULL) 6311 { 6312 live[i] = sbitmap_alloc (num_ssa_names); 6313 bitmap_clear (live[i]); 6314 } 6315 bitmap_set_bit (live[i], SSA_NAME_VERSION (arg)); 6316 } 6317 } 6318 } 6319 6320 for (i = rpo_cnt - 1; i >= 0; --i) 6321 { 6322 basic_block bb = BASIC_BLOCK_FOR_FN (cfun, rpo[i]); 6323 edge e; 6324 edge_iterator ei; 6325 6326 if (!live[rpo[i]]) 6327 { 6328 live[rpo[i]] = sbitmap_alloc (num_ssa_names); 6329 bitmap_clear (live[rpo[i]]); 6330 } 6331 6332 /* Process BB and update the live information with uses in 6333 this block. */ 6334 find_assert_locations_1 (bb, live[rpo[i]]); 6335 6336 /* Merge liveness into the predecessor blocks and free it. */ 6337 if (!bitmap_empty_p (live[rpo[i]])) 6338 { 6339 int pred_rpo = i; 6340 FOR_EACH_EDGE (e, ei, bb->preds) 6341 { 6342 int pred = e->src->index; 6343 if ((e->flags & EDGE_DFS_BACK) || pred == ENTRY_BLOCK) 6344 continue; 6345 6346 if (!live[pred]) 6347 { 6348 live[pred] = sbitmap_alloc (num_ssa_names); 6349 bitmap_clear (live[pred]); 6350 } 6351 bitmap_ior (live[pred], live[pred], live[rpo[i]]); 6352 6353 if (bb_rpo[pred] < pred_rpo) 6354 pred_rpo = bb_rpo[pred]; 6355 } 6356 6357 /* Record the RPO number of the last visited block that needs 6358 live information from this block. */ 6359 last_rpo[rpo[i]] = pred_rpo; 6360 } 6361 else 6362 { 6363 sbitmap_free (live[rpo[i]]); 6364 live[rpo[i]] = NULL; 6365 } 6366 6367 /* We can free all successors live bitmaps if all their 6368 predecessors have been visited already. */ 6369 FOR_EACH_EDGE (e, ei, bb->succs) 6370 if (last_rpo[e->dest->index] == i 6371 && live[e->dest->index]) 6372 { 6373 sbitmap_free (live[e->dest->index]); 6374 live[e->dest->index] = NULL; 6375 } 6376 } 6377 6378 XDELETEVEC (rpo); 6379 XDELETEVEC (bb_rpo); 6380 XDELETEVEC (last_rpo); 6381 for (i = 0; i < last_basic_block_for_fn (cfun); ++i) 6382 if (live[i]) 6383 sbitmap_free (live[i]); 6384 XDELETEVEC (live); 6385 } 6386 6387 /* Create an ASSERT_EXPR for NAME and insert it in the location 6388 indicated by LOC. Return true if we made any edge insertions. */ 6389 6390 static bool 6391 process_assert_insertions_for (tree name, assert_locus *loc) 6392 { 6393 /* Build the comparison expression NAME_i COMP_CODE VAL. */ 6394 gimple *stmt; 6395 tree cond; 6396 gimple *assert_stmt; 6397 edge_iterator ei; 6398 edge e; 6399 6400 /* If we have X <=> X do not insert an assert expr for that. */ 6401 if (loc->expr == loc->val) 6402 return false; 6403 6404 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val); 6405 assert_stmt = build_assert_expr_for (cond, name); 6406 if (loc->e) 6407 { 6408 /* We have been asked to insert the assertion on an edge. This 6409 is used only by COND_EXPR and SWITCH_EXPR assertions. */ 6410 gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND 6411 || (gimple_code (gsi_stmt (loc->si)) 6412 == GIMPLE_SWITCH)); 6413 6414 gsi_insert_on_edge (loc->e, assert_stmt); 6415 return true; 6416 } 6417 6418 /* Otherwise, we can insert right after LOC->SI iff the 6419 statement must not be the last statement in the block. */ 6420 stmt = gsi_stmt (loc->si); 6421 if (!stmt_ends_bb_p (stmt)) 6422 { 6423 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT); 6424 return false; 6425 } 6426 6427 /* If STMT must be the last statement in BB, we can only insert new 6428 assertions on the non-abnormal edge out of BB. Note that since 6429 STMT is not control flow, there may only be one non-abnormal edge 6430 out of BB. */ 6431 FOR_EACH_EDGE (e, ei, loc->bb->succs) 6432 if (!(e->flags & EDGE_ABNORMAL)) 6433 { 6434 gsi_insert_on_edge (e, assert_stmt); 6435 return true; 6436 } 6437 6438 gcc_unreachable (); 6439 } 6440 6441 6442 /* Process all the insertions registered for every name N_i registered 6443 in NEED_ASSERT_FOR. The list of assertions to be inserted are 6444 found in ASSERTS_FOR[i]. */ 6445 6446 static void 6447 process_assert_insertions (void) 6448 { 6449 unsigned i; 6450 bitmap_iterator bi; 6451 bool update_edges_p = false; 6452 int num_asserts = 0; 6453 6454 if (dump_file && (dump_flags & TDF_DETAILS)) 6455 dump_all_asserts (dump_file); 6456 6457 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi) 6458 { 6459 assert_locus *loc = asserts_for[i]; 6460 gcc_assert (loc); 6461 6462 while (loc) 6463 { 6464 assert_locus *next = loc->next; 6465 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc); 6466 free (loc); 6467 loc = next; 6468 num_asserts++; 6469 } 6470 } 6471 6472 if (update_edges_p) 6473 gsi_commit_edge_inserts (); 6474 6475 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted", 6476 num_asserts); 6477 } 6478 6479 6480 /* Traverse the flowgraph looking for conditional jumps to insert range 6481 expressions. These range expressions are meant to provide information 6482 to optimizations that need to reason in terms of value ranges. They 6483 will not be expanded into RTL. For instance, given: 6484 6485 x = ... 6486 y = ... 6487 if (x < y) 6488 y = x - 2; 6489 else 6490 x = y + 3; 6491 6492 this pass will transform the code into: 6493 6494 x = ... 6495 y = ... 6496 if (x < y) 6497 { 6498 x = ASSERT_EXPR <x, x < y> 6499 y = x - 2 6500 } 6501 else 6502 { 6503 y = ASSERT_EXPR <y, x >= y> 6504 x = y + 3 6505 } 6506 6507 The idea is that once copy and constant propagation have run, other 6508 optimizations will be able to determine what ranges of values can 'x' 6509 take in different paths of the code, simply by checking the reaching 6510 definition of 'x'. */ 6511 6512 static void 6513 insert_range_assertions (void) 6514 { 6515 need_assert_for = BITMAP_ALLOC (NULL); 6516 asserts_for = XCNEWVEC (assert_locus *, num_ssa_names); 6517 6518 calculate_dominance_info (CDI_DOMINATORS); 6519 6520 find_assert_locations (); 6521 if (!bitmap_empty_p (need_assert_for)) 6522 { 6523 process_assert_insertions (); 6524 update_ssa (TODO_update_ssa_no_phi); 6525 } 6526 6527 if (dump_file && (dump_flags & TDF_DETAILS)) 6528 { 6529 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n"); 6530 dump_function_to_file (current_function_decl, dump_file, dump_flags); 6531 } 6532 6533 free (asserts_for); 6534 BITMAP_FREE (need_assert_for); 6535 } 6536 6537 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays 6538 and "struct" hacks. If VRP can determine that the 6539 array subscript is a constant, check if it is outside valid 6540 range. If the array subscript is a RANGE, warn if it is 6541 non-overlapping with valid range. 6542 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */ 6543 6544 static void 6545 check_array_ref (location_t location, tree ref, bool ignore_off_by_one) 6546 { 6547 value_range *vr = NULL; 6548 tree low_sub, up_sub; 6549 tree low_bound, up_bound, up_bound_p1; 6550 6551 if (TREE_NO_WARNING (ref)) 6552 return; 6553 6554 low_sub = up_sub = TREE_OPERAND (ref, 1); 6555 up_bound = array_ref_up_bound (ref); 6556 6557 /* Can not check flexible arrays. */ 6558 if (!up_bound 6559 || TREE_CODE (up_bound) != INTEGER_CST) 6560 return; 6561 6562 /* Accesses to trailing arrays via pointers may access storage 6563 beyond the types array bounds. */ 6564 if (warn_array_bounds < 2 6565 && array_at_struct_end_p (ref)) 6566 return; 6567 6568 low_bound = array_ref_low_bound (ref); 6569 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, 6570 build_int_cst (TREE_TYPE (up_bound), 1)); 6571 6572 /* Empty array. */ 6573 if (tree_int_cst_equal (low_bound, up_bound_p1)) 6574 { 6575 warning_at (location, OPT_Warray_bounds, 6576 "array subscript is above array bounds"); 6577 TREE_NO_WARNING (ref) = 1; 6578 } 6579 6580 if (TREE_CODE (low_sub) == SSA_NAME) 6581 { 6582 vr = get_value_range (low_sub); 6583 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE) 6584 { 6585 low_sub = vr->type == VR_RANGE ? vr->max : vr->min; 6586 up_sub = vr->type == VR_RANGE ? vr->min : vr->max; 6587 } 6588 } 6589 6590 if (vr && vr->type == VR_ANTI_RANGE) 6591 { 6592 if (TREE_CODE (up_sub) == INTEGER_CST 6593 && (ignore_off_by_one 6594 ? tree_int_cst_lt (up_bound, up_sub) 6595 : tree_int_cst_le (up_bound, up_sub)) 6596 && TREE_CODE (low_sub) == INTEGER_CST 6597 && tree_int_cst_le (low_sub, low_bound)) 6598 { 6599 warning_at (location, OPT_Warray_bounds, 6600 "array subscript is outside array bounds"); 6601 TREE_NO_WARNING (ref) = 1; 6602 } 6603 } 6604 else if (TREE_CODE (up_sub) == INTEGER_CST 6605 && (ignore_off_by_one 6606 ? !tree_int_cst_le (up_sub, up_bound_p1) 6607 : !tree_int_cst_le (up_sub, up_bound))) 6608 { 6609 if (dump_file && (dump_flags & TDF_DETAILS)) 6610 { 6611 fprintf (dump_file, "Array bound warning for "); 6612 dump_generic_expr (MSG_NOTE, TDF_SLIM, ref); 6613 fprintf (dump_file, "\n"); 6614 } 6615 warning_at (location, OPT_Warray_bounds, 6616 "array subscript is above array bounds"); 6617 TREE_NO_WARNING (ref) = 1; 6618 } 6619 else if (TREE_CODE (low_sub) == INTEGER_CST 6620 && tree_int_cst_lt (low_sub, low_bound)) 6621 { 6622 if (dump_file && (dump_flags & TDF_DETAILS)) 6623 { 6624 fprintf (dump_file, "Array bound warning for "); 6625 dump_generic_expr (MSG_NOTE, TDF_SLIM, ref); 6626 fprintf (dump_file, "\n"); 6627 } 6628 warning_at (location, OPT_Warray_bounds, 6629 "array subscript is below array bounds"); 6630 TREE_NO_WARNING (ref) = 1; 6631 } 6632 } 6633 6634 /* Searches if the expr T, located at LOCATION computes 6635 address of an ARRAY_REF, and call check_array_ref on it. */ 6636 6637 static void 6638 search_for_addr_array (tree t, location_t location) 6639 { 6640 /* Check each ARRAY_REFs in the reference chain. */ 6641 do 6642 { 6643 if (TREE_CODE (t) == ARRAY_REF) 6644 check_array_ref (location, t, true /*ignore_off_by_one*/); 6645 6646 t = TREE_OPERAND (t, 0); 6647 } 6648 while (handled_component_p (t)); 6649 6650 if (TREE_CODE (t) == MEM_REF 6651 && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR 6652 && !TREE_NO_WARNING (t)) 6653 { 6654 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0); 6655 tree low_bound, up_bound, el_sz; 6656 offset_int idx; 6657 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE 6658 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE 6659 || !TYPE_DOMAIN (TREE_TYPE (tem))) 6660 return; 6661 6662 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem))); 6663 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem))); 6664 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem))); 6665 if (!low_bound 6666 || TREE_CODE (low_bound) != INTEGER_CST 6667 || !up_bound 6668 || TREE_CODE (up_bound) != INTEGER_CST 6669 || !el_sz 6670 || TREE_CODE (el_sz) != INTEGER_CST) 6671 return; 6672 6673 idx = mem_ref_offset (t); 6674 idx = wi::sdiv_trunc (idx, wi::to_offset (el_sz)); 6675 if (wi::lts_p (idx, 0)) 6676 { 6677 if (dump_file && (dump_flags & TDF_DETAILS)) 6678 { 6679 fprintf (dump_file, "Array bound warning for "); 6680 dump_generic_expr (MSG_NOTE, TDF_SLIM, t); 6681 fprintf (dump_file, "\n"); 6682 } 6683 warning_at (location, OPT_Warray_bounds, 6684 "array subscript is below array bounds"); 6685 TREE_NO_WARNING (t) = 1; 6686 } 6687 else if (wi::gts_p (idx, (wi::to_offset (up_bound) 6688 - wi::to_offset (low_bound) + 1))) 6689 { 6690 if (dump_file && (dump_flags & TDF_DETAILS)) 6691 { 6692 fprintf (dump_file, "Array bound warning for "); 6693 dump_generic_expr (MSG_NOTE, TDF_SLIM, t); 6694 fprintf (dump_file, "\n"); 6695 } 6696 warning_at (location, OPT_Warray_bounds, 6697 "array subscript is above array bounds"); 6698 TREE_NO_WARNING (t) = 1; 6699 } 6700 } 6701 } 6702 6703 /* walk_tree() callback that checks if *TP is 6704 an ARRAY_REF inside an ADDR_EXPR (in which an array 6705 subscript one outside the valid range is allowed). Call 6706 check_array_ref for each ARRAY_REF found. The location is 6707 passed in DATA. */ 6708 6709 static tree 6710 check_array_bounds (tree *tp, int *walk_subtree, void *data) 6711 { 6712 tree t = *tp; 6713 struct walk_stmt_info *wi = (struct walk_stmt_info *) data; 6714 location_t location; 6715 6716 if (EXPR_HAS_LOCATION (t)) 6717 location = EXPR_LOCATION (t); 6718 else 6719 { 6720 location_t *locp = (location_t *) wi->info; 6721 location = *locp; 6722 } 6723 6724 *walk_subtree = TRUE; 6725 6726 if (TREE_CODE (t) == ARRAY_REF) 6727 check_array_ref (location, t, false /*ignore_off_by_one*/); 6728 6729 else if (TREE_CODE (t) == ADDR_EXPR) 6730 { 6731 search_for_addr_array (t, location); 6732 *walk_subtree = FALSE; 6733 } 6734 6735 return NULL_TREE; 6736 } 6737 6738 /* Walk over all statements of all reachable BBs and call check_array_bounds 6739 on them. */ 6740 6741 static void 6742 check_all_array_refs (void) 6743 { 6744 basic_block bb; 6745 gimple_stmt_iterator si; 6746 6747 FOR_EACH_BB_FN (bb, cfun) 6748 { 6749 edge_iterator ei; 6750 edge e; 6751 bool executable = false; 6752 6753 /* Skip blocks that were found to be unreachable. */ 6754 FOR_EACH_EDGE (e, ei, bb->preds) 6755 executable |= !!(e->flags & EDGE_EXECUTABLE); 6756 if (!executable) 6757 continue; 6758 6759 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) 6760 { 6761 gimple *stmt = gsi_stmt (si); 6762 struct walk_stmt_info wi; 6763 if (!gimple_has_location (stmt) 6764 || is_gimple_debug (stmt)) 6765 continue; 6766 6767 memset (&wi, 0, sizeof (wi)); 6768 6769 location_t loc = gimple_location (stmt); 6770 wi.info = &loc; 6771 6772 walk_gimple_op (gsi_stmt (si), 6773 check_array_bounds, 6774 &wi); 6775 } 6776 } 6777 } 6778 6779 /* Return true if all imm uses of VAR are either in STMT, or 6780 feed (optionally through a chain of single imm uses) GIMPLE_COND 6781 in basic block COND_BB. */ 6782 6783 static bool 6784 all_imm_uses_in_stmt_or_feed_cond (tree var, gimple *stmt, basic_block cond_bb) 6785 { 6786 use_operand_p use_p, use2_p; 6787 imm_use_iterator iter; 6788 6789 FOR_EACH_IMM_USE_FAST (use_p, iter, var) 6790 if (USE_STMT (use_p) != stmt) 6791 { 6792 gimple *use_stmt = USE_STMT (use_p), *use_stmt2; 6793 if (is_gimple_debug (use_stmt)) 6794 continue; 6795 while (is_gimple_assign (use_stmt) 6796 && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME 6797 && single_imm_use (gimple_assign_lhs (use_stmt), 6798 &use2_p, &use_stmt2)) 6799 use_stmt = use_stmt2; 6800 if (gimple_code (use_stmt) != GIMPLE_COND 6801 || gimple_bb (use_stmt) != cond_bb) 6802 return false; 6803 } 6804 return true; 6805 } 6806 6807 /* Handle 6808 _4 = x_3 & 31; 6809 if (_4 != 0) 6810 goto <bb 6>; 6811 else 6812 goto <bb 7>; 6813 <bb 6>: 6814 __builtin_unreachable (); 6815 <bb 7>: 6816 x_5 = ASSERT_EXPR <x_3, ...>; 6817 If x_3 has no other immediate uses (checked by caller), 6818 var is the x_3 var from ASSERT_EXPR, we can clear low 5 bits 6819 from the non-zero bitmask. */ 6820 6821 static void 6822 maybe_set_nonzero_bits (basic_block bb, tree var) 6823 { 6824 edge e = single_pred_edge (bb); 6825 basic_block cond_bb = e->src; 6826 gimple *stmt = last_stmt (cond_bb); 6827 tree cst; 6828 6829 if (stmt == NULL 6830 || gimple_code (stmt) != GIMPLE_COND 6831 || gimple_cond_code (stmt) != ((e->flags & EDGE_TRUE_VALUE) 6832 ? EQ_EXPR : NE_EXPR) 6833 || TREE_CODE (gimple_cond_lhs (stmt)) != SSA_NAME 6834 || !integer_zerop (gimple_cond_rhs (stmt))) 6835 return; 6836 6837 stmt = SSA_NAME_DEF_STMT (gimple_cond_lhs (stmt)); 6838 if (!is_gimple_assign (stmt) 6839 || gimple_assign_rhs_code (stmt) != BIT_AND_EXPR 6840 || TREE_CODE (gimple_assign_rhs2 (stmt)) != INTEGER_CST) 6841 return; 6842 if (gimple_assign_rhs1 (stmt) != var) 6843 { 6844 gimple *stmt2; 6845 6846 if (TREE_CODE (gimple_assign_rhs1 (stmt)) != SSA_NAME) 6847 return; 6848 stmt2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (stmt)); 6849 if (!gimple_assign_cast_p (stmt2) 6850 || gimple_assign_rhs1 (stmt2) != var 6851 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (stmt2)) 6852 || (TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt))) 6853 != TYPE_PRECISION (TREE_TYPE (var)))) 6854 return; 6855 } 6856 cst = gimple_assign_rhs2 (stmt); 6857 set_nonzero_bits (var, wi::bit_and_not (get_nonzero_bits (var), cst)); 6858 } 6859 6860 /* Convert range assertion expressions into the implied copies and 6861 copy propagate away the copies. Doing the trivial copy propagation 6862 here avoids the need to run the full copy propagation pass after 6863 VRP. 6864 6865 FIXME, this will eventually lead to copy propagation removing the 6866 names that had useful range information attached to them. For 6867 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>, 6868 then N_i will have the range [3, +INF]. 6869 6870 However, by converting the assertion into the implied copy 6871 operation N_i = N_j, we will then copy-propagate N_j into the uses 6872 of N_i and lose the range information. We may want to hold on to 6873 ASSERT_EXPRs a little while longer as the ranges could be used in 6874 things like jump threading. 6875 6876 The problem with keeping ASSERT_EXPRs around is that passes after 6877 VRP need to handle them appropriately. 6878 6879 Another approach would be to make the range information a first 6880 class property of the SSA_NAME so that it can be queried from 6881 any pass. This is made somewhat more complex by the need for 6882 multiple ranges to be associated with one SSA_NAME. */ 6883 6884 static void 6885 remove_range_assertions (void) 6886 { 6887 basic_block bb; 6888 gimple_stmt_iterator si; 6889 /* 1 if looking at ASSERT_EXPRs immediately at the beginning of 6890 a basic block preceeded by GIMPLE_COND branching to it and 6891 __builtin_trap, -1 if not yet checked, 0 otherwise. */ 6892 int is_unreachable; 6893 6894 /* Note that the BSI iterator bump happens at the bottom of the 6895 loop and no bump is necessary if we're removing the statement 6896 referenced by the current BSI. */ 6897 FOR_EACH_BB_FN (bb, cfun) 6898 for (si = gsi_after_labels (bb), is_unreachable = -1; !gsi_end_p (si);) 6899 { 6900 gimple *stmt = gsi_stmt (si); 6901 gimple *use_stmt; 6902 6903 if (is_gimple_assign (stmt) 6904 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR) 6905 { 6906 tree lhs = gimple_assign_lhs (stmt); 6907 tree rhs = gimple_assign_rhs1 (stmt); 6908 tree var; 6909 use_operand_p use_p; 6910 imm_use_iterator iter; 6911 6912 var = ASSERT_EXPR_VAR (rhs); 6913 gcc_assert (TREE_CODE (var) == SSA_NAME); 6914 6915 if (!POINTER_TYPE_P (TREE_TYPE (lhs)) 6916 && SSA_NAME_RANGE_INFO (lhs)) 6917 { 6918 if (is_unreachable == -1) 6919 { 6920 is_unreachable = 0; 6921 if (single_pred_p (bb) 6922 && assert_unreachable_fallthru_edge_p 6923 (single_pred_edge (bb))) 6924 is_unreachable = 1; 6925 } 6926 /* Handle 6927 if (x_7 >= 10 && x_7 < 20) 6928 __builtin_unreachable (); 6929 x_8 = ASSERT_EXPR <x_7, ...>; 6930 if the only uses of x_7 are in the ASSERT_EXPR and 6931 in the condition. In that case, we can copy the 6932 range info from x_8 computed in this pass also 6933 for x_7. */ 6934 if (is_unreachable 6935 && all_imm_uses_in_stmt_or_feed_cond (var, stmt, 6936 single_pred (bb))) 6937 { 6938 set_range_info (var, SSA_NAME_RANGE_TYPE (lhs), 6939 SSA_NAME_RANGE_INFO (lhs)->get_min (), 6940 SSA_NAME_RANGE_INFO (lhs)->get_max ()); 6941 maybe_set_nonzero_bits (bb, var); 6942 } 6943 } 6944 6945 /* Propagate the RHS into every use of the LHS. */ 6946 FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs) 6947 FOR_EACH_IMM_USE_ON_STMT (use_p, iter) 6948 SET_USE (use_p, var); 6949 6950 /* And finally, remove the copy, it is not needed. */ 6951 gsi_remove (&si, true); 6952 release_defs (stmt); 6953 } 6954 else 6955 { 6956 if (!is_gimple_debug (gsi_stmt (si))) 6957 is_unreachable = 0; 6958 gsi_next (&si); 6959 } 6960 } 6961 } 6962 6963 6964 /* Return true if STMT is interesting for VRP. */ 6965 6966 static bool 6967 stmt_interesting_for_vrp (gimple *stmt) 6968 { 6969 if (gimple_code (stmt) == GIMPLE_PHI) 6970 { 6971 tree res = gimple_phi_result (stmt); 6972 return (!virtual_operand_p (res) 6973 && (INTEGRAL_TYPE_P (TREE_TYPE (res)) 6974 || POINTER_TYPE_P (TREE_TYPE (res)))); 6975 } 6976 else if (is_gimple_assign (stmt) || is_gimple_call (stmt)) 6977 { 6978 tree lhs = gimple_get_lhs (stmt); 6979 6980 /* In general, assignments with virtual operands are not useful 6981 for deriving ranges, with the obvious exception of calls to 6982 builtin functions. */ 6983 if (lhs && TREE_CODE (lhs) == SSA_NAME 6984 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs)) 6985 || POINTER_TYPE_P (TREE_TYPE (lhs))) 6986 && (is_gimple_call (stmt) 6987 || !gimple_vuse (stmt))) 6988 return true; 6989 else if (is_gimple_call (stmt) && gimple_call_internal_p (stmt)) 6990 switch (gimple_call_internal_fn (stmt)) 6991 { 6992 case IFN_ADD_OVERFLOW: 6993 case IFN_SUB_OVERFLOW: 6994 case IFN_MUL_OVERFLOW: 6995 /* These internal calls return _Complex integer type, 6996 but are interesting to VRP nevertheless. */ 6997 if (lhs && TREE_CODE (lhs) == SSA_NAME) 6998 return true; 6999 break; 7000 default: 7001 break; 7002 } 7003 } 7004 else if (gimple_code (stmt) == GIMPLE_COND 7005 || gimple_code (stmt) == GIMPLE_SWITCH) 7006 return true; 7007 7008 return false; 7009 } 7010 7011 7012 /* Initialize local data structures for VRP. */ 7013 7014 static void 7015 vrp_initialize (void) 7016 { 7017 basic_block bb; 7018 7019 values_propagated = false; 7020 num_vr_values = num_ssa_names; 7021 vr_value = XCNEWVEC (value_range *, num_vr_values); 7022 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names); 7023 7024 FOR_EACH_BB_FN (bb, cfun) 7025 { 7026 for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si); 7027 gsi_next (&si)) 7028 { 7029 gphi *phi = si.phi (); 7030 if (!stmt_interesting_for_vrp (phi)) 7031 { 7032 tree lhs = PHI_RESULT (phi); 7033 set_value_range_to_varying (get_value_range (lhs)); 7034 prop_set_simulate_again (phi, false); 7035 } 7036 else 7037 prop_set_simulate_again (phi, true); 7038 } 7039 7040 for (gimple_stmt_iterator si = gsi_start_bb (bb); !gsi_end_p (si); 7041 gsi_next (&si)) 7042 { 7043 gimple *stmt = gsi_stmt (si); 7044 7045 /* If the statement is a control insn, then we do not 7046 want to avoid simulating the statement once. Failure 7047 to do so means that those edges will never get added. */ 7048 if (stmt_ends_bb_p (stmt)) 7049 prop_set_simulate_again (stmt, true); 7050 else if (!stmt_interesting_for_vrp (stmt)) 7051 { 7052 set_defs_to_varying (stmt); 7053 prop_set_simulate_again (stmt, false); 7054 } 7055 else 7056 prop_set_simulate_again (stmt, true); 7057 } 7058 } 7059 } 7060 7061 /* Return the singleton value-range for NAME or NAME. */ 7062 7063 static inline tree 7064 vrp_valueize (tree name) 7065 { 7066 if (TREE_CODE (name) == SSA_NAME) 7067 { 7068 value_range *vr = get_value_range (name); 7069 if (vr->type == VR_RANGE 7070 && vrp_operand_equal_p (vr->min, vr->max)) 7071 return vr->min; 7072 } 7073 return name; 7074 } 7075 7076 /* Return the singleton value-range for NAME if that is a constant 7077 but signal to not follow SSA edges. */ 7078 7079 static inline tree 7080 vrp_valueize_1 (tree name) 7081 { 7082 if (TREE_CODE (name) == SSA_NAME) 7083 { 7084 /* If the definition may be simulated again we cannot follow 7085 this SSA edge as the SSA propagator does not necessarily 7086 re-visit the use. */ 7087 gimple *def_stmt = SSA_NAME_DEF_STMT (name); 7088 if (!gimple_nop_p (def_stmt) 7089 && prop_simulate_again_p (def_stmt)) 7090 return NULL_TREE; 7091 value_range *vr = get_value_range (name); 7092 if (range_int_cst_singleton_p (vr)) 7093 return vr->min; 7094 } 7095 return name; 7096 } 7097 7098 /* Visit assignment STMT. If it produces an interesting range, record 7099 the SSA name in *OUTPUT_P. */ 7100 7101 static enum ssa_prop_result 7102 vrp_visit_assignment_or_call (gimple *stmt, tree *output_p) 7103 { 7104 tree lhs; 7105 enum gimple_code code = gimple_code (stmt); 7106 lhs = gimple_get_lhs (stmt); 7107 7108 /* We only keep track of ranges in integral and pointer types. */ 7109 if (TREE_CODE (lhs) == SSA_NAME 7110 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs)) 7111 /* It is valid to have NULL MIN/MAX values on a type. See 7112 build_range_type. */ 7113 && TYPE_MIN_VALUE (TREE_TYPE (lhs)) 7114 && TYPE_MAX_VALUE (TREE_TYPE (lhs))) 7115 || POINTER_TYPE_P (TREE_TYPE (lhs)))) 7116 { 7117 value_range new_vr = VR_INITIALIZER; 7118 7119 /* Try folding the statement to a constant first. */ 7120 tree tem = gimple_fold_stmt_to_constant_1 (stmt, vrp_valueize, 7121 vrp_valueize_1); 7122 if (tem && is_gimple_min_invariant (tem)) 7123 set_value_range_to_value (&new_vr, tem, NULL); 7124 /* Then dispatch to value-range extracting functions. */ 7125 else if (code == GIMPLE_CALL) 7126 extract_range_basic (&new_vr, stmt); 7127 else 7128 extract_range_from_assignment (&new_vr, as_a <gassign *> (stmt)); 7129 7130 if (update_value_range (lhs, &new_vr)) 7131 { 7132 *output_p = lhs; 7133 7134 if (dump_file && (dump_flags & TDF_DETAILS)) 7135 { 7136 fprintf (dump_file, "Found new range for "); 7137 print_generic_expr (dump_file, lhs, 0); 7138 fprintf (dump_file, ": "); 7139 dump_value_range (dump_file, &new_vr); 7140 fprintf (dump_file, "\n"); 7141 } 7142 7143 if (new_vr.type == VR_VARYING) 7144 return SSA_PROP_VARYING; 7145 7146 return SSA_PROP_INTERESTING; 7147 } 7148 7149 return SSA_PROP_NOT_INTERESTING; 7150 } 7151 else if (is_gimple_call (stmt) && gimple_call_internal_p (stmt)) 7152 switch (gimple_call_internal_fn (stmt)) 7153 { 7154 case IFN_ADD_OVERFLOW: 7155 case IFN_SUB_OVERFLOW: 7156 case IFN_MUL_OVERFLOW: 7157 /* These internal calls return _Complex integer type, 7158 which VRP does not track, but the immediate uses 7159 thereof might be interesting. */ 7160 if (lhs && TREE_CODE (lhs) == SSA_NAME) 7161 { 7162 imm_use_iterator iter; 7163 use_operand_p use_p; 7164 enum ssa_prop_result res = SSA_PROP_VARYING; 7165 7166 set_value_range_to_varying (get_value_range (lhs)); 7167 7168 FOR_EACH_IMM_USE_FAST (use_p, iter, lhs) 7169 { 7170 gimple *use_stmt = USE_STMT (use_p); 7171 if (!is_gimple_assign (use_stmt)) 7172 continue; 7173 enum tree_code rhs_code = gimple_assign_rhs_code (use_stmt); 7174 if (rhs_code != REALPART_EXPR && rhs_code != IMAGPART_EXPR) 7175 continue; 7176 tree rhs1 = gimple_assign_rhs1 (use_stmt); 7177 tree use_lhs = gimple_assign_lhs (use_stmt); 7178 if (TREE_CODE (rhs1) != rhs_code 7179 || TREE_OPERAND (rhs1, 0) != lhs 7180 || TREE_CODE (use_lhs) != SSA_NAME 7181 || !stmt_interesting_for_vrp (use_stmt) 7182 || (!INTEGRAL_TYPE_P (TREE_TYPE (use_lhs)) 7183 || !TYPE_MIN_VALUE (TREE_TYPE (use_lhs)) 7184 || !TYPE_MAX_VALUE (TREE_TYPE (use_lhs)))) 7185 continue; 7186 7187 /* If there is a change in the value range for any of the 7188 REALPART_EXPR/IMAGPART_EXPR immediate uses, return 7189 SSA_PROP_INTERESTING. If there are any REALPART_EXPR 7190 or IMAGPART_EXPR immediate uses, but none of them have 7191 a change in their value ranges, return 7192 SSA_PROP_NOT_INTERESTING. If there are no 7193 {REAL,IMAG}PART_EXPR uses at all, 7194 return SSA_PROP_VARYING. */ 7195 value_range new_vr = VR_INITIALIZER; 7196 extract_range_basic (&new_vr, use_stmt); 7197 value_range *old_vr = get_value_range (use_lhs); 7198 if (old_vr->type != new_vr.type 7199 || !vrp_operand_equal_p (old_vr->min, new_vr.min) 7200 || !vrp_operand_equal_p (old_vr->max, new_vr.max) 7201 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr.equiv)) 7202 res = SSA_PROP_INTERESTING; 7203 else 7204 res = SSA_PROP_NOT_INTERESTING; 7205 BITMAP_FREE (new_vr.equiv); 7206 if (res == SSA_PROP_INTERESTING) 7207 { 7208 *output_p = lhs; 7209 return res; 7210 } 7211 } 7212 7213 return res; 7214 } 7215 break; 7216 default: 7217 break; 7218 } 7219 7220 /* Every other statement produces no useful ranges. */ 7221 set_defs_to_varying (stmt); 7222 7223 return SSA_PROP_VARYING; 7224 } 7225 7226 /* Helper that gets the value range of the SSA_NAME with version I 7227 or a symbolic range containing the SSA_NAME only if the value range 7228 is varying or undefined. */ 7229 7230 static inline value_range 7231 get_vr_for_comparison (int i) 7232 { 7233 value_range vr = *get_value_range (ssa_name (i)); 7234 7235 /* If name N_i does not have a valid range, use N_i as its own 7236 range. This allows us to compare against names that may 7237 have N_i in their ranges. */ 7238 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED) 7239 { 7240 vr.type = VR_RANGE; 7241 vr.min = ssa_name (i); 7242 vr.max = ssa_name (i); 7243 } 7244 7245 return vr; 7246 } 7247 7248 /* Compare all the value ranges for names equivalent to VAR with VAL 7249 using comparison code COMP. Return the same value returned by 7250 compare_range_with_value, including the setting of 7251 *STRICT_OVERFLOW_P. */ 7252 7253 static tree 7254 compare_name_with_value (enum tree_code comp, tree var, tree val, 7255 bool *strict_overflow_p, bool use_equiv_p) 7256 { 7257 bitmap_iterator bi; 7258 unsigned i; 7259 bitmap e; 7260 tree retval, t; 7261 int used_strict_overflow; 7262 bool sop; 7263 value_range equiv_vr; 7264 7265 /* Get the set of equivalences for VAR. */ 7266 e = get_value_range (var)->equiv; 7267 7268 /* Start at -1. Set it to 0 if we do a comparison without relying 7269 on overflow, or 1 if all comparisons rely on overflow. */ 7270 used_strict_overflow = -1; 7271 7272 /* Compare vars' value range with val. */ 7273 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var)); 7274 sop = false; 7275 retval = compare_range_with_value (comp, &equiv_vr, val, &sop); 7276 if (retval) 7277 used_strict_overflow = sop ? 1 : 0; 7278 7279 /* If the equiv set is empty we have done all work we need to do. */ 7280 if (e == NULL) 7281 { 7282 if (retval 7283 && used_strict_overflow > 0) 7284 *strict_overflow_p = true; 7285 return retval; 7286 } 7287 7288 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi) 7289 { 7290 if (! use_equiv_p 7291 && ! SSA_NAME_IS_DEFAULT_DEF (ssa_name (i)) 7292 && prop_simulate_again_p (SSA_NAME_DEF_STMT (ssa_name (i)))) 7293 continue; 7294 7295 equiv_vr = get_vr_for_comparison (i); 7296 sop = false; 7297 t = compare_range_with_value (comp, &equiv_vr, val, &sop); 7298 if (t) 7299 { 7300 /* If we get different answers from different members 7301 of the equivalence set this check must be in a dead 7302 code region. Folding it to a trap representation 7303 would be correct here. For now just return don't-know. */ 7304 if (retval != NULL 7305 && t != retval) 7306 { 7307 retval = NULL_TREE; 7308 break; 7309 } 7310 retval = t; 7311 7312 if (!sop) 7313 used_strict_overflow = 0; 7314 else if (used_strict_overflow < 0) 7315 used_strict_overflow = 1; 7316 } 7317 } 7318 7319 if (retval 7320 && used_strict_overflow > 0) 7321 *strict_overflow_p = true; 7322 7323 return retval; 7324 } 7325 7326 7327 /* Given a comparison code COMP and names N1 and N2, compare all the 7328 ranges equivalent to N1 against all the ranges equivalent to N2 7329 to determine the value of N1 COMP N2. Return the same value 7330 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate 7331 whether we relied on an overflow infinity in the comparison. */ 7332 7333 7334 static tree 7335 compare_names (enum tree_code comp, tree n1, tree n2, 7336 bool *strict_overflow_p) 7337 { 7338 tree t, retval; 7339 bitmap e1, e2; 7340 bitmap_iterator bi1, bi2; 7341 unsigned i1, i2; 7342 int used_strict_overflow; 7343 static bitmap_obstack *s_obstack = NULL; 7344 static bitmap s_e1 = NULL, s_e2 = NULL; 7345 7346 /* Compare the ranges of every name equivalent to N1 against the 7347 ranges of every name equivalent to N2. */ 7348 e1 = get_value_range (n1)->equiv; 7349 e2 = get_value_range (n2)->equiv; 7350 7351 /* Use the fake bitmaps if e1 or e2 are not available. */ 7352 if (s_obstack == NULL) 7353 { 7354 s_obstack = XNEW (bitmap_obstack); 7355 bitmap_obstack_initialize (s_obstack); 7356 s_e1 = BITMAP_ALLOC (s_obstack); 7357 s_e2 = BITMAP_ALLOC (s_obstack); 7358 } 7359 if (e1 == NULL) 7360 e1 = s_e1; 7361 if (e2 == NULL) 7362 e2 = s_e2; 7363 7364 /* Add N1 and N2 to their own set of equivalences to avoid 7365 duplicating the body of the loop just to check N1 and N2 7366 ranges. */ 7367 bitmap_set_bit (e1, SSA_NAME_VERSION (n1)); 7368 bitmap_set_bit (e2, SSA_NAME_VERSION (n2)); 7369 7370 /* If the equivalence sets have a common intersection, then the two 7371 names can be compared without checking their ranges. */ 7372 if (bitmap_intersect_p (e1, e2)) 7373 { 7374 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); 7375 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); 7376 7377 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR) 7378 ? boolean_true_node 7379 : boolean_false_node; 7380 } 7381 7382 /* Start at -1. Set it to 0 if we do a comparison without relying 7383 on overflow, or 1 if all comparisons rely on overflow. */ 7384 used_strict_overflow = -1; 7385 7386 /* Otherwise, compare all the equivalent ranges. First, add N1 and 7387 N2 to their own set of equivalences to avoid duplicating the body 7388 of the loop just to check N1 and N2 ranges. */ 7389 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1) 7390 { 7391 value_range vr1 = get_vr_for_comparison (i1); 7392 7393 t = retval = NULL_TREE; 7394 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2) 7395 { 7396 bool sop = false; 7397 7398 value_range vr2 = get_vr_for_comparison (i2); 7399 7400 t = compare_ranges (comp, &vr1, &vr2, &sop); 7401 if (t) 7402 { 7403 /* If we get different answers from different members 7404 of the equivalence set this check must be in a dead 7405 code region. Folding it to a trap representation 7406 would be correct here. For now just return don't-know. */ 7407 if (retval != NULL 7408 && t != retval) 7409 { 7410 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); 7411 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); 7412 return NULL_TREE; 7413 } 7414 retval = t; 7415 7416 if (!sop) 7417 used_strict_overflow = 0; 7418 else if (used_strict_overflow < 0) 7419 used_strict_overflow = 1; 7420 } 7421 } 7422 7423 if (retval) 7424 { 7425 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); 7426 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); 7427 if (used_strict_overflow > 0) 7428 *strict_overflow_p = true; 7429 return retval; 7430 } 7431 } 7432 7433 /* None of the equivalent ranges are useful in computing this 7434 comparison. */ 7435 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); 7436 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); 7437 return NULL_TREE; 7438 } 7439 7440 /* Helper function for vrp_evaluate_conditional_warnv & other 7441 optimizers. */ 7442 7443 static tree 7444 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code, 7445 tree op0, tree op1, 7446 bool * strict_overflow_p) 7447 { 7448 value_range *vr0, *vr1; 7449 7450 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL; 7451 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL; 7452 7453 tree res = NULL_TREE; 7454 if (vr0 && vr1) 7455 res = compare_ranges (code, vr0, vr1, strict_overflow_p); 7456 if (!res && vr0) 7457 res = compare_range_with_value (code, vr0, op1, strict_overflow_p); 7458 if (!res && vr1) 7459 res = (compare_range_with_value 7460 (swap_tree_comparison (code), vr1, op0, strict_overflow_p)); 7461 return res; 7462 } 7463 7464 /* Helper function for vrp_evaluate_conditional_warnv. */ 7465 7466 static tree 7467 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0, 7468 tree op1, bool use_equiv_p, 7469 bool *strict_overflow_p, bool *only_ranges) 7470 { 7471 tree ret; 7472 if (only_ranges) 7473 *only_ranges = true; 7474 7475 /* We only deal with integral and pointer types. */ 7476 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0)) 7477 && !POINTER_TYPE_P (TREE_TYPE (op0))) 7478 return NULL_TREE; 7479 7480 if ((ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges 7481 (code, op0, op1, strict_overflow_p))) 7482 return ret; 7483 if (only_ranges) 7484 *only_ranges = false; 7485 /* Do not use compare_names during propagation, it's quadratic. */ 7486 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME 7487 && use_equiv_p) 7488 return compare_names (code, op0, op1, strict_overflow_p); 7489 else if (TREE_CODE (op0) == SSA_NAME) 7490 return compare_name_with_value (code, op0, op1, 7491 strict_overflow_p, use_equiv_p); 7492 else if (TREE_CODE (op1) == SSA_NAME) 7493 return compare_name_with_value (swap_tree_comparison (code), op1, op0, 7494 strict_overflow_p, use_equiv_p); 7495 return NULL_TREE; 7496 } 7497 7498 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range 7499 information. Return NULL if the conditional can not be evaluated. 7500 The ranges of all the names equivalent with the operands in COND 7501 will be used when trying to compute the value. If the result is 7502 based on undefined signed overflow, issue a warning if 7503 appropriate. */ 7504 7505 static tree 7506 vrp_evaluate_conditional (tree_code code, tree op0, tree op1, gimple *stmt) 7507 { 7508 bool sop; 7509 tree ret; 7510 bool only_ranges; 7511 7512 /* Some passes and foldings leak constants with overflow flag set 7513 into the IL. Avoid doing wrong things with these and bail out. */ 7514 if ((TREE_CODE (op0) == INTEGER_CST 7515 && TREE_OVERFLOW (op0)) 7516 || (TREE_CODE (op1) == INTEGER_CST 7517 && TREE_OVERFLOW (op1))) 7518 return NULL_TREE; 7519 7520 sop = false; 7521 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop, 7522 &only_ranges); 7523 7524 if (ret && sop) 7525 { 7526 enum warn_strict_overflow_code wc; 7527 const char* warnmsg; 7528 7529 if (is_gimple_min_invariant (ret)) 7530 { 7531 wc = WARN_STRICT_OVERFLOW_CONDITIONAL; 7532 warnmsg = G_("assuming signed overflow does not occur when " 7533 "simplifying conditional to constant"); 7534 } 7535 else 7536 { 7537 wc = WARN_STRICT_OVERFLOW_COMPARISON; 7538 warnmsg = G_("assuming signed overflow does not occur when " 7539 "simplifying conditional"); 7540 } 7541 7542 if (issue_strict_overflow_warning (wc)) 7543 { 7544 location_t location; 7545 7546 if (!gimple_has_location (stmt)) 7547 location = input_location; 7548 else 7549 location = gimple_location (stmt); 7550 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg); 7551 } 7552 } 7553 7554 if (warn_type_limits 7555 && ret && only_ranges 7556 && TREE_CODE_CLASS (code) == tcc_comparison 7557 && TREE_CODE (op0) == SSA_NAME) 7558 { 7559 /* If the comparison is being folded and the operand on the LHS 7560 is being compared against a constant value that is outside of 7561 the natural range of OP0's type, then the predicate will 7562 always fold regardless of the value of OP0. If -Wtype-limits 7563 was specified, emit a warning. */ 7564 tree type = TREE_TYPE (op0); 7565 value_range *vr0 = get_value_range (op0); 7566 7567 if (vr0->type == VR_RANGE 7568 && INTEGRAL_TYPE_P (type) 7569 && vrp_val_is_min (vr0->min) 7570 && vrp_val_is_max (vr0->max) 7571 && is_gimple_min_invariant (op1)) 7572 { 7573 location_t location; 7574 7575 if (!gimple_has_location (stmt)) 7576 location = input_location; 7577 else 7578 location = gimple_location (stmt); 7579 7580 warning_at (location, OPT_Wtype_limits, 7581 integer_zerop (ret) 7582 ? G_("comparison always false " 7583 "due to limited range of data type") 7584 : G_("comparison always true " 7585 "due to limited range of data type")); 7586 } 7587 } 7588 7589 return ret; 7590 } 7591 7592 7593 /* Visit conditional statement STMT. If we can determine which edge 7594 will be taken out of STMT's basic block, record it in 7595 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return 7596 SSA_PROP_VARYING. */ 7597 7598 static enum ssa_prop_result 7599 vrp_visit_cond_stmt (gcond *stmt, edge *taken_edge_p) 7600 { 7601 tree val; 7602 bool sop; 7603 7604 *taken_edge_p = NULL; 7605 7606 if (dump_file && (dump_flags & TDF_DETAILS)) 7607 { 7608 tree use; 7609 ssa_op_iter i; 7610 7611 fprintf (dump_file, "\nVisiting conditional with predicate: "); 7612 print_gimple_stmt (dump_file, stmt, 0, 0); 7613 fprintf (dump_file, "\nWith known ranges\n"); 7614 7615 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE) 7616 { 7617 fprintf (dump_file, "\t"); 7618 print_generic_expr (dump_file, use, 0); 7619 fprintf (dump_file, ": "); 7620 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]); 7621 } 7622 7623 fprintf (dump_file, "\n"); 7624 } 7625 7626 /* Compute the value of the predicate COND by checking the known 7627 ranges of each of its operands. 7628 7629 Note that we cannot evaluate all the equivalent ranges here 7630 because those ranges may not yet be final and with the current 7631 propagation strategy, we cannot determine when the value ranges 7632 of the names in the equivalence set have changed. 7633 7634 For instance, given the following code fragment 7635 7636 i_5 = PHI <8, i_13> 7637 ... 7638 i_14 = ASSERT_EXPR <i_5, i_5 != 0> 7639 if (i_14 == 1) 7640 ... 7641 7642 Assume that on the first visit to i_14, i_5 has the temporary 7643 range [8, 8] because the second argument to the PHI function is 7644 not yet executable. We derive the range ~[0, 0] for i_14 and the 7645 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for 7646 the first time, since i_14 is equivalent to the range [8, 8], we 7647 determine that the predicate is always false. 7648 7649 On the next round of propagation, i_13 is determined to be 7650 VARYING, which causes i_5 to drop down to VARYING. So, another 7651 visit to i_14 is scheduled. In this second visit, we compute the 7652 exact same range and equivalence set for i_14, namely ~[0, 0] and 7653 { i_5 }. But we did not have the previous range for i_5 7654 registered, so vrp_visit_assignment thinks that the range for 7655 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)' 7656 is not visited again, which stops propagation from visiting 7657 statements in the THEN clause of that if(). 7658 7659 To properly fix this we would need to keep the previous range 7660 value for the names in the equivalence set. This way we would've 7661 discovered that from one visit to the other i_5 changed from 7662 range [8, 8] to VR_VARYING. 7663 7664 However, fixing this apparent limitation may not be worth the 7665 additional checking. Testing on several code bases (GCC, DLV, 7666 MICO, TRAMP3D and SPEC2000) showed that doing this results in 7667 4 more predicates folded in SPEC. */ 7668 sop = false; 7669 7670 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt), 7671 gimple_cond_lhs (stmt), 7672 gimple_cond_rhs (stmt), 7673 false, &sop, NULL); 7674 if (val) 7675 { 7676 if (!sop) 7677 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val); 7678 else 7679 { 7680 if (dump_file && (dump_flags & TDF_DETAILS)) 7681 fprintf (dump_file, 7682 "\nIgnoring predicate evaluation because " 7683 "it assumes that signed overflow is undefined"); 7684 val = NULL_TREE; 7685 } 7686 } 7687 7688 if (dump_file && (dump_flags & TDF_DETAILS)) 7689 { 7690 fprintf (dump_file, "\nPredicate evaluates to: "); 7691 if (val == NULL_TREE) 7692 fprintf (dump_file, "DON'T KNOW\n"); 7693 else 7694 print_generic_stmt (dump_file, val, 0); 7695 } 7696 7697 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING; 7698 } 7699 7700 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL 7701 that includes the value VAL. The search is restricted to the range 7702 [START_IDX, n - 1] where n is the size of VEC. 7703 7704 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is 7705 returned. 7706 7707 If there is no CASE_LABEL for VAL and there is one that is larger than VAL, 7708 it is placed in IDX and false is returned. 7709 7710 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is 7711 returned. */ 7712 7713 static bool 7714 find_case_label_index (gswitch *stmt, size_t start_idx, tree val, size_t *idx) 7715 { 7716 size_t n = gimple_switch_num_labels (stmt); 7717 size_t low, high; 7718 7719 /* Find case label for minimum of the value range or the next one. 7720 At each iteration we are searching in [low, high - 1]. */ 7721 7722 for (low = start_idx, high = n; high != low; ) 7723 { 7724 tree t; 7725 int cmp; 7726 /* Note that i != high, so we never ask for n. */ 7727 size_t i = (high + low) / 2; 7728 t = gimple_switch_label (stmt, i); 7729 7730 /* Cache the result of comparing CASE_LOW and val. */ 7731 cmp = tree_int_cst_compare (CASE_LOW (t), val); 7732 7733 if (cmp == 0) 7734 { 7735 /* Ranges cannot be empty. */ 7736 *idx = i; 7737 return true; 7738 } 7739 else if (cmp > 0) 7740 high = i; 7741 else 7742 { 7743 low = i + 1; 7744 if (CASE_HIGH (t) != NULL 7745 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0) 7746 { 7747 *idx = i; 7748 return true; 7749 } 7750 } 7751 } 7752 7753 *idx = high; 7754 return false; 7755 } 7756 7757 /* Searches the case label vector VEC for the range of CASE_LABELs that is used 7758 for values between MIN and MAX. The first index is placed in MIN_IDX. The 7759 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty 7760 then MAX_IDX < MIN_IDX. 7761 Returns true if the default label is not needed. */ 7762 7763 static bool 7764 find_case_label_range (gswitch *stmt, tree min, tree max, size_t *min_idx, 7765 size_t *max_idx) 7766 { 7767 size_t i, j; 7768 bool min_take_default = !find_case_label_index (stmt, 1, min, &i); 7769 bool max_take_default = !find_case_label_index (stmt, i, max, &j); 7770 7771 if (i == j 7772 && min_take_default 7773 && max_take_default) 7774 { 7775 /* Only the default case label reached. 7776 Return an empty range. */ 7777 *min_idx = 1; 7778 *max_idx = 0; 7779 return false; 7780 } 7781 else 7782 { 7783 bool take_default = min_take_default || max_take_default; 7784 tree low, high; 7785 size_t k; 7786 7787 if (max_take_default) 7788 j--; 7789 7790 /* If the case label range is continuous, we do not need 7791 the default case label. Verify that. */ 7792 high = CASE_LOW (gimple_switch_label (stmt, i)); 7793 if (CASE_HIGH (gimple_switch_label (stmt, i))) 7794 high = CASE_HIGH (gimple_switch_label (stmt, i)); 7795 for (k = i + 1; k <= j; ++k) 7796 { 7797 low = CASE_LOW (gimple_switch_label (stmt, k)); 7798 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high))) 7799 { 7800 take_default = true; 7801 break; 7802 } 7803 high = low; 7804 if (CASE_HIGH (gimple_switch_label (stmt, k))) 7805 high = CASE_HIGH (gimple_switch_label (stmt, k)); 7806 } 7807 7808 *min_idx = i; 7809 *max_idx = j; 7810 return !take_default; 7811 } 7812 } 7813 7814 /* Searches the case label vector VEC for the ranges of CASE_LABELs that are 7815 used in range VR. The indices are placed in MIN_IDX1, MAX_IDX, MIN_IDX2 and 7816 MAX_IDX2. If the ranges of CASE_LABELs are empty then MAX_IDX1 < MIN_IDX1. 7817 Returns true if the default label is not needed. */ 7818 7819 static bool 7820 find_case_label_ranges (gswitch *stmt, value_range *vr, size_t *min_idx1, 7821 size_t *max_idx1, size_t *min_idx2, 7822 size_t *max_idx2) 7823 { 7824 size_t i, j, k, l; 7825 unsigned int n = gimple_switch_num_labels (stmt); 7826 bool take_default; 7827 tree case_low, case_high; 7828 tree min = vr->min, max = vr->max; 7829 7830 gcc_checking_assert (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE); 7831 7832 take_default = !find_case_label_range (stmt, min, max, &i, &j); 7833 7834 /* Set second range to emtpy. */ 7835 *min_idx2 = 1; 7836 *max_idx2 = 0; 7837 7838 if (vr->type == VR_RANGE) 7839 { 7840 *min_idx1 = i; 7841 *max_idx1 = j; 7842 return !take_default; 7843 } 7844 7845 /* Set first range to all case labels. */ 7846 *min_idx1 = 1; 7847 *max_idx1 = n - 1; 7848 7849 if (i > j) 7850 return false; 7851 7852 /* Make sure all the values of case labels [i , j] are contained in 7853 range [MIN, MAX]. */ 7854 case_low = CASE_LOW (gimple_switch_label (stmt, i)); 7855 case_high = CASE_HIGH (gimple_switch_label (stmt, j)); 7856 if (tree_int_cst_compare (case_low, min) < 0) 7857 i += 1; 7858 if (case_high != NULL_TREE 7859 && tree_int_cst_compare (max, case_high) < 0) 7860 j -= 1; 7861 7862 if (i > j) 7863 return false; 7864 7865 /* If the range spans case labels [i, j], the corresponding anti-range spans 7866 the labels [1, i - 1] and [j + 1, n - 1]. */ 7867 k = j + 1; 7868 l = n - 1; 7869 if (k > l) 7870 { 7871 k = 1; 7872 l = 0; 7873 } 7874 7875 j = i - 1; 7876 i = 1; 7877 if (i > j) 7878 { 7879 i = k; 7880 j = l; 7881 k = 1; 7882 l = 0; 7883 } 7884 7885 *min_idx1 = i; 7886 *max_idx1 = j; 7887 *min_idx2 = k; 7888 *max_idx2 = l; 7889 return false; 7890 } 7891 7892 /* Visit switch statement STMT. If we can determine which edge 7893 will be taken out of STMT's basic block, record it in 7894 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return 7895 SSA_PROP_VARYING. */ 7896 7897 static enum ssa_prop_result 7898 vrp_visit_switch_stmt (gswitch *stmt, edge *taken_edge_p) 7899 { 7900 tree op, val; 7901 value_range *vr; 7902 size_t i = 0, j = 0, k, l; 7903 bool take_default; 7904 7905 *taken_edge_p = NULL; 7906 op = gimple_switch_index (stmt); 7907 if (TREE_CODE (op) != SSA_NAME) 7908 return SSA_PROP_VARYING; 7909 7910 vr = get_value_range (op); 7911 if (dump_file && (dump_flags & TDF_DETAILS)) 7912 { 7913 fprintf (dump_file, "\nVisiting switch expression with operand "); 7914 print_generic_expr (dump_file, op, 0); 7915 fprintf (dump_file, " with known range "); 7916 dump_value_range (dump_file, vr); 7917 fprintf (dump_file, "\n"); 7918 } 7919 7920 if ((vr->type != VR_RANGE 7921 && vr->type != VR_ANTI_RANGE) 7922 || symbolic_range_p (vr)) 7923 return SSA_PROP_VARYING; 7924 7925 /* Find the single edge that is taken from the switch expression. */ 7926 take_default = !find_case_label_ranges (stmt, vr, &i, &j, &k, &l); 7927 7928 /* Check if the range spans no CASE_LABEL. If so, we only reach the default 7929 label */ 7930 if (j < i) 7931 { 7932 gcc_assert (take_default); 7933 val = gimple_switch_default_label (stmt); 7934 } 7935 else 7936 { 7937 /* Check if labels with index i to j and maybe the default label 7938 are all reaching the same label. */ 7939 7940 val = gimple_switch_label (stmt, i); 7941 if (take_default 7942 && CASE_LABEL (gimple_switch_default_label (stmt)) 7943 != CASE_LABEL (val)) 7944 { 7945 if (dump_file && (dump_flags & TDF_DETAILS)) 7946 fprintf (dump_file, " not a single destination for this " 7947 "range\n"); 7948 return SSA_PROP_VARYING; 7949 } 7950 for (++i; i <= j; ++i) 7951 { 7952 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val)) 7953 { 7954 if (dump_file && (dump_flags & TDF_DETAILS)) 7955 fprintf (dump_file, " not a single destination for this " 7956 "range\n"); 7957 return SSA_PROP_VARYING; 7958 } 7959 } 7960 for (; k <= l; ++k) 7961 { 7962 if (CASE_LABEL (gimple_switch_label (stmt, k)) != CASE_LABEL (val)) 7963 { 7964 if (dump_file && (dump_flags & TDF_DETAILS)) 7965 fprintf (dump_file, " not a single destination for this " 7966 "range\n"); 7967 return SSA_PROP_VARYING; 7968 } 7969 } 7970 } 7971 7972 *taken_edge_p = find_edge (gimple_bb (stmt), 7973 label_to_block (CASE_LABEL (val))); 7974 7975 if (dump_file && (dump_flags & TDF_DETAILS)) 7976 { 7977 fprintf (dump_file, " will take edge to "); 7978 print_generic_stmt (dump_file, CASE_LABEL (val), 0); 7979 } 7980 7981 return SSA_PROP_INTERESTING; 7982 } 7983 7984 7985 /* Evaluate statement STMT. If the statement produces a useful range, 7986 return SSA_PROP_INTERESTING and record the SSA name with the 7987 interesting range into *OUTPUT_P. 7988 7989 If STMT is a conditional branch and we can determine its truth 7990 value, the taken edge is recorded in *TAKEN_EDGE_P. 7991 7992 If STMT produces a varying value, return SSA_PROP_VARYING. */ 7993 7994 static enum ssa_prop_result 7995 vrp_visit_stmt (gimple *stmt, edge *taken_edge_p, tree *output_p) 7996 { 7997 if (dump_file && (dump_flags & TDF_DETAILS)) 7998 { 7999 fprintf (dump_file, "\nVisiting statement:\n"); 8000 print_gimple_stmt (dump_file, stmt, 0, dump_flags); 8001 } 8002 8003 if (!stmt_interesting_for_vrp (stmt)) 8004 gcc_assert (stmt_ends_bb_p (stmt)); 8005 else if (is_gimple_assign (stmt) || is_gimple_call (stmt)) 8006 return vrp_visit_assignment_or_call (stmt, output_p); 8007 else if (gimple_code (stmt) == GIMPLE_COND) 8008 return vrp_visit_cond_stmt (as_a <gcond *> (stmt), taken_edge_p); 8009 else if (gimple_code (stmt) == GIMPLE_SWITCH) 8010 return vrp_visit_switch_stmt (as_a <gswitch *> (stmt), taken_edge_p); 8011 8012 /* All other statements produce nothing of interest for VRP, so mark 8013 their outputs varying and prevent further simulation. */ 8014 set_defs_to_varying (stmt); 8015 8016 return SSA_PROP_VARYING; 8017 } 8018 8019 /* Union the two value-ranges { *VR0TYPE, *VR0MIN, *VR0MAX } and 8020 { VR1TYPE, VR0MIN, VR0MAX } and store the result 8021 in { *VR0TYPE, *VR0MIN, *VR0MAX }. This may not be the smallest 8022 possible such range. The resulting range is not canonicalized. */ 8023 8024 static void 8025 union_ranges (enum value_range_type *vr0type, 8026 tree *vr0min, tree *vr0max, 8027 enum value_range_type vr1type, 8028 tree vr1min, tree vr1max) 8029 { 8030 bool mineq = vrp_operand_equal_p (*vr0min, vr1min); 8031 bool maxeq = vrp_operand_equal_p (*vr0max, vr1max); 8032 8033 /* [] is vr0, () is vr1 in the following classification comments. */ 8034 if (mineq && maxeq) 8035 { 8036 /* [( )] */ 8037 if (*vr0type == vr1type) 8038 /* Nothing to do for equal ranges. */ 8039 ; 8040 else if ((*vr0type == VR_RANGE 8041 && vr1type == VR_ANTI_RANGE) 8042 || (*vr0type == VR_ANTI_RANGE 8043 && vr1type == VR_RANGE)) 8044 { 8045 /* For anti-range with range union the result is varying. */ 8046 goto give_up; 8047 } 8048 else 8049 gcc_unreachable (); 8050 } 8051 else if (operand_less_p (*vr0max, vr1min) == 1 8052 || operand_less_p (vr1max, *vr0min) == 1) 8053 { 8054 /* [ ] ( ) or ( ) [ ] 8055 If the ranges have an empty intersection, result of the union 8056 operation is the anti-range or if both are anti-ranges 8057 it covers all. */ 8058 if (*vr0type == VR_ANTI_RANGE 8059 && vr1type == VR_ANTI_RANGE) 8060 goto give_up; 8061 else if (*vr0type == VR_ANTI_RANGE 8062 && vr1type == VR_RANGE) 8063 ; 8064 else if (*vr0type == VR_RANGE 8065 && vr1type == VR_ANTI_RANGE) 8066 { 8067 *vr0type = vr1type; 8068 *vr0min = vr1min; 8069 *vr0max = vr1max; 8070 } 8071 else if (*vr0type == VR_RANGE 8072 && vr1type == VR_RANGE) 8073 { 8074 /* The result is the convex hull of both ranges. */ 8075 if (operand_less_p (*vr0max, vr1min) == 1) 8076 { 8077 /* If the result can be an anti-range, create one. */ 8078 if (TREE_CODE (*vr0max) == INTEGER_CST 8079 && TREE_CODE (vr1min) == INTEGER_CST 8080 && vrp_val_is_min (*vr0min) 8081 && vrp_val_is_max (vr1max)) 8082 { 8083 tree min = int_const_binop (PLUS_EXPR, 8084 *vr0max, 8085 build_int_cst (TREE_TYPE (*vr0max), 1)); 8086 tree max = int_const_binop (MINUS_EXPR, 8087 vr1min, 8088 build_int_cst (TREE_TYPE (vr1min), 1)); 8089 if (!operand_less_p (max, min)) 8090 { 8091 *vr0type = VR_ANTI_RANGE; 8092 *vr0min = min; 8093 *vr0max = max; 8094 } 8095 else 8096 *vr0max = vr1max; 8097 } 8098 else 8099 *vr0max = vr1max; 8100 } 8101 else 8102 { 8103 /* If the result can be an anti-range, create one. */ 8104 if (TREE_CODE (vr1max) == INTEGER_CST 8105 && TREE_CODE (*vr0min) == INTEGER_CST 8106 && vrp_val_is_min (vr1min) 8107 && vrp_val_is_max (*vr0max)) 8108 { 8109 tree min = int_const_binop (PLUS_EXPR, 8110 vr1max, 8111 build_int_cst (TREE_TYPE (vr1max), 1)); 8112 tree max = int_const_binop (MINUS_EXPR, 8113 *vr0min, 8114 build_int_cst (TREE_TYPE (*vr0min), 1)); 8115 if (!operand_less_p (max, min)) 8116 { 8117 *vr0type = VR_ANTI_RANGE; 8118 *vr0min = min; 8119 *vr0max = max; 8120 } 8121 else 8122 *vr0min = vr1min; 8123 } 8124 else 8125 *vr0min = vr1min; 8126 } 8127 } 8128 else 8129 gcc_unreachable (); 8130 } 8131 else if ((maxeq || operand_less_p (vr1max, *vr0max) == 1) 8132 && (mineq || operand_less_p (*vr0min, vr1min) == 1)) 8133 { 8134 /* [ ( ) ] or [( ) ] or [ ( )] */ 8135 if (*vr0type == VR_RANGE 8136 && vr1type == VR_RANGE) 8137 ; 8138 else if (*vr0type == VR_ANTI_RANGE 8139 && vr1type == VR_ANTI_RANGE) 8140 { 8141 *vr0type = vr1type; 8142 *vr0min = vr1min; 8143 *vr0max = vr1max; 8144 } 8145 else if (*vr0type == VR_ANTI_RANGE 8146 && vr1type == VR_RANGE) 8147 { 8148 /* Arbitrarily choose the right or left gap. */ 8149 if (!mineq && TREE_CODE (vr1min) == INTEGER_CST) 8150 *vr0max = int_const_binop (MINUS_EXPR, vr1min, 8151 build_int_cst (TREE_TYPE (vr1min), 1)); 8152 else if (!maxeq && TREE_CODE (vr1max) == INTEGER_CST) 8153 *vr0min = int_const_binop (PLUS_EXPR, vr1max, 8154 build_int_cst (TREE_TYPE (vr1max), 1)); 8155 else 8156 goto give_up; 8157 } 8158 else if (*vr0type == VR_RANGE 8159 && vr1type == VR_ANTI_RANGE) 8160 /* The result covers everything. */ 8161 goto give_up; 8162 else 8163 gcc_unreachable (); 8164 } 8165 else if ((maxeq || operand_less_p (*vr0max, vr1max) == 1) 8166 && (mineq || operand_less_p (vr1min, *vr0min) == 1)) 8167 { 8168 /* ( [ ] ) or ([ ] ) or ( [ ]) */ 8169 if (*vr0type == VR_RANGE 8170 && vr1type == VR_RANGE) 8171 { 8172 *vr0type = vr1type; 8173 *vr0min = vr1min; 8174 *vr0max = vr1max; 8175 } 8176 else if (*vr0type == VR_ANTI_RANGE 8177 && vr1type == VR_ANTI_RANGE) 8178 ; 8179 else if (*vr0type == VR_RANGE 8180 && vr1type == VR_ANTI_RANGE) 8181 { 8182 *vr0type = VR_ANTI_RANGE; 8183 if (!mineq && TREE_CODE (*vr0min) == INTEGER_CST) 8184 { 8185 *vr0max = int_const_binop (MINUS_EXPR, *vr0min, 8186 build_int_cst (TREE_TYPE (*vr0min), 1)); 8187 *vr0min = vr1min; 8188 } 8189 else if (!maxeq && TREE_CODE (*vr0max) == INTEGER_CST) 8190 { 8191 *vr0min = int_const_binop (PLUS_EXPR, *vr0max, 8192 build_int_cst (TREE_TYPE (*vr0max), 1)); 8193 *vr0max = vr1max; 8194 } 8195 else 8196 goto give_up; 8197 } 8198 else if (*vr0type == VR_ANTI_RANGE 8199 && vr1type == VR_RANGE) 8200 /* The result covers everything. */ 8201 goto give_up; 8202 else 8203 gcc_unreachable (); 8204 } 8205 else if ((operand_less_p (vr1min, *vr0max) == 1 8206 || operand_equal_p (vr1min, *vr0max, 0)) 8207 && operand_less_p (*vr0min, vr1min) == 1 8208 && operand_less_p (*vr0max, vr1max) == 1) 8209 { 8210 /* [ ( ] ) or [ ]( ) */ 8211 if (*vr0type == VR_RANGE 8212 && vr1type == VR_RANGE) 8213 *vr0max = vr1max; 8214 else if (*vr0type == VR_ANTI_RANGE 8215 && vr1type == VR_ANTI_RANGE) 8216 *vr0min = vr1min; 8217 else if (*vr0type == VR_ANTI_RANGE 8218 && vr1type == VR_RANGE) 8219 { 8220 if (TREE_CODE (vr1min) == INTEGER_CST) 8221 *vr0max = int_const_binop (MINUS_EXPR, vr1min, 8222 build_int_cst (TREE_TYPE (vr1min), 1)); 8223 else 8224 goto give_up; 8225 } 8226 else if (*vr0type == VR_RANGE 8227 && vr1type == VR_ANTI_RANGE) 8228 { 8229 if (TREE_CODE (*vr0max) == INTEGER_CST) 8230 { 8231 *vr0type = vr1type; 8232 *vr0min = int_const_binop (PLUS_EXPR, *vr0max, 8233 build_int_cst (TREE_TYPE (*vr0max), 1)); 8234 *vr0max = vr1max; 8235 } 8236 else 8237 goto give_up; 8238 } 8239 else 8240 gcc_unreachable (); 8241 } 8242 else if ((operand_less_p (*vr0min, vr1max) == 1 8243 || operand_equal_p (*vr0min, vr1max, 0)) 8244 && operand_less_p (vr1min, *vr0min) == 1 8245 && operand_less_p (vr1max, *vr0max) == 1) 8246 { 8247 /* ( [ ) ] or ( )[ ] */ 8248 if (*vr0type == VR_RANGE 8249 && vr1type == VR_RANGE) 8250 *vr0min = vr1min; 8251 else if (*vr0type == VR_ANTI_RANGE 8252 && vr1type == VR_ANTI_RANGE) 8253 *vr0max = vr1max; 8254 else if (*vr0type == VR_ANTI_RANGE 8255 && vr1type == VR_RANGE) 8256 { 8257 if (TREE_CODE (vr1max) == INTEGER_CST) 8258 *vr0min = int_const_binop (PLUS_EXPR, vr1max, 8259 build_int_cst (TREE_TYPE (vr1max), 1)); 8260 else 8261 goto give_up; 8262 } 8263 else if (*vr0type == VR_RANGE 8264 && vr1type == VR_ANTI_RANGE) 8265 { 8266 if (TREE_CODE (*vr0min) == INTEGER_CST) 8267 { 8268 *vr0type = vr1type; 8269 *vr0max = int_const_binop (MINUS_EXPR, *vr0min, 8270 build_int_cst (TREE_TYPE (*vr0min), 1)); 8271 *vr0min = vr1min; 8272 } 8273 else 8274 goto give_up; 8275 } 8276 else 8277 gcc_unreachable (); 8278 } 8279 else 8280 goto give_up; 8281 8282 return; 8283 8284 give_up: 8285 *vr0type = VR_VARYING; 8286 *vr0min = NULL_TREE; 8287 *vr0max = NULL_TREE; 8288 } 8289 8290 /* Intersect the two value-ranges { *VR0TYPE, *VR0MIN, *VR0MAX } and 8291 { VR1TYPE, VR0MIN, VR0MAX } and store the result 8292 in { *VR0TYPE, *VR0MIN, *VR0MAX }. This may not be the smallest 8293 possible such range. The resulting range is not canonicalized. */ 8294 8295 static void 8296 intersect_ranges (enum value_range_type *vr0type, 8297 tree *vr0min, tree *vr0max, 8298 enum value_range_type vr1type, 8299 tree vr1min, tree vr1max) 8300 { 8301 bool mineq = vrp_operand_equal_p (*vr0min, vr1min); 8302 bool maxeq = vrp_operand_equal_p (*vr0max, vr1max); 8303 8304 /* [] is vr0, () is vr1 in the following classification comments. */ 8305 if (mineq && maxeq) 8306 { 8307 /* [( )] */ 8308 if (*vr0type == vr1type) 8309 /* Nothing to do for equal ranges. */ 8310 ; 8311 else if ((*vr0type == VR_RANGE 8312 && vr1type == VR_ANTI_RANGE) 8313 || (*vr0type == VR_ANTI_RANGE 8314 && vr1type == VR_RANGE)) 8315 { 8316 /* For anti-range with range intersection the result is empty. */ 8317 *vr0type = VR_UNDEFINED; 8318 *vr0min = NULL_TREE; 8319 *vr0max = NULL_TREE; 8320 } 8321 else 8322 gcc_unreachable (); 8323 } 8324 else if (operand_less_p (*vr0max, vr1min) == 1 8325 || operand_less_p (vr1max, *vr0min) == 1) 8326 { 8327 /* [ ] ( ) or ( ) [ ] 8328 If the ranges have an empty intersection, the result of the 8329 intersect operation is the range for intersecting an 8330 anti-range with a range or empty when intersecting two ranges. */ 8331 if (*vr0type == VR_RANGE 8332 && vr1type == VR_ANTI_RANGE) 8333 ; 8334 else if (*vr0type == VR_ANTI_RANGE 8335 && vr1type == VR_RANGE) 8336 { 8337 *vr0type = vr1type; 8338 *vr0min = vr1min; 8339 *vr0max = vr1max; 8340 } 8341 else if (*vr0type == VR_RANGE 8342 && vr1type == VR_RANGE) 8343 { 8344 *vr0type = VR_UNDEFINED; 8345 *vr0min = NULL_TREE; 8346 *vr0max = NULL_TREE; 8347 } 8348 else if (*vr0type == VR_ANTI_RANGE 8349 && vr1type == VR_ANTI_RANGE) 8350 { 8351 /* If the anti-ranges are adjacent to each other merge them. */ 8352 if (TREE_CODE (*vr0max) == INTEGER_CST 8353 && TREE_CODE (vr1min) == INTEGER_CST 8354 && operand_less_p (*vr0max, vr1min) == 1 8355 && integer_onep (int_const_binop (MINUS_EXPR, 8356 vr1min, *vr0max))) 8357 *vr0max = vr1max; 8358 else if (TREE_CODE (vr1max) == INTEGER_CST 8359 && TREE_CODE (*vr0min) == INTEGER_CST 8360 && operand_less_p (vr1max, *vr0min) == 1 8361 && integer_onep (int_const_binop (MINUS_EXPR, 8362 *vr0min, vr1max))) 8363 *vr0min = vr1min; 8364 /* Else arbitrarily take VR0. */ 8365 } 8366 } 8367 else if ((maxeq || operand_less_p (vr1max, *vr0max) == 1) 8368 && (mineq || operand_less_p (*vr0min, vr1min) == 1)) 8369 { 8370 /* [ ( ) ] or [( ) ] or [ ( )] */ 8371 if (*vr0type == VR_RANGE 8372 && vr1type == VR_RANGE) 8373 { 8374 /* If both are ranges the result is the inner one. */ 8375 *vr0type = vr1type; 8376 *vr0min = vr1min; 8377 *vr0max = vr1max; 8378 } 8379 else if (*vr0type == VR_RANGE 8380 && vr1type == VR_ANTI_RANGE) 8381 { 8382 /* Choose the right gap if the left one is empty. */ 8383 if (mineq) 8384 { 8385 if (TREE_CODE (vr1max) == INTEGER_CST) 8386 *vr0min = int_const_binop (PLUS_EXPR, vr1max, 8387 build_int_cst (TREE_TYPE (vr1max), 1)); 8388 else 8389 *vr0min = vr1max; 8390 } 8391 /* Choose the left gap if the right one is empty. */ 8392 else if (maxeq) 8393 { 8394 if (TREE_CODE (vr1min) == INTEGER_CST) 8395 *vr0max = int_const_binop (MINUS_EXPR, vr1min, 8396 build_int_cst (TREE_TYPE (vr1min), 1)); 8397 else 8398 *vr0max = vr1min; 8399 } 8400 /* Choose the anti-range if the range is effectively varying. */ 8401 else if (vrp_val_is_min (*vr0min) 8402 && vrp_val_is_max (*vr0max)) 8403 { 8404 *vr0type = vr1type; 8405 *vr0min = vr1min; 8406 *vr0max = vr1max; 8407 } 8408 /* Else choose the range. */ 8409 } 8410 else if (*vr0type == VR_ANTI_RANGE 8411 && vr1type == VR_ANTI_RANGE) 8412 /* If both are anti-ranges the result is the outer one. */ 8413 ; 8414 else if (*vr0type == VR_ANTI_RANGE 8415 && vr1type == VR_RANGE) 8416 { 8417 /* The intersection is empty. */ 8418 *vr0type = VR_UNDEFINED; 8419 *vr0min = NULL_TREE; 8420 *vr0max = NULL_TREE; 8421 } 8422 else 8423 gcc_unreachable (); 8424 } 8425 else if ((maxeq || operand_less_p (*vr0max, vr1max) == 1) 8426 && (mineq || operand_less_p (vr1min, *vr0min) == 1)) 8427 { 8428 /* ( [ ] ) or ([ ] ) or ( [ ]) */ 8429 if (*vr0type == VR_RANGE 8430 && vr1type == VR_RANGE) 8431 /* Choose the inner range. */ 8432 ; 8433 else if (*vr0type == VR_ANTI_RANGE 8434 && vr1type == VR_RANGE) 8435 { 8436 /* Choose the right gap if the left is empty. */ 8437 if (mineq) 8438 { 8439 *vr0type = VR_RANGE; 8440 if (TREE_CODE (*vr0max) == INTEGER_CST) 8441 *vr0min = int_const_binop (PLUS_EXPR, *vr0max, 8442 build_int_cst (TREE_TYPE (*vr0max), 1)); 8443 else 8444 *vr0min = *vr0max; 8445 *vr0max = vr1max; 8446 } 8447 /* Choose the left gap if the right is empty. */ 8448 else if (maxeq) 8449 { 8450 *vr0type = VR_RANGE; 8451 if (TREE_CODE (*vr0min) == INTEGER_CST) 8452 *vr0max = int_const_binop (MINUS_EXPR, *vr0min, 8453 build_int_cst (TREE_TYPE (*vr0min), 1)); 8454 else 8455 *vr0max = *vr0min; 8456 *vr0min = vr1min; 8457 } 8458 /* Choose the anti-range if the range is effectively varying. */ 8459 else if (vrp_val_is_min (vr1min) 8460 && vrp_val_is_max (vr1max)) 8461 ; 8462 /* Else choose the range. */ 8463 else 8464 { 8465 *vr0type = vr1type; 8466 *vr0min = vr1min; 8467 *vr0max = vr1max; 8468 } 8469 } 8470 else if (*vr0type == VR_ANTI_RANGE 8471 && vr1type == VR_ANTI_RANGE) 8472 { 8473 /* If both are anti-ranges the result is the outer one. */ 8474 *vr0type = vr1type; 8475 *vr0min = vr1min; 8476 *vr0max = vr1max; 8477 } 8478 else if (vr1type == VR_ANTI_RANGE 8479 && *vr0type == VR_RANGE) 8480 { 8481 /* The intersection is empty. */ 8482 *vr0type = VR_UNDEFINED; 8483 *vr0min = NULL_TREE; 8484 *vr0max = NULL_TREE; 8485 } 8486 else 8487 gcc_unreachable (); 8488 } 8489 else if ((operand_less_p (vr1min, *vr0max) == 1 8490 || operand_equal_p (vr1min, *vr0max, 0)) 8491 && operand_less_p (*vr0min, vr1min) == 1) 8492 { 8493 /* [ ( ] ) or [ ]( ) */ 8494 if (*vr0type == VR_ANTI_RANGE 8495 && vr1type == VR_ANTI_RANGE) 8496 *vr0max = vr1max; 8497 else if (*vr0type == VR_RANGE 8498 && vr1type == VR_RANGE) 8499 *vr0min = vr1min; 8500 else if (*vr0type == VR_RANGE 8501 && vr1type == VR_ANTI_RANGE) 8502 { 8503 if (TREE_CODE (vr1min) == INTEGER_CST) 8504 *vr0max = int_const_binop (MINUS_EXPR, vr1min, 8505 build_int_cst (TREE_TYPE (vr1min), 1)); 8506 else 8507 *vr0max = vr1min; 8508 } 8509 else if (*vr0type == VR_ANTI_RANGE 8510 && vr1type == VR_RANGE) 8511 { 8512 *vr0type = VR_RANGE; 8513 if (TREE_CODE (*vr0max) == INTEGER_CST) 8514 *vr0min = int_const_binop (PLUS_EXPR, *vr0max, 8515 build_int_cst (TREE_TYPE (*vr0max), 1)); 8516 else 8517 *vr0min = *vr0max; 8518 *vr0max = vr1max; 8519 } 8520 else 8521 gcc_unreachable (); 8522 } 8523 else if ((operand_less_p (*vr0min, vr1max) == 1 8524 || operand_equal_p (*vr0min, vr1max, 0)) 8525 && operand_less_p (vr1min, *vr0min) == 1) 8526 { 8527 /* ( [ ) ] or ( )[ ] */ 8528 if (*vr0type == VR_ANTI_RANGE 8529 && vr1type == VR_ANTI_RANGE) 8530 *vr0min = vr1min; 8531 else if (*vr0type == VR_RANGE 8532 && vr1type == VR_RANGE) 8533 *vr0max = vr1max; 8534 else if (*vr0type == VR_RANGE 8535 && vr1type == VR_ANTI_RANGE) 8536 { 8537 if (TREE_CODE (vr1max) == INTEGER_CST) 8538 *vr0min = int_const_binop (PLUS_EXPR, vr1max, 8539 build_int_cst (TREE_TYPE (vr1max), 1)); 8540 else 8541 *vr0min = vr1max; 8542 } 8543 else if (*vr0type == VR_ANTI_RANGE 8544 && vr1type == VR_RANGE) 8545 { 8546 *vr0type = VR_RANGE; 8547 if (TREE_CODE (*vr0min) == INTEGER_CST) 8548 *vr0max = int_const_binop (MINUS_EXPR, *vr0min, 8549 build_int_cst (TREE_TYPE (*vr0min), 1)); 8550 else 8551 *vr0max = *vr0min; 8552 *vr0min = vr1min; 8553 } 8554 else 8555 gcc_unreachable (); 8556 } 8557 8558 /* As a fallback simply use { *VRTYPE, *VR0MIN, *VR0MAX } as 8559 result for the intersection. That's always a conservative 8560 correct estimate. */ 8561 8562 return; 8563 } 8564 8565 8566 /* Intersect the two value-ranges *VR0 and *VR1 and store the result 8567 in *VR0. This may not be the smallest possible such range. */ 8568 8569 static void 8570 vrp_intersect_ranges_1 (value_range *vr0, value_range *vr1) 8571 { 8572 value_range saved; 8573 8574 /* If either range is VR_VARYING the other one wins. */ 8575 if (vr1->type == VR_VARYING) 8576 return; 8577 if (vr0->type == VR_VARYING) 8578 { 8579 copy_value_range (vr0, vr1); 8580 return; 8581 } 8582 8583 /* When either range is VR_UNDEFINED the resulting range is 8584 VR_UNDEFINED, too. */ 8585 if (vr0->type == VR_UNDEFINED) 8586 return; 8587 if (vr1->type == VR_UNDEFINED) 8588 { 8589 set_value_range_to_undefined (vr0); 8590 return; 8591 } 8592 8593 /* Save the original vr0 so we can return it as conservative intersection 8594 result when our worker turns things to varying. */ 8595 saved = *vr0; 8596 intersect_ranges (&vr0->type, &vr0->min, &vr0->max, 8597 vr1->type, vr1->min, vr1->max); 8598 /* Make sure to canonicalize the result though as the inversion of a 8599 VR_RANGE can still be a VR_RANGE. */ 8600 set_and_canonicalize_value_range (vr0, vr0->type, 8601 vr0->min, vr0->max, vr0->equiv); 8602 /* If that failed, use the saved original VR0. */ 8603 if (vr0->type == VR_VARYING) 8604 { 8605 *vr0 = saved; 8606 return; 8607 } 8608 /* If the result is VR_UNDEFINED there is no need to mess with 8609 the equivalencies. */ 8610 if (vr0->type == VR_UNDEFINED) 8611 return; 8612 8613 /* The resulting set of equivalences for range intersection is the union of 8614 the two sets. */ 8615 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv) 8616 bitmap_ior_into (vr0->equiv, vr1->equiv); 8617 else if (vr1->equiv && !vr0->equiv) 8618 { 8619 vr0->equiv = BITMAP_ALLOC (NULL); 8620 bitmap_copy (vr0->equiv, vr1->equiv); 8621 } 8622 } 8623 8624 static void 8625 vrp_intersect_ranges (value_range *vr0, value_range *vr1) 8626 { 8627 if (dump_file && (dump_flags & TDF_DETAILS)) 8628 { 8629 fprintf (dump_file, "Intersecting\n "); 8630 dump_value_range (dump_file, vr0); 8631 fprintf (dump_file, "\nand\n "); 8632 dump_value_range (dump_file, vr1); 8633 fprintf (dump_file, "\n"); 8634 } 8635 vrp_intersect_ranges_1 (vr0, vr1); 8636 if (dump_file && (dump_flags & TDF_DETAILS)) 8637 { 8638 fprintf (dump_file, "to\n "); 8639 dump_value_range (dump_file, vr0); 8640 fprintf (dump_file, "\n"); 8641 } 8642 } 8643 8644 /* Meet operation for value ranges. Given two value ranges VR0 and 8645 VR1, store in VR0 a range that contains both VR0 and VR1. This 8646 may not be the smallest possible such range. */ 8647 8648 static void 8649 vrp_meet_1 (value_range *vr0, value_range *vr1) 8650 { 8651 value_range saved; 8652 8653 if (vr0->type == VR_UNDEFINED) 8654 { 8655 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr1->equiv); 8656 return; 8657 } 8658 8659 if (vr1->type == VR_UNDEFINED) 8660 { 8661 /* VR0 already has the resulting range. */ 8662 return; 8663 } 8664 8665 if (vr0->type == VR_VARYING) 8666 { 8667 /* Nothing to do. VR0 already has the resulting range. */ 8668 return; 8669 } 8670 8671 if (vr1->type == VR_VARYING) 8672 { 8673 set_value_range_to_varying (vr0); 8674 return; 8675 } 8676 8677 saved = *vr0; 8678 union_ranges (&vr0->type, &vr0->min, &vr0->max, 8679 vr1->type, vr1->min, vr1->max); 8680 if (vr0->type == VR_VARYING) 8681 { 8682 /* Failed to find an efficient meet. Before giving up and setting 8683 the result to VARYING, see if we can at least derive a useful 8684 anti-range. FIXME, all this nonsense about distinguishing 8685 anti-ranges from ranges is necessary because of the odd 8686 semantics of range_includes_zero_p and friends. */ 8687 if (((saved.type == VR_RANGE 8688 && range_includes_zero_p (saved.min, saved.max) == 0) 8689 || (saved.type == VR_ANTI_RANGE 8690 && range_includes_zero_p (saved.min, saved.max) == 1)) 8691 && ((vr1->type == VR_RANGE 8692 && range_includes_zero_p (vr1->min, vr1->max) == 0) 8693 || (vr1->type == VR_ANTI_RANGE 8694 && range_includes_zero_p (vr1->min, vr1->max) == 1))) 8695 { 8696 set_value_range_to_nonnull (vr0, TREE_TYPE (saved.min)); 8697 8698 /* Since this meet operation did not result from the meeting of 8699 two equivalent names, VR0 cannot have any equivalences. */ 8700 if (vr0->equiv) 8701 bitmap_clear (vr0->equiv); 8702 return; 8703 } 8704 8705 set_value_range_to_varying (vr0); 8706 return; 8707 } 8708 set_and_canonicalize_value_range (vr0, vr0->type, vr0->min, vr0->max, 8709 vr0->equiv); 8710 if (vr0->type == VR_VARYING) 8711 return; 8712 8713 /* The resulting set of equivalences is always the intersection of 8714 the two sets. */ 8715 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv) 8716 bitmap_and_into (vr0->equiv, vr1->equiv); 8717 else if (vr0->equiv && !vr1->equiv) 8718 bitmap_clear (vr0->equiv); 8719 } 8720 8721 static void 8722 vrp_meet (value_range *vr0, value_range *vr1) 8723 { 8724 if (dump_file && (dump_flags & TDF_DETAILS)) 8725 { 8726 fprintf (dump_file, "Meeting\n "); 8727 dump_value_range (dump_file, vr0); 8728 fprintf (dump_file, "\nand\n "); 8729 dump_value_range (dump_file, vr1); 8730 fprintf (dump_file, "\n"); 8731 } 8732 vrp_meet_1 (vr0, vr1); 8733 if (dump_file && (dump_flags & TDF_DETAILS)) 8734 { 8735 fprintf (dump_file, "to\n "); 8736 dump_value_range (dump_file, vr0); 8737 fprintf (dump_file, "\n"); 8738 } 8739 } 8740 8741 8742 /* Visit all arguments for PHI node PHI that flow through executable 8743 edges. If a valid value range can be derived from all the incoming 8744 value ranges, set a new range for the LHS of PHI. */ 8745 8746 static enum ssa_prop_result 8747 vrp_visit_phi_node (gphi *phi) 8748 { 8749 size_t i; 8750 tree lhs = PHI_RESULT (phi); 8751 value_range *lhs_vr = get_value_range (lhs); 8752 value_range vr_result = VR_INITIALIZER; 8753 bool first = true; 8754 int edges, old_edges; 8755 struct loop *l; 8756 8757 if (dump_file && (dump_flags & TDF_DETAILS)) 8758 { 8759 fprintf (dump_file, "\nVisiting PHI node: "); 8760 print_gimple_stmt (dump_file, phi, 0, dump_flags); 8761 } 8762 8763 edges = 0; 8764 for (i = 0; i < gimple_phi_num_args (phi); i++) 8765 { 8766 edge e = gimple_phi_arg_edge (phi, i); 8767 8768 if (dump_file && (dump_flags & TDF_DETAILS)) 8769 { 8770 fprintf (dump_file, 8771 " Argument #%d (%d -> %d %sexecutable)\n", 8772 (int) i, e->src->index, e->dest->index, 8773 (e->flags & EDGE_EXECUTABLE) ? "" : "not "); 8774 } 8775 8776 if (e->flags & EDGE_EXECUTABLE) 8777 { 8778 tree arg = PHI_ARG_DEF (phi, i); 8779 value_range vr_arg; 8780 8781 ++edges; 8782 8783 if (TREE_CODE (arg) == SSA_NAME) 8784 { 8785 vr_arg = *(get_value_range (arg)); 8786 /* Do not allow equivalences or symbolic ranges to leak in from 8787 backedges. That creates invalid equivalencies. 8788 See PR53465 and PR54767. */ 8789 if (e->flags & EDGE_DFS_BACK) 8790 { 8791 if (vr_arg.type == VR_RANGE 8792 || vr_arg.type == VR_ANTI_RANGE) 8793 { 8794 vr_arg.equiv = NULL; 8795 if (symbolic_range_p (&vr_arg)) 8796 { 8797 vr_arg.type = VR_VARYING; 8798 vr_arg.min = NULL_TREE; 8799 vr_arg.max = NULL_TREE; 8800 } 8801 } 8802 } 8803 else 8804 { 8805 /* If the non-backedge arguments range is VR_VARYING then 8806 we can still try recording a simple equivalence. */ 8807 if (vr_arg.type == VR_VARYING) 8808 { 8809 vr_arg.type = VR_RANGE; 8810 vr_arg.min = arg; 8811 vr_arg.max = arg; 8812 vr_arg.equiv = NULL; 8813 } 8814 } 8815 } 8816 else 8817 { 8818 if (TREE_OVERFLOW_P (arg)) 8819 arg = drop_tree_overflow (arg); 8820 8821 vr_arg.type = VR_RANGE; 8822 vr_arg.min = arg; 8823 vr_arg.max = arg; 8824 vr_arg.equiv = NULL; 8825 } 8826 8827 if (dump_file && (dump_flags & TDF_DETAILS)) 8828 { 8829 fprintf (dump_file, "\t"); 8830 print_generic_expr (dump_file, arg, dump_flags); 8831 fprintf (dump_file, ": "); 8832 dump_value_range (dump_file, &vr_arg); 8833 fprintf (dump_file, "\n"); 8834 } 8835 8836 if (first) 8837 copy_value_range (&vr_result, &vr_arg); 8838 else 8839 vrp_meet (&vr_result, &vr_arg); 8840 first = false; 8841 8842 if (vr_result.type == VR_VARYING) 8843 break; 8844 } 8845 } 8846 8847 if (vr_result.type == VR_VARYING) 8848 goto varying; 8849 else if (vr_result.type == VR_UNDEFINED) 8850 goto update_range; 8851 8852 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)]; 8853 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges; 8854 8855 /* To prevent infinite iterations in the algorithm, derive ranges 8856 when the new value is slightly bigger or smaller than the 8857 previous one. We don't do this if we have seen a new executable 8858 edge; this helps us avoid an overflow infinity for conditionals 8859 which are not in a loop. If the old value-range was VR_UNDEFINED 8860 use the updated range and iterate one more time. */ 8861 if (edges > 0 8862 && gimple_phi_num_args (phi) > 1 8863 && edges == old_edges 8864 && lhs_vr->type != VR_UNDEFINED) 8865 { 8866 /* Compare old and new ranges, fall back to varying if the 8867 values are not comparable. */ 8868 int cmp_min = compare_values (lhs_vr->min, vr_result.min); 8869 if (cmp_min == -2) 8870 goto varying; 8871 int cmp_max = compare_values (lhs_vr->max, vr_result.max); 8872 if (cmp_max == -2) 8873 goto varying; 8874 8875 /* For non VR_RANGE or for pointers fall back to varying if 8876 the range changed. */ 8877 if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE 8878 || POINTER_TYPE_P (TREE_TYPE (lhs))) 8879 && (cmp_min != 0 || cmp_max != 0)) 8880 goto varying; 8881 8882 /* If the new minimum is larger than the previous one 8883 retain the old value. If the new minimum value is smaller 8884 than the previous one and not -INF go all the way to -INF + 1. 8885 In the first case, to avoid infinite bouncing between different 8886 minimums, and in the other case to avoid iterating millions of 8887 times to reach -INF. Going to -INF + 1 also lets the following 8888 iteration compute whether there will be any overflow, at the 8889 expense of one additional iteration. */ 8890 if (cmp_min < 0) 8891 vr_result.min = lhs_vr->min; 8892 else if (cmp_min > 0 8893 && !vrp_val_is_min (vr_result.min)) 8894 vr_result.min 8895 = int_const_binop (PLUS_EXPR, 8896 vrp_val_min (TREE_TYPE (vr_result.min)), 8897 build_int_cst (TREE_TYPE (vr_result.min), 1)); 8898 8899 /* Similarly for the maximum value. */ 8900 if (cmp_max > 0) 8901 vr_result.max = lhs_vr->max; 8902 else if (cmp_max < 0 8903 && !vrp_val_is_max (vr_result.max)) 8904 vr_result.max 8905 = int_const_binop (MINUS_EXPR, 8906 vrp_val_max (TREE_TYPE (vr_result.min)), 8907 build_int_cst (TREE_TYPE (vr_result.min), 1)); 8908 8909 /* If we dropped either bound to +-INF then if this is a loop 8910 PHI node SCEV may known more about its value-range. */ 8911 if (cmp_min > 0 || cmp_min < 0 8912 || cmp_max < 0 || cmp_max > 0) 8913 goto scev_check; 8914 8915 goto infinite_check; 8916 } 8917 8918 /* If the new range is different than the previous value, keep 8919 iterating. */ 8920 update_range: 8921 if (update_value_range (lhs, &vr_result)) 8922 { 8923 if (dump_file && (dump_flags & TDF_DETAILS)) 8924 { 8925 fprintf (dump_file, "Found new range for "); 8926 print_generic_expr (dump_file, lhs, 0); 8927 fprintf (dump_file, ": "); 8928 dump_value_range (dump_file, &vr_result); 8929 fprintf (dump_file, "\n"); 8930 } 8931 8932 if (vr_result.type == VR_VARYING) 8933 return SSA_PROP_VARYING; 8934 8935 return SSA_PROP_INTERESTING; 8936 } 8937 8938 /* Nothing changed, don't add outgoing edges. */ 8939 return SSA_PROP_NOT_INTERESTING; 8940 8941 varying: 8942 set_value_range_to_varying (&vr_result); 8943 8944 scev_check: 8945 /* If this is a loop PHI node SCEV may known more about its value-range. 8946 scev_check can be reached from two paths, one is a fall through from above 8947 "varying" label, the other is direct goto from code block which tries to 8948 avoid infinite simulation. */ 8949 if ((l = loop_containing_stmt (phi)) 8950 && l->header == gimple_bb (phi)) 8951 adjust_range_with_scev (&vr_result, l, phi, lhs); 8952 8953 infinite_check: 8954 /* If we will end up with a (-INF, +INF) range, set it to 8955 VARYING. Same if the previous max value was invalid for 8956 the type and we end up with vr_result.min > vr_result.max. */ 8957 if ((vr_result.type == VR_RANGE || vr_result.type == VR_ANTI_RANGE) 8958 && !((vrp_val_is_max (vr_result.max) && vrp_val_is_min (vr_result.min)) 8959 || compare_values (vr_result.min, vr_result.max) > 0)) 8960 goto update_range; 8961 8962 /* No match found. Set the LHS to VARYING. */ 8963 set_value_range_to_varying (lhs_vr); 8964 return SSA_PROP_VARYING; 8965 } 8966 8967 /* Simplify boolean operations if the source is known 8968 to be already a boolean. */ 8969 static bool 8970 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) 8971 { 8972 enum tree_code rhs_code = gimple_assign_rhs_code (stmt); 8973 tree lhs, op0, op1; 8974 bool need_conversion; 8975 8976 /* We handle only !=/== case here. */ 8977 gcc_assert (rhs_code == EQ_EXPR || rhs_code == NE_EXPR); 8978 8979 op0 = gimple_assign_rhs1 (stmt); 8980 if (!op_with_boolean_value_range_p (op0)) 8981 return false; 8982 8983 op1 = gimple_assign_rhs2 (stmt); 8984 if (!op_with_boolean_value_range_p (op1)) 8985 return false; 8986 8987 /* Reduce number of cases to handle to NE_EXPR. As there is no 8988 BIT_XNOR_EXPR we cannot replace A == B with a single statement. */ 8989 if (rhs_code == EQ_EXPR) 8990 { 8991 if (TREE_CODE (op1) == INTEGER_CST) 8992 op1 = int_const_binop (BIT_XOR_EXPR, op1, 8993 build_int_cst (TREE_TYPE (op1), 1)); 8994 else 8995 return false; 8996 } 8997 8998 lhs = gimple_assign_lhs (stmt); 8999 need_conversion 9000 = !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0)); 9001 9002 /* Make sure to not sign-extend a 1-bit 1 when converting the result. */ 9003 if (need_conversion 9004 && !TYPE_UNSIGNED (TREE_TYPE (op0)) 9005 && TYPE_PRECISION (TREE_TYPE (op0)) == 1 9006 && TYPE_PRECISION (TREE_TYPE (lhs)) > 1) 9007 return false; 9008 9009 /* For A != 0 we can substitute A itself. */ 9010 if (integer_zerop (op1)) 9011 gimple_assign_set_rhs_with_ops (gsi, 9012 need_conversion 9013 ? NOP_EXPR : TREE_CODE (op0), op0); 9014 /* For A != B we substitute A ^ B. Either with conversion. */ 9015 else if (need_conversion) 9016 { 9017 tree tem = make_ssa_name (TREE_TYPE (op0)); 9018 gassign *newop 9019 = gimple_build_assign (tem, BIT_XOR_EXPR, op0, op1); 9020 gsi_insert_before (gsi, newop, GSI_SAME_STMT); 9021 gimple_assign_set_rhs_with_ops (gsi, NOP_EXPR, tem); 9022 } 9023 /* Or without. */ 9024 else 9025 gimple_assign_set_rhs_with_ops (gsi, BIT_XOR_EXPR, op0, op1); 9026 update_stmt (gsi_stmt (*gsi)); 9027 9028 return true; 9029 } 9030 9031 /* Simplify a division or modulo operator to a right shift or 9032 bitwise and if the first operand is unsigned or is greater 9033 than zero and the second operand is an exact power of two. 9034 For TRUNC_MOD_EXPR op0 % op1 with constant op1, optimize it 9035 into just op0 if op0's range is known to be a subset of 9036 [-op1 + 1, op1 - 1] for signed and [0, op1 - 1] for unsigned 9037 modulo. */ 9038 9039 static bool 9040 simplify_div_or_mod_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) 9041 { 9042 enum tree_code rhs_code = gimple_assign_rhs_code (stmt); 9043 tree val = NULL; 9044 tree op0 = gimple_assign_rhs1 (stmt); 9045 tree op1 = gimple_assign_rhs2 (stmt); 9046 value_range *vr = get_value_range (op0); 9047 9048 if (rhs_code == TRUNC_MOD_EXPR 9049 && TREE_CODE (op1) == INTEGER_CST 9050 && tree_int_cst_sgn (op1) == 1 9051 && range_int_cst_p (vr) 9052 && tree_int_cst_lt (vr->max, op1)) 9053 { 9054 if (TYPE_UNSIGNED (TREE_TYPE (op0)) 9055 || tree_int_cst_sgn (vr->min) >= 0 9056 || tree_int_cst_lt (fold_unary (NEGATE_EXPR, TREE_TYPE (op1), op1), 9057 vr->min)) 9058 { 9059 /* If op0 already has the range op0 % op1 has, 9060 then TRUNC_MOD_EXPR won't change anything. */ 9061 gimple_stmt_iterator gsi = gsi_for_stmt (stmt); 9062 gimple_assign_set_rhs_from_tree (&gsi, op0); 9063 update_stmt (stmt); 9064 return true; 9065 } 9066 } 9067 9068 if (!integer_pow2p (op1)) 9069 { 9070 /* X % -Y can be only optimized into X % Y either if 9071 X is not INT_MIN, or Y is not -1. Fold it now, as after 9072 remove_range_assertions the range info might be not available 9073 anymore. */ 9074 if (rhs_code == TRUNC_MOD_EXPR 9075 && fold_stmt (gsi, follow_single_use_edges)) 9076 return true; 9077 return false; 9078 } 9079 9080 if (TYPE_UNSIGNED (TREE_TYPE (op0))) 9081 val = integer_one_node; 9082 else 9083 { 9084 bool sop = false; 9085 9086 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop); 9087 9088 if (val 9089 && sop 9090 && integer_onep (val) 9091 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) 9092 { 9093 location_t location; 9094 9095 if (!gimple_has_location (stmt)) 9096 location = input_location; 9097 else 9098 location = gimple_location (stmt); 9099 warning_at (location, OPT_Wstrict_overflow, 9100 "assuming signed overflow does not occur when " 9101 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>"); 9102 } 9103 } 9104 9105 if (val && integer_onep (val)) 9106 { 9107 tree t; 9108 9109 if (rhs_code == TRUNC_DIV_EXPR) 9110 { 9111 t = build_int_cst (integer_type_node, tree_log2 (op1)); 9112 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR); 9113 gimple_assign_set_rhs1 (stmt, op0); 9114 gimple_assign_set_rhs2 (stmt, t); 9115 } 9116 else 9117 { 9118 t = build_int_cst (TREE_TYPE (op1), 1); 9119 t = int_const_binop (MINUS_EXPR, op1, t); 9120 t = fold_convert (TREE_TYPE (op0), t); 9121 9122 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR); 9123 gimple_assign_set_rhs1 (stmt, op0); 9124 gimple_assign_set_rhs2 (stmt, t); 9125 } 9126 9127 update_stmt (stmt); 9128 return true; 9129 } 9130 9131 return false; 9132 } 9133 9134 /* Simplify a min or max if the ranges of the two operands are 9135 disjoint. Return true if we do simplify. */ 9136 9137 static bool 9138 simplify_min_or_max_using_ranges (gimple *stmt) 9139 { 9140 tree op0 = gimple_assign_rhs1 (stmt); 9141 tree op1 = gimple_assign_rhs2 (stmt); 9142 bool sop = false; 9143 tree val; 9144 9145 val = (vrp_evaluate_conditional_warnv_with_ops_using_ranges 9146 (LE_EXPR, op0, op1, &sop)); 9147 if (!val) 9148 { 9149 sop = false; 9150 val = (vrp_evaluate_conditional_warnv_with_ops_using_ranges 9151 (LT_EXPR, op0, op1, &sop)); 9152 } 9153 9154 if (val) 9155 { 9156 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) 9157 { 9158 location_t location; 9159 9160 if (!gimple_has_location (stmt)) 9161 location = input_location; 9162 else 9163 location = gimple_location (stmt); 9164 warning_at (location, OPT_Wstrict_overflow, 9165 "assuming signed overflow does not occur when " 9166 "simplifying %<min/max (X,Y)%> to %<X%> or %<Y%>"); 9167 } 9168 9169 /* VAL == TRUE -> OP0 < or <= op1 9170 VAL == FALSE -> OP0 > or >= op1. */ 9171 tree res = ((gimple_assign_rhs_code (stmt) == MAX_EXPR) 9172 == integer_zerop (val)) ? op0 : op1; 9173 gimple_stmt_iterator gsi = gsi_for_stmt (stmt); 9174 gimple_assign_set_rhs_from_tree (&gsi, res); 9175 update_stmt (stmt); 9176 return true; 9177 } 9178 9179 return false; 9180 } 9181 9182 /* If the operand to an ABS_EXPR is >= 0, then eliminate the 9183 ABS_EXPR. If the operand is <= 0, then simplify the 9184 ABS_EXPR into a NEGATE_EXPR. */ 9185 9186 static bool 9187 simplify_abs_using_ranges (gimple *stmt) 9188 { 9189 tree op = gimple_assign_rhs1 (stmt); 9190 value_range *vr = get_value_range (op); 9191 9192 if (vr) 9193 { 9194 tree val = NULL; 9195 bool sop = false; 9196 9197 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop); 9198 if (!val) 9199 { 9200 /* The range is neither <= 0 nor > 0. Now see if it is 9201 either < 0 or >= 0. */ 9202 sop = false; 9203 val = compare_range_with_value (LT_EXPR, vr, integer_zero_node, 9204 &sop); 9205 } 9206 9207 if (val) 9208 { 9209 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) 9210 { 9211 location_t location; 9212 9213 if (!gimple_has_location (stmt)) 9214 location = input_location; 9215 else 9216 location = gimple_location (stmt); 9217 warning_at (location, OPT_Wstrict_overflow, 9218 "assuming signed overflow does not occur when " 9219 "simplifying %<abs (X)%> to %<X%> or %<-X%>"); 9220 } 9221 9222 gimple_assign_set_rhs1 (stmt, op); 9223 if (integer_zerop (val)) 9224 gimple_assign_set_rhs_code (stmt, SSA_NAME); 9225 else 9226 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR); 9227 update_stmt (stmt); 9228 return true; 9229 } 9230 } 9231 9232 return false; 9233 } 9234 9235 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR. 9236 If all the bits that are being cleared by & are already 9237 known to be zero from VR, or all the bits that are being 9238 set by | are already known to be one from VR, the bit 9239 operation is redundant. */ 9240 9241 static bool 9242 simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) 9243 { 9244 tree op0 = gimple_assign_rhs1 (stmt); 9245 tree op1 = gimple_assign_rhs2 (stmt); 9246 tree op = NULL_TREE; 9247 value_range vr0 = VR_INITIALIZER; 9248 value_range vr1 = VR_INITIALIZER; 9249 wide_int may_be_nonzero0, may_be_nonzero1; 9250 wide_int must_be_nonzero0, must_be_nonzero1; 9251 wide_int mask; 9252 9253 if (TREE_CODE (op0) == SSA_NAME) 9254 vr0 = *(get_value_range (op0)); 9255 else if (is_gimple_min_invariant (op0)) 9256 set_value_range_to_value (&vr0, op0, NULL); 9257 else 9258 return false; 9259 9260 if (TREE_CODE (op1) == SSA_NAME) 9261 vr1 = *(get_value_range (op1)); 9262 else if (is_gimple_min_invariant (op1)) 9263 set_value_range_to_value (&vr1, op1, NULL); 9264 else 9265 return false; 9266 9267 if (!zero_nonzero_bits_from_vr (TREE_TYPE (op0), &vr0, &may_be_nonzero0, 9268 &must_be_nonzero0)) 9269 return false; 9270 if (!zero_nonzero_bits_from_vr (TREE_TYPE (op1), &vr1, &may_be_nonzero1, 9271 &must_be_nonzero1)) 9272 return false; 9273 9274 switch (gimple_assign_rhs_code (stmt)) 9275 { 9276 case BIT_AND_EXPR: 9277 mask = may_be_nonzero0.and_not (must_be_nonzero1); 9278 if (mask == 0) 9279 { 9280 op = op0; 9281 break; 9282 } 9283 mask = may_be_nonzero1.and_not (must_be_nonzero0); 9284 if (mask == 0) 9285 { 9286 op = op1; 9287 break; 9288 } 9289 break; 9290 case BIT_IOR_EXPR: 9291 mask = may_be_nonzero0.and_not (must_be_nonzero1); 9292 if (mask == 0) 9293 { 9294 op = op1; 9295 break; 9296 } 9297 mask = may_be_nonzero1.and_not (must_be_nonzero0); 9298 if (mask == 0) 9299 { 9300 op = op0; 9301 break; 9302 } 9303 break; 9304 default: 9305 gcc_unreachable (); 9306 } 9307 9308 if (op == NULL_TREE) 9309 return false; 9310 9311 gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op); 9312 update_stmt (gsi_stmt (*gsi)); 9313 return true; 9314 } 9315 9316 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has 9317 a known value range VR. 9318 9319 If there is one and only one value which will satisfy the 9320 conditional, then return that value. Else return NULL. 9321 9322 If signed overflow must be undefined for the value to satisfy 9323 the conditional, then set *STRICT_OVERFLOW_P to true. */ 9324 9325 static tree 9326 test_for_singularity (enum tree_code cond_code, tree op0, 9327 tree op1, value_range *vr, 9328 bool *strict_overflow_p) 9329 { 9330 tree min = NULL; 9331 tree max = NULL; 9332 9333 /* Extract minimum/maximum values which satisfy the conditional as it was 9334 written. */ 9335 if (cond_code == LE_EXPR || cond_code == LT_EXPR) 9336 { 9337 /* This should not be negative infinity; there is no overflow 9338 here. */ 9339 min = TYPE_MIN_VALUE (TREE_TYPE (op0)); 9340 9341 max = op1; 9342 if (cond_code == LT_EXPR && !is_overflow_infinity (max)) 9343 { 9344 tree one = build_int_cst (TREE_TYPE (op0), 1); 9345 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one); 9346 if (EXPR_P (max)) 9347 TREE_NO_WARNING (max) = 1; 9348 } 9349 } 9350 else if (cond_code == GE_EXPR || cond_code == GT_EXPR) 9351 { 9352 /* This should not be positive infinity; there is no overflow 9353 here. */ 9354 max = TYPE_MAX_VALUE (TREE_TYPE (op0)); 9355 9356 min = op1; 9357 if (cond_code == GT_EXPR && !is_overflow_infinity (min)) 9358 { 9359 tree one = build_int_cst (TREE_TYPE (op0), 1); 9360 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one); 9361 if (EXPR_P (min)) 9362 TREE_NO_WARNING (min) = 1; 9363 } 9364 } 9365 9366 /* Now refine the minimum and maximum values using any 9367 value range information we have for op0. */ 9368 if (min && max) 9369 { 9370 if (compare_values (vr->min, min) == 1) 9371 min = vr->min; 9372 if (compare_values (vr->max, max) == -1) 9373 max = vr->max; 9374 9375 /* If the new min/max values have converged to a single value, 9376 then there is only one value which can satisfy the condition, 9377 return that value. */ 9378 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min)) 9379 { 9380 if ((cond_code == LE_EXPR || cond_code == LT_EXPR) 9381 && is_overflow_infinity (vr->max)) 9382 *strict_overflow_p = true; 9383 if ((cond_code == GE_EXPR || cond_code == GT_EXPR) 9384 && is_overflow_infinity (vr->min)) 9385 *strict_overflow_p = true; 9386 9387 return min; 9388 } 9389 } 9390 return NULL; 9391 } 9392 9393 /* Return whether the value range *VR fits in an integer type specified 9394 by PRECISION and UNSIGNED_P. */ 9395 9396 static bool 9397 range_fits_type_p (value_range *vr, unsigned dest_precision, signop dest_sgn) 9398 { 9399 tree src_type; 9400 unsigned src_precision; 9401 widest_int tem; 9402 signop src_sgn; 9403 9404 /* We can only handle integral and pointer types. */ 9405 src_type = TREE_TYPE (vr->min); 9406 if (!INTEGRAL_TYPE_P (src_type) 9407 && !POINTER_TYPE_P (src_type)) 9408 return false; 9409 9410 /* An extension is fine unless VR is SIGNED and dest_sgn is UNSIGNED, 9411 and so is an identity transform. */ 9412 src_precision = TYPE_PRECISION (TREE_TYPE (vr->min)); 9413 src_sgn = TYPE_SIGN (src_type); 9414 if ((src_precision < dest_precision 9415 && !(dest_sgn == UNSIGNED && src_sgn == SIGNED)) 9416 || (src_precision == dest_precision && src_sgn == dest_sgn)) 9417 return true; 9418 9419 /* Now we can only handle ranges with constant bounds. */ 9420 if (vr->type != VR_RANGE 9421 || TREE_CODE (vr->min) != INTEGER_CST 9422 || TREE_CODE (vr->max) != INTEGER_CST) 9423 return false; 9424 9425 /* For sign changes, the MSB of the wide_int has to be clear. 9426 An unsigned value with its MSB set cannot be represented by 9427 a signed wide_int, while a negative value cannot be represented 9428 by an unsigned wide_int. */ 9429 if (src_sgn != dest_sgn 9430 && (wi::lts_p (vr->min, 0) || wi::lts_p (vr->max, 0))) 9431 return false; 9432 9433 /* Then we can perform the conversion on both ends and compare 9434 the result for equality. */ 9435 tem = wi::ext (wi::to_widest (vr->min), dest_precision, dest_sgn); 9436 if (tem != wi::to_widest (vr->min)) 9437 return false; 9438 tem = wi::ext (wi::to_widest (vr->max), dest_precision, dest_sgn); 9439 if (tem != wi::to_widest (vr->max)) 9440 return false; 9441 9442 return true; 9443 } 9444 9445 /* Simplify a conditional using a relational operator to an equality 9446 test if the range information indicates only one value can satisfy 9447 the original conditional. */ 9448 9449 static bool 9450 simplify_cond_using_ranges (gcond *stmt) 9451 { 9452 tree op0 = gimple_cond_lhs (stmt); 9453 tree op1 = gimple_cond_rhs (stmt); 9454 enum tree_code cond_code = gimple_cond_code (stmt); 9455 9456 if (cond_code != NE_EXPR 9457 && cond_code != EQ_EXPR 9458 && TREE_CODE (op0) == SSA_NAME 9459 && INTEGRAL_TYPE_P (TREE_TYPE (op0)) 9460 && is_gimple_min_invariant (op1)) 9461 { 9462 value_range *vr = get_value_range (op0); 9463 9464 /* If we have range information for OP0, then we might be 9465 able to simplify this conditional. */ 9466 if (vr->type == VR_RANGE) 9467 { 9468 enum warn_strict_overflow_code wc = WARN_STRICT_OVERFLOW_COMPARISON; 9469 bool sop = false; 9470 tree new_tree = test_for_singularity (cond_code, op0, op1, vr, &sop); 9471 9472 if (new_tree 9473 && (!sop || TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))) 9474 { 9475 if (dump_file) 9476 { 9477 fprintf (dump_file, "Simplified relational "); 9478 print_gimple_stmt (dump_file, stmt, 0, 0); 9479 fprintf (dump_file, " into "); 9480 } 9481 9482 gimple_cond_set_code (stmt, EQ_EXPR); 9483 gimple_cond_set_lhs (stmt, op0); 9484 gimple_cond_set_rhs (stmt, new_tree); 9485 9486 update_stmt (stmt); 9487 9488 if (dump_file) 9489 { 9490 print_gimple_stmt (dump_file, stmt, 0, 0); 9491 fprintf (dump_file, "\n"); 9492 } 9493 9494 if (sop && issue_strict_overflow_warning (wc)) 9495 { 9496 location_t location = input_location; 9497 if (gimple_has_location (stmt)) 9498 location = gimple_location (stmt); 9499 9500 warning_at (location, OPT_Wstrict_overflow, 9501 "assuming signed overflow does not occur when " 9502 "simplifying conditional"); 9503 } 9504 9505 return true; 9506 } 9507 9508 /* Try again after inverting the condition. We only deal 9509 with integral types here, so no need to worry about 9510 issues with inverting FP comparisons. */ 9511 sop = false; 9512 new_tree = test_for_singularity 9513 (invert_tree_comparison (cond_code, false), 9514 op0, op1, vr, &sop); 9515 9516 if (new_tree 9517 && (!sop || TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))) 9518 { 9519 if (dump_file) 9520 { 9521 fprintf (dump_file, "Simplified relational "); 9522 print_gimple_stmt (dump_file, stmt, 0, 0); 9523 fprintf (dump_file, " into "); 9524 } 9525 9526 gimple_cond_set_code (stmt, NE_EXPR); 9527 gimple_cond_set_lhs (stmt, op0); 9528 gimple_cond_set_rhs (stmt, new_tree); 9529 9530 update_stmt (stmt); 9531 9532 if (dump_file) 9533 { 9534 print_gimple_stmt (dump_file, stmt, 0, 0); 9535 fprintf (dump_file, "\n"); 9536 } 9537 9538 if (sop && issue_strict_overflow_warning (wc)) 9539 { 9540 location_t location = input_location; 9541 if (gimple_has_location (stmt)) 9542 location = gimple_location (stmt); 9543 9544 warning_at (location, OPT_Wstrict_overflow, 9545 "assuming signed overflow does not occur when " 9546 "simplifying conditional"); 9547 } 9548 9549 return true; 9550 } 9551 } 9552 } 9553 9554 /* If we have a comparison of an SSA_NAME (OP0) against a constant, 9555 see if OP0 was set by a type conversion where the source of 9556 the conversion is another SSA_NAME with a range that fits 9557 into the range of OP0's type. 9558 9559 If so, the conversion is redundant as the earlier SSA_NAME can be 9560 used for the comparison directly if we just massage the constant in the 9561 comparison. */ 9562 if (TREE_CODE (op0) == SSA_NAME 9563 && TREE_CODE (op1) == INTEGER_CST) 9564 { 9565 gimple *def_stmt = SSA_NAME_DEF_STMT (op0); 9566 tree innerop; 9567 9568 if (!is_gimple_assign (def_stmt) 9569 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) 9570 return false; 9571 9572 innerop = gimple_assign_rhs1 (def_stmt); 9573 9574 if (TREE_CODE (innerop) == SSA_NAME 9575 && !POINTER_TYPE_P (TREE_TYPE (innerop)) 9576 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (innerop) 9577 && desired_pro_or_demotion_p (TREE_TYPE (innerop), TREE_TYPE (op0))) 9578 { 9579 value_range *vr = get_value_range (innerop); 9580 9581 if (range_int_cst_p (vr) 9582 && range_fits_type_p (vr, 9583 TYPE_PRECISION (TREE_TYPE (op0)), 9584 TYPE_SIGN (TREE_TYPE (op0))) 9585 && int_fits_type_p (op1, TREE_TYPE (innerop)) 9586 /* The range must not have overflowed, or if it did overflow 9587 we must not be wrapping/trapping overflow and optimizing 9588 with strict overflow semantics. */ 9589 && ((!is_negative_overflow_infinity (vr->min) 9590 && !is_positive_overflow_infinity (vr->max)) 9591 || TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (innerop)))) 9592 { 9593 /* If the range overflowed and the user has asked for warnings 9594 when strict overflow semantics were used to optimize code, 9595 issue an appropriate warning. */ 9596 if (cond_code != EQ_EXPR && cond_code != NE_EXPR 9597 && (is_negative_overflow_infinity (vr->min) 9598 || is_positive_overflow_infinity (vr->max)) 9599 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_CONDITIONAL)) 9600 { 9601 location_t location; 9602 9603 if (!gimple_has_location (stmt)) 9604 location = input_location; 9605 else 9606 location = gimple_location (stmt); 9607 warning_at (location, OPT_Wstrict_overflow, 9608 "assuming signed overflow does not occur when " 9609 "simplifying conditional"); 9610 } 9611 9612 tree newconst = fold_convert (TREE_TYPE (innerop), op1); 9613 gimple_cond_set_lhs (stmt, innerop); 9614 gimple_cond_set_rhs (stmt, newconst); 9615 return true; 9616 } 9617 } 9618 } 9619 9620 return false; 9621 } 9622 9623 /* Simplify a switch statement using the value range of the switch 9624 argument. */ 9625 9626 static bool 9627 simplify_switch_using_ranges (gswitch *stmt) 9628 { 9629 tree op = gimple_switch_index (stmt); 9630 value_range *vr; 9631 bool take_default; 9632 edge e; 9633 edge_iterator ei; 9634 size_t i = 0, j = 0, n, n2; 9635 tree vec2; 9636 switch_update su; 9637 size_t k = 1, l = 0; 9638 9639 if (TREE_CODE (op) == SSA_NAME) 9640 { 9641 vr = get_value_range (op); 9642 9643 /* We can only handle integer ranges. */ 9644 if ((vr->type != VR_RANGE 9645 && vr->type != VR_ANTI_RANGE) 9646 || symbolic_range_p (vr)) 9647 return false; 9648 9649 /* Find case label for min/max of the value range. */ 9650 take_default = !find_case_label_ranges (stmt, vr, &i, &j, &k, &l); 9651 } 9652 else if (TREE_CODE (op) == INTEGER_CST) 9653 { 9654 take_default = !find_case_label_index (stmt, 1, op, &i); 9655 if (take_default) 9656 { 9657 i = 1; 9658 j = 0; 9659 } 9660 else 9661 { 9662 j = i; 9663 } 9664 } 9665 else 9666 return false; 9667 9668 n = gimple_switch_num_labels (stmt); 9669 9670 /* Bail out if this is just all edges taken. */ 9671 if (i == 1 9672 && j == n - 1 9673 && take_default) 9674 return false; 9675 9676 /* Build a new vector of taken case labels. */ 9677 vec2 = make_tree_vec (j - i + 1 + l - k + 1 + (int)take_default); 9678 n2 = 0; 9679 9680 /* Add the default edge, if necessary. */ 9681 if (take_default) 9682 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt); 9683 9684 for (; i <= j; ++i, ++n2) 9685 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i); 9686 9687 for (; k <= l; ++k, ++n2) 9688 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, k); 9689 9690 /* Mark needed edges. */ 9691 for (i = 0; i < n2; ++i) 9692 { 9693 e = find_edge (gimple_bb (stmt), 9694 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i)))); 9695 e->aux = (void *)-1; 9696 } 9697 9698 /* Queue not needed edges for later removal. */ 9699 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs) 9700 { 9701 if (e->aux == (void *)-1) 9702 { 9703 e->aux = NULL; 9704 continue; 9705 } 9706 9707 if (dump_file && (dump_flags & TDF_DETAILS)) 9708 { 9709 fprintf (dump_file, "removing unreachable case label\n"); 9710 } 9711 to_remove_edges.safe_push (e); 9712 e->flags &= ~EDGE_EXECUTABLE; 9713 } 9714 9715 /* And queue an update for the stmt. */ 9716 su.stmt = stmt; 9717 su.vec = vec2; 9718 to_update_switch_stmts.safe_push (su); 9719 return false; 9720 } 9721 9722 /* Simplify an integral conversion from an SSA name in STMT. */ 9723 9724 static bool 9725 simplify_conversion_using_ranges (gimple *stmt) 9726 { 9727 tree innerop, middleop, finaltype; 9728 gimple *def_stmt; 9729 value_range *innervr; 9730 signop inner_sgn, middle_sgn, final_sgn; 9731 unsigned inner_prec, middle_prec, final_prec; 9732 widest_int innermin, innermed, innermax, middlemin, middlemed, middlemax; 9733 9734 finaltype = TREE_TYPE (gimple_assign_lhs (stmt)); 9735 if (!INTEGRAL_TYPE_P (finaltype)) 9736 return false; 9737 middleop = gimple_assign_rhs1 (stmt); 9738 def_stmt = SSA_NAME_DEF_STMT (middleop); 9739 if (!is_gimple_assign (def_stmt) 9740 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) 9741 return false; 9742 innerop = gimple_assign_rhs1 (def_stmt); 9743 if (TREE_CODE (innerop) != SSA_NAME 9744 || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (innerop)) 9745 return false; 9746 9747 /* Get the value-range of the inner operand. */ 9748 innervr = get_value_range (innerop); 9749 if (innervr->type != VR_RANGE 9750 || TREE_CODE (innervr->min) != INTEGER_CST 9751 || TREE_CODE (innervr->max) != INTEGER_CST) 9752 return false; 9753 9754 /* Simulate the conversion chain to check if the result is equal if 9755 the middle conversion is removed. */ 9756 innermin = wi::to_widest (innervr->min); 9757 innermax = wi::to_widest (innervr->max); 9758 9759 inner_prec = TYPE_PRECISION (TREE_TYPE (innerop)); 9760 middle_prec = TYPE_PRECISION (TREE_TYPE (middleop)); 9761 final_prec = TYPE_PRECISION (finaltype); 9762 9763 /* If the first conversion is not injective, the second must not 9764 be widening. */ 9765 if (wi::gtu_p (innermax - innermin, 9766 wi::mask <widest_int> (middle_prec, false)) 9767 && middle_prec < final_prec) 9768 return false; 9769 /* We also want a medium value so that we can track the effect that 9770 narrowing conversions with sign change have. */ 9771 inner_sgn = TYPE_SIGN (TREE_TYPE (innerop)); 9772 if (inner_sgn == UNSIGNED) 9773 innermed = wi::shifted_mask <widest_int> (1, inner_prec - 1, false); 9774 else 9775 innermed = 0; 9776 if (wi::cmp (innermin, innermed, inner_sgn) >= 0 9777 || wi::cmp (innermed, innermax, inner_sgn) >= 0) 9778 innermed = innermin; 9779 9780 middle_sgn = TYPE_SIGN (TREE_TYPE (middleop)); 9781 middlemin = wi::ext (innermin, middle_prec, middle_sgn); 9782 middlemed = wi::ext (innermed, middle_prec, middle_sgn); 9783 middlemax = wi::ext (innermax, middle_prec, middle_sgn); 9784 9785 /* Require that the final conversion applied to both the original 9786 and the intermediate range produces the same result. */ 9787 final_sgn = TYPE_SIGN (finaltype); 9788 if (wi::ext (middlemin, final_prec, final_sgn) 9789 != wi::ext (innermin, final_prec, final_sgn) 9790 || wi::ext (middlemed, final_prec, final_sgn) 9791 != wi::ext (innermed, final_prec, final_sgn) 9792 || wi::ext (middlemax, final_prec, final_sgn) 9793 != wi::ext (innermax, final_prec, final_sgn)) 9794 return false; 9795 9796 gimple_assign_set_rhs1 (stmt, innerop); 9797 update_stmt (stmt); 9798 return true; 9799 } 9800 9801 /* Simplify a conversion from integral SSA name to float in STMT. */ 9802 9803 static bool 9804 simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, 9805 gimple *stmt) 9806 { 9807 tree rhs1 = gimple_assign_rhs1 (stmt); 9808 value_range *vr = get_value_range (rhs1); 9809 machine_mode fltmode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt))); 9810 machine_mode mode; 9811 tree tem; 9812 gassign *conv; 9813 9814 /* We can only handle constant ranges. */ 9815 if (vr->type != VR_RANGE 9816 || TREE_CODE (vr->min) != INTEGER_CST 9817 || TREE_CODE (vr->max) != INTEGER_CST) 9818 return false; 9819 9820 /* First check if we can use a signed type in place of an unsigned. */ 9821 if (TYPE_UNSIGNED (TREE_TYPE (rhs1)) 9822 && (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), 0) 9823 != CODE_FOR_nothing) 9824 && range_fits_type_p (vr, TYPE_PRECISION (TREE_TYPE (rhs1)), SIGNED)) 9825 mode = TYPE_MODE (TREE_TYPE (rhs1)); 9826 /* If we can do the conversion in the current input mode do nothing. */ 9827 else if (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), 9828 TYPE_UNSIGNED (TREE_TYPE (rhs1))) != CODE_FOR_nothing) 9829 return false; 9830 /* Otherwise search for a mode we can use, starting from the narrowest 9831 integer mode available. */ 9832 else 9833 { 9834 mode = GET_CLASS_NARROWEST_MODE (MODE_INT); 9835 do 9836 { 9837 /* If we cannot do a signed conversion to float from mode 9838 or if the value-range does not fit in the signed type 9839 try with a wider mode. */ 9840 if (can_float_p (fltmode, mode, 0) != CODE_FOR_nothing 9841 && range_fits_type_p (vr, GET_MODE_PRECISION (mode), SIGNED)) 9842 break; 9843 9844 mode = GET_MODE_WIDER_MODE (mode); 9845 /* But do not widen the input. Instead leave that to the 9846 optabs expansion code. */ 9847 if (GET_MODE_PRECISION (mode) > TYPE_PRECISION (TREE_TYPE (rhs1))) 9848 return false; 9849 } 9850 while (mode != VOIDmode); 9851 if (mode == VOIDmode) 9852 return false; 9853 } 9854 9855 /* It works, insert a truncation or sign-change before the 9856 float conversion. */ 9857 tem = make_ssa_name (build_nonstandard_integer_type 9858 (GET_MODE_PRECISION (mode), 0)); 9859 conv = gimple_build_assign (tem, NOP_EXPR, rhs1); 9860 gsi_insert_before (gsi, conv, GSI_SAME_STMT); 9861 gimple_assign_set_rhs1 (stmt, tem); 9862 update_stmt (stmt); 9863 9864 return true; 9865 } 9866 9867 /* Simplify an internal fn call using ranges if possible. */ 9868 9869 static bool 9870 simplify_internal_call_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) 9871 { 9872 enum tree_code subcode; 9873 bool is_ubsan = false; 9874 bool ovf = false; 9875 switch (gimple_call_internal_fn (stmt)) 9876 { 9877 case IFN_UBSAN_CHECK_ADD: 9878 subcode = PLUS_EXPR; 9879 is_ubsan = true; 9880 break; 9881 case IFN_UBSAN_CHECK_SUB: 9882 subcode = MINUS_EXPR; 9883 is_ubsan = true; 9884 break; 9885 case IFN_UBSAN_CHECK_MUL: 9886 subcode = MULT_EXPR; 9887 is_ubsan = true; 9888 break; 9889 case IFN_ADD_OVERFLOW: 9890 subcode = PLUS_EXPR; 9891 break; 9892 case IFN_SUB_OVERFLOW: 9893 subcode = MINUS_EXPR; 9894 break; 9895 case IFN_MUL_OVERFLOW: 9896 subcode = MULT_EXPR; 9897 break; 9898 default: 9899 return false; 9900 } 9901 9902 tree op0 = gimple_call_arg (stmt, 0); 9903 tree op1 = gimple_call_arg (stmt, 1); 9904 tree type; 9905 if (is_ubsan) 9906 type = TREE_TYPE (op0); 9907 else if (gimple_call_lhs (stmt) == NULL_TREE) 9908 return false; 9909 else 9910 type = TREE_TYPE (TREE_TYPE (gimple_call_lhs (stmt))); 9911 if (!check_for_binary_op_overflow (subcode, type, op0, op1, &ovf) 9912 || (is_ubsan && ovf)) 9913 return false; 9914 9915 gimple *g; 9916 location_t loc = gimple_location (stmt); 9917 if (is_ubsan) 9918 g = gimple_build_assign (gimple_call_lhs (stmt), subcode, op0, op1); 9919 else 9920 { 9921 int prec = TYPE_PRECISION (type); 9922 tree utype = type; 9923 if (ovf 9924 || !useless_type_conversion_p (type, TREE_TYPE (op0)) 9925 || !useless_type_conversion_p (type, TREE_TYPE (op1))) 9926 utype = build_nonstandard_integer_type (prec, 1); 9927 if (TREE_CODE (op0) == INTEGER_CST) 9928 op0 = fold_convert (utype, op0); 9929 else if (!useless_type_conversion_p (utype, TREE_TYPE (op0))) 9930 { 9931 g = gimple_build_assign (make_ssa_name (utype), NOP_EXPR, op0); 9932 gimple_set_location (g, loc); 9933 gsi_insert_before (gsi, g, GSI_SAME_STMT); 9934 op0 = gimple_assign_lhs (g); 9935 } 9936 if (TREE_CODE (op1) == INTEGER_CST) 9937 op1 = fold_convert (utype, op1); 9938 else if (!useless_type_conversion_p (utype, TREE_TYPE (op1))) 9939 { 9940 g = gimple_build_assign (make_ssa_name (utype), NOP_EXPR, op1); 9941 gimple_set_location (g, loc); 9942 gsi_insert_before (gsi, g, GSI_SAME_STMT); 9943 op1 = gimple_assign_lhs (g); 9944 } 9945 g = gimple_build_assign (make_ssa_name (utype), subcode, op0, op1); 9946 gimple_set_location (g, loc); 9947 gsi_insert_before (gsi, g, GSI_SAME_STMT); 9948 if (utype != type) 9949 { 9950 g = gimple_build_assign (make_ssa_name (type), NOP_EXPR, 9951 gimple_assign_lhs (g)); 9952 gimple_set_location (g, loc); 9953 gsi_insert_before (gsi, g, GSI_SAME_STMT); 9954 } 9955 g = gimple_build_assign (gimple_call_lhs (stmt), COMPLEX_EXPR, 9956 gimple_assign_lhs (g), 9957 build_int_cst (type, ovf)); 9958 } 9959 gimple_set_location (g, loc); 9960 gsi_replace (gsi, g, false); 9961 return true; 9962 } 9963 9964 /* Simplify STMT using ranges if possible. */ 9965 9966 static bool 9967 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi) 9968 { 9969 gimple *stmt = gsi_stmt (*gsi); 9970 if (is_gimple_assign (stmt)) 9971 { 9972 enum tree_code rhs_code = gimple_assign_rhs_code (stmt); 9973 tree rhs1 = gimple_assign_rhs1 (stmt); 9974 9975 switch (rhs_code) 9976 { 9977 case EQ_EXPR: 9978 case NE_EXPR: 9979 /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity 9980 if the RHS is zero or one, and the LHS are known to be boolean 9981 values. */ 9982 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) 9983 return simplify_truth_ops_using_ranges (gsi, stmt); 9984 break; 9985 9986 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR 9987 and BIT_AND_EXPR respectively if the first operand is greater 9988 than zero and the second operand is an exact power of two. 9989 Also optimize TRUNC_MOD_EXPR away if the second operand is 9990 constant and the first operand already has the right value 9991 range. */ 9992 case TRUNC_DIV_EXPR: 9993 case TRUNC_MOD_EXPR: 9994 if (TREE_CODE (rhs1) == SSA_NAME 9995 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) 9996 return simplify_div_or_mod_using_ranges (gsi, stmt); 9997 break; 9998 9999 /* Transform ABS (X) into X or -X as appropriate. */ 10000 case ABS_EXPR: 10001 if (TREE_CODE (rhs1) == SSA_NAME 10002 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) 10003 return simplify_abs_using_ranges (stmt); 10004 break; 10005 10006 case BIT_AND_EXPR: 10007 case BIT_IOR_EXPR: 10008 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR 10009 if all the bits being cleared are already cleared or 10010 all the bits being set are already set. */ 10011 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) 10012 return simplify_bit_ops_using_ranges (gsi, stmt); 10013 break; 10014 10015 CASE_CONVERT: 10016 if (TREE_CODE (rhs1) == SSA_NAME 10017 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) 10018 return simplify_conversion_using_ranges (stmt); 10019 break; 10020 10021 case FLOAT_EXPR: 10022 if (TREE_CODE (rhs1) == SSA_NAME 10023 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) 10024 return simplify_float_conversion_using_ranges (gsi, stmt); 10025 break; 10026 10027 case MIN_EXPR: 10028 case MAX_EXPR: 10029 return simplify_min_or_max_using_ranges (stmt); 10030 break; 10031 10032 default: 10033 break; 10034 } 10035 } 10036 else if (gimple_code (stmt) == GIMPLE_COND) 10037 return simplify_cond_using_ranges (as_a <gcond *> (stmt)); 10038 else if (gimple_code (stmt) == GIMPLE_SWITCH) 10039 return simplify_switch_using_ranges (as_a <gswitch *> (stmt)); 10040 else if (is_gimple_call (stmt) 10041 && gimple_call_internal_p (stmt)) 10042 return simplify_internal_call_using_ranges (gsi, stmt); 10043 10044 return false; 10045 } 10046 10047 /* If the statement pointed by SI has a predicate whose value can be 10048 computed using the value range information computed by VRP, compute 10049 its value and return true. Otherwise, return false. */ 10050 10051 static bool 10052 fold_predicate_in (gimple_stmt_iterator *si) 10053 { 10054 bool assignment_p = false; 10055 tree val; 10056 gimple *stmt = gsi_stmt (*si); 10057 10058 if (is_gimple_assign (stmt) 10059 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison) 10060 { 10061 assignment_p = true; 10062 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt), 10063 gimple_assign_rhs1 (stmt), 10064 gimple_assign_rhs2 (stmt), 10065 stmt); 10066 } 10067 else if (gcond *cond_stmt = dyn_cast <gcond *> (stmt)) 10068 val = vrp_evaluate_conditional (gimple_cond_code (cond_stmt), 10069 gimple_cond_lhs (cond_stmt), 10070 gimple_cond_rhs (cond_stmt), 10071 stmt); 10072 else 10073 return false; 10074 10075 if (val) 10076 { 10077 if (assignment_p) 10078 val = fold_convert (gimple_expr_type (stmt), val); 10079 10080 if (dump_file) 10081 { 10082 fprintf (dump_file, "Folding predicate "); 10083 print_gimple_expr (dump_file, stmt, 0, 0); 10084 fprintf (dump_file, " to "); 10085 print_generic_expr (dump_file, val, 0); 10086 fprintf (dump_file, "\n"); 10087 } 10088 10089 if (is_gimple_assign (stmt)) 10090 gimple_assign_set_rhs_from_tree (si, val); 10091 else 10092 { 10093 gcc_assert (gimple_code (stmt) == GIMPLE_COND); 10094 gcond *cond_stmt = as_a <gcond *> (stmt); 10095 if (integer_zerop (val)) 10096 gimple_cond_make_false (cond_stmt); 10097 else if (integer_onep (val)) 10098 gimple_cond_make_true (cond_stmt); 10099 else 10100 gcc_unreachable (); 10101 } 10102 10103 return true; 10104 } 10105 10106 return false; 10107 } 10108 10109 /* Callback for substitute_and_fold folding the stmt at *SI. */ 10110 10111 static bool 10112 vrp_fold_stmt (gimple_stmt_iterator *si) 10113 { 10114 if (fold_predicate_in (si)) 10115 return true; 10116 10117 return simplify_stmt_using_ranges (si); 10118 } 10119 10120 /* Unwindable const/copy equivalences. */ 10121 const_and_copies *equiv_stack; 10122 10123 /* A trivial wrapper so that we can present the generic jump threading 10124 code with a simple API for simplifying statements. STMT is the 10125 statement we want to simplify, WITHIN_STMT provides the location 10126 for any overflow warnings. */ 10127 10128 static tree 10129 simplify_stmt_for_jump_threading (gimple *stmt, gimple *within_stmt, 10130 class avail_exprs_stack *avail_exprs_stack ATTRIBUTE_UNUSED) 10131 { 10132 if (gcond *cond_stmt = dyn_cast <gcond *> (stmt)) 10133 return vrp_evaluate_conditional (gimple_cond_code (cond_stmt), 10134 gimple_cond_lhs (cond_stmt), 10135 gimple_cond_rhs (cond_stmt), 10136 within_stmt); 10137 10138 if (gassign *assign_stmt = dyn_cast <gassign *> (stmt)) 10139 { 10140 value_range new_vr = VR_INITIALIZER; 10141 tree lhs = gimple_assign_lhs (assign_stmt); 10142 10143 if (TREE_CODE (lhs) == SSA_NAME 10144 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs)) 10145 || POINTER_TYPE_P (TREE_TYPE (lhs)))) 10146 { 10147 extract_range_from_assignment (&new_vr, assign_stmt); 10148 if (range_int_cst_singleton_p (&new_vr)) 10149 return new_vr.min; 10150 } 10151 } 10152 10153 return NULL_TREE; 10154 } 10155 10156 /* Blocks which have more than one predecessor and more than 10157 one successor present jump threading opportunities, i.e., 10158 when the block is reached from a specific predecessor, we 10159 may be able to determine which of the outgoing edges will 10160 be traversed. When this optimization applies, we are able 10161 to avoid conditionals at runtime and we may expose secondary 10162 optimization opportunities. 10163 10164 This routine is effectively a driver for the generic jump 10165 threading code. It basically just presents the generic code 10166 with edges that may be suitable for jump threading. 10167 10168 Unlike DOM, we do not iterate VRP if jump threading was successful. 10169 While iterating may expose new opportunities for VRP, it is expected 10170 those opportunities would be very limited and the compile time cost 10171 to expose those opportunities would be significant. 10172 10173 As jump threading opportunities are discovered, they are registered 10174 for later realization. */ 10175 10176 static void 10177 identify_jump_threads (void) 10178 { 10179 basic_block bb; 10180 gcond *dummy; 10181 int i; 10182 edge e; 10183 10184 /* Ugh. When substituting values earlier in this pass we can 10185 wipe the dominance information. So rebuild the dominator 10186 information as we need it within the jump threading code. */ 10187 calculate_dominance_info (CDI_DOMINATORS); 10188 10189 /* We do not allow VRP information to be used for jump threading 10190 across a back edge in the CFG. Otherwise it becomes too 10191 difficult to avoid eliminating loop exit tests. Of course 10192 EDGE_DFS_BACK is not accurate at this time so we have to 10193 recompute it. */ 10194 mark_dfs_back_edges (); 10195 10196 /* Do not thread across edges we are about to remove. Just marking 10197 them as EDGE_IGNORE will do. */ 10198 FOR_EACH_VEC_ELT (to_remove_edges, i, e) 10199 e->flags |= EDGE_IGNORE; 10200 10201 /* Allocate our unwinder stack to unwind any temporary equivalences 10202 that might be recorded. */ 10203 equiv_stack = new const_and_copies (); 10204 10205 /* To avoid lots of silly node creation, we create a single 10206 conditional and just modify it in-place when attempting to 10207 thread jumps. */ 10208 dummy = gimple_build_cond (EQ_EXPR, 10209 integer_zero_node, integer_zero_node, 10210 NULL, NULL); 10211 10212 /* Walk through all the blocks finding those which present a 10213 potential jump threading opportunity. We could set this up 10214 as a dominator walker and record data during the walk, but 10215 I doubt it's worth the effort for the classes of jump 10216 threading opportunities we are trying to identify at this 10217 point in compilation. */ 10218 FOR_EACH_BB_FN (bb, cfun) 10219 { 10220 gimple *last; 10221 10222 /* If the generic jump threading code does not find this block 10223 interesting, then there is nothing to do. */ 10224 if (! potentially_threadable_block (bb)) 10225 continue; 10226 10227 last = last_stmt (bb); 10228 10229 /* We're basically looking for a switch or any kind of conditional with 10230 integral or pointer type arguments. Note the type of the second 10231 argument will be the same as the first argument, so no need to 10232 check it explicitly. 10233 10234 We also handle the case where there are no statements in the 10235 block. This come up with forwarder blocks that are not 10236 optimized away because they lead to a loop header. But we do 10237 want to thread through them as we can sometimes thread to the 10238 loop exit which is obviously profitable. */ 10239 if (!last 10240 || gimple_code (last) == GIMPLE_SWITCH 10241 || (gimple_code (last) == GIMPLE_COND 10242 && TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME 10243 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last))) 10244 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))) 10245 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME 10246 || is_gimple_min_invariant (gimple_cond_rhs (last))))) 10247 { 10248 edge_iterator ei; 10249 10250 /* We've got a block with multiple predecessors and multiple 10251 successors which also ends in a suitable conditional or 10252 switch statement. For each predecessor, see if we can thread 10253 it to a specific successor. */ 10254 FOR_EACH_EDGE (e, ei, bb->preds) 10255 { 10256 /* Do not thread across edges marked to ignoreor abnormal 10257 edges in the CFG. */ 10258 if (e->flags & (EDGE_IGNORE | EDGE_COMPLEX)) 10259 continue; 10260 10261 thread_across_edge (dummy, e, true, equiv_stack, NULL, 10262 simplify_stmt_for_jump_threading); 10263 } 10264 } 10265 } 10266 10267 /* Clear EDGE_IGNORE. */ 10268 FOR_EACH_VEC_ELT (to_remove_edges, i, e) 10269 e->flags &= ~EDGE_IGNORE; 10270 10271 /* We do not actually update the CFG or SSA graphs at this point as 10272 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet 10273 handle ASSERT_EXPRs gracefully. */ 10274 } 10275 10276 /* We identified all the jump threading opportunities earlier, but could 10277 not transform the CFG at that time. This routine transforms the 10278 CFG and arranges for the dominator tree to be rebuilt if necessary. 10279 10280 Note the SSA graph update will occur during the normal TODO 10281 processing by the pass manager. */ 10282 static void 10283 finalize_jump_threads (void) 10284 { 10285 thread_through_all_blocks (false); 10286 delete equiv_stack; 10287 } 10288 10289 10290 /* Traverse all the blocks folding conditionals with known ranges. */ 10291 10292 static void 10293 vrp_finalize (bool warn_array_bounds_p) 10294 { 10295 size_t i; 10296 10297 values_propagated = true; 10298 10299 if (dump_file) 10300 { 10301 fprintf (dump_file, "\nValue ranges after VRP:\n\n"); 10302 dump_all_value_ranges (dump_file); 10303 fprintf (dump_file, "\n"); 10304 } 10305 10306 /* Set value range to non pointer SSA_NAMEs. */ 10307 for (i = 0; i < num_vr_values; i++) 10308 if (vr_value[i]) 10309 { 10310 tree name = ssa_name (i); 10311 10312 if (!name 10313 || POINTER_TYPE_P (TREE_TYPE (name)) 10314 || (vr_value[i]->type == VR_VARYING) 10315 || (vr_value[i]->type == VR_UNDEFINED)) 10316 continue; 10317 10318 if ((TREE_CODE (vr_value[i]->min) == INTEGER_CST) 10319 && (TREE_CODE (vr_value[i]->max) == INTEGER_CST) 10320 && (vr_value[i]->type == VR_RANGE 10321 || vr_value[i]->type == VR_ANTI_RANGE)) 10322 set_range_info (name, vr_value[i]->type, vr_value[i]->min, 10323 vr_value[i]->max); 10324 } 10325 10326 substitute_and_fold (op_with_constant_singleton_value_range, 10327 vrp_fold_stmt, false); 10328 10329 if (warn_array_bounds && warn_array_bounds_p) 10330 check_all_array_refs (); 10331 10332 /* We must identify jump threading opportunities before we release 10333 the datastructures built by VRP. */ 10334 identify_jump_threads (); 10335 10336 /* Free allocated memory. */ 10337 for (i = 0; i < num_vr_values; i++) 10338 if (vr_value[i]) 10339 { 10340 BITMAP_FREE (vr_value[i]->equiv); 10341 free (vr_value[i]); 10342 } 10343 10344 free (vr_value); 10345 free (vr_phi_edge_counts); 10346 10347 /* So that we can distinguish between VRP data being available 10348 and not available. */ 10349 vr_value = NULL; 10350 vr_phi_edge_counts = NULL; 10351 } 10352 10353 10354 /* Main entry point to VRP (Value Range Propagation). This pass is 10355 loosely based on J. R. C. Patterson, ``Accurate Static Branch 10356 Prediction by Value Range Propagation,'' in SIGPLAN Conference on 10357 Programming Language Design and Implementation, pp. 67-78, 1995. 10358 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html 10359 10360 This is essentially an SSA-CCP pass modified to deal with ranges 10361 instead of constants. 10362 10363 While propagating ranges, we may find that two or more SSA name 10364 have equivalent, though distinct ranges. For instance, 10365 10366 1 x_9 = p_3->a; 10367 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0> 10368 3 if (p_4 == q_2) 10369 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>; 10370 5 endif 10371 6 if (q_2) 10372 10373 In the code above, pointer p_5 has range [q_2, q_2], but from the 10374 code we can also determine that p_5 cannot be NULL and, if q_2 had 10375 a non-varying range, p_5's range should also be compatible with it. 10376 10377 These equivalences are created by two expressions: ASSERT_EXPR and 10378 copy operations. Since p_5 is an assertion on p_4, and p_4 was the 10379 result of another assertion, then we can use the fact that p_5 and 10380 p_4 are equivalent when evaluating p_5's range. 10381 10382 Together with value ranges, we also propagate these equivalences 10383 between names so that we can take advantage of information from 10384 multiple ranges when doing final replacement. Note that this 10385 equivalency relation is transitive but not symmetric. 10386 10387 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we 10388 cannot assert that q_2 is equivalent to p_5 because q_2 may be used 10389 in contexts where that assertion does not hold (e.g., in line 6). 10390 10391 TODO, the main difference between this pass and Patterson's is that 10392 we do not propagate edge probabilities. We only compute whether 10393 edges can be taken or not. That is, instead of having a spectrum 10394 of jump probabilities between 0 and 1, we only deal with 0, 1 and 10395 DON'T KNOW. In the future, it may be worthwhile to propagate 10396 probabilities to aid branch prediction. */ 10397 10398 static unsigned int 10399 execute_vrp (bool warn_array_bounds_p) 10400 { 10401 int i; 10402 edge e; 10403 switch_update *su; 10404 10405 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS); 10406 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa); 10407 scev_initialize (); 10408 10409 /* ??? This ends up using stale EDGE_DFS_BACK for liveness computation. 10410 Inserting assertions may split edges which will invalidate 10411 EDGE_DFS_BACK. */ 10412 insert_range_assertions (); 10413 10414 to_remove_edges.create (10); 10415 to_update_switch_stmts.create (5); 10416 threadedge_initialize_values (); 10417 10418 /* For visiting PHI nodes we need EDGE_DFS_BACK computed. */ 10419 mark_dfs_back_edges (); 10420 10421 vrp_initialize (); 10422 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node); 10423 vrp_finalize (warn_array_bounds_p); 10424 10425 free_numbers_of_iterations_estimates (cfun); 10426 10427 /* ASSERT_EXPRs must be removed before finalizing jump threads 10428 as finalizing jump threads calls the CFG cleanup code which 10429 does not properly handle ASSERT_EXPRs. */ 10430 remove_range_assertions (); 10431 10432 /* If we exposed any new variables, go ahead and put them into 10433 SSA form now, before we handle jump threading. This simplifies 10434 interactions between rewriting of _DECL nodes into SSA form 10435 and rewriting SSA_NAME nodes into SSA form after block 10436 duplication and CFG manipulation. */ 10437 update_ssa (TODO_update_ssa); 10438 10439 finalize_jump_threads (); 10440 10441 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the 10442 CFG in a broken state and requires a cfg_cleanup run. */ 10443 FOR_EACH_VEC_ELT (to_remove_edges, i, e) 10444 remove_edge (e); 10445 /* Update SWITCH_EXPR case label vector. */ 10446 FOR_EACH_VEC_ELT (to_update_switch_stmts, i, su) 10447 { 10448 size_t j; 10449 size_t n = TREE_VEC_LENGTH (su->vec); 10450 tree label; 10451 gimple_switch_set_num_labels (su->stmt, n); 10452 for (j = 0; j < n; j++) 10453 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j)); 10454 /* As we may have replaced the default label with a regular one 10455 make sure to make it a real default label again. This ensures 10456 optimal expansion. */ 10457 label = gimple_switch_label (su->stmt, 0); 10458 CASE_LOW (label) = NULL_TREE; 10459 CASE_HIGH (label) = NULL_TREE; 10460 } 10461 10462 if (to_remove_edges.length () > 0) 10463 { 10464 free_dominance_info (CDI_DOMINATORS); 10465 loops_state_set (LOOPS_NEED_FIXUP); 10466 } 10467 10468 to_remove_edges.release (); 10469 to_update_switch_stmts.release (); 10470 threadedge_finalize_values (); 10471 10472 scev_finalize (); 10473 loop_optimizer_finalize (); 10474 return 0; 10475 } 10476 10477 namespace { 10478 10479 const pass_data pass_data_vrp = 10480 { 10481 GIMPLE_PASS, /* type */ 10482 "vrp", /* name */ 10483 OPTGROUP_NONE, /* optinfo_flags */ 10484 TV_TREE_VRP, /* tv_id */ 10485 PROP_ssa, /* properties_required */ 10486 0, /* properties_provided */ 10487 0, /* properties_destroyed */ 10488 0, /* todo_flags_start */ 10489 ( TODO_cleanup_cfg | TODO_update_ssa ), /* todo_flags_finish */ 10490 }; 10491 10492 class pass_vrp : public gimple_opt_pass 10493 { 10494 public: 10495 pass_vrp (gcc::context *ctxt) 10496 : gimple_opt_pass (pass_data_vrp, ctxt), warn_array_bounds_p (false) 10497 {} 10498 10499 /* opt_pass methods: */ 10500 opt_pass * clone () { return new pass_vrp (m_ctxt); } 10501 void set_pass_param (unsigned int n, bool param) 10502 { 10503 gcc_assert (n == 0); 10504 warn_array_bounds_p = param; 10505 } 10506 virtual bool gate (function *) { return flag_tree_vrp != 0; } 10507 virtual unsigned int execute (function *) 10508 { return execute_vrp (warn_array_bounds_p); } 10509 10510 private: 10511 bool warn_array_bounds_p; 10512 }; // class pass_vrp 10513 10514 } // anon namespace 10515 10516 gimple_opt_pass * 10517 make_pass_vrp (gcc::context *ctxt) 10518 { 10519 return new pass_vrp (ctxt); 10520 } 10521