1 /* Support routines for Value Range Propagation (VRP). 2 Copyright (C) 2005-2018 Free Software Foundation, Inc. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 GCC is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GCC; see the file COPYING3. If not see 18 <http://www.gnu.org/licenses/>. */ 19 20 #include "config.h" 21 #include "system.h" 22 #include "coretypes.h" 23 #include "backend.h" 24 #include "insn-codes.h" 25 #include "tree.h" 26 #include "gimple.h" 27 #include "ssa.h" 28 #include "optabs-tree.h" 29 #include "gimple-pretty-print.h" 30 #include "diagnostic-core.h" 31 #include "flags.h" 32 #include "fold-const.h" 33 #include "calls.h" 34 #include "cfganal.h" 35 #include "gimple-fold.h" 36 #include "gimple-iterator.h" 37 #include "tree-cfg.h" 38 #include "tree-ssa-loop-niter.h" 39 #include "tree-ssa-loop.h" 40 #include "intl.h" 41 #include "cfgloop.h" 42 #include "tree-scalar-evolution.h" 43 #include "tree-ssa-propagate.h" 44 #include "tree-chrec.h" 45 #include "omp-general.h" 46 #include "case-cfn-macros.h" 47 #include "alloc-pool.h" 48 #include "attribs.h" 49 #include "vr-values.h" 50 51 /* Set value range VR to a non-negative range of type TYPE. */ 52 53 static inline void 54 set_value_range_to_nonnegative (value_range *vr, tree type) 55 { 56 tree zero = build_int_cst (type, 0); 57 set_value_range (vr, VR_RANGE, zero, vrp_val_max (type), vr->equiv); 58 } 59 60 /* Set value range VR to a range of a truthvalue of type TYPE. */ 61 62 static inline void 63 set_value_range_to_truthvalue (value_range *vr, tree type) 64 { 65 if (TYPE_PRECISION (type) == 1) 66 set_value_range_to_varying (vr); 67 else 68 set_value_range (vr, VR_RANGE, 69 build_int_cst (type, 0), build_int_cst (type, 1), 70 vr->equiv); 71 } 72 73 74 /* Return value range information for VAR. 75 76 If we have no values ranges recorded (ie, VRP is not running), then 77 return NULL. Otherwise create an empty range if none existed for VAR. */ 78 79 value_range * 80 vr_values::get_value_range (const_tree var) 81 { 82 static const value_range vr_const_varying 83 = { VR_VARYING, NULL_TREE, NULL_TREE, NULL }; 84 value_range *vr; 85 tree sym; 86 unsigned ver = SSA_NAME_VERSION (var); 87 88 /* If we have no recorded ranges, then return NULL. */ 89 if (! vr_value) 90 return NULL; 91 92 /* If we query the range for a new SSA name return an unmodifiable VARYING. 93 We should get here at most from the substitute-and-fold stage which 94 will never try to change values. */ 95 if (ver >= num_vr_values) 96 return CONST_CAST (value_range *, &vr_const_varying); 97 98 vr = vr_value[ver]; 99 if (vr) 100 return vr; 101 102 /* After propagation finished do not allocate new value-ranges. */ 103 if (values_propagated) 104 return CONST_CAST (value_range *, &vr_const_varying); 105 106 /* Create a default value range. */ 107 vr_value[ver] = vr = vrp_value_range_pool.allocate (); 108 memset (vr, 0, sizeof (*vr)); 109 110 /* Defer allocating the equivalence set. */ 111 vr->equiv = NULL; 112 113 /* If VAR is a default definition of a parameter, the variable can 114 take any value in VAR's type. */ 115 if (SSA_NAME_IS_DEFAULT_DEF (var)) 116 { 117 sym = SSA_NAME_VAR (var); 118 if (TREE_CODE (sym) == PARM_DECL) 119 { 120 /* Try to use the "nonnull" attribute to create ~[0, 0] 121 anti-ranges for pointers. Note that this is only valid with 122 default definitions of PARM_DECLs. */ 123 if (POINTER_TYPE_P (TREE_TYPE (sym)) 124 && (nonnull_arg_p (sym) 125 || get_ptr_nonnull (var))) 126 set_value_range_to_nonnull (vr, TREE_TYPE (sym)); 127 else if (INTEGRAL_TYPE_P (TREE_TYPE (sym))) 128 { 129 wide_int min, max; 130 value_range_type rtype = get_range_info (var, &min, &max); 131 if (rtype == VR_RANGE || rtype == VR_ANTI_RANGE) 132 set_value_range (vr, rtype, 133 wide_int_to_tree (TREE_TYPE (var), min), 134 wide_int_to_tree (TREE_TYPE (var), max), 135 NULL); 136 else 137 set_value_range_to_varying (vr); 138 } 139 else 140 set_value_range_to_varying (vr); 141 } 142 else if (TREE_CODE (sym) == RESULT_DECL 143 && DECL_BY_REFERENCE (sym)) 144 set_value_range_to_nonnull (vr, TREE_TYPE (sym)); 145 } 146 147 return vr; 148 } 149 150 /* Set value-ranges of all SSA names defined by STMT to varying. */ 151 152 void 153 vr_values::set_defs_to_varying (gimple *stmt) 154 { 155 ssa_op_iter i; 156 tree def; 157 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF) 158 { 159 value_range *vr = get_value_range (def); 160 /* Avoid writing to vr_const_varying get_value_range may return. */ 161 if (vr->type != VR_VARYING) 162 set_value_range_to_varying (vr); 163 } 164 } 165 166 /* Update the value range and equivalence set for variable VAR to 167 NEW_VR. Return true if NEW_VR is different from VAR's previous 168 value. 169 170 NOTE: This function assumes that NEW_VR is a temporary value range 171 object created for the sole purpose of updating VAR's range. The 172 storage used by the equivalence set from NEW_VR will be freed by 173 this function. Do not call update_value_range when NEW_VR 174 is the range object associated with another SSA name. */ 175 176 bool 177 vr_values::update_value_range (const_tree var, value_range *new_vr) 178 { 179 value_range *old_vr; 180 bool is_new; 181 182 /* If there is a value-range on the SSA name from earlier analysis 183 factor that in. */ 184 if (INTEGRAL_TYPE_P (TREE_TYPE (var))) 185 { 186 wide_int min, max; 187 value_range_type rtype = get_range_info (var, &min, &max); 188 if (rtype == VR_RANGE || rtype == VR_ANTI_RANGE) 189 { 190 tree nr_min, nr_max; 191 nr_min = wide_int_to_tree (TREE_TYPE (var), min); 192 nr_max = wide_int_to_tree (TREE_TYPE (var), max); 193 value_range nr = VR_INITIALIZER; 194 set_and_canonicalize_value_range (&nr, rtype, nr_min, nr_max, NULL); 195 vrp_intersect_ranges (new_vr, &nr); 196 } 197 } 198 199 /* Update the value range, if necessary. */ 200 old_vr = get_value_range (var); 201 is_new = old_vr->type != new_vr->type 202 || !vrp_operand_equal_p (old_vr->min, new_vr->min) 203 || !vrp_operand_equal_p (old_vr->max, new_vr->max) 204 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv); 205 206 if (is_new) 207 { 208 /* Do not allow transitions up the lattice. The following 209 is slightly more awkward than just new_vr->type < old_vr->type 210 because VR_RANGE and VR_ANTI_RANGE need to be considered 211 the same. We may not have is_new when transitioning to 212 UNDEFINED. If old_vr->type is VARYING, we shouldn't be 213 called. */ 214 if (new_vr->type == VR_UNDEFINED) 215 { 216 BITMAP_FREE (new_vr->equiv); 217 set_value_range_to_varying (old_vr); 218 set_value_range_to_varying (new_vr); 219 return true; 220 } 221 else 222 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max, 223 new_vr->equiv); 224 } 225 226 BITMAP_FREE (new_vr->equiv); 227 228 return is_new; 229 } 230 231 232 /* Add VAR and VAR's equivalence set to EQUIV. This is the central 233 point where equivalence processing can be turned on/off. */ 234 235 void 236 vr_values::add_equivalence (bitmap *equiv, const_tree var) 237 { 238 unsigned ver = SSA_NAME_VERSION (var); 239 value_range *vr = get_value_range (var); 240 241 if (*equiv == NULL) 242 *equiv = BITMAP_ALLOC (&vrp_equiv_obstack); 243 bitmap_set_bit (*equiv, ver); 244 if (vr && vr->equiv) 245 bitmap_ior_into (*equiv, vr->equiv); 246 } 247 248 /* Return true if value range VR involves exactly one symbol SYM. */ 249 250 static bool 251 symbolic_range_based_on_p (value_range *vr, const_tree sym) 252 { 253 bool neg, min_has_symbol, max_has_symbol; 254 tree inv; 255 256 if (is_gimple_min_invariant (vr->min)) 257 min_has_symbol = false; 258 else if (get_single_symbol (vr->min, &neg, &inv) == sym) 259 min_has_symbol = true; 260 else 261 return false; 262 263 if (is_gimple_min_invariant (vr->max)) 264 max_has_symbol = false; 265 else if (get_single_symbol (vr->max, &neg, &inv) == sym) 266 max_has_symbol = true; 267 else 268 return false; 269 270 return (min_has_symbol || max_has_symbol); 271 } 272 273 /* Return true if the result of assignment STMT is know to be non-zero. */ 274 275 static bool 276 gimple_assign_nonzero_p (gimple *stmt) 277 { 278 enum tree_code code = gimple_assign_rhs_code (stmt); 279 bool strict_overflow_p; 280 switch (get_gimple_rhs_class (code)) 281 { 282 case GIMPLE_UNARY_RHS: 283 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt), 284 gimple_expr_type (stmt), 285 gimple_assign_rhs1 (stmt), 286 &strict_overflow_p); 287 case GIMPLE_BINARY_RHS: 288 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt), 289 gimple_expr_type (stmt), 290 gimple_assign_rhs1 (stmt), 291 gimple_assign_rhs2 (stmt), 292 &strict_overflow_p); 293 case GIMPLE_TERNARY_RHS: 294 return false; 295 case GIMPLE_SINGLE_RHS: 296 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt), 297 &strict_overflow_p); 298 case GIMPLE_INVALID_RHS: 299 gcc_unreachable (); 300 default: 301 gcc_unreachable (); 302 } 303 } 304 305 /* Return true if STMT is known to compute a non-zero value. */ 306 307 static bool 308 gimple_stmt_nonzero_p (gimple *stmt) 309 { 310 switch (gimple_code (stmt)) 311 { 312 case GIMPLE_ASSIGN: 313 return gimple_assign_nonzero_p (stmt); 314 case GIMPLE_CALL: 315 { 316 tree fndecl = gimple_call_fndecl (stmt); 317 if (!fndecl) return false; 318 if (flag_delete_null_pointer_checks && !flag_check_new 319 && DECL_IS_OPERATOR_NEW (fndecl) 320 && !TREE_NOTHROW (fndecl)) 321 return true; 322 /* References are always non-NULL. */ 323 if (flag_delete_null_pointer_checks 324 && TREE_CODE (TREE_TYPE (fndecl)) == REFERENCE_TYPE) 325 return true; 326 if (flag_delete_null_pointer_checks && 327 lookup_attribute ("returns_nonnull", 328 TYPE_ATTRIBUTES (gimple_call_fntype (stmt)))) 329 return true; 330 331 gcall *call_stmt = as_a<gcall *> (stmt); 332 unsigned rf = gimple_call_return_flags (call_stmt); 333 if (rf & ERF_RETURNS_ARG) 334 { 335 unsigned argnum = rf & ERF_RETURN_ARG_MASK; 336 if (argnum < gimple_call_num_args (call_stmt)) 337 { 338 tree arg = gimple_call_arg (call_stmt, argnum); 339 if (SSA_VAR_P (arg) 340 && infer_nonnull_range_by_attribute (stmt, arg)) 341 return true; 342 } 343 } 344 return gimple_alloca_call_p (stmt); 345 } 346 default: 347 gcc_unreachable (); 348 } 349 } 350 /* Like tree_expr_nonzero_p, but this function uses value ranges 351 obtained so far. */ 352 353 bool 354 vr_values::vrp_stmt_computes_nonzero (gimple *stmt) 355 { 356 if (gimple_stmt_nonzero_p (stmt)) 357 return true; 358 359 /* If we have an expression of the form &X->a, then the expression 360 is nonnull if X is nonnull. */ 361 if (is_gimple_assign (stmt) 362 && gimple_assign_rhs_code (stmt) == ADDR_EXPR) 363 { 364 tree expr = gimple_assign_rhs1 (stmt); 365 tree base = get_base_address (TREE_OPERAND (expr, 0)); 366 367 if (base != NULL_TREE 368 && TREE_CODE (base) == MEM_REF 369 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) 370 { 371 value_range *vr = get_value_range (TREE_OPERAND (base, 0)); 372 if (range_is_nonnull (vr)) 373 return true; 374 } 375 } 376 377 return false; 378 } 379 380 /* Returns true if EXPR is a valid value (as expected by compare_values) -- 381 a gimple invariant, or SSA_NAME +- CST. */ 382 383 static bool 384 valid_value_p (tree expr) 385 { 386 if (TREE_CODE (expr) == SSA_NAME) 387 return true; 388 389 if (TREE_CODE (expr) == PLUS_EXPR 390 || TREE_CODE (expr) == MINUS_EXPR) 391 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME 392 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST); 393 394 return is_gimple_min_invariant (expr); 395 } 396 397 /* If OP has a value range with a single constant value return that, 398 otherwise return NULL_TREE. This returns OP itself if OP is a 399 constant. */ 400 401 tree 402 vr_values::op_with_constant_singleton_value_range (tree op) 403 { 404 if (is_gimple_min_invariant (op)) 405 return op; 406 407 if (TREE_CODE (op) != SSA_NAME) 408 return NULL_TREE; 409 410 return value_range_constant_singleton (get_value_range (op)); 411 } 412 413 /* Return true if op is in a boolean [0, 1] value-range. */ 414 415 bool 416 vr_values::op_with_boolean_value_range_p (tree op) 417 { 418 value_range *vr; 419 420 if (TYPE_PRECISION (TREE_TYPE (op)) == 1) 421 return true; 422 423 if (integer_zerop (op) 424 || integer_onep (op)) 425 return true; 426 427 if (TREE_CODE (op) != SSA_NAME) 428 return false; 429 430 vr = get_value_range (op); 431 return (vr->type == VR_RANGE 432 && integer_zerop (vr->min) 433 && integer_onep (vr->max)); 434 } 435 436 /* Extract value range information for VAR when (OP COND_CODE LIMIT) is 437 true and store it in *VR_P. */ 438 439 void 440 vr_values::extract_range_for_var_from_comparison_expr (tree var, 441 enum tree_code cond_code, 442 tree op, tree limit, 443 value_range *vr_p) 444 { 445 tree min, max, type; 446 value_range *limit_vr; 447 type = TREE_TYPE (var); 448 449 /* For pointer arithmetic, we only keep track of pointer equality 450 and inequality. If we arrive here with unfolded conditions like 451 _1 > _1 do not derive anything. */ 452 if ((POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR) 453 || limit == var) 454 { 455 set_value_range_to_varying (vr_p); 456 return; 457 } 458 459 /* If LIMIT is another SSA name and LIMIT has a range of its own, 460 try to use LIMIT's range to avoid creating symbolic ranges 461 unnecessarily. */ 462 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL; 463 464 /* LIMIT's range is only interesting if it has any useful information. */ 465 if (! limit_vr 466 || limit_vr->type == VR_UNDEFINED 467 || limit_vr->type == VR_VARYING 468 || (symbolic_range_p (limit_vr) 469 && ! (limit_vr->type == VR_RANGE 470 && (limit_vr->min == limit_vr->max 471 || operand_equal_p (limit_vr->min, limit_vr->max, 0))))) 472 limit_vr = NULL; 473 474 /* Initially, the new range has the same set of equivalences of 475 VAR's range. This will be revised before returning the final 476 value. Since assertions may be chained via mutually exclusive 477 predicates, we will need to trim the set of equivalences before 478 we are done. */ 479 gcc_assert (vr_p->equiv == NULL); 480 add_equivalence (&vr_p->equiv, var); 481 482 /* Extract a new range based on the asserted comparison for VAR and 483 LIMIT's value range. Notice that if LIMIT has an anti-range, we 484 will only use it for equality comparisons (EQ_EXPR). For any 485 other kind of assertion, we cannot derive a range from LIMIT's 486 anti-range that can be used to describe the new range. For 487 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10], 488 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is 489 no single range for x_2 that could describe LE_EXPR, so we might 490 as well build the range [b_4, +INF] for it. 491 One special case we handle is extracting a range from a 492 range test encoded as (unsigned)var + CST <= limit. */ 493 if (TREE_CODE (op) == NOP_EXPR 494 || TREE_CODE (op) == PLUS_EXPR) 495 { 496 if (TREE_CODE (op) == PLUS_EXPR) 497 { 498 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (op, 1)), 499 TREE_OPERAND (op, 1)); 500 max = int_const_binop (PLUS_EXPR, limit, min); 501 op = TREE_OPERAND (op, 0); 502 } 503 else 504 { 505 min = build_int_cst (TREE_TYPE (var), 0); 506 max = limit; 507 } 508 509 /* Make sure to not set TREE_OVERFLOW on the final type 510 conversion. We are willingly interpreting large positive 511 unsigned values as negative signed values here. */ 512 min = force_fit_type (TREE_TYPE (var), wi::to_widest (min), 0, false); 513 max = force_fit_type (TREE_TYPE (var), wi::to_widest (max), 0, false); 514 515 /* We can transform a max, min range to an anti-range or 516 vice-versa. Use set_and_canonicalize_value_range which does 517 this for us. */ 518 if (cond_code == LE_EXPR) 519 set_and_canonicalize_value_range (vr_p, VR_RANGE, 520 min, max, vr_p->equiv); 521 else if (cond_code == GT_EXPR) 522 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE, 523 min, max, vr_p->equiv); 524 else 525 gcc_unreachable (); 526 } 527 else if (cond_code == EQ_EXPR) 528 { 529 enum value_range_type range_type; 530 531 if (limit_vr) 532 { 533 range_type = limit_vr->type; 534 min = limit_vr->min; 535 max = limit_vr->max; 536 } 537 else 538 { 539 range_type = VR_RANGE; 540 min = limit; 541 max = limit; 542 } 543 544 set_value_range (vr_p, range_type, min, max, vr_p->equiv); 545 546 /* When asserting the equality VAR == LIMIT and LIMIT is another 547 SSA name, the new range will also inherit the equivalence set 548 from LIMIT. */ 549 if (TREE_CODE (limit) == SSA_NAME) 550 add_equivalence (&vr_p->equiv, limit); 551 } 552 else if (cond_code == NE_EXPR) 553 { 554 /* As described above, when LIMIT's range is an anti-range and 555 this assertion is an inequality (NE_EXPR), then we cannot 556 derive anything from the anti-range. For instance, if 557 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does 558 not imply that VAR's range is [0, 0]. So, in the case of 559 anti-ranges, we just assert the inequality using LIMIT and 560 not its anti-range. 561 562 If LIMIT_VR is a range, we can only use it to build a new 563 anti-range if LIMIT_VR is a single-valued range. For 564 instance, if LIMIT_VR is [0, 1], the predicate 565 VAR != [0, 1] does not mean that VAR's range is ~[0, 1]. 566 Rather, it means that for value 0 VAR should be ~[0, 0] 567 and for value 1, VAR should be ~[1, 1]. We cannot 568 represent these ranges. 569 570 The only situation in which we can build a valid 571 anti-range is when LIMIT_VR is a single-valued range 572 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case, 573 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */ 574 if (limit_vr 575 && limit_vr->type == VR_RANGE 576 && compare_values (limit_vr->min, limit_vr->max) == 0) 577 { 578 min = limit_vr->min; 579 max = limit_vr->max; 580 } 581 else 582 { 583 /* In any other case, we cannot use LIMIT's range to build a 584 valid anti-range. */ 585 min = max = limit; 586 } 587 588 /* If MIN and MAX cover the whole range for their type, then 589 just use the original LIMIT. */ 590 if (INTEGRAL_TYPE_P (type) 591 && vrp_val_is_min (min) 592 && vrp_val_is_max (max)) 593 min = max = limit; 594 595 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE, 596 min, max, vr_p->equiv); 597 } 598 else if (cond_code == LE_EXPR || cond_code == LT_EXPR) 599 { 600 min = TYPE_MIN_VALUE (type); 601 602 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE) 603 max = limit; 604 else 605 { 606 /* If LIMIT_VR is of the form [N1, N2], we need to build the 607 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for 608 LT_EXPR. */ 609 max = limit_vr->max; 610 } 611 612 /* If the maximum value forces us to be out of bounds, simply punt. 613 It would be pointless to try and do anything more since this 614 all should be optimized away above us. */ 615 if (cond_code == LT_EXPR 616 && compare_values (max, min) == 0) 617 set_value_range_to_varying (vr_p); 618 else 619 { 620 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */ 621 if (cond_code == LT_EXPR) 622 { 623 if (TYPE_PRECISION (TREE_TYPE (max)) == 1 624 && !TYPE_UNSIGNED (TREE_TYPE (max))) 625 max = fold_build2 (PLUS_EXPR, TREE_TYPE (max), max, 626 build_int_cst (TREE_TYPE (max), -1)); 627 else 628 max = fold_build2 (MINUS_EXPR, TREE_TYPE (max), max, 629 build_int_cst (TREE_TYPE (max), 1)); 630 /* Signal to compare_values_warnv this expr doesn't overflow. */ 631 if (EXPR_P (max)) 632 TREE_NO_WARNING (max) = 1; 633 } 634 635 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv); 636 } 637 } 638 else if (cond_code == GE_EXPR || cond_code == GT_EXPR) 639 { 640 max = TYPE_MAX_VALUE (type); 641 642 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE) 643 min = limit; 644 else 645 { 646 /* If LIMIT_VR is of the form [N1, N2], we need to build the 647 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for 648 GT_EXPR. */ 649 min = limit_vr->min; 650 } 651 652 /* If the minimum value forces us to be out of bounds, simply punt. 653 It would be pointless to try and do anything more since this 654 all should be optimized away above us. */ 655 if (cond_code == GT_EXPR 656 && compare_values (min, max) == 0) 657 set_value_range_to_varying (vr_p); 658 else 659 { 660 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */ 661 if (cond_code == GT_EXPR) 662 { 663 if (TYPE_PRECISION (TREE_TYPE (min)) == 1 664 && !TYPE_UNSIGNED (TREE_TYPE (min))) 665 min = fold_build2 (MINUS_EXPR, TREE_TYPE (min), min, 666 build_int_cst (TREE_TYPE (min), -1)); 667 else 668 min = fold_build2 (PLUS_EXPR, TREE_TYPE (min), min, 669 build_int_cst (TREE_TYPE (min), 1)); 670 /* Signal to compare_values_warnv this expr doesn't overflow. */ 671 if (EXPR_P (min)) 672 TREE_NO_WARNING (min) = 1; 673 } 674 675 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv); 676 } 677 } 678 else 679 gcc_unreachable (); 680 681 /* Finally intersect the new range with what we already know about var. */ 682 vrp_intersect_ranges (vr_p, get_value_range (var)); 683 } 684 685 /* Extract value range information from an ASSERT_EXPR EXPR and store 686 it in *VR_P. */ 687 688 void 689 vr_values::extract_range_from_assert (value_range *vr_p, tree expr) 690 { 691 tree var = ASSERT_EXPR_VAR (expr); 692 tree cond = ASSERT_EXPR_COND (expr); 693 tree limit, op; 694 enum tree_code cond_code; 695 gcc_assert (COMPARISON_CLASS_P (cond)); 696 697 /* Find VAR in the ASSERT_EXPR conditional. */ 698 if (var == TREE_OPERAND (cond, 0) 699 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR 700 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR) 701 { 702 /* If the predicate is of the form VAR COMP LIMIT, then we just 703 take LIMIT from the RHS and use the same comparison code. */ 704 cond_code = TREE_CODE (cond); 705 limit = TREE_OPERAND (cond, 1); 706 op = TREE_OPERAND (cond, 0); 707 } 708 else 709 { 710 /* If the predicate is of the form LIMIT COMP VAR, then we need 711 to flip around the comparison code to create the proper range 712 for VAR. */ 713 cond_code = swap_tree_comparison (TREE_CODE (cond)); 714 limit = TREE_OPERAND (cond, 0); 715 op = TREE_OPERAND (cond, 1); 716 } 717 extract_range_for_var_from_comparison_expr (var, cond_code, op, 718 limit, vr_p); 719 } 720 721 /* Extract range information from SSA name VAR and store it in VR. If 722 VAR has an interesting range, use it. Otherwise, create the 723 range [VAR, VAR] and return it. This is useful in situations where 724 we may have conditionals testing values of VARYING names. For 725 instance, 726 727 x_3 = y_5; 728 if (x_3 > y_5) 729 ... 730 731 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is 732 always false. */ 733 734 void 735 vr_values::extract_range_from_ssa_name (value_range *vr, tree var) 736 { 737 value_range *var_vr = get_value_range (var); 738 739 if (var_vr->type != VR_VARYING) 740 copy_value_range (vr, var_vr); 741 else 742 set_value_range (vr, VR_RANGE, var, var, NULL); 743 744 add_equivalence (&vr->equiv, var); 745 } 746 747 /* Extract range information from a binary expression OP0 CODE OP1 based on 748 the ranges of each of its operands with resulting type EXPR_TYPE. 749 The resulting range is stored in *VR. */ 750 751 void 752 vr_values::extract_range_from_binary_expr (value_range *vr, 753 enum tree_code code, 754 tree expr_type, tree op0, tree op1) 755 { 756 value_range vr0 = VR_INITIALIZER; 757 value_range vr1 = VR_INITIALIZER; 758 759 /* Get value ranges for each operand. For constant operands, create 760 a new value range with the operand to simplify processing. */ 761 if (TREE_CODE (op0) == SSA_NAME) 762 vr0 = *(get_value_range (op0)); 763 else if (is_gimple_min_invariant (op0)) 764 set_value_range_to_value (&vr0, op0, NULL); 765 else 766 set_value_range_to_varying (&vr0); 767 768 if (TREE_CODE (op1) == SSA_NAME) 769 vr1 = *(get_value_range (op1)); 770 else if (is_gimple_min_invariant (op1)) 771 set_value_range_to_value (&vr1, op1, NULL); 772 else 773 set_value_range_to_varying (&vr1); 774 775 /* If one argument is varying, we can sometimes still deduce a 776 range for the output: any + [3, +INF] is in [MIN+3, +INF]. */ 777 if (INTEGRAL_TYPE_P (TREE_TYPE (op0)) 778 && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0))) 779 { 780 if (vr0.type == VR_VARYING && vr1.type != VR_VARYING) 781 { 782 vr0.type = VR_RANGE; 783 vr0.min = vrp_val_min (expr_type); 784 vr0.max = vrp_val_max (expr_type); 785 } 786 else if (vr1.type == VR_VARYING && vr0.type != VR_VARYING) 787 { 788 vr1.type = VR_RANGE; 789 vr1.min = vrp_val_min (expr_type); 790 vr1.max = vrp_val_max (expr_type); 791 } 792 } 793 794 extract_range_from_binary_expr_1 (vr, code, expr_type, &vr0, &vr1); 795 796 /* Try harder for PLUS and MINUS if the range of one operand is symbolic 797 and based on the other operand, for example if it was deduced from a 798 symbolic comparison. When a bound of the range of the first operand 799 is invariant, we set the corresponding bound of the new range to INF 800 in order to avoid recursing on the range of the second operand. */ 801 if (vr->type == VR_VARYING 802 && (code == PLUS_EXPR || code == MINUS_EXPR) 803 && TREE_CODE (op1) == SSA_NAME 804 && vr0.type == VR_RANGE 805 && symbolic_range_based_on_p (&vr0, op1)) 806 { 807 const bool minus_p = (code == MINUS_EXPR); 808 value_range n_vr1 = VR_INITIALIZER; 809 810 /* Try with VR0 and [-INF, OP1]. */ 811 if (is_gimple_min_invariant (minus_p ? vr0.max : vr0.min)) 812 set_value_range (&n_vr1, VR_RANGE, vrp_val_min (expr_type), op1, NULL); 813 814 /* Try with VR0 and [OP1, +INF]. */ 815 else if (is_gimple_min_invariant (minus_p ? vr0.min : vr0.max)) 816 set_value_range (&n_vr1, VR_RANGE, op1, vrp_val_max (expr_type), NULL); 817 818 /* Try with VR0 and [OP1, OP1]. */ 819 else 820 set_value_range (&n_vr1, VR_RANGE, op1, op1, NULL); 821 822 extract_range_from_binary_expr_1 (vr, code, expr_type, &vr0, &n_vr1); 823 } 824 825 if (vr->type == VR_VARYING 826 && (code == PLUS_EXPR || code == MINUS_EXPR) 827 && TREE_CODE (op0) == SSA_NAME 828 && vr1.type == VR_RANGE 829 && symbolic_range_based_on_p (&vr1, op0)) 830 { 831 const bool minus_p = (code == MINUS_EXPR); 832 value_range n_vr0 = VR_INITIALIZER; 833 834 /* Try with [-INF, OP0] and VR1. */ 835 if (is_gimple_min_invariant (minus_p ? vr1.max : vr1.min)) 836 set_value_range (&n_vr0, VR_RANGE, vrp_val_min (expr_type), op0, NULL); 837 838 /* Try with [OP0, +INF] and VR1. */ 839 else if (is_gimple_min_invariant (minus_p ? vr1.min : vr1.max)) 840 set_value_range (&n_vr0, VR_RANGE, op0, vrp_val_max (expr_type), NULL); 841 842 /* Try with [OP0, OP0] and VR1. */ 843 else 844 set_value_range (&n_vr0, VR_RANGE, op0, op0, NULL); 845 846 extract_range_from_binary_expr_1 (vr, code, expr_type, &n_vr0, &vr1); 847 } 848 849 /* If we didn't derive a range for MINUS_EXPR, and 850 op1's range is ~[op0,op0] or vice-versa, then we 851 can derive a non-null range. This happens often for 852 pointer subtraction. */ 853 if (vr->type == VR_VARYING 854 && (code == MINUS_EXPR || code == POINTER_DIFF_EXPR) 855 && TREE_CODE (op0) == SSA_NAME 856 && ((vr0.type == VR_ANTI_RANGE 857 && vr0.min == op1 858 && vr0.min == vr0.max) 859 || (vr1.type == VR_ANTI_RANGE 860 && vr1.min == op0 861 && vr1.min == vr1.max))) 862 set_value_range_to_nonnull (vr, expr_type); 863 } 864 865 /* Extract range information from a unary expression CODE OP0 based on 866 the range of its operand with resulting type TYPE. 867 The resulting range is stored in *VR. */ 868 869 void 870 vr_values::extract_range_from_unary_expr (value_range *vr, enum tree_code code, 871 tree type, tree op0) 872 { 873 value_range vr0 = VR_INITIALIZER; 874 875 /* Get value ranges for the operand. For constant operands, create 876 a new value range with the operand to simplify processing. */ 877 if (TREE_CODE (op0) == SSA_NAME) 878 vr0 = *(get_value_range (op0)); 879 else if (is_gimple_min_invariant (op0)) 880 set_value_range_to_value (&vr0, op0, NULL); 881 else 882 set_value_range_to_varying (&vr0); 883 884 ::extract_range_from_unary_expr (vr, code, type, &vr0, TREE_TYPE (op0)); 885 } 886 887 888 /* Extract range information from a conditional expression STMT based on 889 the ranges of each of its operands and the expression code. */ 890 891 void 892 vr_values::extract_range_from_cond_expr (value_range *vr, gassign *stmt) 893 { 894 tree op0, op1; 895 value_range vr0 = VR_INITIALIZER; 896 value_range vr1 = VR_INITIALIZER; 897 898 /* Get value ranges for each operand. For constant operands, create 899 a new value range with the operand to simplify processing. */ 900 op0 = gimple_assign_rhs2 (stmt); 901 if (TREE_CODE (op0) == SSA_NAME) 902 vr0 = *(get_value_range (op0)); 903 else if (is_gimple_min_invariant (op0)) 904 set_value_range_to_value (&vr0, op0, NULL); 905 else 906 set_value_range_to_varying (&vr0); 907 908 op1 = gimple_assign_rhs3 (stmt); 909 if (TREE_CODE (op1) == SSA_NAME) 910 vr1 = *(get_value_range (op1)); 911 else if (is_gimple_min_invariant (op1)) 912 set_value_range_to_value (&vr1, op1, NULL); 913 else 914 set_value_range_to_varying (&vr1); 915 916 /* The resulting value range is the union of the operand ranges */ 917 copy_value_range (vr, &vr0); 918 vrp_meet (vr, &vr1); 919 } 920 921 922 /* Extract range information from a comparison expression EXPR based 923 on the range of its operand and the expression code. */ 924 925 void 926 vr_values::extract_range_from_comparison (value_range *vr, enum tree_code code, 927 tree type, tree op0, tree op1) 928 { 929 bool sop; 930 tree val; 931 932 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop, 933 NULL); 934 if (val) 935 { 936 /* Since this expression was found on the RHS of an assignment, 937 its type may be different from _Bool. Convert VAL to EXPR's 938 type. */ 939 val = fold_convert (type, val); 940 if (is_gimple_min_invariant (val)) 941 set_value_range_to_value (vr, val, vr->equiv); 942 else 943 set_value_range (vr, VR_RANGE, val, val, vr->equiv); 944 } 945 else 946 /* The result of a comparison is always true or false. */ 947 set_value_range_to_truthvalue (vr, type); 948 } 949 950 /* Helper function for simplify_internal_call_using_ranges and 951 extract_range_basic. Return true if OP0 SUBCODE OP1 for 952 SUBCODE {PLUS,MINUS,MULT}_EXPR is known to never overflow or 953 always overflow. Set *OVF to true if it is known to always 954 overflow. */ 955 956 bool 957 vr_values::check_for_binary_op_overflow (enum tree_code subcode, tree type, 958 tree op0, tree op1, bool *ovf) 959 { 960 value_range vr0 = VR_INITIALIZER; 961 value_range vr1 = VR_INITIALIZER; 962 if (TREE_CODE (op0) == SSA_NAME) 963 vr0 = *get_value_range (op0); 964 else if (TREE_CODE (op0) == INTEGER_CST) 965 set_value_range_to_value (&vr0, op0, NULL); 966 else 967 set_value_range_to_varying (&vr0); 968 969 if (TREE_CODE (op1) == SSA_NAME) 970 vr1 = *get_value_range (op1); 971 else if (TREE_CODE (op1) == INTEGER_CST) 972 set_value_range_to_value (&vr1, op1, NULL); 973 else 974 set_value_range_to_varying (&vr1); 975 976 if (!range_int_cst_p (&vr0) 977 || TREE_OVERFLOW (vr0.min) 978 || TREE_OVERFLOW (vr0.max)) 979 { 980 vr0.min = vrp_val_min (TREE_TYPE (op0)); 981 vr0.max = vrp_val_max (TREE_TYPE (op0)); 982 } 983 if (!range_int_cst_p (&vr1) 984 || TREE_OVERFLOW (vr1.min) 985 || TREE_OVERFLOW (vr1.max)) 986 { 987 vr1.min = vrp_val_min (TREE_TYPE (op1)); 988 vr1.max = vrp_val_max (TREE_TYPE (op1)); 989 } 990 *ovf = arith_overflowed_p (subcode, type, vr0.min, 991 subcode == MINUS_EXPR ? vr1.max : vr1.min); 992 if (arith_overflowed_p (subcode, type, vr0.max, 993 subcode == MINUS_EXPR ? vr1.min : vr1.max) != *ovf) 994 return false; 995 if (subcode == MULT_EXPR) 996 { 997 if (arith_overflowed_p (subcode, type, vr0.min, vr1.max) != *ovf 998 || arith_overflowed_p (subcode, type, vr0.max, vr1.min) != *ovf) 999 return false; 1000 } 1001 if (*ovf) 1002 { 1003 /* So far we found that there is an overflow on the boundaries. 1004 That doesn't prove that there is an overflow even for all values 1005 in between the boundaries. For that compute widest_int range 1006 of the result and see if it doesn't overlap the range of 1007 type. */ 1008 widest_int wmin, wmax; 1009 widest_int w[4]; 1010 int i; 1011 w[0] = wi::to_widest (vr0.min); 1012 w[1] = wi::to_widest (vr0.max); 1013 w[2] = wi::to_widest (vr1.min); 1014 w[3] = wi::to_widest (vr1.max); 1015 for (i = 0; i < 4; i++) 1016 { 1017 widest_int wt; 1018 switch (subcode) 1019 { 1020 case PLUS_EXPR: 1021 wt = wi::add (w[i & 1], w[2 + (i & 2) / 2]); 1022 break; 1023 case MINUS_EXPR: 1024 wt = wi::sub (w[i & 1], w[2 + (i & 2) / 2]); 1025 break; 1026 case MULT_EXPR: 1027 wt = wi::mul (w[i & 1], w[2 + (i & 2) / 2]); 1028 break; 1029 default: 1030 gcc_unreachable (); 1031 } 1032 if (i == 0) 1033 { 1034 wmin = wt; 1035 wmax = wt; 1036 } 1037 else 1038 { 1039 wmin = wi::smin (wmin, wt); 1040 wmax = wi::smax (wmax, wt); 1041 } 1042 } 1043 /* The result of op0 CODE op1 is known to be in range 1044 [wmin, wmax]. */ 1045 widest_int wtmin = wi::to_widest (vrp_val_min (type)); 1046 widest_int wtmax = wi::to_widest (vrp_val_max (type)); 1047 /* If all values in [wmin, wmax] are smaller than 1048 [wtmin, wtmax] or all are larger than [wtmin, wtmax], 1049 the arithmetic operation will always overflow. */ 1050 if (wmax < wtmin || wmin > wtmax) 1051 return true; 1052 return false; 1053 } 1054 return true; 1055 } 1056 1057 /* Try to derive a nonnegative or nonzero range out of STMT relying 1058 primarily on generic routines in fold in conjunction with range data. 1059 Store the result in *VR */ 1060 1061 void 1062 vr_values::extract_range_basic (value_range *vr, gimple *stmt) 1063 { 1064 bool sop; 1065 tree type = gimple_expr_type (stmt); 1066 1067 if (is_gimple_call (stmt)) 1068 { 1069 tree arg; 1070 int mini, maxi, zerov = 0, prec; 1071 enum tree_code subcode = ERROR_MARK; 1072 combined_fn cfn = gimple_call_combined_fn (stmt); 1073 scalar_int_mode mode; 1074 1075 switch (cfn) 1076 { 1077 case CFN_BUILT_IN_CONSTANT_P: 1078 /* If the call is __builtin_constant_p and the argument is a 1079 function parameter resolve it to false. This avoids bogus 1080 array bound warnings. 1081 ??? We could do this as early as inlining is finished. */ 1082 arg = gimple_call_arg (stmt, 0); 1083 if (TREE_CODE (arg) == SSA_NAME 1084 && SSA_NAME_IS_DEFAULT_DEF (arg) 1085 && TREE_CODE (SSA_NAME_VAR (arg)) == PARM_DECL 1086 && cfun->after_inlining) 1087 { 1088 set_value_range_to_null (vr, type); 1089 return; 1090 } 1091 break; 1092 /* Both __builtin_ffs* and __builtin_popcount return 1093 [0, prec]. */ 1094 CASE_CFN_FFS: 1095 CASE_CFN_POPCOUNT: 1096 arg = gimple_call_arg (stmt, 0); 1097 prec = TYPE_PRECISION (TREE_TYPE (arg)); 1098 mini = 0; 1099 maxi = prec; 1100 if (TREE_CODE (arg) == SSA_NAME) 1101 { 1102 value_range *vr0 = get_value_range (arg); 1103 /* If arg is non-zero, then ffs or popcount 1104 are non-zero. */ 1105 if ((vr0->type == VR_RANGE 1106 && range_includes_zero_p (vr0->min, vr0->max) == 0) 1107 || (vr0->type == VR_ANTI_RANGE 1108 && range_includes_zero_p (vr0->min, vr0->max) == 1)) 1109 mini = 1; 1110 /* If some high bits are known to be zero, 1111 we can decrease the maximum. */ 1112 if (vr0->type == VR_RANGE 1113 && TREE_CODE (vr0->max) == INTEGER_CST 1114 && !operand_less_p (vr0->min, 1115 build_zero_cst (TREE_TYPE (vr0->min)))) 1116 maxi = tree_floor_log2 (vr0->max) + 1; 1117 } 1118 goto bitop_builtin; 1119 /* __builtin_parity* returns [0, 1]. */ 1120 CASE_CFN_PARITY: 1121 mini = 0; 1122 maxi = 1; 1123 goto bitop_builtin; 1124 /* __builtin_c[lt]z* return [0, prec-1], except for 1125 when the argument is 0, but that is undefined behavior. 1126 On many targets where the CLZ RTL or optab value is defined 1127 for 0 the value is prec, so include that in the range 1128 by default. */ 1129 CASE_CFN_CLZ: 1130 arg = gimple_call_arg (stmt, 0); 1131 prec = TYPE_PRECISION (TREE_TYPE (arg)); 1132 mini = 0; 1133 maxi = prec; 1134 mode = SCALAR_INT_TYPE_MODE (TREE_TYPE (arg)); 1135 if (optab_handler (clz_optab, mode) != CODE_FOR_nothing 1136 && CLZ_DEFINED_VALUE_AT_ZERO (mode, zerov) 1137 /* Handle only the single common value. */ 1138 && zerov != prec) 1139 /* Magic value to give up, unless vr0 proves 1140 arg is non-zero. */ 1141 mini = -2; 1142 if (TREE_CODE (arg) == SSA_NAME) 1143 { 1144 value_range *vr0 = get_value_range (arg); 1145 /* From clz of VR_RANGE minimum we can compute 1146 result maximum. */ 1147 if (vr0->type == VR_RANGE 1148 && TREE_CODE (vr0->min) == INTEGER_CST) 1149 { 1150 maxi = prec - 1 - tree_floor_log2 (vr0->min); 1151 if (maxi != prec) 1152 mini = 0; 1153 } 1154 else if (vr0->type == VR_ANTI_RANGE 1155 && integer_zerop (vr0->min)) 1156 { 1157 maxi = prec - 1; 1158 mini = 0; 1159 } 1160 if (mini == -2) 1161 break; 1162 /* From clz of VR_RANGE maximum we can compute 1163 result minimum. */ 1164 if (vr0->type == VR_RANGE 1165 && TREE_CODE (vr0->max) == INTEGER_CST) 1166 { 1167 mini = prec - 1 - tree_floor_log2 (vr0->max); 1168 if (mini == prec) 1169 break; 1170 } 1171 } 1172 if (mini == -2) 1173 break; 1174 goto bitop_builtin; 1175 /* __builtin_ctz* return [0, prec-1], except for 1176 when the argument is 0, but that is undefined behavior. 1177 If there is a ctz optab for this mode and 1178 CTZ_DEFINED_VALUE_AT_ZERO, include that in the range, 1179 otherwise just assume 0 won't be seen. */ 1180 CASE_CFN_CTZ: 1181 arg = gimple_call_arg (stmt, 0); 1182 prec = TYPE_PRECISION (TREE_TYPE (arg)); 1183 mini = 0; 1184 maxi = prec - 1; 1185 mode = SCALAR_INT_TYPE_MODE (TREE_TYPE (arg)); 1186 if (optab_handler (ctz_optab, mode) != CODE_FOR_nothing 1187 && CTZ_DEFINED_VALUE_AT_ZERO (mode, zerov)) 1188 { 1189 /* Handle only the two common values. */ 1190 if (zerov == -1) 1191 mini = -1; 1192 else if (zerov == prec) 1193 maxi = prec; 1194 else 1195 /* Magic value to give up, unless vr0 proves 1196 arg is non-zero. */ 1197 mini = -2; 1198 } 1199 if (TREE_CODE (arg) == SSA_NAME) 1200 { 1201 value_range *vr0 = get_value_range (arg); 1202 /* If arg is non-zero, then use [0, prec - 1]. */ 1203 if ((vr0->type == VR_RANGE 1204 && integer_nonzerop (vr0->min)) 1205 || (vr0->type == VR_ANTI_RANGE 1206 && integer_zerop (vr0->min))) 1207 { 1208 mini = 0; 1209 maxi = prec - 1; 1210 } 1211 /* If some high bits are known to be zero, 1212 we can decrease the result maximum. */ 1213 if (vr0->type == VR_RANGE 1214 && TREE_CODE (vr0->max) == INTEGER_CST) 1215 { 1216 maxi = tree_floor_log2 (vr0->max); 1217 /* For vr0 [0, 0] give up. */ 1218 if (maxi == -1) 1219 break; 1220 } 1221 } 1222 if (mini == -2) 1223 break; 1224 goto bitop_builtin; 1225 /* __builtin_clrsb* returns [0, prec-1]. */ 1226 CASE_CFN_CLRSB: 1227 arg = gimple_call_arg (stmt, 0); 1228 prec = TYPE_PRECISION (TREE_TYPE (arg)); 1229 mini = 0; 1230 maxi = prec - 1; 1231 goto bitop_builtin; 1232 bitop_builtin: 1233 set_value_range (vr, VR_RANGE, build_int_cst (type, mini), 1234 build_int_cst (type, maxi), NULL); 1235 return; 1236 case CFN_UBSAN_CHECK_ADD: 1237 subcode = PLUS_EXPR; 1238 break; 1239 case CFN_UBSAN_CHECK_SUB: 1240 subcode = MINUS_EXPR; 1241 break; 1242 case CFN_UBSAN_CHECK_MUL: 1243 subcode = MULT_EXPR; 1244 break; 1245 case CFN_GOACC_DIM_SIZE: 1246 case CFN_GOACC_DIM_POS: 1247 /* Optimizing these two internal functions helps the loop 1248 optimizer eliminate outer comparisons. Size is [1,N] 1249 and pos is [0,N-1]. */ 1250 { 1251 bool is_pos = cfn == CFN_GOACC_DIM_POS; 1252 int axis = oacc_get_ifn_dim_arg (stmt); 1253 int size = oacc_get_fn_dim_size (current_function_decl, axis); 1254 1255 if (!size) 1256 /* If it's dynamic, the backend might know a hardware 1257 limitation. */ 1258 size = targetm.goacc.dim_limit (axis); 1259 1260 tree type = TREE_TYPE (gimple_call_lhs (stmt)); 1261 set_value_range (vr, VR_RANGE, 1262 build_int_cst (type, is_pos ? 0 : 1), 1263 size ? build_int_cst (type, size - is_pos) 1264 : vrp_val_max (type), NULL); 1265 } 1266 return; 1267 case CFN_BUILT_IN_STRLEN: 1268 if (tree lhs = gimple_call_lhs (stmt)) 1269 if (ptrdiff_type_node 1270 && (TYPE_PRECISION (ptrdiff_type_node) 1271 == TYPE_PRECISION (TREE_TYPE (lhs)))) 1272 { 1273 tree type = TREE_TYPE (lhs); 1274 tree max = vrp_val_max (ptrdiff_type_node); 1275 wide_int wmax = wi::to_wide (max, TYPE_PRECISION (TREE_TYPE (max))); 1276 tree range_min = build_zero_cst (type); 1277 tree range_max = wide_int_to_tree (type, wmax - 1); 1278 set_value_range (vr, VR_RANGE, range_min, range_max, NULL); 1279 return; 1280 } 1281 break; 1282 default: 1283 break; 1284 } 1285 if (subcode != ERROR_MARK) 1286 { 1287 bool saved_flag_wrapv = flag_wrapv; 1288 /* Pretend the arithmetics is wrapping. If there is 1289 any overflow, we'll complain, but will actually do 1290 wrapping operation. */ 1291 flag_wrapv = 1; 1292 extract_range_from_binary_expr (vr, subcode, type, 1293 gimple_call_arg (stmt, 0), 1294 gimple_call_arg (stmt, 1)); 1295 flag_wrapv = saved_flag_wrapv; 1296 1297 /* If for both arguments vrp_valueize returned non-NULL, 1298 this should have been already folded and if not, it 1299 wasn't folded because of overflow. Avoid removing the 1300 UBSAN_CHECK_* calls in that case. */ 1301 if (vr->type == VR_RANGE 1302 && (vr->min == vr->max 1303 || operand_equal_p (vr->min, vr->max, 0))) 1304 set_value_range_to_varying (vr); 1305 return; 1306 } 1307 } 1308 /* Handle extraction of the two results (result of arithmetics and 1309 a flag whether arithmetics overflowed) from {ADD,SUB,MUL}_OVERFLOW 1310 internal function. Similarly from ATOMIC_COMPARE_EXCHANGE. */ 1311 else if (is_gimple_assign (stmt) 1312 && (gimple_assign_rhs_code (stmt) == REALPART_EXPR 1313 || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR) 1314 && INTEGRAL_TYPE_P (type)) 1315 { 1316 enum tree_code code = gimple_assign_rhs_code (stmt); 1317 tree op = gimple_assign_rhs1 (stmt); 1318 if (TREE_CODE (op) == code && TREE_CODE (TREE_OPERAND (op, 0)) == SSA_NAME) 1319 { 1320 gimple *g = SSA_NAME_DEF_STMT (TREE_OPERAND (op, 0)); 1321 if (is_gimple_call (g) && gimple_call_internal_p (g)) 1322 { 1323 enum tree_code subcode = ERROR_MARK; 1324 switch (gimple_call_internal_fn (g)) 1325 { 1326 case IFN_ADD_OVERFLOW: 1327 subcode = PLUS_EXPR; 1328 break; 1329 case IFN_SUB_OVERFLOW: 1330 subcode = MINUS_EXPR; 1331 break; 1332 case IFN_MUL_OVERFLOW: 1333 subcode = MULT_EXPR; 1334 break; 1335 case IFN_ATOMIC_COMPARE_EXCHANGE: 1336 if (code == IMAGPART_EXPR) 1337 { 1338 /* This is the boolean return value whether compare and 1339 exchange changed anything or not. */ 1340 set_value_range (vr, VR_RANGE, build_int_cst (type, 0), 1341 build_int_cst (type, 1), NULL); 1342 return; 1343 } 1344 break; 1345 default: 1346 break; 1347 } 1348 if (subcode != ERROR_MARK) 1349 { 1350 tree op0 = gimple_call_arg (g, 0); 1351 tree op1 = gimple_call_arg (g, 1); 1352 if (code == IMAGPART_EXPR) 1353 { 1354 bool ovf = false; 1355 if (check_for_binary_op_overflow (subcode, type, 1356 op0, op1, &ovf)) 1357 set_value_range_to_value (vr, 1358 build_int_cst (type, ovf), 1359 NULL); 1360 else if (TYPE_PRECISION (type) == 1 1361 && !TYPE_UNSIGNED (type)) 1362 set_value_range_to_varying (vr); 1363 else 1364 set_value_range (vr, VR_RANGE, build_int_cst (type, 0), 1365 build_int_cst (type, 1), NULL); 1366 } 1367 else if (types_compatible_p (type, TREE_TYPE (op0)) 1368 && types_compatible_p (type, TREE_TYPE (op1))) 1369 { 1370 bool saved_flag_wrapv = flag_wrapv; 1371 /* Pretend the arithmetics is wrapping. If there is 1372 any overflow, IMAGPART_EXPR will be set. */ 1373 flag_wrapv = 1; 1374 extract_range_from_binary_expr (vr, subcode, type, 1375 op0, op1); 1376 flag_wrapv = saved_flag_wrapv; 1377 } 1378 else 1379 { 1380 value_range vr0 = VR_INITIALIZER; 1381 value_range vr1 = VR_INITIALIZER; 1382 bool saved_flag_wrapv = flag_wrapv; 1383 /* Pretend the arithmetics is wrapping. If there is 1384 any overflow, IMAGPART_EXPR will be set. */ 1385 flag_wrapv = 1; 1386 extract_range_from_unary_expr (&vr0, NOP_EXPR, 1387 type, op0); 1388 extract_range_from_unary_expr (&vr1, NOP_EXPR, 1389 type, op1); 1390 extract_range_from_binary_expr_1 (vr, subcode, type, 1391 &vr0, &vr1); 1392 flag_wrapv = saved_flag_wrapv; 1393 } 1394 return; 1395 } 1396 } 1397 } 1398 } 1399 if (INTEGRAL_TYPE_P (type) 1400 && gimple_stmt_nonnegative_warnv_p (stmt, &sop)) 1401 set_value_range_to_nonnegative (vr, type); 1402 else if (vrp_stmt_computes_nonzero (stmt)) 1403 set_value_range_to_nonnull (vr, type); 1404 else 1405 set_value_range_to_varying (vr); 1406 } 1407 1408 1409 /* Try to compute a useful range out of assignment STMT and store it 1410 in *VR. */ 1411 1412 void 1413 vr_values::extract_range_from_assignment (value_range *vr, gassign *stmt) 1414 { 1415 enum tree_code code = gimple_assign_rhs_code (stmt); 1416 1417 if (code == ASSERT_EXPR) 1418 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt)); 1419 else if (code == SSA_NAME) 1420 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt)); 1421 else if (TREE_CODE_CLASS (code) == tcc_binary) 1422 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt), 1423 gimple_expr_type (stmt), 1424 gimple_assign_rhs1 (stmt), 1425 gimple_assign_rhs2 (stmt)); 1426 else if (TREE_CODE_CLASS (code) == tcc_unary) 1427 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt), 1428 gimple_expr_type (stmt), 1429 gimple_assign_rhs1 (stmt)); 1430 else if (code == COND_EXPR) 1431 extract_range_from_cond_expr (vr, stmt); 1432 else if (TREE_CODE_CLASS (code) == tcc_comparison) 1433 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt), 1434 gimple_expr_type (stmt), 1435 gimple_assign_rhs1 (stmt), 1436 gimple_assign_rhs2 (stmt)); 1437 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS 1438 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt))) 1439 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL); 1440 else 1441 set_value_range_to_varying (vr); 1442 1443 if (vr->type == VR_VARYING) 1444 extract_range_basic (vr, stmt); 1445 } 1446 1447 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP: 1448 1449 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for 1450 all the values in the ranges. 1451 1452 - Return BOOLEAN_FALSE_NODE if the comparison always returns false. 1453 1454 - Return NULL_TREE if it is not always possible to determine the 1455 value of the comparison. 1456 1457 Also set *STRICT_OVERFLOW_P to indicate whether comparision evaluation 1458 assumed signed overflow is undefined. */ 1459 1460 1461 static tree 1462 compare_ranges (enum tree_code comp, value_range *vr0, value_range *vr1, 1463 bool *strict_overflow_p) 1464 { 1465 /* VARYING or UNDEFINED ranges cannot be compared. */ 1466 if (vr0->type == VR_VARYING 1467 || vr0->type == VR_UNDEFINED 1468 || vr1->type == VR_VARYING 1469 || vr1->type == VR_UNDEFINED) 1470 return NULL_TREE; 1471 1472 /* Anti-ranges need to be handled separately. */ 1473 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE) 1474 { 1475 /* If both are anti-ranges, then we cannot compute any 1476 comparison. */ 1477 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE) 1478 return NULL_TREE; 1479 1480 /* These comparisons are never statically computable. */ 1481 if (comp == GT_EXPR 1482 || comp == GE_EXPR 1483 || comp == LT_EXPR 1484 || comp == LE_EXPR) 1485 return NULL_TREE; 1486 1487 /* Equality can be computed only between a range and an 1488 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */ 1489 if (vr0->type == VR_RANGE) 1490 { 1491 /* To simplify processing, make VR0 the anti-range. */ 1492 value_range *tmp = vr0; 1493 vr0 = vr1; 1494 vr1 = tmp; 1495 } 1496 1497 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR); 1498 1499 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0 1500 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0) 1501 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node; 1502 1503 return NULL_TREE; 1504 } 1505 1506 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the 1507 operands around and change the comparison code. */ 1508 if (comp == GT_EXPR || comp == GE_EXPR) 1509 { 1510 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR; 1511 std::swap (vr0, vr1); 1512 } 1513 1514 if (comp == EQ_EXPR) 1515 { 1516 /* Equality may only be computed if both ranges represent 1517 exactly one value. */ 1518 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0 1519 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0) 1520 { 1521 int cmp_min = compare_values_warnv (vr0->min, vr1->min, 1522 strict_overflow_p); 1523 int cmp_max = compare_values_warnv (vr0->max, vr1->max, 1524 strict_overflow_p); 1525 if (cmp_min == 0 && cmp_max == 0) 1526 return boolean_true_node; 1527 else if (cmp_min != -2 && cmp_max != -2) 1528 return boolean_false_node; 1529 } 1530 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */ 1531 else if (compare_values_warnv (vr0->min, vr1->max, 1532 strict_overflow_p) == 1 1533 || compare_values_warnv (vr1->min, vr0->max, 1534 strict_overflow_p) == 1) 1535 return boolean_false_node; 1536 1537 return NULL_TREE; 1538 } 1539 else if (comp == NE_EXPR) 1540 { 1541 int cmp1, cmp2; 1542 1543 /* If VR0 is completely to the left or completely to the right 1544 of VR1, they are always different. Notice that we need to 1545 make sure that both comparisons yield similar results to 1546 avoid comparing values that cannot be compared at 1547 compile-time. */ 1548 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p); 1549 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p); 1550 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1)) 1551 return boolean_true_node; 1552 1553 /* If VR0 and VR1 represent a single value and are identical, 1554 return false. */ 1555 else if (compare_values_warnv (vr0->min, vr0->max, 1556 strict_overflow_p) == 0 1557 && compare_values_warnv (vr1->min, vr1->max, 1558 strict_overflow_p) == 0 1559 && compare_values_warnv (vr0->min, vr1->min, 1560 strict_overflow_p) == 0 1561 && compare_values_warnv (vr0->max, vr1->max, 1562 strict_overflow_p) == 0) 1563 return boolean_false_node; 1564 1565 /* Otherwise, they may or may not be different. */ 1566 else 1567 return NULL_TREE; 1568 } 1569 else if (comp == LT_EXPR || comp == LE_EXPR) 1570 { 1571 int tst; 1572 1573 /* If VR0 is to the left of VR1, return true. */ 1574 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p); 1575 if ((comp == LT_EXPR && tst == -1) 1576 || (comp == LE_EXPR && (tst == -1 || tst == 0))) 1577 return boolean_true_node; 1578 1579 /* If VR0 is to the right of VR1, return false. */ 1580 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p); 1581 if ((comp == LT_EXPR && (tst == 0 || tst == 1)) 1582 || (comp == LE_EXPR && tst == 1)) 1583 return boolean_false_node; 1584 1585 /* Otherwise, we don't know. */ 1586 return NULL_TREE; 1587 } 1588 1589 gcc_unreachable (); 1590 } 1591 1592 /* Given a value range VR, a value VAL and a comparison code COMP, return 1593 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the 1594 values in VR. Return BOOLEAN_FALSE_NODE if the comparison 1595 always returns false. Return NULL_TREE if it is not always 1596 possible to determine the value of the comparison. Also set 1597 *STRICT_OVERFLOW_P to indicate whether comparision evaluation 1598 assumed signed overflow is undefined. */ 1599 1600 static tree 1601 compare_range_with_value (enum tree_code comp, value_range *vr, tree val, 1602 bool *strict_overflow_p) 1603 { 1604 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED) 1605 return NULL_TREE; 1606 1607 /* Anti-ranges need to be handled separately. */ 1608 if (vr->type == VR_ANTI_RANGE) 1609 { 1610 /* For anti-ranges, the only predicates that we can compute at 1611 compile time are equality and inequality. */ 1612 if (comp == GT_EXPR 1613 || comp == GE_EXPR 1614 || comp == LT_EXPR 1615 || comp == LE_EXPR) 1616 return NULL_TREE; 1617 1618 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */ 1619 if (value_inside_range (val, vr->min, vr->max) == 1) 1620 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node; 1621 1622 return NULL_TREE; 1623 } 1624 1625 if (comp == EQ_EXPR) 1626 { 1627 /* EQ_EXPR may only be computed if VR represents exactly 1628 one value. */ 1629 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0) 1630 { 1631 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p); 1632 if (cmp == 0) 1633 return boolean_true_node; 1634 else if (cmp == -1 || cmp == 1 || cmp == 2) 1635 return boolean_false_node; 1636 } 1637 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1 1638 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1) 1639 return boolean_false_node; 1640 1641 return NULL_TREE; 1642 } 1643 else if (comp == NE_EXPR) 1644 { 1645 /* If VAL is not inside VR, then they are always different. */ 1646 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1 1647 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1) 1648 return boolean_true_node; 1649 1650 /* If VR represents exactly one value equal to VAL, then return 1651 false. */ 1652 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0 1653 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0) 1654 return boolean_false_node; 1655 1656 /* Otherwise, they may or may not be different. */ 1657 return NULL_TREE; 1658 } 1659 else if (comp == LT_EXPR || comp == LE_EXPR) 1660 { 1661 int tst; 1662 1663 /* If VR is to the left of VAL, return true. */ 1664 tst = compare_values_warnv (vr->max, val, strict_overflow_p); 1665 if ((comp == LT_EXPR && tst == -1) 1666 || (comp == LE_EXPR && (tst == -1 || tst == 0))) 1667 return boolean_true_node; 1668 1669 /* If VR is to the right of VAL, return false. */ 1670 tst = compare_values_warnv (vr->min, val, strict_overflow_p); 1671 if ((comp == LT_EXPR && (tst == 0 || tst == 1)) 1672 || (comp == LE_EXPR && tst == 1)) 1673 return boolean_false_node; 1674 1675 /* Otherwise, we don't know. */ 1676 return NULL_TREE; 1677 } 1678 else if (comp == GT_EXPR || comp == GE_EXPR) 1679 { 1680 int tst; 1681 1682 /* If VR is to the right of VAL, return true. */ 1683 tst = compare_values_warnv (vr->min, val, strict_overflow_p); 1684 if ((comp == GT_EXPR && tst == 1) 1685 || (comp == GE_EXPR && (tst == 0 || tst == 1))) 1686 return boolean_true_node; 1687 1688 /* If VR is to the left of VAL, return false. */ 1689 tst = compare_values_warnv (vr->max, val, strict_overflow_p); 1690 if ((comp == GT_EXPR && (tst == -1 || tst == 0)) 1691 || (comp == GE_EXPR && tst == -1)) 1692 return boolean_false_node; 1693 1694 /* Otherwise, we don't know. */ 1695 return NULL_TREE; 1696 } 1697 1698 gcc_unreachable (); 1699 } 1700 /* Given a range VR, a LOOP and a variable VAR, determine whether it 1701 would be profitable to adjust VR using scalar evolution information 1702 for VAR. If so, update VR with the new limits. */ 1703 1704 void 1705 vr_values::adjust_range_with_scev (value_range *vr, struct loop *loop, 1706 gimple *stmt, tree var) 1707 { 1708 tree init, step, chrec, tmin, tmax, min, max, type, tem; 1709 enum ev_direction dir; 1710 1711 /* TODO. Don't adjust anti-ranges. An anti-range may provide 1712 better opportunities than a regular range, but I'm not sure. */ 1713 if (vr->type == VR_ANTI_RANGE) 1714 return; 1715 1716 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var)); 1717 1718 /* Like in PR19590, scev can return a constant function. */ 1719 if (is_gimple_min_invariant (chrec)) 1720 { 1721 set_value_range_to_value (vr, chrec, vr->equiv); 1722 return; 1723 } 1724 1725 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC) 1726 return; 1727 1728 init = initial_condition_in_loop_num (chrec, loop->num); 1729 tem = op_with_constant_singleton_value_range (init); 1730 if (tem) 1731 init = tem; 1732 step = evolution_part_in_loop_num (chrec, loop->num); 1733 tem = op_with_constant_singleton_value_range (step); 1734 if (tem) 1735 step = tem; 1736 1737 /* If STEP is symbolic, we can't know whether INIT will be the 1738 minimum or maximum value in the range. Also, unless INIT is 1739 a simple expression, compare_values and possibly other functions 1740 in tree-vrp won't be able to handle it. */ 1741 if (step == NULL_TREE 1742 || !is_gimple_min_invariant (step) 1743 || !valid_value_p (init)) 1744 return; 1745 1746 dir = scev_direction (chrec); 1747 if (/* Do not adjust ranges if we do not know whether the iv increases 1748 or decreases, ... */ 1749 dir == EV_DIR_UNKNOWN 1750 /* ... or if it may wrap. */ 1751 || scev_probably_wraps_p (NULL_TREE, init, step, stmt, 1752 get_chrec_loop (chrec), true)) 1753 return; 1754 1755 type = TREE_TYPE (var); 1756 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type)) 1757 tmin = lower_bound_in_type (type, type); 1758 else 1759 tmin = TYPE_MIN_VALUE (type); 1760 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type)) 1761 tmax = upper_bound_in_type (type, type); 1762 else 1763 tmax = TYPE_MAX_VALUE (type); 1764 1765 /* Try to use estimated number of iterations for the loop to constrain the 1766 final value in the evolution. */ 1767 if (TREE_CODE (step) == INTEGER_CST 1768 && is_gimple_val (init) 1769 && (TREE_CODE (init) != SSA_NAME 1770 || get_value_range (init)->type == VR_RANGE)) 1771 { 1772 widest_int nit; 1773 1774 /* We are only entering here for loop header PHI nodes, so using 1775 the number of latch executions is the correct thing to use. */ 1776 if (max_loop_iterations (loop, &nit)) 1777 { 1778 value_range maxvr = VR_INITIALIZER; 1779 signop sgn = TYPE_SIGN (TREE_TYPE (step)); 1780 bool overflow; 1781 1782 widest_int wtmp = wi::mul (wi::to_widest (step), nit, sgn, 1783 &overflow); 1784 /* If the multiplication overflowed we can't do a meaningful 1785 adjustment. Likewise if the result doesn't fit in the type 1786 of the induction variable. For a signed type we have to 1787 check whether the result has the expected signedness which 1788 is that of the step as number of iterations is unsigned. */ 1789 if (!overflow 1790 && wi::fits_to_tree_p (wtmp, TREE_TYPE (init)) 1791 && (sgn == UNSIGNED 1792 || wi::gts_p (wtmp, 0) == wi::gts_p (wi::to_wide (step), 0))) 1793 { 1794 tem = wide_int_to_tree (TREE_TYPE (init), wtmp); 1795 extract_range_from_binary_expr (&maxvr, PLUS_EXPR, 1796 TREE_TYPE (init), init, tem); 1797 /* Likewise if the addition did. */ 1798 if (maxvr.type == VR_RANGE) 1799 { 1800 value_range initvr = VR_INITIALIZER; 1801 1802 if (TREE_CODE (init) == SSA_NAME) 1803 initvr = *(get_value_range (init)); 1804 else if (is_gimple_min_invariant (init)) 1805 set_value_range_to_value (&initvr, init, NULL); 1806 else 1807 return; 1808 1809 /* Check if init + nit * step overflows. Though we checked 1810 scev {init, step}_loop doesn't wrap, it is not enough 1811 because the loop may exit immediately. Overflow could 1812 happen in the plus expression in this case. */ 1813 if ((dir == EV_DIR_DECREASES 1814 && compare_values (maxvr.min, initvr.min) != -1) 1815 || (dir == EV_DIR_GROWS 1816 && compare_values (maxvr.max, initvr.max) != 1)) 1817 return; 1818 1819 tmin = maxvr.min; 1820 tmax = maxvr.max; 1821 } 1822 } 1823 } 1824 } 1825 1826 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED) 1827 { 1828 min = tmin; 1829 max = tmax; 1830 1831 /* For VARYING or UNDEFINED ranges, just about anything we get 1832 from scalar evolutions should be better. */ 1833 1834 if (dir == EV_DIR_DECREASES) 1835 max = init; 1836 else 1837 min = init; 1838 } 1839 else if (vr->type == VR_RANGE) 1840 { 1841 min = vr->min; 1842 max = vr->max; 1843 1844 if (dir == EV_DIR_DECREASES) 1845 { 1846 /* INIT is the maximum value. If INIT is lower than VR->MAX 1847 but no smaller than VR->MIN, set VR->MAX to INIT. */ 1848 if (compare_values (init, max) == -1) 1849 max = init; 1850 1851 /* According to the loop information, the variable does not 1852 overflow. */ 1853 if (compare_values (min, tmin) == -1) 1854 min = tmin; 1855 1856 } 1857 else 1858 { 1859 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */ 1860 if (compare_values (init, min) == 1) 1861 min = init; 1862 1863 if (compare_values (tmax, max) == -1) 1864 max = tmax; 1865 } 1866 } 1867 else 1868 return; 1869 1870 /* If we just created an invalid range with the minimum 1871 greater than the maximum, we fail conservatively. 1872 This should happen only in unreachable 1873 parts of code, or for invalid programs. */ 1874 if (compare_values (min, max) == 1) 1875 return; 1876 1877 /* Even for valid range info, sometimes overflow flag will leak in. 1878 As GIMPLE IL should have no constants with TREE_OVERFLOW set, we 1879 drop them. */ 1880 if (TREE_OVERFLOW_P (min)) 1881 min = drop_tree_overflow (min); 1882 if (TREE_OVERFLOW_P (max)) 1883 max = drop_tree_overflow (max); 1884 1885 set_value_range (vr, VR_RANGE, min, max, vr->equiv); 1886 } 1887 1888 /* Dump value ranges of all SSA_NAMEs to FILE. */ 1889 1890 void 1891 vr_values::dump_all_value_ranges (FILE *file) 1892 { 1893 size_t i; 1894 1895 for (i = 0; i < num_vr_values; i++) 1896 { 1897 if (vr_value[i]) 1898 { 1899 print_generic_expr (file, ssa_name (i)); 1900 fprintf (file, ": "); 1901 dump_value_range (file, vr_value[i]); 1902 fprintf (file, "\n"); 1903 } 1904 } 1905 1906 fprintf (file, "\n"); 1907 } 1908 1909 /* Initialize VRP lattice. */ 1910 1911 vr_values::vr_values () : vrp_value_range_pool ("Tree VRP value ranges") 1912 { 1913 values_propagated = false; 1914 num_vr_values = num_ssa_names; 1915 vr_value = XCNEWVEC (value_range *, num_vr_values); 1916 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names); 1917 bitmap_obstack_initialize (&vrp_equiv_obstack); 1918 } 1919 1920 /* Free VRP lattice. */ 1921 1922 vr_values::~vr_values () 1923 { 1924 /* Free allocated memory. */ 1925 free (vr_value); 1926 free (vr_phi_edge_counts); 1927 bitmap_obstack_release (&vrp_equiv_obstack); 1928 vrp_value_range_pool.release (); 1929 1930 /* So that we can distinguish between VRP data being available 1931 and not available. */ 1932 vr_value = NULL; 1933 vr_phi_edge_counts = NULL; 1934 } 1935 1936 1937 /* A hack. */ 1938 static class vr_values *x_vr_values; 1939 1940 /* Return the singleton value-range for NAME or NAME. */ 1941 1942 static inline tree 1943 vrp_valueize (tree name) 1944 { 1945 if (TREE_CODE (name) == SSA_NAME) 1946 { 1947 value_range *vr = x_vr_values->get_value_range (name); 1948 if (vr->type == VR_RANGE 1949 && (TREE_CODE (vr->min) == SSA_NAME 1950 || is_gimple_min_invariant (vr->min)) 1951 && vrp_operand_equal_p (vr->min, vr->max)) 1952 return vr->min; 1953 } 1954 return name; 1955 } 1956 1957 /* Return the singleton value-range for NAME if that is a constant 1958 but signal to not follow SSA edges. */ 1959 1960 static inline tree 1961 vrp_valueize_1 (tree name) 1962 { 1963 if (TREE_CODE (name) == SSA_NAME) 1964 { 1965 /* If the definition may be simulated again we cannot follow 1966 this SSA edge as the SSA propagator does not necessarily 1967 re-visit the use. */ 1968 gimple *def_stmt = SSA_NAME_DEF_STMT (name); 1969 if (!gimple_nop_p (def_stmt) 1970 && prop_simulate_again_p (def_stmt)) 1971 return NULL_TREE; 1972 value_range *vr = x_vr_values->get_value_range (name); 1973 if (range_int_cst_singleton_p (vr)) 1974 return vr->min; 1975 } 1976 return name; 1977 } 1978 1979 /* Given STMT, an assignment or call, return its LHS if the type 1980 of the LHS is suitable for VRP analysis, else return NULL_TREE. */ 1981 1982 tree 1983 get_output_for_vrp (gimple *stmt) 1984 { 1985 if (!is_gimple_assign (stmt) && !is_gimple_call (stmt)) 1986 return NULL_TREE; 1987 1988 /* We only keep track of ranges in integral and pointer types. */ 1989 tree lhs = gimple_get_lhs (stmt); 1990 if (TREE_CODE (lhs) == SSA_NAME 1991 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs)) 1992 /* It is valid to have NULL MIN/MAX values on a type. See 1993 build_range_type. */ 1994 && TYPE_MIN_VALUE (TREE_TYPE (lhs)) 1995 && TYPE_MAX_VALUE (TREE_TYPE (lhs))) 1996 || POINTER_TYPE_P (TREE_TYPE (lhs)))) 1997 return lhs; 1998 1999 return NULL_TREE; 2000 } 2001 2002 /* Visit assignment STMT. If it produces an interesting range, record 2003 the range in VR and set LHS to OUTPUT_P. */ 2004 2005 void 2006 vr_values::vrp_visit_assignment_or_call (gimple *stmt, tree *output_p, 2007 value_range *vr) 2008 { 2009 tree lhs = get_output_for_vrp (stmt); 2010 *output_p = lhs; 2011 2012 /* We only keep track of ranges in integral and pointer types. */ 2013 if (lhs) 2014 { 2015 enum gimple_code code = gimple_code (stmt); 2016 2017 /* Try folding the statement to a constant first. */ 2018 x_vr_values = this; 2019 tree tem = gimple_fold_stmt_to_constant_1 (stmt, vrp_valueize, 2020 vrp_valueize_1); 2021 x_vr_values = NULL; 2022 if (tem) 2023 { 2024 if (TREE_CODE (tem) == SSA_NAME 2025 && (SSA_NAME_IS_DEFAULT_DEF (tem) 2026 || ! prop_simulate_again_p (SSA_NAME_DEF_STMT (tem)))) 2027 { 2028 extract_range_from_ssa_name (vr, tem); 2029 return; 2030 } 2031 else if (is_gimple_min_invariant (tem)) 2032 { 2033 set_value_range_to_value (vr, tem, NULL); 2034 return; 2035 } 2036 } 2037 /* Then dispatch to value-range extracting functions. */ 2038 if (code == GIMPLE_CALL) 2039 extract_range_basic (vr, stmt); 2040 else 2041 extract_range_from_assignment (vr, as_a <gassign *> (stmt)); 2042 } 2043 } 2044 2045 /* Helper that gets the value range of the SSA_NAME with version I 2046 or a symbolic range containing the SSA_NAME only if the value range 2047 is varying or undefined. */ 2048 2049 value_range 2050 vr_values::get_vr_for_comparison (int i) 2051 { 2052 value_range vr = *get_value_range (ssa_name (i)); 2053 2054 /* If name N_i does not have a valid range, use N_i as its own 2055 range. This allows us to compare against names that may 2056 have N_i in their ranges. */ 2057 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED) 2058 { 2059 vr.type = VR_RANGE; 2060 vr.min = ssa_name (i); 2061 vr.max = ssa_name (i); 2062 } 2063 2064 return vr; 2065 } 2066 2067 /* Compare all the value ranges for names equivalent to VAR with VAL 2068 using comparison code COMP. Return the same value returned by 2069 compare_range_with_value, including the setting of 2070 *STRICT_OVERFLOW_P. */ 2071 2072 tree 2073 vr_values::compare_name_with_value (enum tree_code comp, tree var, tree val, 2074 bool *strict_overflow_p, bool use_equiv_p) 2075 { 2076 bitmap_iterator bi; 2077 unsigned i; 2078 bitmap e; 2079 tree retval, t; 2080 int used_strict_overflow; 2081 bool sop; 2082 value_range equiv_vr; 2083 2084 /* Get the set of equivalences for VAR. */ 2085 e = get_value_range (var)->equiv; 2086 2087 /* Start at -1. Set it to 0 if we do a comparison without relying 2088 on overflow, or 1 if all comparisons rely on overflow. */ 2089 used_strict_overflow = -1; 2090 2091 /* Compare vars' value range with val. */ 2092 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var)); 2093 sop = false; 2094 retval = compare_range_with_value (comp, &equiv_vr, val, &sop); 2095 if (retval) 2096 used_strict_overflow = sop ? 1 : 0; 2097 2098 /* If the equiv set is empty we have done all work we need to do. */ 2099 if (e == NULL) 2100 { 2101 if (retval 2102 && used_strict_overflow > 0) 2103 *strict_overflow_p = true; 2104 return retval; 2105 } 2106 2107 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi) 2108 { 2109 tree name = ssa_name (i); 2110 if (! name) 2111 continue; 2112 2113 if (! use_equiv_p 2114 && ! SSA_NAME_IS_DEFAULT_DEF (name) 2115 && prop_simulate_again_p (SSA_NAME_DEF_STMT (name))) 2116 continue; 2117 2118 equiv_vr = get_vr_for_comparison (i); 2119 sop = false; 2120 t = compare_range_with_value (comp, &equiv_vr, val, &sop); 2121 if (t) 2122 { 2123 /* If we get different answers from different members 2124 of the equivalence set this check must be in a dead 2125 code region. Folding it to a trap representation 2126 would be correct here. For now just return don't-know. */ 2127 if (retval != NULL 2128 && t != retval) 2129 { 2130 retval = NULL_TREE; 2131 break; 2132 } 2133 retval = t; 2134 2135 if (!sop) 2136 used_strict_overflow = 0; 2137 else if (used_strict_overflow < 0) 2138 used_strict_overflow = 1; 2139 } 2140 } 2141 2142 if (retval 2143 && used_strict_overflow > 0) 2144 *strict_overflow_p = true; 2145 2146 return retval; 2147 } 2148 2149 2150 /* Given a comparison code COMP and names N1 and N2, compare all the 2151 ranges equivalent to N1 against all the ranges equivalent to N2 2152 to determine the value of N1 COMP N2. Return the same value 2153 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate 2154 whether we relied on undefined signed overflow in the comparison. */ 2155 2156 2157 tree 2158 vr_values::compare_names (enum tree_code comp, tree n1, tree n2, 2159 bool *strict_overflow_p) 2160 { 2161 tree t, retval; 2162 bitmap e1, e2; 2163 bitmap_iterator bi1, bi2; 2164 unsigned i1, i2; 2165 int used_strict_overflow; 2166 static bitmap_obstack *s_obstack = NULL; 2167 static bitmap s_e1 = NULL, s_e2 = NULL; 2168 2169 /* Compare the ranges of every name equivalent to N1 against the 2170 ranges of every name equivalent to N2. */ 2171 e1 = get_value_range (n1)->equiv; 2172 e2 = get_value_range (n2)->equiv; 2173 2174 /* Use the fake bitmaps if e1 or e2 are not available. */ 2175 if (s_obstack == NULL) 2176 { 2177 s_obstack = XNEW (bitmap_obstack); 2178 bitmap_obstack_initialize (s_obstack); 2179 s_e1 = BITMAP_ALLOC (s_obstack); 2180 s_e2 = BITMAP_ALLOC (s_obstack); 2181 } 2182 if (e1 == NULL) 2183 e1 = s_e1; 2184 if (e2 == NULL) 2185 e2 = s_e2; 2186 2187 /* Add N1 and N2 to their own set of equivalences to avoid 2188 duplicating the body of the loop just to check N1 and N2 2189 ranges. */ 2190 bitmap_set_bit (e1, SSA_NAME_VERSION (n1)); 2191 bitmap_set_bit (e2, SSA_NAME_VERSION (n2)); 2192 2193 /* If the equivalence sets have a common intersection, then the two 2194 names can be compared without checking their ranges. */ 2195 if (bitmap_intersect_p (e1, e2)) 2196 { 2197 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); 2198 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); 2199 2200 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR) 2201 ? boolean_true_node 2202 : boolean_false_node; 2203 } 2204 2205 /* Start at -1. Set it to 0 if we do a comparison without relying 2206 on overflow, or 1 if all comparisons rely on overflow. */ 2207 used_strict_overflow = -1; 2208 2209 /* Otherwise, compare all the equivalent ranges. First, add N1 and 2210 N2 to their own set of equivalences to avoid duplicating the body 2211 of the loop just to check N1 and N2 ranges. */ 2212 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1) 2213 { 2214 if (! ssa_name (i1)) 2215 continue; 2216 2217 value_range vr1 = get_vr_for_comparison (i1); 2218 2219 t = retval = NULL_TREE; 2220 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2) 2221 { 2222 if (! ssa_name (i2)) 2223 continue; 2224 2225 bool sop = false; 2226 2227 value_range vr2 = get_vr_for_comparison (i2); 2228 2229 t = compare_ranges (comp, &vr1, &vr2, &sop); 2230 if (t) 2231 { 2232 /* If we get different answers from different members 2233 of the equivalence set this check must be in a dead 2234 code region. Folding it to a trap representation 2235 would be correct here. For now just return don't-know. */ 2236 if (retval != NULL 2237 && t != retval) 2238 { 2239 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); 2240 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); 2241 return NULL_TREE; 2242 } 2243 retval = t; 2244 2245 if (!sop) 2246 used_strict_overflow = 0; 2247 else if (used_strict_overflow < 0) 2248 used_strict_overflow = 1; 2249 } 2250 } 2251 2252 if (retval) 2253 { 2254 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); 2255 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); 2256 if (used_strict_overflow > 0) 2257 *strict_overflow_p = true; 2258 return retval; 2259 } 2260 } 2261 2262 /* None of the equivalent ranges are useful in computing this 2263 comparison. */ 2264 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1)); 2265 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2)); 2266 return NULL_TREE; 2267 } 2268 2269 /* Helper function for vrp_evaluate_conditional_warnv & other 2270 optimizers. */ 2271 2272 tree 2273 vr_values::vrp_evaluate_conditional_warnv_with_ops_using_ranges 2274 (enum tree_code code, tree op0, tree op1, bool * strict_overflow_p) 2275 { 2276 value_range *vr0, *vr1; 2277 2278 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL; 2279 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL; 2280 2281 tree res = NULL_TREE; 2282 if (vr0 && vr1) 2283 res = compare_ranges (code, vr0, vr1, strict_overflow_p); 2284 if (!res && vr0) 2285 res = compare_range_with_value (code, vr0, op1, strict_overflow_p); 2286 if (!res && vr1) 2287 res = (compare_range_with_value 2288 (swap_tree_comparison (code), vr1, op0, strict_overflow_p)); 2289 return res; 2290 } 2291 2292 /* Helper function for vrp_evaluate_conditional_warnv. */ 2293 2294 tree 2295 vr_values::vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, 2296 tree op0, tree op1, 2297 bool use_equiv_p, 2298 bool *strict_overflow_p, 2299 bool *only_ranges) 2300 { 2301 tree ret; 2302 if (only_ranges) 2303 *only_ranges = true; 2304 2305 /* We only deal with integral and pointer types. */ 2306 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0)) 2307 && !POINTER_TYPE_P (TREE_TYPE (op0))) 2308 return NULL_TREE; 2309 2310 /* If OP0 CODE OP1 is an overflow comparison, if it can be expressed 2311 as a simple equality test, then prefer that over its current form 2312 for evaluation. 2313 2314 An overflow test which collapses to an equality test can always be 2315 expressed as a comparison of one argument against zero. Overflow 2316 occurs when the chosen argument is zero and does not occur if the 2317 chosen argument is not zero. */ 2318 tree x; 2319 if (overflow_comparison_p (code, op0, op1, use_equiv_p, &x)) 2320 { 2321 wide_int max = wi::max_value (TYPE_PRECISION (TREE_TYPE (op0)), UNSIGNED); 2322 /* B = A - 1; if (A < B) -> B = A - 1; if (A == 0) 2323 B = A - 1; if (A > B) -> B = A - 1; if (A != 0) 2324 B = A + 1; if (B < A) -> B = A + 1; if (B == 0) 2325 B = A + 1; if (B > A) -> B = A + 1; if (B != 0) */ 2326 if (integer_zerop (x)) 2327 { 2328 op1 = x; 2329 code = (code == LT_EXPR || code == LE_EXPR) ? EQ_EXPR : NE_EXPR; 2330 } 2331 /* B = A + 1; if (A > B) -> B = A + 1; if (B == 0) 2332 B = A + 1; if (A < B) -> B = A + 1; if (B != 0) 2333 B = A - 1; if (B > A) -> B = A - 1; if (A == 0) 2334 B = A - 1; if (B < A) -> B = A - 1; if (A != 0) */ 2335 else if (wi::to_wide (x) == max - 1) 2336 { 2337 op0 = op1; 2338 op1 = wide_int_to_tree (TREE_TYPE (op0), 0); 2339 code = (code == GT_EXPR || code == GE_EXPR) ? EQ_EXPR : NE_EXPR; 2340 } 2341 } 2342 2343 if ((ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges 2344 (code, op0, op1, strict_overflow_p))) 2345 return ret; 2346 if (only_ranges) 2347 *only_ranges = false; 2348 /* Do not use compare_names during propagation, it's quadratic. */ 2349 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME 2350 && use_equiv_p) 2351 return compare_names (code, op0, op1, strict_overflow_p); 2352 else if (TREE_CODE (op0) == SSA_NAME) 2353 return compare_name_with_value (code, op0, op1, 2354 strict_overflow_p, use_equiv_p); 2355 else if (TREE_CODE (op1) == SSA_NAME) 2356 return compare_name_with_value (swap_tree_comparison (code), op1, op0, 2357 strict_overflow_p, use_equiv_p); 2358 return NULL_TREE; 2359 } 2360 2361 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range 2362 information. Return NULL if the conditional can not be evaluated. 2363 The ranges of all the names equivalent with the operands in COND 2364 will be used when trying to compute the value. If the result is 2365 based on undefined signed overflow, issue a warning if 2366 appropriate. */ 2367 2368 tree 2369 vr_values::vrp_evaluate_conditional (tree_code code, tree op0, 2370 tree op1, gimple *stmt) 2371 { 2372 bool sop; 2373 tree ret; 2374 bool only_ranges; 2375 2376 /* Some passes and foldings leak constants with overflow flag set 2377 into the IL. Avoid doing wrong things with these and bail out. */ 2378 if ((TREE_CODE (op0) == INTEGER_CST 2379 && TREE_OVERFLOW (op0)) 2380 || (TREE_CODE (op1) == INTEGER_CST 2381 && TREE_OVERFLOW (op1))) 2382 return NULL_TREE; 2383 2384 sop = false; 2385 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop, 2386 &only_ranges); 2387 2388 if (ret && sop) 2389 { 2390 enum warn_strict_overflow_code wc; 2391 const char* warnmsg; 2392 2393 if (is_gimple_min_invariant (ret)) 2394 { 2395 wc = WARN_STRICT_OVERFLOW_CONDITIONAL; 2396 warnmsg = G_("assuming signed overflow does not occur when " 2397 "simplifying conditional to constant"); 2398 } 2399 else 2400 { 2401 wc = WARN_STRICT_OVERFLOW_COMPARISON; 2402 warnmsg = G_("assuming signed overflow does not occur when " 2403 "simplifying conditional"); 2404 } 2405 2406 if (issue_strict_overflow_warning (wc)) 2407 { 2408 location_t location; 2409 2410 if (!gimple_has_location (stmt)) 2411 location = input_location; 2412 else 2413 location = gimple_location (stmt); 2414 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg); 2415 } 2416 } 2417 2418 if (warn_type_limits 2419 && ret && only_ranges 2420 && TREE_CODE_CLASS (code) == tcc_comparison 2421 && TREE_CODE (op0) == SSA_NAME) 2422 { 2423 /* If the comparison is being folded and the operand on the LHS 2424 is being compared against a constant value that is outside of 2425 the natural range of OP0's type, then the predicate will 2426 always fold regardless of the value of OP0. If -Wtype-limits 2427 was specified, emit a warning. */ 2428 tree type = TREE_TYPE (op0); 2429 value_range *vr0 = get_value_range (op0); 2430 2431 if (vr0->type == VR_RANGE 2432 && INTEGRAL_TYPE_P (type) 2433 && vrp_val_is_min (vr0->min) 2434 && vrp_val_is_max (vr0->max) 2435 && is_gimple_min_invariant (op1)) 2436 { 2437 location_t location; 2438 2439 if (!gimple_has_location (stmt)) 2440 location = input_location; 2441 else 2442 location = gimple_location (stmt); 2443 2444 warning_at (location, OPT_Wtype_limits, 2445 integer_zerop (ret) 2446 ? G_("comparison always false " 2447 "due to limited range of data type") 2448 : G_("comparison always true " 2449 "due to limited range of data type")); 2450 } 2451 } 2452 2453 return ret; 2454 } 2455 2456 2457 /* Visit conditional statement STMT. If we can determine which edge 2458 will be taken out of STMT's basic block, record it in 2459 *TAKEN_EDGE_P. Otherwise, set *TAKEN_EDGE_P to NULL. */ 2460 2461 void 2462 vr_values::vrp_visit_cond_stmt (gcond *stmt, edge *taken_edge_p) 2463 { 2464 tree val; 2465 2466 *taken_edge_p = NULL; 2467 2468 if (dump_file && (dump_flags & TDF_DETAILS)) 2469 { 2470 tree use; 2471 ssa_op_iter i; 2472 2473 fprintf (dump_file, "\nVisiting conditional with predicate: "); 2474 print_gimple_stmt (dump_file, stmt, 0); 2475 fprintf (dump_file, "\nWith known ranges\n"); 2476 2477 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE) 2478 { 2479 fprintf (dump_file, "\t"); 2480 print_generic_expr (dump_file, use); 2481 fprintf (dump_file, ": "); 2482 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]); 2483 } 2484 2485 fprintf (dump_file, "\n"); 2486 } 2487 2488 /* Compute the value of the predicate COND by checking the known 2489 ranges of each of its operands. 2490 2491 Note that we cannot evaluate all the equivalent ranges here 2492 because those ranges may not yet be final and with the current 2493 propagation strategy, we cannot determine when the value ranges 2494 of the names in the equivalence set have changed. 2495 2496 For instance, given the following code fragment 2497 2498 i_5 = PHI <8, i_13> 2499 ... 2500 i_14 = ASSERT_EXPR <i_5, i_5 != 0> 2501 if (i_14 == 1) 2502 ... 2503 2504 Assume that on the first visit to i_14, i_5 has the temporary 2505 range [8, 8] because the second argument to the PHI function is 2506 not yet executable. We derive the range ~[0, 0] for i_14 and the 2507 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for 2508 the first time, since i_14 is equivalent to the range [8, 8], we 2509 determine that the predicate is always false. 2510 2511 On the next round of propagation, i_13 is determined to be 2512 VARYING, which causes i_5 to drop down to VARYING. So, another 2513 visit to i_14 is scheduled. In this second visit, we compute the 2514 exact same range and equivalence set for i_14, namely ~[0, 0] and 2515 { i_5 }. But we did not have the previous range for i_5 2516 registered, so vrp_visit_assignment thinks that the range for 2517 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)' 2518 is not visited again, which stops propagation from visiting 2519 statements in the THEN clause of that if(). 2520 2521 To properly fix this we would need to keep the previous range 2522 value for the names in the equivalence set. This way we would've 2523 discovered that from one visit to the other i_5 changed from 2524 range [8, 8] to VR_VARYING. 2525 2526 However, fixing this apparent limitation may not be worth the 2527 additional checking. Testing on several code bases (GCC, DLV, 2528 MICO, TRAMP3D and SPEC2000) showed that doing this results in 2529 4 more predicates folded in SPEC. */ 2530 2531 bool sop; 2532 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt), 2533 gimple_cond_lhs (stmt), 2534 gimple_cond_rhs (stmt), 2535 false, &sop, NULL); 2536 if (val) 2537 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val); 2538 2539 if (dump_file && (dump_flags & TDF_DETAILS)) 2540 { 2541 fprintf (dump_file, "\nPredicate evaluates to: "); 2542 if (val == NULL_TREE) 2543 fprintf (dump_file, "DON'T KNOW\n"); 2544 else 2545 print_generic_stmt (dump_file, val); 2546 } 2547 } 2548 2549 /* Searches the case label vector VEC for the ranges of CASE_LABELs that are 2550 used in range VR. The indices are placed in MIN_IDX1, MAX_IDX, MIN_IDX2 and 2551 MAX_IDX2. If the ranges of CASE_LABELs are empty then MAX_IDX1 < MIN_IDX1. 2552 Returns true if the default label is not needed. */ 2553 2554 static bool 2555 find_case_label_ranges (gswitch *stmt, value_range *vr, size_t *min_idx1, 2556 size_t *max_idx1, size_t *min_idx2, 2557 size_t *max_idx2) 2558 { 2559 size_t i, j, k, l; 2560 unsigned int n = gimple_switch_num_labels (stmt); 2561 bool take_default; 2562 tree case_low, case_high; 2563 tree min = vr->min, max = vr->max; 2564 2565 gcc_checking_assert (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE); 2566 2567 take_default = !find_case_label_range (stmt, min, max, &i, &j); 2568 2569 /* Set second range to emtpy. */ 2570 *min_idx2 = 1; 2571 *max_idx2 = 0; 2572 2573 if (vr->type == VR_RANGE) 2574 { 2575 *min_idx1 = i; 2576 *max_idx1 = j; 2577 return !take_default; 2578 } 2579 2580 /* Set first range to all case labels. */ 2581 *min_idx1 = 1; 2582 *max_idx1 = n - 1; 2583 2584 if (i > j) 2585 return false; 2586 2587 /* Make sure all the values of case labels [i , j] are contained in 2588 range [MIN, MAX]. */ 2589 case_low = CASE_LOW (gimple_switch_label (stmt, i)); 2590 case_high = CASE_HIGH (gimple_switch_label (stmt, j)); 2591 if (tree_int_cst_compare (case_low, min) < 0) 2592 i += 1; 2593 if (case_high != NULL_TREE 2594 && tree_int_cst_compare (max, case_high) < 0) 2595 j -= 1; 2596 2597 if (i > j) 2598 return false; 2599 2600 /* If the range spans case labels [i, j], the corresponding anti-range spans 2601 the labels [1, i - 1] and [j + 1, n - 1]. */ 2602 k = j + 1; 2603 l = n - 1; 2604 if (k > l) 2605 { 2606 k = 1; 2607 l = 0; 2608 } 2609 2610 j = i - 1; 2611 i = 1; 2612 if (i > j) 2613 { 2614 i = k; 2615 j = l; 2616 k = 1; 2617 l = 0; 2618 } 2619 2620 *min_idx1 = i; 2621 *max_idx1 = j; 2622 *min_idx2 = k; 2623 *max_idx2 = l; 2624 return false; 2625 } 2626 2627 /* Visit switch statement STMT. If we can determine which edge 2628 will be taken out of STMT's basic block, record it in 2629 *TAKEN_EDGE_P. Otherwise, *TAKEN_EDGE_P set to NULL. */ 2630 2631 void 2632 vr_values::vrp_visit_switch_stmt (gswitch *stmt, edge *taken_edge_p) 2633 { 2634 tree op, val; 2635 value_range *vr; 2636 size_t i = 0, j = 0, k, l; 2637 bool take_default; 2638 2639 *taken_edge_p = NULL; 2640 op = gimple_switch_index (stmt); 2641 if (TREE_CODE (op) != SSA_NAME) 2642 return; 2643 2644 vr = get_value_range (op); 2645 if (dump_file && (dump_flags & TDF_DETAILS)) 2646 { 2647 fprintf (dump_file, "\nVisiting switch expression with operand "); 2648 print_generic_expr (dump_file, op); 2649 fprintf (dump_file, " with known range "); 2650 dump_value_range (dump_file, vr); 2651 fprintf (dump_file, "\n"); 2652 } 2653 2654 if ((vr->type != VR_RANGE 2655 && vr->type != VR_ANTI_RANGE) 2656 || symbolic_range_p (vr)) 2657 return; 2658 2659 /* Find the single edge that is taken from the switch expression. */ 2660 take_default = !find_case_label_ranges (stmt, vr, &i, &j, &k, &l); 2661 2662 /* Check if the range spans no CASE_LABEL. If so, we only reach the default 2663 label */ 2664 if (j < i) 2665 { 2666 gcc_assert (take_default); 2667 val = gimple_switch_default_label (stmt); 2668 } 2669 else 2670 { 2671 /* Check if labels with index i to j and maybe the default label 2672 are all reaching the same label. */ 2673 2674 val = gimple_switch_label (stmt, i); 2675 if (take_default 2676 && CASE_LABEL (gimple_switch_default_label (stmt)) 2677 != CASE_LABEL (val)) 2678 { 2679 if (dump_file && (dump_flags & TDF_DETAILS)) 2680 fprintf (dump_file, " not a single destination for this " 2681 "range\n"); 2682 return; 2683 } 2684 for (++i; i <= j; ++i) 2685 { 2686 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val)) 2687 { 2688 if (dump_file && (dump_flags & TDF_DETAILS)) 2689 fprintf (dump_file, " not a single destination for this " 2690 "range\n"); 2691 return; 2692 } 2693 } 2694 for (; k <= l; ++k) 2695 { 2696 if (CASE_LABEL (gimple_switch_label (stmt, k)) != CASE_LABEL (val)) 2697 { 2698 if (dump_file && (dump_flags & TDF_DETAILS)) 2699 fprintf (dump_file, " not a single destination for this " 2700 "range\n"); 2701 return; 2702 } 2703 } 2704 } 2705 2706 *taken_edge_p = find_edge (gimple_bb (stmt), 2707 label_to_block (CASE_LABEL (val))); 2708 2709 if (dump_file && (dump_flags & TDF_DETAILS)) 2710 { 2711 fprintf (dump_file, " will take edge to "); 2712 print_generic_stmt (dump_file, CASE_LABEL (val)); 2713 } 2714 } 2715 2716 2717 /* Evaluate statement STMT. If the statement produces a useful range, 2718 set VR and corepsponding OUTPUT_P. 2719 2720 If STMT is a conditional branch and we can determine its truth 2721 value, the taken edge is recorded in *TAKEN_EDGE_P. */ 2722 2723 void 2724 vr_values::extract_range_from_stmt (gimple *stmt, edge *taken_edge_p, 2725 tree *output_p, value_range *vr) 2726 { 2727 2728 if (dump_file && (dump_flags & TDF_DETAILS)) 2729 { 2730 fprintf (dump_file, "\nVisiting statement:\n"); 2731 print_gimple_stmt (dump_file, stmt, 0, dump_flags); 2732 } 2733 2734 if (!stmt_interesting_for_vrp (stmt)) 2735 gcc_assert (stmt_ends_bb_p (stmt)); 2736 else if (is_gimple_assign (stmt) || is_gimple_call (stmt)) 2737 vrp_visit_assignment_or_call (stmt, output_p, vr); 2738 else if (gimple_code (stmt) == GIMPLE_COND) 2739 vrp_visit_cond_stmt (as_a <gcond *> (stmt), taken_edge_p); 2740 else if (gimple_code (stmt) == GIMPLE_SWITCH) 2741 vrp_visit_switch_stmt (as_a <gswitch *> (stmt), taken_edge_p); 2742 } 2743 2744 /* Visit all arguments for PHI node PHI that flow through executable 2745 edges. If a valid value range can be derived from all the incoming 2746 value ranges, set a new range in VR_RESULT. */ 2747 2748 void 2749 vr_values::extract_range_from_phi_node (gphi *phi, value_range *vr_result) 2750 { 2751 size_t i; 2752 tree lhs = PHI_RESULT (phi); 2753 value_range *lhs_vr = get_value_range (lhs); 2754 bool first = true; 2755 int edges, old_edges; 2756 struct loop *l; 2757 2758 if (dump_file && (dump_flags & TDF_DETAILS)) 2759 { 2760 fprintf (dump_file, "\nVisiting PHI node: "); 2761 print_gimple_stmt (dump_file, phi, 0, dump_flags); 2762 } 2763 2764 bool may_simulate_backedge_again = false; 2765 edges = 0; 2766 for (i = 0; i < gimple_phi_num_args (phi); i++) 2767 { 2768 edge e = gimple_phi_arg_edge (phi, i); 2769 2770 if (dump_file && (dump_flags & TDF_DETAILS)) 2771 { 2772 fprintf (dump_file, 2773 " Argument #%d (%d -> %d %sexecutable)\n", 2774 (int) i, e->src->index, e->dest->index, 2775 (e->flags & EDGE_EXECUTABLE) ? "" : "not "); 2776 } 2777 2778 if (e->flags & EDGE_EXECUTABLE) 2779 { 2780 tree arg = PHI_ARG_DEF (phi, i); 2781 value_range vr_arg; 2782 2783 ++edges; 2784 2785 if (TREE_CODE (arg) == SSA_NAME) 2786 { 2787 /* See if we are eventually going to change one of the args. */ 2788 gimple *def_stmt = SSA_NAME_DEF_STMT (arg); 2789 if (! gimple_nop_p (def_stmt) 2790 && prop_simulate_again_p (def_stmt) 2791 && e->flags & EDGE_DFS_BACK) 2792 may_simulate_backedge_again = true; 2793 2794 vr_arg = *(get_value_range (arg)); 2795 /* Do not allow equivalences or symbolic ranges to leak in from 2796 backedges. That creates invalid equivalencies. 2797 See PR53465 and PR54767. */ 2798 if (e->flags & EDGE_DFS_BACK) 2799 { 2800 if (vr_arg.type == VR_RANGE 2801 || vr_arg.type == VR_ANTI_RANGE) 2802 { 2803 vr_arg.equiv = NULL; 2804 if (symbolic_range_p (&vr_arg)) 2805 { 2806 vr_arg.type = VR_VARYING; 2807 vr_arg.min = NULL_TREE; 2808 vr_arg.max = NULL_TREE; 2809 } 2810 } 2811 } 2812 else 2813 { 2814 /* If the non-backedge arguments range is VR_VARYING then 2815 we can still try recording a simple equivalence. */ 2816 if (vr_arg.type == VR_VARYING) 2817 { 2818 vr_arg.type = VR_RANGE; 2819 vr_arg.min = arg; 2820 vr_arg.max = arg; 2821 vr_arg.equiv = NULL; 2822 } 2823 } 2824 } 2825 else 2826 { 2827 if (TREE_OVERFLOW_P (arg)) 2828 arg = drop_tree_overflow (arg); 2829 2830 vr_arg.type = VR_RANGE; 2831 vr_arg.min = arg; 2832 vr_arg.max = arg; 2833 vr_arg.equiv = NULL; 2834 } 2835 2836 if (dump_file && (dump_flags & TDF_DETAILS)) 2837 { 2838 fprintf (dump_file, "\t"); 2839 print_generic_expr (dump_file, arg, dump_flags); 2840 fprintf (dump_file, ": "); 2841 dump_value_range (dump_file, &vr_arg); 2842 fprintf (dump_file, "\n"); 2843 } 2844 2845 if (first) 2846 copy_value_range (vr_result, &vr_arg); 2847 else 2848 vrp_meet (vr_result, &vr_arg); 2849 first = false; 2850 2851 if (vr_result->type == VR_VARYING) 2852 break; 2853 } 2854 } 2855 2856 if (vr_result->type == VR_VARYING) 2857 goto varying; 2858 else if (vr_result->type == VR_UNDEFINED) 2859 goto update_range; 2860 2861 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)]; 2862 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges; 2863 2864 /* To prevent infinite iterations in the algorithm, derive ranges 2865 when the new value is slightly bigger or smaller than the 2866 previous one. We don't do this if we have seen a new executable 2867 edge; this helps us avoid an infinity for conditionals 2868 which are not in a loop. If the old value-range was VR_UNDEFINED 2869 use the updated range and iterate one more time. If we will not 2870 simulate this PHI again via the backedge allow us to iterate. */ 2871 if (edges > 0 2872 && gimple_phi_num_args (phi) > 1 2873 && edges == old_edges 2874 && lhs_vr->type != VR_UNDEFINED 2875 && may_simulate_backedge_again) 2876 { 2877 /* Compare old and new ranges, fall back to varying if the 2878 values are not comparable. */ 2879 int cmp_min = compare_values (lhs_vr->min, vr_result->min); 2880 if (cmp_min == -2) 2881 goto varying; 2882 int cmp_max = compare_values (lhs_vr->max, vr_result->max); 2883 if (cmp_max == -2) 2884 goto varying; 2885 2886 /* For non VR_RANGE or for pointers fall back to varying if 2887 the range changed. */ 2888 if ((lhs_vr->type != VR_RANGE || vr_result->type != VR_RANGE 2889 || POINTER_TYPE_P (TREE_TYPE (lhs))) 2890 && (cmp_min != 0 || cmp_max != 0)) 2891 goto varying; 2892 2893 /* If the new minimum is larger than the previous one 2894 retain the old value. If the new minimum value is smaller 2895 than the previous one and not -INF go all the way to -INF + 1. 2896 In the first case, to avoid infinite bouncing between different 2897 minimums, and in the other case to avoid iterating millions of 2898 times to reach -INF. Going to -INF + 1 also lets the following 2899 iteration compute whether there will be any overflow, at the 2900 expense of one additional iteration. */ 2901 if (cmp_min < 0) 2902 vr_result->min = lhs_vr->min; 2903 else if (cmp_min > 0 2904 && !vrp_val_is_min (vr_result->min)) 2905 vr_result->min 2906 = int_const_binop (PLUS_EXPR, 2907 vrp_val_min (TREE_TYPE (vr_result->min)), 2908 build_int_cst (TREE_TYPE (vr_result->min), 1)); 2909 2910 /* Similarly for the maximum value. */ 2911 if (cmp_max > 0) 2912 vr_result->max = lhs_vr->max; 2913 else if (cmp_max < 0 2914 && !vrp_val_is_max (vr_result->max)) 2915 vr_result->max 2916 = int_const_binop (MINUS_EXPR, 2917 vrp_val_max (TREE_TYPE (vr_result->min)), 2918 build_int_cst (TREE_TYPE (vr_result->min), 1)); 2919 2920 /* If we dropped either bound to +-INF then if this is a loop 2921 PHI node SCEV may known more about its value-range. */ 2922 if (cmp_min > 0 || cmp_min < 0 2923 || cmp_max < 0 || cmp_max > 0) 2924 goto scev_check; 2925 2926 goto infinite_check; 2927 } 2928 2929 goto update_range; 2930 2931 varying: 2932 set_value_range_to_varying (vr_result); 2933 2934 scev_check: 2935 /* If this is a loop PHI node SCEV may known more about its value-range. 2936 scev_check can be reached from two paths, one is a fall through from above 2937 "varying" label, the other is direct goto from code block which tries to 2938 avoid infinite simulation. */ 2939 if (scev_initialized_p () 2940 && (l = loop_containing_stmt (phi)) 2941 && l->header == gimple_bb (phi)) 2942 adjust_range_with_scev (vr_result, l, phi, lhs); 2943 2944 infinite_check: 2945 /* If we will end up with a (-INF, +INF) range, set it to 2946 VARYING. Same if the previous max value was invalid for 2947 the type and we end up with vr_result.min > vr_result.max. */ 2948 if ((vr_result->type == VR_RANGE || vr_result->type == VR_ANTI_RANGE) 2949 && !((vrp_val_is_max (vr_result->max) && vrp_val_is_min (vr_result->min)) 2950 || compare_values (vr_result->min, vr_result->max) > 0)) 2951 ; 2952 else 2953 set_value_range_to_varying (vr_result); 2954 2955 /* If the new range is different than the previous value, keep 2956 iterating. */ 2957 update_range: 2958 return; 2959 } 2960 2961 /* Simplify boolean operations if the source is known 2962 to be already a boolean. */ 2963 bool 2964 vr_values::simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, 2965 gimple *stmt) 2966 { 2967 enum tree_code rhs_code = gimple_assign_rhs_code (stmt); 2968 tree lhs, op0, op1; 2969 bool need_conversion; 2970 2971 /* We handle only !=/== case here. */ 2972 gcc_assert (rhs_code == EQ_EXPR || rhs_code == NE_EXPR); 2973 2974 op0 = gimple_assign_rhs1 (stmt); 2975 if (!op_with_boolean_value_range_p (op0)) 2976 return false; 2977 2978 op1 = gimple_assign_rhs2 (stmt); 2979 if (!op_with_boolean_value_range_p (op1)) 2980 return false; 2981 2982 /* Reduce number of cases to handle to NE_EXPR. As there is no 2983 BIT_XNOR_EXPR we cannot replace A == B with a single statement. */ 2984 if (rhs_code == EQ_EXPR) 2985 { 2986 if (TREE_CODE (op1) == INTEGER_CST) 2987 op1 = int_const_binop (BIT_XOR_EXPR, op1, 2988 build_int_cst (TREE_TYPE (op1), 1)); 2989 else 2990 return false; 2991 } 2992 2993 lhs = gimple_assign_lhs (stmt); 2994 need_conversion 2995 = !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0)); 2996 2997 /* Make sure to not sign-extend a 1-bit 1 when converting the result. */ 2998 if (need_conversion 2999 && !TYPE_UNSIGNED (TREE_TYPE (op0)) 3000 && TYPE_PRECISION (TREE_TYPE (op0)) == 1 3001 && TYPE_PRECISION (TREE_TYPE (lhs)) > 1) 3002 return false; 3003 3004 /* For A != 0 we can substitute A itself. */ 3005 if (integer_zerop (op1)) 3006 gimple_assign_set_rhs_with_ops (gsi, 3007 need_conversion 3008 ? NOP_EXPR : TREE_CODE (op0), op0); 3009 /* For A != B we substitute A ^ B. Either with conversion. */ 3010 else if (need_conversion) 3011 { 3012 tree tem = make_ssa_name (TREE_TYPE (op0)); 3013 gassign *newop 3014 = gimple_build_assign (tem, BIT_XOR_EXPR, op0, op1); 3015 gsi_insert_before (gsi, newop, GSI_SAME_STMT); 3016 if (INTEGRAL_TYPE_P (TREE_TYPE (tem)) 3017 && TYPE_PRECISION (TREE_TYPE (tem)) > 1) 3018 set_range_info (tem, VR_RANGE, 3019 wi::zero (TYPE_PRECISION (TREE_TYPE (tem))), 3020 wi::one (TYPE_PRECISION (TREE_TYPE (tem)))); 3021 gimple_assign_set_rhs_with_ops (gsi, NOP_EXPR, tem); 3022 } 3023 /* Or without. */ 3024 else 3025 gimple_assign_set_rhs_with_ops (gsi, BIT_XOR_EXPR, op0, op1); 3026 update_stmt (gsi_stmt (*gsi)); 3027 fold_stmt (gsi, follow_single_use_edges); 3028 3029 return true; 3030 } 3031 3032 /* Simplify a division or modulo operator to a right shift or bitwise and 3033 if the first operand is unsigned or is greater than zero and the second 3034 operand is an exact power of two. For TRUNC_MOD_EXPR op0 % op1 with 3035 constant op1 (op1min = op1) or with op1 in [op1min, op1max] range, 3036 optimize it into just op0 if op0's range is known to be a subset of 3037 [-op1min + 1, op1min - 1] for signed and [0, op1min - 1] for unsigned 3038 modulo. */ 3039 3040 bool 3041 vr_values::simplify_div_or_mod_using_ranges (gimple_stmt_iterator *gsi, 3042 gimple *stmt) 3043 { 3044 enum tree_code rhs_code = gimple_assign_rhs_code (stmt); 3045 tree val = NULL; 3046 tree op0 = gimple_assign_rhs1 (stmt); 3047 tree op1 = gimple_assign_rhs2 (stmt); 3048 tree op0min = NULL_TREE, op0max = NULL_TREE; 3049 tree op1min = op1; 3050 value_range *vr = NULL; 3051 3052 if (TREE_CODE (op0) == INTEGER_CST) 3053 { 3054 op0min = op0; 3055 op0max = op0; 3056 } 3057 else 3058 { 3059 vr = get_value_range (op0); 3060 if (range_int_cst_p (vr)) 3061 { 3062 op0min = vr->min; 3063 op0max = vr->max; 3064 } 3065 } 3066 3067 if (rhs_code == TRUNC_MOD_EXPR 3068 && TREE_CODE (op1) == SSA_NAME) 3069 { 3070 value_range *vr1 = get_value_range (op1); 3071 if (range_int_cst_p (vr1)) 3072 op1min = vr1->min; 3073 } 3074 if (rhs_code == TRUNC_MOD_EXPR 3075 && TREE_CODE (op1min) == INTEGER_CST 3076 && tree_int_cst_sgn (op1min) == 1 3077 && op0max 3078 && tree_int_cst_lt (op0max, op1min)) 3079 { 3080 if (TYPE_UNSIGNED (TREE_TYPE (op0)) 3081 || tree_int_cst_sgn (op0min) >= 0 3082 || tree_int_cst_lt (fold_unary (NEGATE_EXPR, TREE_TYPE (op1min), op1min), 3083 op0min)) 3084 { 3085 /* If op0 already has the range op0 % op1 has, 3086 then TRUNC_MOD_EXPR won't change anything. */ 3087 gimple_assign_set_rhs_from_tree (gsi, op0); 3088 return true; 3089 } 3090 } 3091 3092 if (TREE_CODE (op0) != SSA_NAME) 3093 return false; 3094 3095 if (!integer_pow2p (op1)) 3096 { 3097 /* X % -Y can be only optimized into X % Y either if 3098 X is not INT_MIN, or Y is not -1. Fold it now, as after 3099 remove_range_assertions the range info might be not available 3100 anymore. */ 3101 if (rhs_code == TRUNC_MOD_EXPR 3102 && fold_stmt (gsi, follow_single_use_edges)) 3103 return true; 3104 return false; 3105 } 3106 3107 if (TYPE_UNSIGNED (TREE_TYPE (op0))) 3108 val = integer_one_node; 3109 else 3110 { 3111 bool sop = false; 3112 3113 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop); 3114 3115 if (val 3116 && sop 3117 && integer_onep (val) 3118 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) 3119 { 3120 location_t location; 3121 3122 if (!gimple_has_location (stmt)) 3123 location = input_location; 3124 else 3125 location = gimple_location (stmt); 3126 warning_at (location, OPT_Wstrict_overflow, 3127 "assuming signed overflow does not occur when " 3128 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>"); 3129 } 3130 } 3131 3132 if (val && integer_onep (val)) 3133 { 3134 tree t; 3135 3136 if (rhs_code == TRUNC_DIV_EXPR) 3137 { 3138 t = build_int_cst (integer_type_node, tree_log2 (op1)); 3139 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR); 3140 gimple_assign_set_rhs1 (stmt, op0); 3141 gimple_assign_set_rhs2 (stmt, t); 3142 } 3143 else 3144 { 3145 t = build_int_cst (TREE_TYPE (op1), 1); 3146 t = int_const_binop (MINUS_EXPR, op1, t); 3147 t = fold_convert (TREE_TYPE (op0), t); 3148 3149 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR); 3150 gimple_assign_set_rhs1 (stmt, op0); 3151 gimple_assign_set_rhs2 (stmt, t); 3152 } 3153 3154 update_stmt (stmt); 3155 fold_stmt (gsi, follow_single_use_edges); 3156 return true; 3157 } 3158 3159 return false; 3160 } 3161 3162 /* Simplify a min or max if the ranges of the two operands are 3163 disjoint. Return true if we do simplify. */ 3164 3165 bool 3166 vr_values::simplify_min_or_max_using_ranges (gimple_stmt_iterator *gsi, 3167 gimple *stmt) 3168 { 3169 tree op0 = gimple_assign_rhs1 (stmt); 3170 tree op1 = gimple_assign_rhs2 (stmt); 3171 bool sop = false; 3172 tree val; 3173 3174 val = (vrp_evaluate_conditional_warnv_with_ops_using_ranges 3175 (LE_EXPR, op0, op1, &sop)); 3176 if (!val) 3177 { 3178 sop = false; 3179 val = (vrp_evaluate_conditional_warnv_with_ops_using_ranges 3180 (LT_EXPR, op0, op1, &sop)); 3181 } 3182 3183 if (val) 3184 { 3185 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) 3186 { 3187 location_t location; 3188 3189 if (!gimple_has_location (stmt)) 3190 location = input_location; 3191 else 3192 location = gimple_location (stmt); 3193 warning_at (location, OPT_Wstrict_overflow, 3194 "assuming signed overflow does not occur when " 3195 "simplifying %<min/max (X,Y)%> to %<X%> or %<Y%>"); 3196 } 3197 3198 /* VAL == TRUE -> OP0 < or <= op1 3199 VAL == FALSE -> OP0 > or >= op1. */ 3200 tree res = ((gimple_assign_rhs_code (stmt) == MAX_EXPR) 3201 == integer_zerop (val)) ? op0 : op1; 3202 gimple_assign_set_rhs_from_tree (gsi, res); 3203 return true; 3204 } 3205 3206 return false; 3207 } 3208 3209 /* If the operand to an ABS_EXPR is >= 0, then eliminate the 3210 ABS_EXPR. If the operand is <= 0, then simplify the 3211 ABS_EXPR into a NEGATE_EXPR. */ 3212 3213 bool 3214 vr_values::simplify_abs_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) 3215 { 3216 tree op = gimple_assign_rhs1 (stmt); 3217 value_range *vr = get_value_range (op); 3218 3219 if (vr) 3220 { 3221 tree val = NULL; 3222 bool sop = false; 3223 3224 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop); 3225 if (!val) 3226 { 3227 /* The range is neither <= 0 nor > 0. Now see if it is 3228 either < 0 or >= 0. */ 3229 sop = false; 3230 val = compare_range_with_value (LT_EXPR, vr, integer_zero_node, 3231 &sop); 3232 } 3233 3234 if (val) 3235 { 3236 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) 3237 { 3238 location_t location; 3239 3240 if (!gimple_has_location (stmt)) 3241 location = input_location; 3242 else 3243 location = gimple_location (stmt); 3244 warning_at (location, OPT_Wstrict_overflow, 3245 "assuming signed overflow does not occur when " 3246 "simplifying %<abs (X)%> to %<X%> or %<-X%>"); 3247 } 3248 3249 gimple_assign_set_rhs1 (stmt, op); 3250 if (integer_zerop (val)) 3251 gimple_assign_set_rhs_code (stmt, SSA_NAME); 3252 else 3253 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR); 3254 update_stmt (stmt); 3255 fold_stmt (gsi, follow_single_use_edges); 3256 return true; 3257 } 3258 } 3259 3260 return false; 3261 } 3262 3263 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR. 3264 If all the bits that are being cleared by & are already 3265 known to be zero from VR, or all the bits that are being 3266 set by | are already known to be one from VR, the bit 3267 operation is redundant. */ 3268 3269 bool 3270 vr_values::simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, 3271 gimple *stmt) 3272 { 3273 tree op0 = gimple_assign_rhs1 (stmt); 3274 tree op1 = gimple_assign_rhs2 (stmt); 3275 tree op = NULL_TREE; 3276 value_range vr0 = VR_INITIALIZER; 3277 value_range vr1 = VR_INITIALIZER; 3278 wide_int may_be_nonzero0, may_be_nonzero1; 3279 wide_int must_be_nonzero0, must_be_nonzero1; 3280 wide_int mask; 3281 3282 if (TREE_CODE (op0) == SSA_NAME) 3283 vr0 = *(get_value_range (op0)); 3284 else if (is_gimple_min_invariant (op0)) 3285 set_value_range_to_value (&vr0, op0, NULL); 3286 else 3287 return false; 3288 3289 if (TREE_CODE (op1) == SSA_NAME) 3290 vr1 = *(get_value_range (op1)); 3291 else if (is_gimple_min_invariant (op1)) 3292 set_value_range_to_value (&vr1, op1, NULL); 3293 else 3294 return false; 3295 3296 if (!zero_nonzero_bits_from_vr (TREE_TYPE (op0), &vr0, &may_be_nonzero0, 3297 &must_be_nonzero0)) 3298 return false; 3299 if (!zero_nonzero_bits_from_vr (TREE_TYPE (op1), &vr1, &may_be_nonzero1, 3300 &must_be_nonzero1)) 3301 return false; 3302 3303 switch (gimple_assign_rhs_code (stmt)) 3304 { 3305 case BIT_AND_EXPR: 3306 mask = wi::bit_and_not (may_be_nonzero0, must_be_nonzero1); 3307 if (mask == 0) 3308 { 3309 op = op0; 3310 break; 3311 } 3312 mask = wi::bit_and_not (may_be_nonzero1, must_be_nonzero0); 3313 if (mask == 0) 3314 { 3315 op = op1; 3316 break; 3317 } 3318 break; 3319 case BIT_IOR_EXPR: 3320 mask = wi::bit_and_not (may_be_nonzero0, must_be_nonzero1); 3321 if (mask == 0) 3322 { 3323 op = op1; 3324 break; 3325 } 3326 mask = wi::bit_and_not (may_be_nonzero1, must_be_nonzero0); 3327 if (mask == 0) 3328 { 3329 op = op0; 3330 break; 3331 } 3332 break; 3333 default: 3334 gcc_unreachable (); 3335 } 3336 3337 if (op == NULL_TREE) 3338 return false; 3339 3340 gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op); 3341 update_stmt (gsi_stmt (*gsi)); 3342 return true; 3343 } 3344 3345 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has 3346 a known value range VR. 3347 3348 If there is one and only one value which will satisfy the 3349 conditional, then return that value. Else return NULL. 3350 3351 If signed overflow must be undefined for the value to satisfy 3352 the conditional, then set *STRICT_OVERFLOW_P to true. */ 3353 3354 static tree 3355 test_for_singularity (enum tree_code cond_code, tree op0, 3356 tree op1, value_range *vr) 3357 { 3358 tree min = NULL; 3359 tree max = NULL; 3360 3361 /* Extract minimum/maximum values which satisfy the conditional as it was 3362 written. */ 3363 if (cond_code == LE_EXPR || cond_code == LT_EXPR) 3364 { 3365 min = TYPE_MIN_VALUE (TREE_TYPE (op0)); 3366 3367 max = op1; 3368 if (cond_code == LT_EXPR) 3369 { 3370 tree one = build_int_cst (TREE_TYPE (op0), 1); 3371 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one); 3372 /* Signal to compare_values_warnv this expr doesn't overflow. */ 3373 if (EXPR_P (max)) 3374 TREE_NO_WARNING (max) = 1; 3375 } 3376 } 3377 else if (cond_code == GE_EXPR || cond_code == GT_EXPR) 3378 { 3379 max = TYPE_MAX_VALUE (TREE_TYPE (op0)); 3380 3381 min = op1; 3382 if (cond_code == GT_EXPR) 3383 { 3384 tree one = build_int_cst (TREE_TYPE (op0), 1); 3385 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one); 3386 /* Signal to compare_values_warnv this expr doesn't overflow. */ 3387 if (EXPR_P (min)) 3388 TREE_NO_WARNING (min) = 1; 3389 } 3390 } 3391 3392 /* Now refine the minimum and maximum values using any 3393 value range information we have for op0. */ 3394 if (min && max) 3395 { 3396 if (compare_values (vr->min, min) == 1) 3397 min = vr->min; 3398 if (compare_values (vr->max, max) == -1) 3399 max = vr->max; 3400 3401 /* If the new min/max values have converged to a single value, 3402 then there is only one value which can satisfy the condition, 3403 return that value. */ 3404 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min)) 3405 return min; 3406 } 3407 return NULL; 3408 } 3409 3410 /* Return whether the value range *VR fits in an integer type specified 3411 by PRECISION and UNSIGNED_P. */ 3412 3413 static bool 3414 range_fits_type_p (value_range *vr, unsigned dest_precision, signop dest_sgn) 3415 { 3416 tree src_type; 3417 unsigned src_precision; 3418 widest_int tem; 3419 signop src_sgn; 3420 3421 /* We can only handle integral and pointer types. */ 3422 src_type = TREE_TYPE (vr->min); 3423 if (!INTEGRAL_TYPE_P (src_type) 3424 && !POINTER_TYPE_P (src_type)) 3425 return false; 3426 3427 /* An extension is fine unless VR is SIGNED and dest_sgn is UNSIGNED, 3428 and so is an identity transform. */ 3429 src_precision = TYPE_PRECISION (TREE_TYPE (vr->min)); 3430 src_sgn = TYPE_SIGN (src_type); 3431 if ((src_precision < dest_precision 3432 && !(dest_sgn == UNSIGNED && src_sgn == SIGNED)) 3433 || (src_precision == dest_precision && src_sgn == dest_sgn)) 3434 return true; 3435 3436 /* Now we can only handle ranges with constant bounds. */ 3437 if (vr->type != VR_RANGE 3438 || TREE_CODE (vr->min) != INTEGER_CST 3439 || TREE_CODE (vr->max) != INTEGER_CST) 3440 return false; 3441 3442 /* For sign changes, the MSB of the wide_int has to be clear. 3443 An unsigned value with its MSB set cannot be represented by 3444 a signed wide_int, while a negative value cannot be represented 3445 by an unsigned wide_int. */ 3446 if (src_sgn != dest_sgn 3447 && (wi::lts_p (wi::to_wide (vr->min), 0) 3448 || wi::lts_p (wi::to_wide (vr->max), 0))) 3449 return false; 3450 3451 /* Then we can perform the conversion on both ends and compare 3452 the result for equality. */ 3453 tem = wi::ext (wi::to_widest (vr->min), dest_precision, dest_sgn); 3454 if (tem != wi::to_widest (vr->min)) 3455 return false; 3456 tem = wi::ext (wi::to_widest (vr->max), dest_precision, dest_sgn); 3457 if (tem != wi::to_widest (vr->max)) 3458 return false; 3459 3460 return true; 3461 } 3462 3463 /* Simplify a conditional using a relational operator to an equality 3464 test if the range information indicates only one value can satisfy 3465 the original conditional. */ 3466 3467 bool 3468 vr_values::simplify_cond_using_ranges_1 (gcond *stmt) 3469 { 3470 tree op0 = gimple_cond_lhs (stmt); 3471 tree op1 = gimple_cond_rhs (stmt); 3472 enum tree_code cond_code = gimple_cond_code (stmt); 3473 3474 if (cond_code != NE_EXPR 3475 && cond_code != EQ_EXPR 3476 && TREE_CODE (op0) == SSA_NAME 3477 && INTEGRAL_TYPE_P (TREE_TYPE (op0)) 3478 && is_gimple_min_invariant (op1)) 3479 { 3480 value_range *vr = get_value_range (op0); 3481 3482 /* If we have range information for OP0, then we might be 3483 able to simplify this conditional. */ 3484 if (vr->type == VR_RANGE) 3485 { 3486 tree new_tree = test_for_singularity (cond_code, op0, op1, vr); 3487 if (new_tree) 3488 { 3489 if (dump_file) 3490 { 3491 fprintf (dump_file, "Simplified relational "); 3492 print_gimple_stmt (dump_file, stmt, 0); 3493 fprintf (dump_file, " into "); 3494 } 3495 3496 gimple_cond_set_code (stmt, EQ_EXPR); 3497 gimple_cond_set_lhs (stmt, op0); 3498 gimple_cond_set_rhs (stmt, new_tree); 3499 3500 update_stmt (stmt); 3501 3502 if (dump_file) 3503 { 3504 print_gimple_stmt (dump_file, stmt, 0); 3505 fprintf (dump_file, "\n"); 3506 } 3507 3508 return true; 3509 } 3510 3511 /* Try again after inverting the condition. We only deal 3512 with integral types here, so no need to worry about 3513 issues with inverting FP comparisons. */ 3514 new_tree = test_for_singularity 3515 (invert_tree_comparison (cond_code, false), 3516 op0, op1, vr); 3517 if (new_tree) 3518 { 3519 if (dump_file) 3520 { 3521 fprintf (dump_file, "Simplified relational "); 3522 print_gimple_stmt (dump_file, stmt, 0); 3523 fprintf (dump_file, " into "); 3524 } 3525 3526 gimple_cond_set_code (stmt, NE_EXPR); 3527 gimple_cond_set_lhs (stmt, op0); 3528 gimple_cond_set_rhs (stmt, new_tree); 3529 3530 update_stmt (stmt); 3531 3532 if (dump_file) 3533 { 3534 print_gimple_stmt (dump_file, stmt, 0); 3535 fprintf (dump_file, "\n"); 3536 } 3537 3538 return true; 3539 } 3540 } 3541 } 3542 return false; 3543 } 3544 3545 /* STMT is a conditional at the end of a basic block. 3546 3547 If the conditional is of the form SSA_NAME op constant and the SSA_NAME 3548 was set via a type conversion, try to replace the SSA_NAME with the RHS 3549 of the type conversion. Doing so makes the conversion dead which helps 3550 subsequent passes. */ 3551 3552 void 3553 vr_values::simplify_cond_using_ranges_2 (gcond *stmt) 3554 { 3555 tree op0 = gimple_cond_lhs (stmt); 3556 tree op1 = gimple_cond_rhs (stmt); 3557 3558 /* If we have a comparison of an SSA_NAME (OP0) against a constant, 3559 see if OP0 was set by a type conversion where the source of 3560 the conversion is another SSA_NAME with a range that fits 3561 into the range of OP0's type. 3562 3563 If so, the conversion is redundant as the earlier SSA_NAME can be 3564 used for the comparison directly if we just massage the constant in the 3565 comparison. */ 3566 if (TREE_CODE (op0) == SSA_NAME 3567 && TREE_CODE (op1) == INTEGER_CST) 3568 { 3569 gimple *def_stmt = SSA_NAME_DEF_STMT (op0); 3570 tree innerop; 3571 3572 if (!is_gimple_assign (def_stmt) 3573 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) 3574 return; 3575 3576 innerop = gimple_assign_rhs1 (def_stmt); 3577 3578 if (TREE_CODE (innerop) == SSA_NAME 3579 && !POINTER_TYPE_P (TREE_TYPE (innerop)) 3580 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (innerop) 3581 && desired_pro_or_demotion_p (TREE_TYPE (innerop), TREE_TYPE (op0))) 3582 { 3583 value_range *vr = get_value_range (innerop); 3584 3585 if (range_int_cst_p (vr) 3586 && range_fits_type_p (vr, 3587 TYPE_PRECISION (TREE_TYPE (op0)), 3588 TYPE_SIGN (TREE_TYPE (op0))) 3589 && int_fits_type_p (op1, TREE_TYPE (innerop))) 3590 { 3591 tree newconst = fold_convert (TREE_TYPE (innerop), op1); 3592 gimple_cond_set_lhs (stmt, innerop); 3593 gimple_cond_set_rhs (stmt, newconst); 3594 update_stmt (stmt); 3595 if (dump_file && (dump_flags & TDF_DETAILS)) 3596 { 3597 fprintf (dump_file, "Folded into: "); 3598 print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); 3599 fprintf (dump_file, "\n"); 3600 } 3601 } 3602 } 3603 } 3604 } 3605 3606 /* Simplify a switch statement using the value range of the switch 3607 argument. */ 3608 3609 bool 3610 vr_values::simplify_switch_using_ranges (gswitch *stmt) 3611 { 3612 tree op = gimple_switch_index (stmt); 3613 value_range *vr = NULL; 3614 bool take_default; 3615 edge e; 3616 edge_iterator ei; 3617 size_t i = 0, j = 0, n, n2; 3618 tree vec2; 3619 switch_update su; 3620 size_t k = 1, l = 0; 3621 3622 if (TREE_CODE (op) == SSA_NAME) 3623 { 3624 vr = get_value_range (op); 3625 3626 /* We can only handle integer ranges. */ 3627 if ((vr->type != VR_RANGE 3628 && vr->type != VR_ANTI_RANGE) 3629 || symbolic_range_p (vr)) 3630 return false; 3631 3632 /* Find case label for min/max of the value range. */ 3633 take_default = !find_case_label_ranges (stmt, vr, &i, &j, &k, &l); 3634 } 3635 else if (TREE_CODE (op) == INTEGER_CST) 3636 { 3637 take_default = !find_case_label_index (stmt, 1, op, &i); 3638 if (take_default) 3639 { 3640 i = 1; 3641 j = 0; 3642 } 3643 else 3644 { 3645 j = i; 3646 } 3647 } 3648 else 3649 return false; 3650 3651 n = gimple_switch_num_labels (stmt); 3652 3653 /* We can truncate the case label ranges that partially overlap with OP's 3654 value range. */ 3655 size_t min_idx = 1, max_idx = 0; 3656 if (vr != NULL) 3657 find_case_label_range (stmt, vr->min, vr->max, &min_idx, &max_idx); 3658 if (min_idx <= max_idx) 3659 { 3660 tree min_label = gimple_switch_label (stmt, min_idx); 3661 tree max_label = gimple_switch_label (stmt, max_idx); 3662 3663 /* Avoid changing the type of the case labels when truncating. */ 3664 tree case_label_type = TREE_TYPE (CASE_LOW (min_label)); 3665 tree vr_min = fold_convert (case_label_type, vr->min); 3666 tree vr_max = fold_convert (case_label_type, vr->max); 3667 3668 if (vr->type == VR_RANGE) 3669 { 3670 /* If OP's value range is [2,8] and the low label range is 3671 0 ... 3, truncate the label's range to 2 .. 3. */ 3672 if (tree_int_cst_compare (CASE_LOW (min_label), vr_min) < 0 3673 && CASE_HIGH (min_label) != NULL_TREE 3674 && tree_int_cst_compare (CASE_HIGH (min_label), vr_min) >= 0) 3675 CASE_LOW (min_label) = vr_min; 3676 3677 /* If OP's value range is [2,8] and the high label range is 3678 7 ... 10, truncate the label's range to 7 .. 8. */ 3679 if (tree_int_cst_compare (CASE_LOW (max_label), vr_max) <= 0 3680 && CASE_HIGH (max_label) != NULL_TREE 3681 && tree_int_cst_compare (CASE_HIGH (max_label), vr_max) > 0) 3682 CASE_HIGH (max_label) = vr_max; 3683 } 3684 else if (vr->type == VR_ANTI_RANGE) 3685 { 3686 tree one_cst = build_one_cst (case_label_type); 3687 3688 if (min_label == max_label) 3689 { 3690 /* If OP's value range is ~[7,8] and the label's range is 3691 7 ... 10, truncate the label's range to 9 ... 10. */ 3692 if (tree_int_cst_compare (CASE_LOW (min_label), vr_min) == 0 3693 && CASE_HIGH (min_label) != NULL_TREE 3694 && tree_int_cst_compare (CASE_HIGH (min_label), vr_max) > 0) 3695 CASE_LOW (min_label) 3696 = int_const_binop (PLUS_EXPR, vr_max, one_cst); 3697 3698 /* If OP's value range is ~[7,8] and the label's range is 3699 5 ... 8, truncate the label's range to 5 ... 6. */ 3700 if (tree_int_cst_compare (CASE_LOW (min_label), vr_min) < 0 3701 && CASE_HIGH (min_label) != NULL_TREE 3702 && tree_int_cst_compare (CASE_HIGH (min_label), vr_max) == 0) 3703 CASE_HIGH (min_label) 3704 = int_const_binop (MINUS_EXPR, vr_min, one_cst); 3705 } 3706 else 3707 { 3708 /* If OP's value range is ~[2,8] and the low label range is 3709 0 ... 3, truncate the label's range to 0 ... 1. */ 3710 if (tree_int_cst_compare (CASE_LOW (min_label), vr_min) < 0 3711 && CASE_HIGH (min_label) != NULL_TREE 3712 && tree_int_cst_compare (CASE_HIGH (min_label), vr_min) >= 0) 3713 CASE_HIGH (min_label) 3714 = int_const_binop (MINUS_EXPR, vr_min, one_cst); 3715 3716 /* If OP's value range is ~[2,8] and the high label range is 3717 7 ... 10, truncate the label's range to 9 ... 10. */ 3718 if (tree_int_cst_compare (CASE_LOW (max_label), vr_max) <= 0 3719 && CASE_HIGH (max_label) != NULL_TREE 3720 && tree_int_cst_compare (CASE_HIGH (max_label), vr_max) > 0) 3721 CASE_LOW (max_label) 3722 = int_const_binop (PLUS_EXPR, vr_max, one_cst); 3723 } 3724 } 3725 3726 /* Canonicalize singleton case ranges. */ 3727 if (tree_int_cst_equal (CASE_LOW (min_label), CASE_HIGH (min_label))) 3728 CASE_HIGH (min_label) = NULL_TREE; 3729 if (tree_int_cst_equal (CASE_LOW (max_label), CASE_HIGH (max_label))) 3730 CASE_HIGH (max_label) = NULL_TREE; 3731 } 3732 3733 /* We can also eliminate case labels that lie completely outside OP's value 3734 range. */ 3735 3736 /* Bail out if this is just all edges taken. */ 3737 if (i == 1 3738 && j == n - 1 3739 && take_default) 3740 return false; 3741 3742 /* Build a new vector of taken case labels. */ 3743 vec2 = make_tree_vec (j - i + 1 + l - k + 1 + (int)take_default); 3744 n2 = 0; 3745 3746 /* Add the default edge, if necessary. */ 3747 if (take_default) 3748 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt); 3749 3750 for (; i <= j; ++i, ++n2) 3751 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i); 3752 3753 for (; k <= l; ++k, ++n2) 3754 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, k); 3755 3756 /* Mark needed edges. */ 3757 for (i = 0; i < n2; ++i) 3758 { 3759 e = find_edge (gimple_bb (stmt), 3760 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i)))); 3761 e->aux = (void *)-1; 3762 } 3763 3764 /* Queue not needed edges for later removal. */ 3765 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs) 3766 { 3767 if (e->aux == (void *)-1) 3768 { 3769 e->aux = NULL; 3770 continue; 3771 } 3772 3773 if (dump_file && (dump_flags & TDF_DETAILS)) 3774 { 3775 fprintf (dump_file, "removing unreachable case label\n"); 3776 } 3777 to_remove_edges.safe_push (e); 3778 e->flags &= ~EDGE_EXECUTABLE; 3779 } 3780 3781 /* And queue an update for the stmt. */ 3782 su.stmt = stmt; 3783 su.vec = vec2; 3784 to_update_switch_stmts.safe_push (su); 3785 return false; 3786 } 3787 3788 /* Simplify an integral conversion from an SSA name in STMT. */ 3789 3790 static bool 3791 simplify_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt) 3792 { 3793 tree innerop, middleop, finaltype; 3794 gimple *def_stmt; 3795 signop inner_sgn, middle_sgn, final_sgn; 3796 unsigned inner_prec, middle_prec, final_prec; 3797 widest_int innermin, innermed, innermax, middlemin, middlemed, middlemax; 3798 3799 finaltype = TREE_TYPE (gimple_assign_lhs (stmt)); 3800 if (!INTEGRAL_TYPE_P (finaltype)) 3801 return false; 3802 middleop = gimple_assign_rhs1 (stmt); 3803 def_stmt = SSA_NAME_DEF_STMT (middleop); 3804 if (!is_gimple_assign (def_stmt) 3805 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))) 3806 return false; 3807 innerop = gimple_assign_rhs1 (def_stmt); 3808 if (TREE_CODE (innerop) != SSA_NAME 3809 || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (innerop)) 3810 return false; 3811 3812 /* Get the value-range of the inner operand. Use get_range_info in 3813 case innerop was created during substitute-and-fold. */ 3814 wide_int imin, imax; 3815 if (!INTEGRAL_TYPE_P (TREE_TYPE (innerop)) 3816 || get_range_info (innerop, &imin, &imax) != VR_RANGE) 3817 return false; 3818 innermin = widest_int::from (imin, TYPE_SIGN (TREE_TYPE (innerop))); 3819 innermax = widest_int::from (imax, TYPE_SIGN (TREE_TYPE (innerop))); 3820 3821 /* Simulate the conversion chain to check if the result is equal if 3822 the middle conversion is removed. */ 3823 inner_prec = TYPE_PRECISION (TREE_TYPE (innerop)); 3824 middle_prec = TYPE_PRECISION (TREE_TYPE (middleop)); 3825 final_prec = TYPE_PRECISION (finaltype); 3826 3827 /* If the first conversion is not injective, the second must not 3828 be widening. */ 3829 if (wi::gtu_p (innermax - innermin, 3830 wi::mask <widest_int> (middle_prec, false)) 3831 && middle_prec < final_prec) 3832 return false; 3833 /* We also want a medium value so that we can track the effect that 3834 narrowing conversions with sign change have. */ 3835 inner_sgn = TYPE_SIGN (TREE_TYPE (innerop)); 3836 if (inner_sgn == UNSIGNED) 3837 innermed = wi::shifted_mask <widest_int> (1, inner_prec - 1, false); 3838 else 3839 innermed = 0; 3840 if (wi::cmp (innermin, innermed, inner_sgn) >= 0 3841 || wi::cmp (innermed, innermax, inner_sgn) >= 0) 3842 innermed = innermin; 3843 3844 middle_sgn = TYPE_SIGN (TREE_TYPE (middleop)); 3845 middlemin = wi::ext (innermin, middle_prec, middle_sgn); 3846 middlemed = wi::ext (innermed, middle_prec, middle_sgn); 3847 middlemax = wi::ext (innermax, middle_prec, middle_sgn); 3848 3849 /* Require that the final conversion applied to both the original 3850 and the intermediate range produces the same result. */ 3851 final_sgn = TYPE_SIGN (finaltype); 3852 if (wi::ext (middlemin, final_prec, final_sgn) 3853 != wi::ext (innermin, final_prec, final_sgn) 3854 || wi::ext (middlemed, final_prec, final_sgn) 3855 != wi::ext (innermed, final_prec, final_sgn) 3856 || wi::ext (middlemax, final_prec, final_sgn) 3857 != wi::ext (innermax, final_prec, final_sgn)) 3858 return false; 3859 3860 gimple_assign_set_rhs1 (stmt, innerop); 3861 fold_stmt (gsi, follow_single_use_edges); 3862 return true; 3863 } 3864 3865 /* Simplify a conversion from integral SSA name to float in STMT. */ 3866 3867 bool 3868 vr_values::simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, 3869 gimple *stmt) 3870 { 3871 tree rhs1 = gimple_assign_rhs1 (stmt); 3872 value_range *vr = get_value_range (rhs1); 3873 scalar_float_mode fltmode 3874 = SCALAR_FLOAT_TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt))); 3875 scalar_int_mode mode; 3876 tree tem; 3877 gassign *conv; 3878 3879 /* We can only handle constant ranges. */ 3880 if (vr->type != VR_RANGE 3881 || TREE_CODE (vr->min) != INTEGER_CST 3882 || TREE_CODE (vr->max) != INTEGER_CST) 3883 return false; 3884 3885 /* First check if we can use a signed type in place of an unsigned. */ 3886 scalar_int_mode rhs_mode = SCALAR_INT_TYPE_MODE (TREE_TYPE (rhs1)); 3887 if (TYPE_UNSIGNED (TREE_TYPE (rhs1)) 3888 && can_float_p (fltmode, rhs_mode, 0) != CODE_FOR_nothing 3889 && range_fits_type_p (vr, TYPE_PRECISION (TREE_TYPE (rhs1)), SIGNED)) 3890 mode = rhs_mode; 3891 /* If we can do the conversion in the current input mode do nothing. */ 3892 else if (can_float_p (fltmode, rhs_mode, 3893 TYPE_UNSIGNED (TREE_TYPE (rhs1))) != CODE_FOR_nothing) 3894 return false; 3895 /* Otherwise search for a mode we can use, starting from the narrowest 3896 integer mode available. */ 3897 else 3898 { 3899 mode = NARROWEST_INT_MODE; 3900 for (;;) 3901 { 3902 /* If we cannot do a signed conversion to float from mode 3903 or if the value-range does not fit in the signed type 3904 try with a wider mode. */ 3905 if (can_float_p (fltmode, mode, 0) != CODE_FOR_nothing 3906 && range_fits_type_p (vr, GET_MODE_PRECISION (mode), SIGNED)) 3907 break; 3908 3909 /* But do not widen the input. Instead leave that to the 3910 optabs expansion code. */ 3911 if (!GET_MODE_WIDER_MODE (mode).exists (&mode) 3912 || GET_MODE_PRECISION (mode) > TYPE_PRECISION (TREE_TYPE (rhs1))) 3913 return false; 3914 } 3915 } 3916 3917 /* It works, insert a truncation or sign-change before the 3918 float conversion. */ 3919 tem = make_ssa_name (build_nonstandard_integer_type 3920 (GET_MODE_PRECISION (mode), 0)); 3921 conv = gimple_build_assign (tem, NOP_EXPR, rhs1); 3922 gsi_insert_before (gsi, conv, GSI_SAME_STMT); 3923 gimple_assign_set_rhs1 (stmt, tem); 3924 fold_stmt (gsi, follow_single_use_edges); 3925 3926 return true; 3927 } 3928 3929 /* Simplify an internal fn call using ranges if possible. */ 3930 3931 bool 3932 vr_values::simplify_internal_call_using_ranges (gimple_stmt_iterator *gsi, 3933 gimple *stmt) 3934 { 3935 enum tree_code subcode; 3936 bool is_ubsan = false; 3937 bool ovf = false; 3938 switch (gimple_call_internal_fn (stmt)) 3939 { 3940 case IFN_UBSAN_CHECK_ADD: 3941 subcode = PLUS_EXPR; 3942 is_ubsan = true; 3943 break; 3944 case IFN_UBSAN_CHECK_SUB: 3945 subcode = MINUS_EXPR; 3946 is_ubsan = true; 3947 break; 3948 case IFN_UBSAN_CHECK_MUL: 3949 subcode = MULT_EXPR; 3950 is_ubsan = true; 3951 break; 3952 case IFN_ADD_OVERFLOW: 3953 subcode = PLUS_EXPR; 3954 break; 3955 case IFN_SUB_OVERFLOW: 3956 subcode = MINUS_EXPR; 3957 break; 3958 case IFN_MUL_OVERFLOW: 3959 subcode = MULT_EXPR; 3960 break; 3961 default: 3962 return false; 3963 } 3964 3965 tree op0 = gimple_call_arg (stmt, 0); 3966 tree op1 = gimple_call_arg (stmt, 1); 3967 tree type; 3968 if (is_ubsan) 3969 { 3970 type = TREE_TYPE (op0); 3971 if (VECTOR_TYPE_P (type)) 3972 return false; 3973 } 3974 else if (gimple_call_lhs (stmt) == NULL_TREE) 3975 return false; 3976 else 3977 type = TREE_TYPE (TREE_TYPE (gimple_call_lhs (stmt))); 3978 if (!check_for_binary_op_overflow (subcode, type, op0, op1, &ovf) 3979 || (is_ubsan && ovf)) 3980 return false; 3981 3982 gimple *g; 3983 location_t loc = gimple_location (stmt); 3984 if (is_ubsan) 3985 g = gimple_build_assign (gimple_call_lhs (stmt), subcode, op0, op1); 3986 else 3987 { 3988 int prec = TYPE_PRECISION (type); 3989 tree utype = type; 3990 if (ovf 3991 || !useless_type_conversion_p (type, TREE_TYPE (op0)) 3992 || !useless_type_conversion_p (type, TREE_TYPE (op1))) 3993 utype = build_nonstandard_integer_type (prec, 1); 3994 if (TREE_CODE (op0) == INTEGER_CST) 3995 op0 = fold_convert (utype, op0); 3996 else if (!useless_type_conversion_p (utype, TREE_TYPE (op0))) 3997 { 3998 g = gimple_build_assign (make_ssa_name (utype), NOP_EXPR, op0); 3999 gimple_set_location (g, loc); 4000 gsi_insert_before (gsi, g, GSI_SAME_STMT); 4001 op0 = gimple_assign_lhs (g); 4002 } 4003 if (TREE_CODE (op1) == INTEGER_CST) 4004 op1 = fold_convert (utype, op1); 4005 else if (!useless_type_conversion_p (utype, TREE_TYPE (op1))) 4006 { 4007 g = gimple_build_assign (make_ssa_name (utype), NOP_EXPR, op1); 4008 gimple_set_location (g, loc); 4009 gsi_insert_before (gsi, g, GSI_SAME_STMT); 4010 op1 = gimple_assign_lhs (g); 4011 } 4012 g = gimple_build_assign (make_ssa_name (utype), subcode, op0, op1); 4013 gimple_set_location (g, loc); 4014 gsi_insert_before (gsi, g, GSI_SAME_STMT); 4015 if (utype != type) 4016 { 4017 g = gimple_build_assign (make_ssa_name (type), NOP_EXPR, 4018 gimple_assign_lhs (g)); 4019 gimple_set_location (g, loc); 4020 gsi_insert_before (gsi, g, GSI_SAME_STMT); 4021 } 4022 g = gimple_build_assign (gimple_call_lhs (stmt), COMPLEX_EXPR, 4023 gimple_assign_lhs (g), 4024 build_int_cst (type, ovf)); 4025 } 4026 gimple_set_location (g, loc); 4027 gsi_replace (gsi, g, false); 4028 return true; 4029 } 4030 4031 /* Return true if VAR is a two-valued variable. Set a and b with the 4032 two-values when it is true. Return false otherwise. */ 4033 4034 bool 4035 vr_values::two_valued_val_range_p (tree var, tree *a, tree *b) 4036 { 4037 value_range *vr = get_value_range (var); 4038 if ((vr->type != VR_RANGE 4039 && vr->type != VR_ANTI_RANGE) 4040 || TREE_CODE (vr->min) != INTEGER_CST 4041 || TREE_CODE (vr->max) != INTEGER_CST) 4042 return false; 4043 4044 if (vr->type == VR_RANGE 4045 && wi::to_wide (vr->max) - wi::to_wide (vr->min) == 1) 4046 { 4047 *a = vr->min; 4048 *b = vr->max; 4049 return true; 4050 } 4051 4052 /* ~[TYPE_MIN + 1, TYPE_MAX - 1] */ 4053 if (vr->type == VR_ANTI_RANGE 4054 && (wi::to_wide (vr->min) 4055 - wi::to_wide (vrp_val_min (TREE_TYPE (var)))) == 1 4056 && (wi::to_wide (vrp_val_max (TREE_TYPE (var))) 4057 - wi::to_wide (vr->max)) == 1) 4058 { 4059 *a = vrp_val_min (TREE_TYPE (var)); 4060 *b = vrp_val_max (TREE_TYPE (var)); 4061 return true; 4062 } 4063 4064 return false; 4065 } 4066 4067 /* Simplify STMT using ranges if possible. */ 4068 4069 bool 4070 vr_values::simplify_stmt_using_ranges (gimple_stmt_iterator *gsi) 4071 { 4072 gimple *stmt = gsi_stmt (*gsi); 4073 if (is_gimple_assign (stmt)) 4074 { 4075 enum tree_code rhs_code = gimple_assign_rhs_code (stmt); 4076 tree rhs1 = gimple_assign_rhs1 (stmt); 4077 tree rhs2 = gimple_assign_rhs2 (stmt); 4078 tree lhs = gimple_assign_lhs (stmt); 4079 tree val1 = NULL_TREE, val2 = NULL_TREE; 4080 use_operand_p use_p; 4081 gimple *use_stmt; 4082 4083 /* Convert: 4084 LHS = CST BINOP VAR 4085 Where VAR is two-valued and LHS is used in GIMPLE_COND only 4086 To: 4087 LHS = VAR == VAL1 ? (CST BINOP VAL1) : (CST BINOP VAL2) 4088 4089 Also handles: 4090 LHS = VAR BINOP CST 4091 Where VAR is two-valued and LHS is used in GIMPLE_COND only 4092 To: 4093 LHS = VAR == VAL1 ? (VAL1 BINOP CST) : (VAL2 BINOP CST) */ 4094 4095 if (TREE_CODE_CLASS (rhs_code) == tcc_binary 4096 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)) 4097 && ((TREE_CODE (rhs1) == INTEGER_CST 4098 && TREE_CODE (rhs2) == SSA_NAME) 4099 || (TREE_CODE (rhs2) == INTEGER_CST 4100 && TREE_CODE (rhs1) == SSA_NAME)) 4101 && single_imm_use (lhs, &use_p, &use_stmt) 4102 && gimple_code (use_stmt) == GIMPLE_COND) 4103 4104 { 4105 tree new_rhs1 = NULL_TREE; 4106 tree new_rhs2 = NULL_TREE; 4107 tree cmp_var = NULL_TREE; 4108 4109 if (TREE_CODE (rhs2) == SSA_NAME 4110 && two_valued_val_range_p (rhs2, &val1, &val2)) 4111 { 4112 /* Optimize RHS1 OP [VAL1, VAL2]. */ 4113 new_rhs1 = int_const_binop (rhs_code, rhs1, val1); 4114 new_rhs2 = int_const_binop (rhs_code, rhs1, val2); 4115 cmp_var = rhs2; 4116 } 4117 else if (TREE_CODE (rhs1) == SSA_NAME 4118 && two_valued_val_range_p (rhs1, &val1, &val2)) 4119 { 4120 /* Optimize [VAL1, VAL2] OP RHS2. */ 4121 new_rhs1 = int_const_binop (rhs_code, val1, rhs2); 4122 new_rhs2 = int_const_binop (rhs_code, val2, rhs2); 4123 cmp_var = rhs1; 4124 } 4125 4126 /* If we could not find two-vals or the optimzation is invalid as 4127 in divide by zero, new_rhs1 / new_rhs will be NULL_TREE. */ 4128 if (new_rhs1 && new_rhs2) 4129 { 4130 tree cond = build2 (EQ_EXPR, boolean_type_node, cmp_var, val1); 4131 gimple_assign_set_rhs_with_ops (gsi, 4132 COND_EXPR, cond, 4133 new_rhs1, 4134 new_rhs2); 4135 update_stmt (gsi_stmt (*gsi)); 4136 fold_stmt (gsi, follow_single_use_edges); 4137 return true; 4138 } 4139 } 4140 4141 switch (rhs_code) 4142 { 4143 case EQ_EXPR: 4144 case NE_EXPR: 4145 /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity 4146 if the RHS is zero or one, and the LHS are known to be boolean 4147 values. */ 4148 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) 4149 return simplify_truth_ops_using_ranges (gsi, stmt); 4150 break; 4151 4152 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR 4153 and BIT_AND_EXPR respectively if the first operand is greater 4154 than zero and the second operand is an exact power of two. 4155 Also optimize TRUNC_MOD_EXPR away if the second operand is 4156 constant and the first operand already has the right value 4157 range. */ 4158 case TRUNC_DIV_EXPR: 4159 case TRUNC_MOD_EXPR: 4160 if ((TREE_CODE (rhs1) == SSA_NAME 4161 || TREE_CODE (rhs1) == INTEGER_CST) 4162 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) 4163 return simplify_div_or_mod_using_ranges (gsi, stmt); 4164 break; 4165 4166 /* Transform ABS (X) into X or -X as appropriate. */ 4167 case ABS_EXPR: 4168 if (TREE_CODE (rhs1) == SSA_NAME 4169 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) 4170 return simplify_abs_using_ranges (gsi, stmt); 4171 break; 4172 4173 case BIT_AND_EXPR: 4174 case BIT_IOR_EXPR: 4175 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR 4176 if all the bits being cleared are already cleared or 4177 all the bits being set are already set. */ 4178 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) 4179 return simplify_bit_ops_using_ranges (gsi, stmt); 4180 break; 4181 4182 CASE_CONVERT: 4183 if (TREE_CODE (rhs1) == SSA_NAME 4184 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) 4185 return simplify_conversion_using_ranges (gsi, stmt); 4186 break; 4187 4188 case FLOAT_EXPR: 4189 if (TREE_CODE (rhs1) == SSA_NAME 4190 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1))) 4191 return simplify_float_conversion_using_ranges (gsi, stmt); 4192 break; 4193 4194 case MIN_EXPR: 4195 case MAX_EXPR: 4196 return simplify_min_or_max_using_ranges (gsi, stmt); 4197 4198 default: 4199 break; 4200 } 4201 } 4202 else if (gimple_code (stmt) == GIMPLE_COND) 4203 return simplify_cond_using_ranges_1 (as_a <gcond *> (stmt)); 4204 else if (gimple_code (stmt) == GIMPLE_SWITCH) 4205 return simplify_switch_using_ranges (as_a <gswitch *> (stmt)); 4206 else if (is_gimple_call (stmt) 4207 && gimple_call_internal_p (stmt)) 4208 return simplify_internal_call_using_ranges (gsi, stmt); 4209 4210 return false; 4211 } 4212 4213 void 4214 vr_values::set_vr_value (tree var, value_range *vr) 4215 { 4216 if (SSA_NAME_VERSION (var) >= num_vr_values) 4217 return; 4218 vr_value[SSA_NAME_VERSION (var)] = vr; 4219 } 4220 4221