1 //===- InstructionSimplify.cpp - Fold instruction operands ----------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements routines for folding instructions into simpler forms 10 // that do not require creating new instructions. This does constant folding 11 // ("add i32 1, 1" -> "2") but can also handle non-constant operands, either 12 // returning a constant ("and i32 %x, 0" -> "0") or an already existing value 13 // ("and i32 %x, %x" -> "%x"). All operands are assumed to have already been 14 // simplified: This is usually true and assuming it simplifies the logic (if 15 // they have not been simplified then results are correct but maybe suboptimal). 16 // 17 //===----------------------------------------------------------------------===// 18 19 #include "llvm/Analysis/InstructionSimplify.h" 20 #include "llvm/ADT/SetVector.h" 21 #include "llvm/ADT/Statistic.h" 22 #include "llvm/Analysis/AliasAnalysis.h" 23 #include "llvm/Analysis/AssumptionCache.h" 24 #include "llvm/Analysis/CaptureTracking.h" 25 #include "llvm/Analysis/CmpInstAnalysis.h" 26 #include "llvm/Analysis/ConstantFolding.h" 27 #include "llvm/Analysis/LoopAnalysisManager.h" 28 #include "llvm/Analysis/MemoryBuiltins.h" 29 #include "llvm/Analysis/ValueTracking.h" 30 #include "llvm/Analysis/VectorUtils.h" 31 #include "llvm/IR/ConstantRange.h" 32 #include "llvm/IR/DataLayout.h" 33 #include "llvm/IR/Dominators.h" 34 #include "llvm/IR/GetElementPtrTypeIterator.h" 35 #include "llvm/IR/GlobalAlias.h" 36 #include "llvm/IR/InstrTypes.h" 37 #include "llvm/IR/Instructions.h" 38 #include "llvm/IR/Operator.h" 39 #include "llvm/IR/PatternMatch.h" 40 #include "llvm/IR/ValueHandle.h" 41 #include "llvm/Support/KnownBits.h" 42 #include <algorithm> 43 using namespace llvm; 44 using namespace llvm::PatternMatch; 45 46 #define DEBUG_TYPE "instsimplify" 47 48 enum { RecursionLimit = 3 }; 49 50 STATISTIC(NumExpand, "Number of expansions"); 51 STATISTIC(NumReassoc, "Number of reassociations"); 52 53 static Value *SimplifyAndInst(Value *, Value *, const SimplifyQuery &, unsigned); 54 static Value *simplifyUnOp(unsigned, Value *, const SimplifyQuery &, unsigned); 55 static Value *simplifyFPUnOp(unsigned, Value *, const FastMathFlags &, 56 const SimplifyQuery &, unsigned); 57 static Value *SimplifyBinOp(unsigned, Value *, Value *, const SimplifyQuery &, 58 unsigned); 59 static Value *SimplifyBinOp(unsigned, Value *, Value *, const FastMathFlags &, 60 const SimplifyQuery &, unsigned); 61 static Value *SimplifyCmpInst(unsigned, Value *, Value *, const SimplifyQuery &, 62 unsigned); 63 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, 64 const SimplifyQuery &Q, unsigned MaxRecurse); 65 static Value *SimplifyOrInst(Value *, Value *, const SimplifyQuery &, unsigned); 66 static Value *SimplifyXorInst(Value *, Value *, const SimplifyQuery &, unsigned); 67 static Value *SimplifyCastInst(unsigned, Value *, Type *, 68 const SimplifyQuery &, unsigned); 69 static Value *SimplifyGEPInst(Type *, ArrayRef<Value *>, const SimplifyQuery &, 70 unsigned); 71 72 static Value *foldSelectWithBinaryOp(Value *Cond, Value *TrueVal, 73 Value *FalseVal) { 74 BinaryOperator::BinaryOps BinOpCode; 75 if (auto *BO = dyn_cast<BinaryOperator>(Cond)) 76 BinOpCode = BO->getOpcode(); 77 else 78 return nullptr; 79 80 CmpInst::Predicate ExpectedPred, Pred1, Pred2; 81 if (BinOpCode == BinaryOperator::Or) { 82 ExpectedPred = ICmpInst::ICMP_NE; 83 } else if (BinOpCode == BinaryOperator::And) { 84 ExpectedPred = ICmpInst::ICMP_EQ; 85 } else 86 return nullptr; 87 88 // %A = icmp eq %TV, %FV 89 // %B = icmp eq %X, %Y (and one of these is a select operand) 90 // %C = and %A, %B 91 // %D = select %C, %TV, %FV 92 // --> 93 // %FV 94 95 // %A = icmp ne %TV, %FV 96 // %B = icmp ne %X, %Y (and one of these is a select operand) 97 // %C = or %A, %B 98 // %D = select %C, %TV, %FV 99 // --> 100 // %TV 101 Value *X, *Y; 102 if (!match(Cond, m_c_BinOp(m_c_ICmp(Pred1, m_Specific(TrueVal), 103 m_Specific(FalseVal)), 104 m_ICmp(Pred2, m_Value(X), m_Value(Y)))) || 105 Pred1 != Pred2 || Pred1 != ExpectedPred) 106 return nullptr; 107 108 if (X == TrueVal || X == FalseVal || Y == TrueVal || Y == FalseVal) 109 return BinOpCode == BinaryOperator::Or ? TrueVal : FalseVal; 110 111 return nullptr; 112 } 113 114 /// For a boolean type or a vector of boolean type, return false or a vector 115 /// with every element false. 116 static Constant *getFalse(Type *Ty) { 117 return ConstantInt::getFalse(Ty); 118 } 119 120 /// For a boolean type or a vector of boolean type, return true or a vector 121 /// with every element true. 122 static Constant *getTrue(Type *Ty) { 123 return ConstantInt::getTrue(Ty); 124 } 125 126 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"? 127 static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS, 128 Value *RHS) { 129 CmpInst *Cmp = dyn_cast<CmpInst>(V); 130 if (!Cmp) 131 return false; 132 CmpInst::Predicate CPred = Cmp->getPredicate(); 133 Value *CLHS = Cmp->getOperand(0), *CRHS = Cmp->getOperand(1); 134 if (CPred == Pred && CLHS == LHS && CRHS == RHS) 135 return true; 136 return CPred == CmpInst::getSwappedPredicate(Pred) && CLHS == RHS && 137 CRHS == LHS; 138 } 139 140 /// Does the given value dominate the specified phi node? 141 static bool valueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) { 142 Instruction *I = dyn_cast<Instruction>(V); 143 if (!I) 144 // Arguments and constants dominate all instructions. 145 return true; 146 147 // If we are processing instructions (and/or basic blocks) that have not been 148 // fully added to a function, the parent nodes may still be null. Simply 149 // return the conservative answer in these cases. 150 if (!I->getParent() || !P->getParent() || !I->getFunction()) 151 return false; 152 153 // If we have a DominatorTree then do a precise test. 154 if (DT) 155 return DT->dominates(I, P); 156 157 // Otherwise, if the instruction is in the entry block and is not an invoke, 158 // then it obviously dominates all phi nodes. 159 if (I->getParent() == &I->getFunction()->getEntryBlock() && 160 !isa<InvokeInst>(I)) 161 return true; 162 163 return false; 164 } 165 166 /// Simplify "A op (B op' C)" by distributing op over op', turning it into 167 /// "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is 168 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS. 169 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)". 170 /// Returns the simplified value, or null if no simplification was performed. 171 static Value *ExpandBinOp(Instruction::BinaryOps Opcode, Value *LHS, Value *RHS, 172 Instruction::BinaryOps OpcodeToExpand, 173 const SimplifyQuery &Q, unsigned MaxRecurse) { 174 // Recursion is always used, so bail out at once if we already hit the limit. 175 if (!MaxRecurse--) 176 return nullptr; 177 178 // Check whether the expression has the form "(A op' B) op C". 179 if (BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS)) 180 if (Op0->getOpcode() == OpcodeToExpand) { 181 // It does! Try turning it into "(A op C) op' (B op C)". 182 Value *A = Op0->getOperand(0), *B = Op0->getOperand(1), *C = RHS; 183 // Do "A op C" and "B op C" both simplify? 184 if (Value *L = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) 185 if (Value *R = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) { 186 // They do! Return "L op' R" if it simplifies or is already available. 187 // If "L op' R" equals "A op' B" then "L op' R" is just the LHS. 188 if ((L == A && R == B) || (Instruction::isCommutative(OpcodeToExpand) 189 && L == B && R == A)) { 190 ++NumExpand; 191 return LHS; 192 } 193 // Otherwise return "L op' R" if it simplifies. 194 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) { 195 ++NumExpand; 196 return V; 197 } 198 } 199 } 200 201 // Check whether the expression has the form "A op (B op' C)". 202 if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS)) 203 if (Op1->getOpcode() == OpcodeToExpand) { 204 // It does! Try turning it into "(A op B) op' (A op C)". 205 Value *A = LHS, *B = Op1->getOperand(0), *C = Op1->getOperand(1); 206 // Do "A op B" and "A op C" both simplify? 207 if (Value *L = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) 208 if (Value *R = SimplifyBinOp(Opcode, A, C, Q, MaxRecurse)) { 209 // They do! Return "L op' R" if it simplifies or is already available. 210 // If "L op' R" equals "B op' C" then "L op' R" is just the RHS. 211 if ((L == B && R == C) || (Instruction::isCommutative(OpcodeToExpand) 212 && L == C && R == B)) { 213 ++NumExpand; 214 return RHS; 215 } 216 // Otherwise return "L op' R" if it simplifies. 217 if (Value *V = SimplifyBinOp(OpcodeToExpand, L, R, Q, MaxRecurse)) { 218 ++NumExpand; 219 return V; 220 } 221 } 222 } 223 224 return nullptr; 225 } 226 227 /// Generic simplifications for associative binary operations. 228 /// Returns the simpler value, or null if none was found. 229 static Value *SimplifyAssociativeBinOp(Instruction::BinaryOps Opcode, 230 Value *LHS, Value *RHS, 231 const SimplifyQuery &Q, 232 unsigned MaxRecurse) { 233 assert(Instruction::isAssociative(Opcode) && "Not an associative operation!"); 234 235 // Recursion is always used, so bail out at once if we already hit the limit. 236 if (!MaxRecurse--) 237 return nullptr; 238 239 BinaryOperator *Op0 = dyn_cast<BinaryOperator>(LHS); 240 BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS); 241 242 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely. 243 if (Op0 && Op0->getOpcode() == Opcode) { 244 Value *A = Op0->getOperand(0); 245 Value *B = Op0->getOperand(1); 246 Value *C = RHS; 247 248 // Does "B op C" simplify? 249 if (Value *V = SimplifyBinOp(Opcode, B, C, Q, MaxRecurse)) { 250 // It does! Return "A op V" if it simplifies or is already available. 251 // If V equals B then "A op V" is just the LHS. 252 if (V == B) return LHS; 253 // Otherwise return "A op V" if it simplifies. 254 if (Value *W = SimplifyBinOp(Opcode, A, V, Q, MaxRecurse)) { 255 ++NumReassoc; 256 return W; 257 } 258 } 259 } 260 261 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely. 262 if (Op1 && Op1->getOpcode() == Opcode) { 263 Value *A = LHS; 264 Value *B = Op1->getOperand(0); 265 Value *C = Op1->getOperand(1); 266 267 // Does "A op B" simplify? 268 if (Value *V = SimplifyBinOp(Opcode, A, B, Q, MaxRecurse)) { 269 // It does! Return "V op C" if it simplifies or is already available. 270 // If V equals B then "V op C" is just the RHS. 271 if (V == B) return RHS; 272 // Otherwise return "V op C" if it simplifies. 273 if (Value *W = SimplifyBinOp(Opcode, V, C, Q, MaxRecurse)) { 274 ++NumReassoc; 275 return W; 276 } 277 } 278 } 279 280 // The remaining transforms require commutativity as well as associativity. 281 if (!Instruction::isCommutative(Opcode)) 282 return nullptr; 283 284 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely. 285 if (Op0 && Op0->getOpcode() == Opcode) { 286 Value *A = Op0->getOperand(0); 287 Value *B = Op0->getOperand(1); 288 Value *C = RHS; 289 290 // Does "C op A" simplify? 291 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) { 292 // It does! Return "V op B" if it simplifies or is already available. 293 // If V equals A then "V op B" is just the LHS. 294 if (V == A) return LHS; 295 // Otherwise return "V op B" if it simplifies. 296 if (Value *W = SimplifyBinOp(Opcode, V, B, Q, MaxRecurse)) { 297 ++NumReassoc; 298 return W; 299 } 300 } 301 } 302 303 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely. 304 if (Op1 && Op1->getOpcode() == Opcode) { 305 Value *A = LHS; 306 Value *B = Op1->getOperand(0); 307 Value *C = Op1->getOperand(1); 308 309 // Does "C op A" simplify? 310 if (Value *V = SimplifyBinOp(Opcode, C, A, Q, MaxRecurse)) { 311 // It does! Return "B op V" if it simplifies or is already available. 312 // If V equals C then "B op V" is just the RHS. 313 if (V == C) return RHS; 314 // Otherwise return "B op V" if it simplifies. 315 if (Value *W = SimplifyBinOp(Opcode, B, V, Q, MaxRecurse)) { 316 ++NumReassoc; 317 return W; 318 } 319 } 320 } 321 322 return nullptr; 323 } 324 325 /// In the case of a binary operation with a select instruction as an operand, 326 /// try to simplify the binop by seeing whether evaluating it on both branches 327 /// of the select results in the same value. Returns the common value if so, 328 /// otherwise returns null. 329 static Value *ThreadBinOpOverSelect(Instruction::BinaryOps Opcode, Value *LHS, 330 Value *RHS, const SimplifyQuery &Q, 331 unsigned MaxRecurse) { 332 // Recursion is always used, so bail out at once if we already hit the limit. 333 if (!MaxRecurse--) 334 return nullptr; 335 336 SelectInst *SI; 337 if (isa<SelectInst>(LHS)) { 338 SI = cast<SelectInst>(LHS); 339 } else { 340 assert(isa<SelectInst>(RHS) && "No select instruction operand!"); 341 SI = cast<SelectInst>(RHS); 342 } 343 344 // Evaluate the BinOp on the true and false branches of the select. 345 Value *TV; 346 Value *FV; 347 if (SI == LHS) { 348 TV = SimplifyBinOp(Opcode, SI->getTrueValue(), RHS, Q, MaxRecurse); 349 FV = SimplifyBinOp(Opcode, SI->getFalseValue(), RHS, Q, MaxRecurse); 350 } else { 351 TV = SimplifyBinOp(Opcode, LHS, SI->getTrueValue(), Q, MaxRecurse); 352 FV = SimplifyBinOp(Opcode, LHS, SI->getFalseValue(), Q, MaxRecurse); 353 } 354 355 // If they simplified to the same value, then return the common value. 356 // If they both failed to simplify then return null. 357 if (TV == FV) 358 return TV; 359 360 // If one branch simplified to undef, return the other one. 361 if (TV && isa<UndefValue>(TV)) 362 return FV; 363 if (FV && isa<UndefValue>(FV)) 364 return TV; 365 366 // If applying the operation did not change the true and false select values, 367 // then the result of the binop is the select itself. 368 if (TV == SI->getTrueValue() && FV == SI->getFalseValue()) 369 return SI; 370 371 // If one branch simplified and the other did not, and the simplified 372 // value is equal to the unsimplified one, return the simplified value. 373 // For example, select (cond, X, X & Z) & Z -> X & Z. 374 if ((FV && !TV) || (TV && !FV)) { 375 // Check that the simplified value has the form "X op Y" where "op" is the 376 // same as the original operation. 377 Instruction *Simplified = dyn_cast<Instruction>(FV ? FV : TV); 378 if (Simplified && Simplified->getOpcode() == unsigned(Opcode)) { 379 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS". 380 // We already know that "op" is the same as for the simplified value. See 381 // if the operands match too. If so, return the simplified value. 382 Value *UnsimplifiedBranch = FV ? SI->getTrueValue() : SI->getFalseValue(); 383 Value *UnsimplifiedLHS = SI == LHS ? UnsimplifiedBranch : LHS; 384 Value *UnsimplifiedRHS = SI == LHS ? RHS : UnsimplifiedBranch; 385 if (Simplified->getOperand(0) == UnsimplifiedLHS && 386 Simplified->getOperand(1) == UnsimplifiedRHS) 387 return Simplified; 388 if (Simplified->isCommutative() && 389 Simplified->getOperand(1) == UnsimplifiedLHS && 390 Simplified->getOperand(0) == UnsimplifiedRHS) 391 return Simplified; 392 } 393 } 394 395 return nullptr; 396 } 397 398 /// In the case of a comparison with a select instruction, try to simplify the 399 /// comparison by seeing whether both branches of the select result in the same 400 /// value. Returns the common value if so, otherwise returns null. 401 static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS, 402 Value *RHS, const SimplifyQuery &Q, 403 unsigned MaxRecurse) { 404 // Recursion is always used, so bail out at once if we already hit the limit. 405 if (!MaxRecurse--) 406 return nullptr; 407 408 // Make sure the select is on the LHS. 409 if (!isa<SelectInst>(LHS)) { 410 std::swap(LHS, RHS); 411 Pred = CmpInst::getSwappedPredicate(Pred); 412 } 413 assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!"); 414 SelectInst *SI = cast<SelectInst>(LHS); 415 Value *Cond = SI->getCondition(); 416 Value *TV = SI->getTrueValue(); 417 Value *FV = SI->getFalseValue(); 418 419 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it. 420 // Does "cmp TV, RHS" simplify? 421 Value *TCmp = SimplifyCmpInst(Pred, TV, RHS, Q, MaxRecurse); 422 if (TCmp == Cond) { 423 // It not only simplified, it simplified to the select condition. Replace 424 // it with 'true'. 425 TCmp = getTrue(Cond->getType()); 426 } else if (!TCmp) { 427 // It didn't simplify. However if "cmp TV, RHS" is equal to the select 428 // condition then we can replace it with 'true'. Otherwise give up. 429 if (!isSameCompare(Cond, Pred, TV, RHS)) 430 return nullptr; 431 TCmp = getTrue(Cond->getType()); 432 } 433 434 // Does "cmp FV, RHS" simplify? 435 Value *FCmp = SimplifyCmpInst(Pred, FV, RHS, Q, MaxRecurse); 436 if (FCmp == Cond) { 437 // It not only simplified, it simplified to the select condition. Replace 438 // it with 'false'. 439 FCmp = getFalse(Cond->getType()); 440 } else if (!FCmp) { 441 // It didn't simplify. However if "cmp FV, RHS" is equal to the select 442 // condition then we can replace it with 'false'. Otherwise give up. 443 if (!isSameCompare(Cond, Pred, FV, RHS)) 444 return nullptr; 445 FCmp = getFalse(Cond->getType()); 446 } 447 448 // If both sides simplified to the same value, then use it as the result of 449 // the original comparison. 450 if (TCmp == FCmp) 451 return TCmp; 452 453 // The remaining cases only make sense if the select condition has the same 454 // type as the result of the comparison, so bail out if this is not so. 455 if (Cond->getType()->isVectorTy() != RHS->getType()->isVectorTy()) 456 return nullptr; 457 // If the false value simplified to false, then the result of the compare 458 // is equal to "Cond && TCmp". This also catches the case when the false 459 // value simplified to false and the true value to true, returning "Cond". 460 if (match(FCmp, m_Zero())) 461 if (Value *V = SimplifyAndInst(Cond, TCmp, Q, MaxRecurse)) 462 return V; 463 // If the true value simplified to true, then the result of the compare 464 // is equal to "Cond || FCmp". 465 if (match(TCmp, m_One())) 466 if (Value *V = SimplifyOrInst(Cond, FCmp, Q, MaxRecurse)) 467 return V; 468 // Finally, if the false value simplified to true and the true value to 469 // false, then the result of the compare is equal to "!Cond". 470 if (match(FCmp, m_One()) && match(TCmp, m_Zero())) 471 if (Value *V = 472 SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()), 473 Q, MaxRecurse)) 474 return V; 475 476 return nullptr; 477 } 478 479 /// In the case of a binary operation with an operand that is a PHI instruction, 480 /// try to simplify the binop by seeing whether evaluating it on the incoming 481 /// phi values yields the same result for every value. If so returns the common 482 /// value, otherwise returns null. 483 static Value *ThreadBinOpOverPHI(Instruction::BinaryOps Opcode, Value *LHS, 484 Value *RHS, const SimplifyQuery &Q, 485 unsigned MaxRecurse) { 486 // Recursion is always used, so bail out at once if we already hit the limit. 487 if (!MaxRecurse--) 488 return nullptr; 489 490 PHINode *PI; 491 if (isa<PHINode>(LHS)) { 492 PI = cast<PHINode>(LHS); 493 // Bail out if RHS and the phi may be mutually interdependent due to a loop. 494 if (!valueDominatesPHI(RHS, PI, Q.DT)) 495 return nullptr; 496 } else { 497 assert(isa<PHINode>(RHS) && "No PHI instruction operand!"); 498 PI = cast<PHINode>(RHS); 499 // Bail out if LHS and the phi may be mutually interdependent due to a loop. 500 if (!valueDominatesPHI(LHS, PI, Q.DT)) 501 return nullptr; 502 } 503 504 // Evaluate the BinOp on the incoming phi values. 505 Value *CommonValue = nullptr; 506 for (Value *Incoming : PI->incoming_values()) { 507 // If the incoming value is the phi node itself, it can safely be skipped. 508 if (Incoming == PI) continue; 509 Value *V = PI == LHS ? 510 SimplifyBinOp(Opcode, Incoming, RHS, Q, MaxRecurse) : 511 SimplifyBinOp(Opcode, LHS, Incoming, Q, MaxRecurse); 512 // If the operation failed to simplify, or simplified to a different value 513 // to previously, then give up. 514 if (!V || (CommonValue && V != CommonValue)) 515 return nullptr; 516 CommonValue = V; 517 } 518 519 return CommonValue; 520 } 521 522 /// In the case of a comparison with a PHI instruction, try to simplify the 523 /// comparison by seeing whether comparing with all of the incoming phi values 524 /// yields the same result every time. If so returns the common result, 525 /// otherwise returns null. 526 static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS, 527 const SimplifyQuery &Q, unsigned MaxRecurse) { 528 // Recursion is always used, so bail out at once if we already hit the limit. 529 if (!MaxRecurse--) 530 return nullptr; 531 532 // Make sure the phi is on the LHS. 533 if (!isa<PHINode>(LHS)) { 534 std::swap(LHS, RHS); 535 Pred = CmpInst::getSwappedPredicate(Pred); 536 } 537 assert(isa<PHINode>(LHS) && "Not comparing with a phi instruction!"); 538 PHINode *PI = cast<PHINode>(LHS); 539 540 // Bail out if RHS and the phi may be mutually interdependent due to a loop. 541 if (!valueDominatesPHI(RHS, PI, Q.DT)) 542 return nullptr; 543 544 // Evaluate the BinOp on the incoming phi values. 545 Value *CommonValue = nullptr; 546 for (unsigned u = 0, e = PI->getNumIncomingValues(); u < e; ++u) { 547 Value *Incoming = PI->getIncomingValue(u); 548 Instruction *InTI = PI->getIncomingBlock(u)->getTerminator(); 549 // If the incoming value is the phi node itself, it can safely be skipped. 550 if (Incoming == PI) continue; 551 // Change the context instruction to the "edge" that flows into the phi. 552 // This is important because that is where incoming is actually "evaluated" 553 // even though it is used later somewhere else. 554 Value *V = SimplifyCmpInst(Pred, Incoming, RHS, Q.getWithInstruction(InTI), 555 MaxRecurse); 556 // If the operation failed to simplify, or simplified to a different value 557 // to previously, then give up. 558 if (!V || (CommonValue && V != CommonValue)) 559 return nullptr; 560 CommonValue = V; 561 } 562 563 return CommonValue; 564 } 565 566 static Constant *foldOrCommuteConstant(Instruction::BinaryOps Opcode, 567 Value *&Op0, Value *&Op1, 568 const SimplifyQuery &Q) { 569 if (auto *CLHS = dyn_cast<Constant>(Op0)) { 570 if (auto *CRHS = dyn_cast<Constant>(Op1)) 571 return ConstantFoldBinaryOpOperands(Opcode, CLHS, CRHS, Q.DL); 572 573 // Canonicalize the constant to the RHS if this is a commutative operation. 574 if (Instruction::isCommutative(Opcode)) 575 std::swap(Op0, Op1); 576 } 577 return nullptr; 578 } 579 580 /// Given operands for an Add, see if we can fold the result. 581 /// If not, this returns null. 582 static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool IsNSW, bool IsNUW, 583 const SimplifyQuery &Q, unsigned MaxRecurse) { 584 if (Constant *C = foldOrCommuteConstant(Instruction::Add, Op0, Op1, Q)) 585 return C; 586 587 // X + undef -> undef 588 if (match(Op1, m_Undef())) 589 return Op1; 590 591 // X + 0 -> X 592 if (match(Op1, m_Zero())) 593 return Op0; 594 595 // If two operands are negative, return 0. 596 if (isKnownNegation(Op0, Op1)) 597 return Constant::getNullValue(Op0->getType()); 598 599 // X + (Y - X) -> Y 600 // (Y - X) + X -> Y 601 // Eg: X + -X -> 0 602 Value *Y = nullptr; 603 if (match(Op1, m_Sub(m_Value(Y), m_Specific(Op0))) || 604 match(Op0, m_Sub(m_Value(Y), m_Specific(Op1)))) 605 return Y; 606 607 // X + ~X -> -1 since ~X = -X-1 608 Type *Ty = Op0->getType(); 609 if (match(Op0, m_Not(m_Specific(Op1))) || 610 match(Op1, m_Not(m_Specific(Op0)))) 611 return Constant::getAllOnesValue(Ty); 612 613 // add nsw/nuw (xor Y, signmask), signmask --> Y 614 // The no-wrapping add guarantees that the top bit will be set by the add. 615 // Therefore, the xor must be clearing the already set sign bit of Y. 616 if ((IsNSW || IsNUW) && match(Op1, m_SignMask()) && 617 match(Op0, m_Xor(m_Value(Y), m_SignMask()))) 618 return Y; 619 620 // add nuw %x, -1 -> -1, because %x can only be 0. 621 if (IsNUW && match(Op1, m_AllOnes())) 622 return Op1; // Which is -1. 623 624 /// i1 add -> xor. 625 if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1)) 626 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1)) 627 return V; 628 629 // Try some generic simplifications for associative operations. 630 if (Value *V = SimplifyAssociativeBinOp(Instruction::Add, Op0, Op1, Q, 631 MaxRecurse)) 632 return V; 633 634 // Threading Add over selects and phi nodes is pointless, so don't bother. 635 // Threading over the select in "A + select(cond, B, C)" means evaluating 636 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and 637 // only if B and C are equal. If B and C are equal then (since we assume 638 // that operands have already been simplified) "select(cond, B, C)" should 639 // have been simplified to the common value of B and C already. Analysing 640 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly 641 // for threading over phi nodes. 642 643 return nullptr; 644 } 645 646 Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool IsNSW, bool IsNUW, 647 const SimplifyQuery &Query) { 648 return ::SimplifyAddInst(Op0, Op1, IsNSW, IsNUW, Query, RecursionLimit); 649 } 650 651 /// Compute the base pointer and cumulative constant offsets for V. 652 /// 653 /// This strips all constant offsets off of V, leaving it the base pointer, and 654 /// accumulates the total constant offset applied in the returned constant. It 655 /// returns 0 if V is not a pointer, and returns the constant '0' if there are 656 /// no constant offsets applied. 657 /// 658 /// This is very similar to GetPointerBaseWithConstantOffset except it doesn't 659 /// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc. 660 /// folding. 661 static Constant *stripAndComputeConstantOffsets(const DataLayout &DL, Value *&V, 662 bool AllowNonInbounds = false) { 663 assert(V->getType()->isPtrOrPtrVectorTy()); 664 665 Type *IntPtrTy = DL.getIntPtrType(V->getType())->getScalarType(); 666 APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth()); 667 668 V = V->stripAndAccumulateConstantOffsets(DL, Offset, AllowNonInbounds); 669 // As that strip may trace through `addrspacecast`, need to sext or trunc 670 // the offset calculated. 671 IntPtrTy = DL.getIntPtrType(V->getType())->getScalarType(); 672 Offset = Offset.sextOrTrunc(IntPtrTy->getIntegerBitWidth()); 673 674 Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset); 675 if (V->getType()->isVectorTy()) 676 return ConstantVector::getSplat(V->getType()->getVectorNumElements(), 677 OffsetIntPtr); 678 return OffsetIntPtr; 679 } 680 681 /// Compute the constant difference between two pointer values. 682 /// If the difference is not a constant, returns zero. 683 static Constant *computePointerDifference(const DataLayout &DL, Value *LHS, 684 Value *RHS) { 685 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS); 686 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS); 687 688 // If LHS and RHS are not related via constant offsets to the same base 689 // value, there is nothing we can do here. 690 if (LHS != RHS) 691 return nullptr; 692 693 // Otherwise, the difference of LHS - RHS can be computed as: 694 // LHS - RHS 695 // = (LHSOffset + Base) - (RHSOffset + Base) 696 // = LHSOffset - RHSOffset 697 return ConstantExpr::getSub(LHSOffset, RHSOffset); 698 } 699 700 /// Given operands for a Sub, see if we can fold the result. 701 /// If not, this returns null. 702 static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, 703 const SimplifyQuery &Q, unsigned MaxRecurse) { 704 if (Constant *C = foldOrCommuteConstant(Instruction::Sub, Op0, Op1, Q)) 705 return C; 706 707 // X - undef -> undef 708 // undef - X -> undef 709 if (match(Op0, m_Undef()) || match(Op1, m_Undef())) 710 return UndefValue::get(Op0->getType()); 711 712 // X - 0 -> X 713 if (match(Op1, m_Zero())) 714 return Op0; 715 716 // X - X -> 0 717 if (Op0 == Op1) 718 return Constant::getNullValue(Op0->getType()); 719 720 // Is this a negation? 721 if (match(Op0, m_Zero())) { 722 // 0 - X -> 0 if the sub is NUW. 723 if (isNUW) 724 return Constant::getNullValue(Op0->getType()); 725 726 KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 727 if (Known.Zero.isMaxSignedValue()) { 728 // Op1 is either 0 or the minimum signed value. If the sub is NSW, then 729 // Op1 must be 0 because negating the minimum signed value is undefined. 730 if (isNSW) 731 return Constant::getNullValue(Op0->getType()); 732 733 // 0 - X -> X if X is 0 or the minimum signed value. 734 return Op1; 735 } 736 } 737 738 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies. 739 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X 740 Value *X = nullptr, *Y = nullptr, *Z = Op1; 741 if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z 742 // See if "V === Y - Z" simplifies. 743 if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, Q, MaxRecurse-1)) 744 // It does! Now see if "X + V" simplifies. 745 if (Value *W = SimplifyBinOp(Instruction::Add, X, V, Q, MaxRecurse-1)) { 746 // It does, we successfully reassociated! 747 ++NumReassoc; 748 return W; 749 } 750 // See if "V === X - Z" simplifies. 751 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1)) 752 // It does! Now see if "Y + V" simplifies. 753 if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, Q, MaxRecurse-1)) { 754 // It does, we successfully reassociated! 755 ++NumReassoc; 756 return W; 757 } 758 } 759 760 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies. 761 // For example, X - (X + 1) -> -1 762 X = Op0; 763 if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z) 764 // See if "V === X - Y" simplifies. 765 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1)) 766 // It does! Now see if "V - Z" simplifies. 767 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, Q, MaxRecurse-1)) { 768 // It does, we successfully reassociated! 769 ++NumReassoc; 770 return W; 771 } 772 // See if "V === X - Z" simplifies. 773 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, Q, MaxRecurse-1)) 774 // It does! Now see if "V - Y" simplifies. 775 if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, Q, MaxRecurse-1)) { 776 // It does, we successfully reassociated! 777 ++NumReassoc; 778 return W; 779 } 780 } 781 782 // Z - (X - Y) -> (Z - X) + Y if everything simplifies. 783 // For example, X - (X - Y) -> Y. 784 Z = Op0; 785 if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y) 786 // See if "V === Z - X" simplifies. 787 if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, Q, MaxRecurse-1)) 788 // It does! Now see if "V + Y" simplifies. 789 if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, Q, MaxRecurse-1)) { 790 // It does, we successfully reassociated! 791 ++NumReassoc; 792 return W; 793 } 794 795 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies. 796 if (MaxRecurse && match(Op0, m_Trunc(m_Value(X))) && 797 match(Op1, m_Trunc(m_Value(Y)))) 798 if (X->getType() == Y->getType()) 799 // See if "V === X - Y" simplifies. 800 if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, Q, MaxRecurse-1)) 801 // It does! Now see if "trunc V" simplifies. 802 if (Value *W = SimplifyCastInst(Instruction::Trunc, V, Op0->getType(), 803 Q, MaxRecurse - 1)) 804 // It does, return the simplified "trunc V". 805 return W; 806 807 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...). 808 if (match(Op0, m_PtrToInt(m_Value(X))) && 809 match(Op1, m_PtrToInt(m_Value(Y)))) 810 if (Constant *Result = computePointerDifference(Q.DL, X, Y)) 811 return ConstantExpr::getIntegerCast(Result, Op0->getType(), true); 812 813 // i1 sub -> xor. 814 if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1)) 815 if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1)) 816 return V; 817 818 // Threading Sub over selects and phi nodes is pointless, so don't bother. 819 // Threading over the select in "A - select(cond, B, C)" means evaluating 820 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and 821 // only if B and C are equal. If B and C are equal then (since we assume 822 // that operands have already been simplified) "select(cond, B, C)" should 823 // have been simplified to the common value of B and C already. Analysing 824 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly 825 // for threading over phi nodes. 826 827 return nullptr; 828 } 829 830 Value *llvm::SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, 831 const SimplifyQuery &Q) { 832 return ::SimplifySubInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit); 833 } 834 835 /// Given operands for a Mul, see if we can fold the result. 836 /// If not, this returns null. 837 static Value *SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, 838 unsigned MaxRecurse) { 839 if (Constant *C = foldOrCommuteConstant(Instruction::Mul, Op0, Op1, Q)) 840 return C; 841 842 // X * undef -> 0 843 // X * 0 -> 0 844 if (match(Op1, m_CombineOr(m_Undef(), m_Zero()))) 845 return Constant::getNullValue(Op0->getType()); 846 847 // X * 1 -> X 848 if (match(Op1, m_One())) 849 return Op0; 850 851 // (X / Y) * Y -> X if the division is exact. 852 Value *X = nullptr; 853 if (Q.IIQ.UseInstrInfo && 854 (match(Op0, 855 m_Exact(m_IDiv(m_Value(X), m_Specific(Op1)))) || // (X / Y) * Y 856 match(Op1, m_Exact(m_IDiv(m_Value(X), m_Specific(Op0)))))) // Y * (X / Y) 857 return X; 858 859 // i1 mul -> and. 860 if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1)) 861 if (Value *V = SimplifyAndInst(Op0, Op1, Q, MaxRecurse-1)) 862 return V; 863 864 // Try some generic simplifications for associative operations. 865 if (Value *V = SimplifyAssociativeBinOp(Instruction::Mul, Op0, Op1, Q, 866 MaxRecurse)) 867 return V; 868 869 // Mul distributes over Add. Try some generic simplifications based on this. 870 if (Value *V = ExpandBinOp(Instruction::Mul, Op0, Op1, Instruction::Add, 871 Q, MaxRecurse)) 872 return V; 873 874 // If the operation is with the result of a select instruction, check whether 875 // operating on either branch of the select always yields the same value. 876 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) 877 if (Value *V = ThreadBinOpOverSelect(Instruction::Mul, Op0, Op1, Q, 878 MaxRecurse)) 879 return V; 880 881 // If the operation is with the result of a phi instruction, check whether 882 // operating on all incoming values of the phi always yields the same value. 883 if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) 884 if (Value *V = ThreadBinOpOverPHI(Instruction::Mul, Op0, Op1, Q, 885 MaxRecurse)) 886 return V; 887 888 return nullptr; 889 } 890 891 Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) { 892 return ::SimplifyMulInst(Op0, Op1, Q, RecursionLimit); 893 } 894 895 /// Check for common or similar folds of integer division or integer remainder. 896 /// This applies to all 4 opcodes (sdiv/udiv/srem/urem). 897 static Value *simplifyDivRem(Value *Op0, Value *Op1, bool IsDiv) { 898 Type *Ty = Op0->getType(); 899 900 // X / undef -> undef 901 // X % undef -> undef 902 if (match(Op1, m_Undef())) 903 return Op1; 904 905 // X / 0 -> undef 906 // X % 0 -> undef 907 // We don't need to preserve faults! 908 if (match(Op1, m_Zero())) 909 return UndefValue::get(Ty); 910 911 // If any element of a constant divisor vector is zero or undef, the whole op 912 // is undef. 913 auto *Op1C = dyn_cast<Constant>(Op1); 914 if (Op1C && Ty->isVectorTy()) { 915 unsigned NumElts = Ty->getVectorNumElements(); 916 for (unsigned i = 0; i != NumElts; ++i) { 917 Constant *Elt = Op1C->getAggregateElement(i); 918 if (Elt && (Elt->isNullValue() || isa<UndefValue>(Elt))) 919 return UndefValue::get(Ty); 920 } 921 } 922 923 // undef / X -> 0 924 // undef % X -> 0 925 if (match(Op0, m_Undef())) 926 return Constant::getNullValue(Ty); 927 928 // 0 / X -> 0 929 // 0 % X -> 0 930 if (match(Op0, m_Zero())) 931 return Constant::getNullValue(Op0->getType()); 932 933 // X / X -> 1 934 // X % X -> 0 935 if (Op0 == Op1) 936 return IsDiv ? ConstantInt::get(Ty, 1) : Constant::getNullValue(Ty); 937 938 // X / 1 -> X 939 // X % 1 -> 0 940 // If this is a boolean op (single-bit element type), we can't have 941 // division-by-zero or remainder-by-zero, so assume the divisor is 1. 942 // Similarly, if we're zero-extending a boolean divisor, then assume it's a 1. 943 Value *X; 944 if (match(Op1, m_One()) || Ty->isIntOrIntVectorTy(1) || 945 (match(Op1, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))) 946 return IsDiv ? Op0 : Constant::getNullValue(Ty); 947 948 return nullptr; 949 } 950 951 /// Given a predicate and two operands, return true if the comparison is true. 952 /// This is a helper for div/rem simplification where we return some other value 953 /// when we can prove a relationship between the operands. 954 static bool isICmpTrue(ICmpInst::Predicate Pred, Value *LHS, Value *RHS, 955 const SimplifyQuery &Q, unsigned MaxRecurse) { 956 Value *V = SimplifyICmpInst(Pred, LHS, RHS, Q, MaxRecurse); 957 Constant *C = dyn_cast_or_null<Constant>(V); 958 return (C && C->isAllOnesValue()); 959 } 960 961 /// Return true if we can simplify X / Y to 0. Remainder can adapt that answer 962 /// to simplify X % Y to X. 963 static bool isDivZero(Value *X, Value *Y, const SimplifyQuery &Q, 964 unsigned MaxRecurse, bool IsSigned) { 965 // Recursion is always used, so bail out at once if we already hit the limit. 966 if (!MaxRecurse--) 967 return false; 968 969 if (IsSigned) { 970 // |X| / |Y| --> 0 971 // 972 // We require that 1 operand is a simple constant. That could be extended to 973 // 2 variables if we computed the sign bit for each. 974 // 975 // Make sure that a constant is not the minimum signed value because taking 976 // the abs() of that is undefined. 977 Type *Ty = X->getType(); 978 const APInt *C; 979 if (match(X, m_APInt(C)) && !C->isMinSignedValue()) { 980 // Is the variable divisor magnitude always greater than the constant 981 // dividend magnitude? 982 // |Y| > |C| --> Y < -abs(C) or Y > abs(C) 983 Constant *PosDividendC = ConstantInt::get(Ty, C->abs()); 984 Constant *NegDividendC = ConstantInt::get(Ty, -C->abs()); 985 if (isICmpTrue(CmpInst::ICMP_SLT, Y, NegDividendC, Q, MaxRecurse) || 986 isICmpTrue(CmpInst::ICMP_SGT, Y, PosDividendC, Q, MaxRecurse)) 987 return true; 988 } 989 if (match(Y, m_APInt(C))) { 990 // Special-case: we can't take the abs() of a minimum signed value. If 991 // that's the divisor, then all we have to do is prove that the dividend 992 // is also not the minimum signed value. 993 if (C->isMinSignedValue()) 994 return isICmpTrue(CmpInst::ICMP_NE, X, Y, Q, MaxRecurse); 995 996 // Is the variable dividend magnitude always less than the constant 997 // divisor magnitude? 998 // |X| < |C| --> X > -abs(C) and X < abs(C) 999 Constant *PosDivisorC = ConstantInt::get(Ty, C->abs()); 1000 Constant *NegDivisorC = ConstantInt::get(Ty, -C->abs()); 1001 if (isICmpTrue(CmpInst::ICMP_SGT, X, NegDivisorC, Q, MaxRecurse) && 1002 isICmpTrue(CmpInst::ICMP_SLT, X, PosDivisorC, Q, MaxRecurse)) 1003 return true; 1004 } 1005 return false; 1006 } 1007 1008 // IsSigned == false. 1009 // Is the dividend unsigned less than the divisor? 1010 return isICmpTrue(ICmpInst::ICMP_ULT, X, Y, Q, MaxRecurse); 1011 } 1012 1013 /// These are simplifications common to SDiv and UDiv. 1014 static Value *simplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1, 1015 const SimplifyQuery &Q, unsigned MaxRecurse) { 1016 if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q)) 1017 return C; 1018 1019 if (Value *V = simplifyDivRem(Op0, Op1, true)) 1020 return V; 1021 1022 bool IsSigned = Opcode == Instruction::SDiv; 1023 1024 // (X * Y) / Y -> X if the multiplication does not overflow. 1025 Value *X; 1026 if (match(Op0, m_c_Mul(m_Value(X), m_Specific(Op1)))) { 1027 auto *Mul = cast<OverflowingBinaryOperator>(Op0); 1028 // If the Mul does not overflow, then we are good to go. 1029 if ((IsSigned && Q.IIQ.hasNoSignedWrap(Mul)) || 1030 (!IsSigned && Q.IIQ.hasNoUnsignedWrap(Mul))) 1031 return X; 1032 // If X has the form X = A / Y, then X * Y cannot overflow. 1033 if ((IsSigned && match(X, m_SDiv(m_Value(), m_Specific(Op1)))) || 1034 (!IsSigned && match(X, m_UDiv(m_Value(), m_Specific(Op1))))) 1035 return X; 1036 } 1037 1038 // (X rem Y) / Y -> 0 1039 if ((IsSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) || 1040 (!IsSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1))))) 1041 return Constant::getNullValue(Op0->getType()); 1042 1043 // (X /u C1) /u C2 -> 0 if C1 * C2 overflow 1044 ConstantInt *C1, *C2; 1045 if (!IsSigned && match(Op0, m_UDiv(m_Value(X), m_ConstantInt(C1))) && 1046 match(Op1, m_ConstantInt(C2))) { 1047 bool Overflow; 1048 (void)C1->getValue().umul_ov(C2->getValue(), Overflow); 1049 if (Overflow) 1050 return Constant::getNullValue(Op0->getType()); 1051 } 1052 1053 // If the operation is with the result of a select instruction, check whether 1054 // operating on either branch of the select always yields the same value. 1055 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) 1056 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse)) 1057 return V; 1058 1059 // If the operation is with the result of a phi instruction, check whether 1060 // operating on all incoming values of the phi always yields the same value. 1061 if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) 1062 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse)) 1063 return V; 1064 1065 if (isDivZero(Op0, Op1, Q, MaxRecurse, IsSigned)) 1066 return Constant::getNullValue(Op0->getType()); 1067 1068 return nullptr; 1069 } 1070 1071 /// These are simplifications common to SRem and URem. 1072 static Value *simplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1, 1073 const SimplifyQuery &Q, unsigned MaxRecurse) { 1074 if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q)) 1075 return C; 1076 1077 if (Value *V = simplifyDivRem(Op0, Op1, false)) 1078 return V; 1079 1080 // (X % Y) % Y -> X % Y 1081 if ((Opcode == Instruction::SRem && 1082 match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) || 1083 (Opcode == Instruction::URem && 1084 match(Op0, m_URem(m_Value(), m_Specific(Op1))))) 1085 return Op0; 1086 1087 // (X << Y) % X -> 0 1088 if (Q.IIQ.UseInstrInfo && 1089 ((Opcode == Instruction::SRem && 1090 match(Op0, m_NSWShl(m_Specific(Op1), m_Value()))) || 1091 (Opcode == Instruction::URem && 1092 match(Op0, m_NUWShl(m_Specific(Op1), m_Value()))))) 1093 return Constant::getNullValue(Op0->getType()); 1094 1095 // If the operation is with the result of a select instruction, check whether 1096 // operating on either branch of the select always yields the same value. 1097 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) 1098 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse)) 1099 return V; 1100 1101 // If the operation is with the result of a phi instruction, check whether 1102 // operating on all incoming values of the phi always yields the same value. 1103 if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) 1104 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse)) 1105 return V; 1106 1107 // If X / Y == 0, then X % Y == X. 1108 if (isDivZero(Op0, Op1, Q, MaxRecurse, Opcode == Instruction::SRem)) 1109 return Op0; 1110 1111 return nullptr; 1112 } 1113 1114 /// Given operands for an SDiv, see if we can fold the result. 1115 /// If not, this returns null. 1116 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, 1117 unsigned MaxRecurse) { 1118 // If two operands are negated and no signed overflow, return -1. 1119 if (isKnownNegation(Op0, Op1, /*NeedNSW=*/true)) 1120 return Constant::getAllOnesValue(Op0->getType()); 1121 1122 return simplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse); 1123 } 1124 1125 Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) { 1126 return ::SimplifySDivInst(Op0, Op1, Q, RecursionLimit); 1127 } 1128 1129 /// Given operands for a UDiv, see if we can fold the result. 1130 /// If not, this returns null. 1131 static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, 1132 unsigned MaxRecurse) { 1133 return simplifyDiv(Instruction::UDiv, Op0, Op1, Q, MaxRecurse); 1134 } 1135 1136 Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) { 1137 return ::SimplifyUDivInst(Op0, Op1, Q, RecursionLimit); 1138 } 1139 1140 /// Given operands for an SRem, see if we can fold the result. 1141 /// If not, this returns null. 1142 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, 1143 unsigned MaxRecurse) { 1144 // If the divisor is 0, the result is undefined, so assume the divisor is -1. 1145 // srem Op0, (sext i1 X) --> srem Op0, -1 --> 0 1146 Value *X; 1147 if (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)) 1148 return ConstantInt::getNullValue(Op0->getType()); 1149 1150 // If the two operands are negated, return 0. 1151 if (isKnownNegation(Op0, Op1)) 1152 return ConstantInt::getNullValue(Op0->getType()); 1153 1154 return simplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse); 1155 } 1156 1157 Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) { 1158 return ::SimplifySRemInst(Op0, Op1, Q, RecursionLimit); 1159 } 1160 1161 /// Given operands for a URem, see if we can fold the result. 1162 /// If not, this returns null. 1163 static Value *SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, 1164 unsigned MaxRecurse) { 1165 return simplifyRem(Instruction::URem, Op0, Op1, Q, MaxRecurse); 1166 } 1167 1168 Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) { 1169 return ::SimplifyURemInst(Op0, Op1, Q, RecursionLimit); 1170 } 1171 1172 /// Returns true if a shift by \c Amount always yields undef. 1173 static bool isUndefShift(Value *Amount) { 1174 Constant *C = dyn_cast<Constant>(Amount); 1175 if (!C) 1176 return false; 1177 1178 // X shift by undef -> undef because it may shift by the bitwidth. 1179 if (isa<UndefValue>(C)) 1180 return true; 1181 1182 // Shifting by the bitwidth or more is undefined. 1183 if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) 1184 if (CI->getValue().getLimitedValue() >= 1185 CI->getType()->getScalarSizeInBits()) 1186 return true; 1187 1188 // If all lanes of a vector shift are undefined the whole shift is. 1189 if (isa<ConstantVector>(C) || isa<ConstantDataVector>(C)) { 1190 for (unsigned I = 0, E = C->getType()->getVectorNumElements(); I != E; ++I) 1191 if (!isUndefShift(C->getAggregateElement(I))) 1192 return false; 1193 return true; 1194 } 1195 1196 return false; 1197 } 1198 1199 /// Given operands for an Shl, LShr or AShr, see if we can fold the result. 1200 /// If not, this returns null. 1201 static Value *SimplifyShift(Instruction::BinaryOps Opcode, Value *Op0, 1202 Value *Op1, const SimplifyQuery &Q, unsigned MaxRecurse) { 1203 if (Constant *C = foldOrCommuteConstant(Opcode, Op0, Op1, Q)) 1204 return C; 1205 1206 // 0 shift by X -> 0 1207 if (match(Op0, m_Zero())) 1208 return Constant::getNullValue(Op0->getType()); 1209 1210 // X shift by 0 -> X 1211 // Shift-by-sign-extended bool must be shift-by-0 because shift-by-all-ones 1212 // would be poison. 1213 Value *X; 1214 if (match(Op1, m_Zero()) || 1215 (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))) 1216 return Op0; 1217 1218 // Fold undefined shifts. 1219 if (isUndefShift(Op1)) 1220 return UndefValue::get(Op0->getType()); 1221 1222 // If the operation is with the result of a select instruction, check whether 1223 // operating on either branch of the select always yields the same value. 1224 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) 1225 if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, Q, MaxRecurse)) 1226 return V; 1227 1228 // If the operation is with the result of a phi instruction, check whether 1229 // operating on all incoming values of the phi always yields the same value. 1230 if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) 1231 if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, Q, MaxRecurse)) 1232 return V; 1233 1234 // If any bits in the shift amount make that value greater than or equal to 1235 // the number of bits in the type, the shift is undefined. 1236 KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 1237 if (Known.One.getLimitedValue() >= Known.getBitWidth()) 1238 return UndefValue::get(Op0->getType()); 1239 1240 // If all valid bits in the shift amount are known zero, the first operand is 1241 // unchanged. 1242 unsigned NumValidShiftBits = Log2_32_Ceil(Known.getBitWidth()); 1243 if (Known.countMinTrailingZeros() >= NumValidShiftBits) 1244 return Op0; 1245 1246 return nullptr; 1247 } 1248 1249 /// Given operands for an Shl, LShr or AShr, see if we can 1250 /// fold the result. If not, this returns null. 1251 static Value *SimplifyRightShift(Instruction::BinaryOps Opcode, Value *Op0, 1252 Value *Op1, bool isExact, const SimplifyQuery &Q, 1253 unsigned MaxRecurse) { 1254 if (Value *V = SimplifyShift(Opcode, Op0, Op1, Q, MaxRecurse)) 1255 return V; 1256 1257 // X >> X -> 0 1258 if (Op0 == Op1) 1259 return Constant::getNullValue(Op0->getType()); 1260 1261 // undef >> X -> 0 1262 // undef >> X -> undef (if it's exact) 1263 if (match(Op0, m_Undef())) 1264 return isExact ? Op0 : Constant::getNullValue(Op0->getType()); 1265 1266 // The low bit cannot be shifted out of an exact shift if it is set. 1267 if (isExact) { 1268 KnownBits Op0Known = computeKnownBits(Op0, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT); 1269 if (Op0Known.One[0]) 1270 return Op0; 1271 } 1272 1273 return nullptr; 1274 } 1275 1276 /// Given operands for an Shl, see if we can fold the result. 1277 /// If not, this returns null. 1278 static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, 1279 const SimplifyQuery &Q, unsigned MaxRecurse) { 1280 if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, Q, MaxRecurse)) 1281 return V; 1282 1283 // undef << X -> 0 1284 // undef << X -> undef if (if it's NSW/NUW) 1285 if (match(Op0, m_Undef())) 1286 return isNSW || isNUW ? Op0 : Constant::getNullValue(Op0->getType()); 1287 1288 // (X >> A) << A -> X 1289 Value *X; 1290 if (Q.IIQ.UseInstrInfo && 1291 match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1))))) 1292 return X; 1293 1294 // shl nuw i8 C, %x -> C iff C has sign bit set. 1295 if (isNUW && match(Op0, m_Negative())) 1296 return Op0; 1297 // NOTE: could use computeKnownBits() / LazyValueInfo, 1298 // but the cost-benefit analysis suggests it isn't worth it. 1299 1300 return nullptr; 1301 } 1302 1303 Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW, 1304 const SimplifyQuery &Q) { 1305 return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, Q, RecursionLimit); 1306 } 1307 1308 /// Given operands for an LShr, see if we can fold the result. 1309 /// If not, this returns null. 1310 static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact, 1311 const SimplifyQuery &Q, unsigned MaxRecurse) { 1312 if (Value *V = SimplifyRightShift(Instruction::LShr, Op0, Op1, isExact, Q, 1313 MaxRecurse)) 1314 return V; 1315 1316 // (X << A) >> A -> X 1317 Value *X; 1318 if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1)))) 1319 return X; 1320 1321 // ((X << A) | Y) >> A -> X if effective width of Y is not larger than A. 1322 // We can return X as we do in the above case since OR alters no bits in X. 1323 // SimplifyDemandedBits in InstCombine can do more general optimization for 1324 // bit manipulation. This pattern aims to provide opportunities for other 1325 // optimizers by supporting a simple but common case in InstSimplify. 1326 Value *Y; 1327 const APInt *ShRAmt, *ShLAmt; 1328 if (match(Op1, m_APInt(ShRAmt)) && 1329 match(Op0, m_c_Or(m_NUWShl(m_Value(X), m_APInt(ShLAmt)), m_Value(Y))) && 1330 *ShRAmt == *ShLAmt) { 1331 const KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 1332 const unsigned Width = Op0->getType()->getScalarSizeInBits(); 1333 const unsigned EffWidthY = Width - YKnown.countMinLeadingZeros(); 1334 if (ShRAmt->uge(EffWidthY)) 1335 return X; 1336 } 1337 1338 return nullptr; 1339 } 1340 1341 Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact, 1342 const SimplifyQuery &Q) { 1343 return ::SimplifyLShrInst(Op0, Op1, isExact, Q, RecursionLimit); 1344 } 1345 1346 /// Given operands for an AShr, see if we can fold the result. 1347 /// If not, this returns null. 1348 static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, 1349 const SimplifyQuery &Q, unsigned MaxRecurse) { 1350 if (Value *V = SimplifyRightShift(Instruction::AShr, Op0, Op1, isExact, Q, 1351 MaxRecurse)) 1352 return V; 1353 1354 // all ones >>a X -> -1 1355 // Do not return Op0 because it may contain undef elements if it's a vector. 1356 if (match(Op0, m_AllOnes())) 1357 return Constant::getAllOnesValue(Op0->getType()); 1358 1359 // (X << A) >> A -> X 1360 Value *X; 1361 if (Q.IIQ.UseInstrInfo && match(Op0, m_NSWShl(m_Value(X), m_Specific(Op1)))) 1362 return X; 1363 1364 // Arithmetic shifting an all-sign-bit value is a no-op. 1365 unsigned NumSignBits = ComputeNumSignBits(Op0, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 1366 if (NumSignBits == Op0->getType()->getScalarSizeInBits()) 1367 return Op0; 1368 1369 return nullptr; 1370 } 1371 1372 Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact, 1373 const SimplifyQuery &Q) { 1374 return ::SimplifyAShrInst(Op0, Op1, isExact, Q, RecursionLimit); 1375 } 1376 1377 /// Commuted variants are assumed to be handled by calling this function again 1378 /// with the parameters swapped. 1379 static Value *simplifyUnsignedRangeCheck(ICmpInst *ZeroICmp, 1380 ICmpInst *UnsignedICmp, bool IsAnd, 1381 const SimplifyQuery &Q) { 1382 Value *X, *Y; 1383 1384 ICmpInst::Predicate EqPred; 1385 if (!match(ZeroICmp, m_ICmp(EqPred, m_Value(Y), m_Zero())) || 1386 !ICmpInst::isEquality(EqPred)) 1387 return nullptr; 1388 1389 ICmpInst::Predicate UnsignedPred; 1390 1391 Value *A, *B; 1392 // Y = (A - B); 1393 if (match(Y, m_Sub(m_Value(A), m_Value(B)))) { 1394 if (match(UnsignedICmp, 1395 m_c_ICmp(UnsignedPred, m_Specific(A), m_Specific(B))) && 1396 ICmpInst::isUnsigned(UnsignedPred)) { 1397 if (UnsignedICmp->getOperand(0) != A) 1398 UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred); 1399 1400 // A >=/<= B || (A - B) != 0 <--> true 1401 if ((UnsignedPred == ICmpInst::ICMP_UGE || 1402 UnsignedPred == ICmpInst::ICMP_ULE) && 1403 EqPred == ICmpInst::ICMP_NE && !IsAnd) 1404 return ConstantInt::getTrue(UnsignedICmp->getType()); 1405 // A </> B && (A - B) == 0 <--> false 1406 if ((UnsignedPred == ICmpInst::ICMP_ULT || 1407 UnsignedPred == ICmpInst::ICMP_UGT) && 1408 EqPred == ICmpInst::ICMP_EQ && IsAnd) 1409 return ConstantInt::getFalse(UnsignedICmp->getType()); 1410 1411 // A </> B && (A - B) != 0 <--> A </> B 1412 // A </> B || (A - B) != 0 <--> (A - B) != 0 1413 if (EqPred == ICmpInst::ICMP_NE && (UnsignedPred == ICmpInst::ICMP_ULT || 1414 UnsignedPred == ICmpInst::ICMP_UGT)) 1415 return IsAnd ? UnsignedICmp : ZeroICmp; 1416 1417 // A <=/>= B && (A - B) == 0 <--> (A - B) == 0 1418 // A <=/>= B || (A - B) == 0 <--> A <=/>= B 1419 if (EqPred == ICmpInst::ICMP_EQ && (UnsignedPred == ICmpInst::ICMP_ULE || 1420 UnsignedPred == ICmpInst::ICMP_UGE)) 1421 return IsAnd ? ZeroICmp : UnsignedICmp; 1422 } 1423 1424 // Given Y = (A - B) 1425 // Y >= A && Y != 0 --> Y >= A iff B != 0 1426 // Y < A || Y == 0 --> Y < A iff B != 0 1427 if (match(UnsignedICmp, 1428 m_c_ICmp(UnsignedPred, m_Specific(Y), m_Specific(A)))) { 1429 if (UnsignedICmp->getOperand(0) != Y) 1430 UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred); 1431 1432 if (UnsignedPred == ICmpInst::ICMP_UGE && IsAnd && 1433 EqPred == ICmpInst::ICMP_NE && 1434 isKnownNonZero(B, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT)) 1435 return UnsignedICmp; 1436 if (UnsignedPred == ICmpInst::ICMP_ULT && !IsAnd && 1437 EqPred == ICmpInst::ICMP_EQ && 1438 isKnownNonZero(B, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT)) 1439 return UnsignedICmp; 1440 } 1441 } 1442 1443 if (match(UnsignedICmp, m_ICmp(UnsignedPred, m_Value(X), m_Specific(Y))) && 1444 ICmpInst::isUnsigned(UnsignedPred)) 1445 ; 1446 else if (match(UnsignedICmp, 1447 m_ICmp(UnsignedPred, m_Specific(Y), m_Value(X))) && 1448 ICmpInst::isUnsigned(UnsignedPred)) 1449 UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred); 1450 else 1451 return nullptr; 1452 1453 // X < Y && Y != 0 --> X < Y 1454 // X < Y || Y != 0 --> Y != 0 1455 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_NE) 1456 return IsAnd ? UnsignedICmp : ZeroICmp; 1457 1458 // X <= Y && Y != 0 --> X <= Y iff X != 0 1459 // X <= Y || Y != 0 --> Y != 0 iff X != 0 1460 if (UnsignedPred == ICmpInst::ICMP_ULE && EqPred == ICmpInst::ICMP_NE && 1461 isKnownNonZero(X, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT)) 1462 return IsAnd ? UnsignedICmp : ZeroICmp; 1463 1464 // X >= Y && Y == 0 --> Y == 0 1465 // X >= Y || Y == 0 --> X >= Y 1466 if (UnsignedPred == ICmpInst::ICMP_UGE && EqPred == ICmpInst::ICMP_EQ) 1467 return IsAnd ? ZeroICmp : UnsignedICmp; 1468 1469 // X > Y && Y == 0 --> Y == 0 iff X != 0 1470 // X > Y || Y == 0 --> X > Y iff X != 0 1471 if (UnsignedPred == ICmpInst::ICMP_UGT && EqPred == ICmpInst::ICMP_EQ && 1472 isKnownNonZero(X, Q.DL, /*Depth=*/0, Q.AC, Q.CxtI, Q.DT)) 1473 return IsAnd ? ZeroICmp : UnsignedICmp; 1474 1475 // X < Y && Y == 0 --> false 1476 if (UnsignedPred == ICmpInst::ICMP_ULT && EqPred == ICmpInst::ICMP_EQ && 1477 IsAnd) 1478 return getFalse(UnsignedICmp->getType()); 1479 1480 // X >= Y || Y != 0 --> true 1481 if (UnsignedPred == ICmpInst::ICMP_UGE && EqPred == ICmpInst::ICMP_NE && 1482 !IsAnd) 1483 return getTrue(UnsignedICmp->getType()); 1484 1485 return nullptr; 1486 } 1487 1488 /// Commuted variants are assumed to be handled by calling this function again 1489 /// with the parameters swapped. 1490 static Value *simplifyAndOfICmpsWithSameOperands(ICmpInst *Op0, ICmpInst *Op1) { 1491 ICmpInst::Predicate Pred0, Pred1; 1492 Value *A ,*B; 1493 if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) || 1494 !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B)))) 1495 return nullptr; 1496 1497 // We have (icmp Pred0, A, B) & (icmp Pred1, A, B). 1498 // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we 1499 // can eliminate Op1 from this 'and'. 1500 if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1)) 1501 return Op0; 1502 1503 // Check for any combination of predicates that are guaranteed to be disjoint. 1504 if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) || 1505 (Pred0 == ICmpInst::ICMP_EQ && ICmpInst::isFalseWhenEqual(Pred1)) || 1506 (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT) || 1507 (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT)) 1508 return getFalse(Op0->getType()); 1509 1510 return nullptr; 1511 } 1512 1513 /// Commuted variants are assumed to be handled by calling this function again 1514 /// with the parameters swapped. 1515 static Value *simplifyOrOfICmpsWithSameOperands(ICmpInst *Op0, ICmpInst *Op1) { 1516 ICmpInst::Predicate Pred0, Pred1; 1517 Value *A ,*B; 1518 if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) || 1519 !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B)))) 1520 return nullptr; 1521 1522 // We have (icmp Pred0, A, B) | (icmp Pred1, A, B). 1523 // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we 1524 // can eliminate Op0 from this 'or'. 1525 if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0, Pred1)) 1526 return Op1; 1527 1528 // Check for any combination of predicates that cover the entire range of 1529 // possibilities. 1530 if ((Pred0 == ICmpInst::getInversePredicate(Pred1)) || 1531 (Pred0 == ICmpInst::ICMP_NE && ICmpInst::isTrueWhenEqual(Pred1)) || 1532 (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGE) || 1533 (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGE)) 1534 return getTrue(Op0->getType()); 1535 1536 return nullptr; 1537 } 1538 1539 /// Test if a pair of compares with a shared operand and 2 constants has an 1540 /// empty set intersection, full set union, or if one compare is a superset of 1541 /// the other. 1542 static Value *simplifyAndOrOfICmpsWithConstants(ICmpInst *Cmp0, ICmpInst *Cmp1, 1543 bool IsAnd) { 1544 // Look for this pattern: {and/or} (icmp X, C0), (icmp X, C1)). 1545 if (Cmp0->getOperand(0) != Cmp1->getOperand(0)) 1546 return nullptr; 1547 1548 const APInt *C0, *C1; 1549 if (!match(Cmp0->getOperand(1), m_APInt(C0)) || 1550 !match(Cmp1->getOperand(1), m_APInt(C1))) 1551 return nullptr; 1552 1553 auto Range0 = ConstantRange::makeExactICmpRegion(Cmp0->getPredicate(), *C0); 1554 auto Range1 = ConstantRange::makeExactICmpRegion(Cmp1->getPredicate(), *C1); 1555 1556 // For and-of-compares, check if the intersection is empty: 1557 // (icmp X, C0) && (icmp X, C1) --> empty set --> false 1558 if (IsAnd && Range0.intersectWith(Range1).isEmptySet()) 1559 return getFalse(Cmp0->getType()); 1560 1561 // For or-of-compares, check if the union is full: 1562 // (icmp X, C0) || (icmp X, C1) --> full set --> true 1563 if (!IsAnd && Range0.unionWith(Range1).isFullSet()) 1564 return getTrue(Cmp0->getType()); 1565 1566 // Is one range a superset of the other? 1567 // If this is and-of-compares, take the smaller set: 1568 // (icmp sgt X, 4) && (icmp sgt X, 42) --> icmp sgt X, 42 1569 // If this is or-of-compares, take the larger set: 1570 // (icmp sgt X, 4) || (icmp sgt X, 42) --> icmp sgt X, 4 1571 if (Range0.contains(Range1)) 1572 return IsAnd ? Cmp1 : Cmp0; 1573 if (Range1.contains(Range0)) 1574 return IsAnd ? Cmp0 : Cmp1; 1575 1576 return nullptr; 1577 } 1578 1579 static Value *simplifyAndOrOfICmpsWithZero(ICmpInst *Cmp0, ICmpInst *Cmp1, 1580 bool IsAnd) { 1581 ICmpInst::Predicate P0 = Cmp0->getPredicate(), P1 = Cmp1->getPredicate(); 1582 if (!match(Cmp0->getOperand(1), m_Zero()) || 1583 !match(Cmp1->getOperand(1), m_Zero()) || P0 != P1) 1584 return nullptr; 1585 1586 if ((IsAnd && P0 != ICmpInst::ICMP_NE) || (!IsAnd && P1 != ICmpInst::ICMP_EQ)) 1587 return nullptr; 1588 1589 // We have either "(X == 0 || Y == 0)" or "(X != 0 && Y != 0)". 1590 Value *X = Cmp0->getOperand(0); 1591 Value *Y = Cmp1->getOperand(0); 1592 1593 // If one of the compares is a masked version of a (not) null check, then 1594 // that compare implies the other, so we eliminate the other. Optionally, look 1595 // through a pointer-to-int cast to match a null check of a pointer type. 1596 1597 // (X == 0) || (([ptrtoint] X & ?) == 0) --> ([ptrtoint] X & ?) == 0 1598 // (X == 0) || ((? & [ptrtoint] X) == 0) --> (? & [ptrtoint] X) == 0 1599 // (X != 0) && (([ptrtoint] X & ?) != 0) --> ([ptrtoint] X & ?) != 0 1600 // (X != 0) && ((? & [ptrtoint] X) != 0) --> (? & [ptrtoint] X) != 0 1601 if (match(Y, m_c_And(m_Specific(X), m_Value())) || 1602 match(Y, m_c_And(m_PtrToInt(m_Specific(X)), m_Value()))) 1603 return Cmp1; 1604 1605 // (([ptrtoint] Y & ?) == 0) || (Y == 0) --> ([ptrtoint] Y & ?) == 0 1606 // ((? & [ptrtoint] Y) == 0) || (Y == 0) --> (? & [ptrtoint] Y) == 0 1607 // (([ptrtoint] Y & ?) != 0) && (Y != 0) --> ([ptrtoint] Y & ?) != 0 1608 // ((? & [ptrtoint] Y) != 0) && (Y != 0) --> (? & [ptrtoint] Y) != 0 1609 if (match(X, m_c_And(m_Specific(Y), m_Value())) || 1610 match(X, m_c_And(m_PtrToInt(m_Specific(Y)), m_Value()))) 1611 return Cmp0; 1612 1613 return nullptr; 1614 } 1615 1616 static Value *simplifyAndOfICmpsWithAdd(ICmpInst *Op0, ICmpInst *Op1, 1617 const InstrInfoQuery &IIQ) { 1618 // (icmp (add V, C0), C1) & (icmp V, C0) 1619 ICmpInst::Predicate Pred0, Pred1; 1620 const APInt *C0, *C1; 1621 Value *V; 1622 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1)))) 1623 return nullptr; 1624 1625 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value()))) 1626 return nullptr; 1627 1628 auto *AddInst = cast<OverflowingBinaryOperator>(Op0->getOperand(0)); 1629 if (AddInst->getOperand(1) != Op1->getOperand(1)) 1630 return nullptr; 1631 1632 Type *ITy = Op0->getType(); 1633 bool isNSW = IIQ.hasNoSignedWrap(AddInst); 1634 bool isNUW = IIQ.hasNoUnsignedWrap(AddInst); 1635 1636 const APInt Delta = *C1 - *C0; 1637 if (C0->isStrictlyPositive()) { 1638 if (Delta == 2) { 1639 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_SGT) 1640 return getFalse(ITy); 1641 if (Pred0 == ICmpInst::ICMP_SLT && Pred1 == ICmpInst::ICMP_SGT && isNSW) 1642 return getFalse(ITy); 1643 } 1644 if (Delta == 1) { 1645 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_SGT) 1646 return getFalse(ITy); 1647 if (Pred0 == ICmpInst::ICMP_SLE && Pred1 == ICmpInst::ICMP_SGT && isNSW) 1648 return getFalse(ITy); 1649 } 1650 } 1651 if (C0->getBoolValue() && isNUW) { 1652 if (Delta == 2) 1653 if (Pred0 == ICmpInst::ICMP_ULT && Pred1 == ICmpInst::ICMP_UGT) 1654 return getFalse(ITy); 1655 if (Delta == 1) 1656 if (Pred0 == ICmpInst::ICMP_ULE && Pred1 == ICmpInst::ICMP_UGT) 1657 return getFalse(ITy); 1658 } 1659 1660 return nullptr; 1661 } 1662 1663 static Value *simplifyAndOfICmps(ICmpInst *Op0, ICmpInst *Op1, 1664 const SimplifyQuery &Q) { 1665 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/true, Q)) 1666 return X; 1667 if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/true, Q)) 1668 return X; 1669 1670 if (Value *X = simplifyAndOfICmpsWithSameOperands(Op0, Op1)) 1671 return X; 1672 if (Value *X = simplifyAndOfICmpsWithSameOperands(Op1, Op0)) 1673 return X; 1674 1675 if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, true)) 1676 return X; 1677 1678 if (Value *X = simplifyAndOrOfICmpsWithZero(Op0, Op1, true)) 1679 return X; 1680 1681 if (Value *X = simplifyAndOfICmpsWithAdd(Op0, Op1, Q.IIQ)) 1682 return X; 1683 if (Value *X = simplifyAndOfICmpsWithAdd(Op1, Op0, Q.IIQ)) 1684 return X; 1685 1686 return nullptr; 1687 } 1688 1689 static Value *simplifyOrOfICmpsWithAdd(ICmpInst *Op0, ICmpInst *Op1, 1690 const InstrInfoQuery &IIQ) { 1691 // (icmp (add V, C0), C1) | (icmp V, C0) 1692 ICmpInst::Predicate Pred0, Pred1; 1693 const APInt *C0, *C1; 1694 Value *V; 1695 if (!match(Op0, m_ICmp(Pred0, m_Add(m_Value(V), m_APInt(C0)), m_APInt(C1)))) 1696 return nullptr; 1697 1698 if (!match(Op1, m_ICmp(Pred1, m_Specific(V), m_Value()))) 1699 return nullptr; 1700 1701 auto *AddInst = cast<BinaryOperator>(Op0->getOperand(0)); 1702 if (AddInst->getOperand(1) != Op1->getOperand(1)) 1703 return nullptr; 1704 1705 Type *ITy = Op0->getType(); 1706 bool isNSW = IIQ.hasNoSignedWrap(AddInst); 1707 bool isNUW = IIQ.hasNoUnsignedWrap(AddInst); 1708 1709 const APInt Delta = *C1 - *C0; 1710 if (C0->isStrictlyPositive()) { 1711 if (Delta == 2) { 1712 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_SLE) 1713 return getTrue(ITy); 1714 if (Pred0 == ICmpInst::ICMP_SGE && Pred1 == ICmpInst::ICMP_SLE && isNSW) 1715 return getTrue(ITy); 1716 } 1717 if (Delta == 1) { 1718 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_SLE) 1719 return getTrue(ITy); 1720 if (Pred0 == ICmpInst::ICMP_SGT && Pred1 == ICmpInst::ICMP_SLE && isNSW) 1721 return getTrue(ITy); 1722 } 1723 } 1724 if (C0->getBoolValue() && isNUW) { 1725 if (Delta == 2) 1726 if (Pred0 == ICmpInst::ICMP_UGE && Pred1 == ICmpInst::ICMP_ULE) 1727 return getTrue(ITy); 1728 if (Delta == 1) 1729 if (Pred0 == ICmpInst::ICMP_UGT && Pred1 == ICmpInst::ICMP_ULE) 1730 return getTrue(ITy); 1731 } 1732 1733 return nullptr; 1734 } 1735 1736 static Value *simplifyOrOfICmps(ICmpInst *Op0, ICmpInst *Op1, 1737 const SimplifyQuery &Q) { 1738 if (Value *X = simplifyUnsignedRangeCheck(Op0, Op1, /*IsAnd=*/false, Q)) 1739 return X; 1740 if (Value *X = simplifyUnsignedRangeCheck(Op1, Op0, /*IsAnd=*/false, Q)) 1741 return X; 1742 1743 if (Value *X = simplifyOrOfICmpsWithSameOperands(Op0, Op1)) 1744 return X; 1745 if (Value *X = simplifyOrOfICmpsWithSameOperands(Op1, Op0)) 1746 return X; 1747 1748 if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, false)) 1749 return X; 1750 1751 if (Value *X = simplifyAndOrOfICmpsWithZero(Op0, Op1, false)) 1752 return X; 1753 1754 if (Value *X = simplifyOrOfICmpsWithAdd(Op0, Op1, Q.IIQ)) 1755 return X; 1756 if (Value *X = simplifyOrOfICmpsWithAdd(Op1, Op0, Q.IIQ)) 1757 return X; 1758 1759 return nullptr; 1760 } 1761 1762 static Value *simplifyAndOrOfFCmps(const TargetLibraryInfo *TLI, 1763 FCmpInst *LHS, FCmpInst *RHS, bool IsAnd) { 1764 Value *LHS0 = LHS->getOperand(0), *LHS1 = LHS->getOperand(1); 1765 Value *RHS0 = RHS->getOperand(0), *RHS1 = RHS->getOperand(1); 1766 if (LHS0->getType() != RHS0->getType()) 1767 return nullptr; 1768 1769 FCmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate(); 1770 if ((PredL == FCmpInst::FCMP_ORD && PredR == FCmpInst::FCMP_ORD && IsAnd) || 1771 (PredL == FCmpInst::FCMP_UNO && PredR == FCmpInst::FCMP_UNO && !IsAnd)) { 1772 // (fcmp ord NNAN, X) & (fcmp ord X, Y) --> fcmp ord X, Y 1773 // (fcmp ord NNAN, X) & (fcmp ord Y, X) --> fcmp ord Y, X 1774 // (fcmp ord X, NNAN) & (fcmp ord X, Y) --> fcmp ord X, Y 1775 // (fcmp ord X, NNAN) & (fcmp ord Y, X) --> fcmp ord Y, X 1776 // (fcmp uno NNAN, X) | (fcmp uno X, Y) --> fcmp uno X, Y 1777 // (fcmp uno NNAN, X) | (fcmp uno Y, X) --> fcmp uno Y, X 1778 // (fcmp uno X, NNAN) | (fcmp uno X, Y) --> fcmp uno X, Y 1779 // (fcmp uno X, NNAN) | (fcmp uno Y, X) --> fcmp uno Y, X 1780 if ((isKnownNeverNaN(LHS0, TLI) && (LHS1 == RHS0 || LHS1 == RHS1)) || 1781 (isKnownNeverNaN(LHS1, TLI) && (LHS0 == RHS0 || LHS0 == RHS1))) 1782 return RHS; 1783 1784 // (fcmp ord X, Y) & (fcmp ord NNAN, X) --> fcmp ord X, Y 1785 // (fcmp ord Y, X) & (fcmp ord NNAN, X) --> fcmp ord Y, X 1786 // (fcmp ord X, Y) & (fcmp ord X, NNAN) --> fcmp ord X, Y 1787 // (fcmp ord Y, X) & (fcmp ord X, NNAN) --> fcmp ord Y, X 1788 // (fcmp uno X, Y) | (fcmp uno NNAN, X) --> fcmp uno X, Y 1789 // (fcmp uno Y, X) | (fcmp uno NNAN, X) --> fcmp uno Y, X 1790 // (fcmp uno X, Y) | (fcmp uno X, NNAN) --> fcmp uno X, Y 1791 // (fcmp uno Y, X) | (fcmp uno X, NNAN) --> fcmp uno Y, X 1792 if ((isKnownNeverNaN(RHS0, TLI) && (RHS1 == LHS0 || RHS1 == LHS1)) || 1793 (isKnownNeverNaN(RHS1, TLI) && (RHS0 == LHS0 || RHS0 == LHS1))) 1794 return LHS; 1795 } 1796 1797 return nullptr; 1798 } 1799 1800 static Value *simplifyAndOrOfCmps(const SimplifyQuery &Q, 1801 Value *Op0, Value *Op1, bool IsAnd) { 1802 // Look through casts of the 'and' operands to find compares. 1803 auto *Cast0 = dyn_cast<CastInst>(Op0); 1804 auto *Cast1 = dyn_cast<CastInst>(Op1); 1805 if (Cast0 && Cast1 && Cast0->getOpcode() == Cast1->getOpcode() && 1806 Cast0->getSrcTy() == Cast1->getSrcTy()) { 1807 Op0 = Cast0->getOperand(0); 1808 Op1 = Cast1->getOperand(0); 1809 } 1810 1811 Value *V = nullptr; 1812 auto *ICmp0 = dyn_cast<ICmpInst>(Op0); 1813 auto *ICmp1 = dyn_cast<ICmpInst>(Op1); 1814 if (ICmp0 && ICmp1) 1815 V = IsAnd ? simplifyAndOfICmps(ICmp0, ICmp1, Q) 1816 : simplifyOrOfICmps(ICmp0, ICmp1, Q); 1817 1818 auto *FCmp0 = dyn_cast<FCmpInst>(Op0); 1819 auto *FCmp1 = dyn_cast<FCmpInst>(Op1); 1820 if (FCmp0 && FCmp1) 1821 V = simplifyAndOrOfFCmps(Q.TLI, FCmp0, FCmp1, IsAnd); 1822 1823 if (!V) 1824 return nullptr; 1825 if (!Cast0) 1826 return V; 1827 1828 // If we looked through casts, we can only handle a constant simplification 1829 // because we are not allowed to create a cast instruction here. 1830 if (auto *C = dyn_cast<Constant>(V)) 1831 return ConstantExpr::getCast(Cast0->getOpcode(), C, Cast0->getType()); 1832 1833 return nullptr; 1834 } 1835 1836 /// Check that the Op1 is in expected form, i.e.: 1837 /// %Agg = tail call { i4, i1 } @llvm.[us]mul.with.overflow.i4(i4 %X, i4 %???) 1838 /// %Op1 = extractvalue { i4, i1 } %Agg, 1 1839 static bool omitCheckForZeroBeforeMulWithOverflowInternal(Value *Op1, 1840 Value *X) { 1841 auto *Extract = dyn_cast<ExtractValueInst>(Op1); 1842 // We should only be extracting the overflow bit. 1843 if (!Extract || !Extract->getIndices().equals(1)) 1844 return false; 1845 Value *Agg = Extract->getAggregateOperand(); 1846 // This should be a multiplication-with-overflow intrinsic. 1847 if (!match(Agg, m_CombineOr(m_Intrinsic<Intrinsic::umul_with_overflow>(), 1848 m_Intrinsic<Intrinsic::smul_with_overflow>()))) 1849 return false; 1850 // One of its multipliers should be the value we checked for zero before. 1851 if (!match(Agg, m_CombineOr(m_Argument<0>(m_Specific(X)), 1852 m_Argument<1>(m_Specific(X))))) 1853 return false; 1854 return true; 1855 } 1856 1857 /// The @llvm.[us]mul.with.overflow intrinsic could have been folded from some 1858 /// other form of check, e.g. one that was using division; it may have been 1859 /// guarded against division-by-zero. We can drop that check now. 1860 /// Look for: 1861 /// %Op0 = icmp ne i4 %X, 0 1862 /// %Agg = tail call { i4, i1 } @llvm.[us]mul.with.overflow.i4(i4 %X, i4 %???) 1863 /// %Op1 = extractvalue { i4, i1 } %Agg, 1 1864 /// %??? = and i1 %Op0, %Op1 1865 /// We can just return %Op1 1866 static Value *omitCheckForZeroBeforeMulWithOverflow(Value *Op0, Value *Op1) { 1867 ICmpInst::Predicate Pred; 1868 Value *X; 1869 if (!match(Op0, m_ICmp(Pred, m_Value(X), m_Zero())) || 1870 Pred != ICmpInst::Predicate::ICMP_NE) 1871 return nullptr; 1872 // Is Op1 in expected form? 1873 if (!omitCheckForZeroBeforeMulWithOverflowInternal(Op1, X)) 1874 return nullptr; 1875 // Can omit 'and', and just return the overflow bit. 1876 return Op1; 1877 } 1878 1879 /// The @llvm.[us]mul.with.overflow intrinsic could have been folded from some 1880 /// other form of check, e.g. one that was using division; it may have been 1881 /// guarded against division-by-zero. We can drop that check now. 1882 /// Look for: 1883 /// %Op0 = icmp eq i4 %X, 0 1884 /// %Agg = tail call { i4, i1 } @llvm.[us]mul.with.overflow.i4(i4 %X, i4 %???) 1885 /// %Op1 = extractvalue { i4, i1 } %Agg, 1 1886 /// %NotOp1 = xor i1 %Op1, true 1887 /// %or = or i1 %Op0, %NotOp1 1888 /// We can just return %NotOp1 1889 static Value *omitCheckForZeroBeforeInvertedMulWithOverflow(Value *Op0, 1890 Value *NotOp1) { 1891 ICmpInst::Predicate Pred; 1892 Value *X; 1893 if (!match(Op0, m_ICmp(Pred, m_Value(X), m_Zero())) || 1894 Pred != ICmpInst::Predicate::ICMP_EQ) 1895 return nullptr; 1896 // We expect the other hand of an 'or' to be a 'not'. 1897 Value *Op1; 1898 if (!match(NotOp1, m_Not(m_Value(Op1)))) 1899 return nullptr; 1900 // Is Op1 in expected form? 1901 if (!omitCheckForZeroBeforeMulWithOverflowInternal(Op1, X)) 1902 return nullptr; 1903 // Can omit 'and', and just return the inverted overflow bit. 1904 return NotOp1; 1905 } 1906 1907 /// Given operands for an And, see if we can fold the result. 1908 /// If not, this returns null. 1909 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, 1910 unsigned MaxRecurse) { 1911 if (Constant *C = foldOrCommuteConstant(Instruction::And, Op0, Op1, Q)) 1912 return C; 1913 1914 // X & undef -> 0 1915 if (match(Op1, m_Undef())) 1916 return Constant::getNullValue(Op0->getType()); 1917 1918 // X & X = X 1919 if (Op0 == Op1) 1920 return Op0; 1921 1922 // X & 0 = 0 1923 if (match(Op1, m_Zero())) 1924 return Constant::getNullValue(Op0->getType()); 1925 1926 // X & -1 = X 1927 if (match(Op1, m_AllOnes())) 1928 return Op0; 1929 1930 // A & ~A = ~A & A = 0 1931 if (match(Op0, m_Not(m_Specific(Op1))) || 1932 match(Op1, m_Not(m_Specific(Op0)))) 1933 return Constant::getNullValue(Op0->getType()); 1934 1935 // (A | ?) & A = A 1936 if (match(Op0, m_c_Or(m_Specific(Op1), m_Value()))) 1937 return Op1; 1938 1939 // A & (A | ?) = A 1940 if (match(Op1, m_c_Or(m_Specific(Op0), m_Value()))) 1941 return Op0; 1942 1943 // A mask that only clears known zeros of a shifted value is a no-op. 1944 Value *X; 1945 const APInt *Mask; 1946 const APInt *ShAmt; 1947 if (match(Op1, m_APInt(Mask))) { 1948 // If all bits in the inverted and shifted mask are clear: 1949 // and (shl X, ShAmt), Mask --> shl X, ShAmt 1950 if (match(Op0, m_Shl(m_Value(X), m_APInt(ShAmt))) && 1951 (~(*Mask)).lshr(*ShAmt).isNullValue()) 1952 return Op0; 1953 1954 // If all bits in the inverted and shifted mask are clear: 1955 // and (lshr X, ShAmt), Mask --> lshr X, ShAmt 1956 if (match(Op0, m_LShr(m_Value(X), m_APInt(ShAmt))) && 1957 (~(*Mask)).shl(*ShAmt).isNullValue()) 1958 return Op0; 1959 } 1960 1961 // If we have a multiplication overflow check that is being 'and'ed with a 1962 // check that one of the multipliers is not zero, we can omit the 'and', and 1963 // only keep the overflow check. 1964 if (Value *V = omitCheckForZeroBeforeMulWithOverflow(Op0, Op1)) 1965 return V; 1966 if (Value *V = omitCheckForZeroBeforeMulWithOverflow(Op1, Op0)) 1967 return V; 1968 1969 // A & (-A) = A if A is a power of two or zero. 1970 if (match(Op0, m_Neg(m_Specific(Op1))) || 1971 match(Op1, m_Neg(m_Specific(Op0)))) { 1972 if (isKnownToBeAPowerOfTwo(Op0, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI, 1973 Q.DT)) 1974 return Op0; 1975 if (isKnownToBeAPowerOfTwo(Op1, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI, 1976 Q.DT)) 1977 return Op1; 1978 } 1979 1980 // This is a similar pattern used for checking if a value is a power-of-2: 1981 // (A - 1) & A --> 0 (if A is a power-of-2 or 0) 1982 // A & (A - 1) --> 0 (if A is a power-of-2 or 0) 1983 if (match(Op0, m_Add(m_Specific(Op1), m_AllOnes())) && 1984 isKnownToBeAPowerOfTwo(Op1, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI, Q.DT)) 1985 return Constant::getNullValue(Op1->getType()); 1986 if (match(Op1, m_Add(m_Specific(Op0), m_AllOnes())) && 1987 isKnownToBeAPowerOfTwo(Op0, Q.DL, /*OrZero*/ true, 0, Q.AC, Q.CxtI, Q.DT)) 1988 return Constant::getNullValue(Op0->getType()); 1989 1990 if (Value *V = simplifyAndOrOfCmps(Q, Op0, Op1, true)) 1991 return V; 1992 1993 // Try some generic simplifications for associative operations. 1994 if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q, 1995 MaxRecurse)) 1996 return V; 1997 1998 // And distributes over Or. Try some generic simplifications based on this. 1999 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Or, 2000 Q, MaxRecurse)) 2001 return V; 2002 2003 // And distributes over Xor. Try some generic simplifications based on this. 2004 if (Value *V = ExpandBinOp(Instruction::And, Op0, Op1, Instruction::Xor, 2005 Q, MaxRecurse)) 2006 return V; 2007 2008 // If the operation is with the result of a select instruction, check whether 2009 // operating on either branch of the select always yields the same value. 2010 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) 2011 if (Value *V = ThreadBinOpOverSelect(Instruction::And, Op0, Op1, Q, 2012 MaxRecurse)) 2013 return V; 2014 2015 // If the operation is with the result of a phi instruction, check whether 2016 // operating on all incoming values of the phi always yields the same value. 2017 if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) 2018 if (Value *V = ThreadBinOpOverPHI(Instruction::And, Op0, Op1, Q, 2019 MaxRecurse)) 2020 return V; 2021 2022 // Assuming the effective width of Y is not larger than A, i.e. all bits 2023 // from X and Y are disjoint in (X << A) | Y, 2024 // if the mask of this AND op covers all bits of X or Y, while it covers 2025 // no bits from the other, we can bypass this AND op. E.g., 2026 // ((X << A) | Y) & Mask -> Y, 2027 // if Mask = ((1 << effective_width_of(Y)) - 1) 2028 // ((X << A) | Y) & Mask -> X << A, 2029 // if Mask = ((1 << effective_width_of(X)) - 1) << A 2030 // SimplifyDemandedBits in InstCombine can optimize the general case. 2031 // This pattern aims to help other passes for a common case. 2032 Value *Y, *XShifted; 2033 if (match(Op1, m_APInt(Mask)) && 2034 match(Op0, m_c_Or(m_CombineAnd(m_NUWShl(m_Value(X), m_APInt(ShAmt)), 2035 m_Value(XShifted)), 2036 m_Value(Y)))) { 2037 const unsigned Width = Op0->getType()->getScalarSizeInBits(); 2038 const unsigned ShftCnt = ShAmt->getLimitedValue(Width); 2039 const KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2040 const unsigned EffWidthY = Width - YKnown.countMinLeadingZeros(); 2041 if (EffWidthY <= ShftCnt) { 2042 const KnownBits XKnown = computeKnownBits(X, Q.DL, 0, Q.AC, Q.CxtI, 2043 Q.DT); 2044 const unsigned EffWidthX = Width - XKnown.countMinLeadingZeros(); 2045 const APInt EffBitsY = APInt::getLowBitsSet(Width, EffWidthY); 2046 const APInt EffBitsX = APInt::getLowBitsSet(Width, EffWidthX) << ShftCnt; 2047 // If the mask is extracting all bits from X or Y as is, we can skip 2048 // this AND op. 2049 if (EffBitsY.isSubsetOf(*Mask) && !EffBitsX.intersects(*Mask)) 2050 return Y; 2051 if (EffBitsX.isSubsetOf(*Mask) && !EffBitsY.intersects(*Mask)) 2052 return XShifted; 2053 } 2054 } 2055 2056 return nullptr; 2057 } 2058 2059 Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) { 2060 return ::SimplifyAndInst(Op0, Op1, Q, RecursionLimit); 2061 } 2062 2063 /// Given operands for an Or, see if we can fold the result. 2064 /// If not, this returns null. 2065 static Value *SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, 2066 unsigned MaxRecurse) { 2067 if (Constant *C = foldOrCommuteConstant(Instruction::Or, Op0, Op1, Q)) 2068 return C; 2069 2070 // X | undef -> -1 2071 // X | -1 = -1 2072 // Do not return Op1 because it may contain undef elements if it's a vector. 2073 if (match(Op1, m_Undef()) || match(Op1, m_AllOnes())) 2074 return Constant::getAllOnesValue(Op0->getType()); 2075 2076 // X | X = X 2077 // X | 0 = X 2078 if (Op0 == Op1 || match(Op1, m_Zero())) 2079 return Op0; 2080 2081 // A | ~A = ~A | A = -1 2082 if (match(Op0, m_Not(m_Specific(Op1))) || 2083 match(Op1, m_Not(m_Specific(Op0)))) 2084 return Constant::getAllOnesValue(Op0->getType()); 2085 2086 // (A & ?) | A = A 2087 if (match(Op0, m_c_And(m_Specific(Op1), m_Value()))) 2088 return Op1; 2089 2090 // A | (A & ?) = A 2091 if (match(Op1, m_c_And(m_Specific(Op0), m_Value()))) 2092 return Op0; 2093 2094 // ~(A & ?) | A = -1 2095 if (match(Op0, m_Not(m_c_And(m_Specific(Op1), m_Value())))) 2096 return Constant::getAllOnesValue(Op1->getType()); 2097 2098 // A | ~(A & ?) = -1 2099 if (match(Op1, m_Not(m_c_And(m_Specific(Op1), m_Value())))) 2100 return Constant::getAllOnesValue(Op0->getType()); 2101 2102 Value *A, *B; 2103 // (A & ~B) | (A ^ B) -> (A ^ B) 2104 // (~B & A) | (A ^ B) -> (A ^ B) 2105 // (A & ~B) | (B ^ A) -> (B ^ A) 2106 // (~B & A) | (B ^ A) -> (B ^ A) 2107 if (match(Op1, m_Xor(m_Value(A), m_Value(B))) && 2108 (match(Op0, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) || 2109 match(Op0, m_c_And(m_Not(m_Specific(A)), m_Specific(B))))) 2110 return Op1; 2111 2112 // Commute the 'or' operands. 2113 // (A ^ B) | (A & ~B) -> (A ^ B) 2114 // (A ^ B) | (~B & A) -> (A ^ B) 2115 // (B ^ A) | (A & ~B) -> (B ^ A) 2116 // (B ^ A) | (~B & A) -> (B ^ A) 2117 if (match(Op0, m_Xor(m_Value(A), m_Value(B))) && 2118 (match(Op1, m_c_And(m_Specific(A), m_Not(m_Specific(B)))) || 2119 match(Op1, m_c_And(m_Not(m_Specific(A)), m_Specific(B))))) 2120 return Op0; 2121 2122 // (A & B) | (~A ^ B) -> (~A ^ B) 2123 // (B & A) | (~A ^ B) -> (~A ^ B) 2124 // (A & B) | (B ^ ~A) -> (B ^ ~A) 2125 // (B & A) | (B ^ ~A) -> (B ^ ~A) 2126 if (match(Op0, m_And(m_Value(A), m_Value(B))) && 2127 (match(Op1, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) || 2128 match(Op1, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B))))) 2129 return Op1; 2130 2131 // (~A ^ B) | (A & B) -> (~A ^ B) 2132 // (~A ^ B) | (B & A) -> (~A ^ B) 2133 // (B ^ ~A) | (A & B) -> (B ^ ~A) 2134 // (B ^ ~A) | (B & A) -> (B ^ ~A) 2135 if (match(Op1, m_And(m_Value(A), m_Value(B))) && 2136 (match(Op0, m_c_Xor(m_Specific(A), m_Not(m_Specific(B)))) || 2137 match(Op0, m_c_Xor(m_Not(m_Specific(A)), m_Specific(B))))) 2138 return Op0; 2139 2140 if (Value *V = simplifyAndOrOfCmps(Q, Op0, Op1, false)) 2141 return V; 2142 2143 // If we have a multiplication overflow check that is being 'and'ed with a 2144 // check that one of the multipliers is not zero, we can omit the 'and', and 2145 // only keep the overflow check. 2146 if (Value *V = omitCheckForZeroBeforeInvertedMulWithOverflow(Op0, Op1)) 2147 return V; 2148 if (Value *V = omitCheckForZeroBeforeInvertedMulWithOverflow(Op1, Op0)) 2149 return V; 2150 2151 // Try some generic simplifications for associative operations. 2152 if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, Q, 2153 MaxRecurse)) 2154 return V; 2155 2156 // Or distributes over And. Try some generic simplifications based on this. 2157 if (Value *V = ExpandBinOp(Instruction::Or, Op0, Op1, Instruction::And, Q, 2158 MaxRecurse)) 2159 return V; 2160 2161 // If the operation is with the result of a select instruction, check whether 2162 // operating on either branch of the select always yields the same value. 2163 if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1)) 2164 if (Value *V = ThreadBinOpOverSelect(Instruction::Or, Op0, Op1, Q, 2165 MaxRecurse)) 2166 return V; 2167 2168 // (A & C1)|(B & C2) 2169 const APInt *C1, *C2; 2170 if (match(Op0, m_And(m_Value(A), m_APInt(C1))) && 2171 match(Op1, m_And(m_Value(B), m_APInt(C2)))) { 2172 if (*C1 == ~*C2) { 2173 // (A & C1)|(B & C2) 2174 // If we have: ((V + N) & C1) | (V & C2) 2175 // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0 2176 // replace with V+N. 2177 Value *N; 2178 if (C2->isMask() && // C2 == 0+1+ 2179 match(A, m_c_Add(m_Specific(B), m_Value(N)))) { 2180 // Add commutes, try both ways. 2181 if (MaskedValueIsZero(N, *C2, Q.DL, 0, Q.AC, Q.CxtI, Q.DT)) 2182 return A; 2183 } 2184 // Or commutes, try both ways. 2185 if (C1->isMask() && 2186 match(B, m_c_Add(m_Specific(A), m_Value(N)))) { 2187 // Add commutes, try both ways. 2188 if (MaskedValueIsZero(N, *C1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT)) 2189 return B; 2190 } 2191 } 2192 } 2193 2194 // If the operation is with the result of a phi instruction, check whether 2195 // operating on all incoming values of the phi always yields the same value. 2196 if (isa<PHINode>(Op0) || isa<PHINode>(Op1)) 2197 if (Value *V = ThreadBinOpOverPHI(Instruction::Or, Op0, Op1, Q, MaxRecurse)) 2198 return V; 2199 2200 return nullptr; 2201 } 2202 2203 Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) { 2204 return ::SimplifyOrInst(Op0, Op1, Q, RecursionLimit); 2205 } 2206 2207 /// Given operands for a Xor, see if we can fold the result. 2208 /// If not, this returns null. 2209 static Value *SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q, 2210 unsigned MaxRecurse) { 2211 if (Constant *C = foldOrCommuteConstant(Instruction::Xor, Op0, Op1, Q)) 2212 return C; 2213 2214 // A ^ undef -> undef 2215 if (match(Op1, m_Undef())) 2216 return Op1; 2217 2218 // A ^ 0 = A 2219 if (match(Op1, m_Zero())) 2220 return Op0; 2221 2222 // A ^ A = 0 2223 if (Op0 == Op1) 2224 return Constant::getNullValue(Op0->getType()); 2225 2226 // A ^ ~A = ~A ^ A = -1 2227 if (match(Op0, m_Not(m_Specific(Op1))) || 2228 match(Op1, m_Not(m_Specific(Op0)))) 2229 return Constant::getAllOnesValue(Op0->getType()); 2230 2231 // Try some generic simplifications for associative operations. 2232 if (Value *V = SimplifyAssociativeBinOp(Instruction::Xor, Op0, Op1, Q, 2233 MaxRecurse)) 2234 return V; 2235 2236 // Threading Xor over selects and phi nodes is pointless, so don't bother. 2237 // Threading over the select in "A ^ select(cond, B, C)" means evaluating 2238 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and 2239 // only if B and C are equal. If B and C are equal then (since we assume 2240 // that operands have already been simplified) "select(cond, B, C)" should 2241 // have been simplified to the common value of B and C already. Analysing 2242 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly 2243 // for threading over phi nodes. 2244 2245 return nullptr; 2246 } 2247 2248 Value *llvm::SimplifyXorInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) { 2249 return ::SimplifyXorInst(Op0, Op1, Q, RecursionLimit); 2250 } 2251 2252 2253 static Type *GetCompareTy(Value *Op) { 2254 return CmpInst::makeCmpResultType(Op->getType()); 2255 } 2256 2257 /// Rummage around inside V looking for something equivalent to the comparison 2258 /// "LHS Pred RHS". Return such a value if found, otherwise return null. 2259 /// Helper function for analyzing max/min idioms. 2260 static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred, 2261 Value *LHS, Value *RHS) { 2262 SelectInst *SI = dyn_cast<SelectInst>(V); 2263 if (!SI) 2264 return nullptr; 2265 CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition()); 2266 if (!Cmp) 2267 return nullptr; 2268 Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1); 2269 if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS) 2270 return Cmp; 2271 if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) && 2272 LHS == CmpRHS && RHS == CmpLHS) 2273 return Cmp; 2274 return nullptr; 2275 } 2276 2277 // A significant optimization not implemented here is assuming that alloca 2278 // addresses are not equal to incoming argument values. They don't *alias*, 2279 // as we say, but that doesn't mean they aren't equal, so we take a 2280 // conservative approach. 2281 // 2282 // This is inspired in part by C++11 5.10p1: 2283 // "Two pointers of the same type compare equal if and only if they are both 2284 // null, both point to the same function, or both represent the same 2285 // address." 2286 // 2287 // This is pretty permissive. 2288 // 2289 // It's also partly due to C11 6.5.9p6: 2290 // "Two pointers compare equal if and only if both are null pointers, both are 2291 // pointers to the same object (including a pointer to an object and a 2292 // subobject at its beginning) or function, both are pointers to one past the 2293 // last element of the same array object, or one is a pointer to one past the 2294 // end of one array object and the other is a pointer to the start of a 2295 // different array object that happens to immediately follow the first array 2296 // object in the address space.) 2297 // 2298 // C11's version is more restrictive, however there's no reason why an argument 2299 // couldn't be a one-past-the-end value for a stack object in the caller and be 2300 // equal to the beginning of a stack object in the callee. 2301 // 2302 // If the C and C++ standards are ever made sufficiently restrictive in this 2303 // area, it may be possible to update LLVM's semantics accordingly and reinstate 2304 // this optimization. 2305 static Constant * 2306 computePointerICmp(const DataLayout &DL, const TargetLibraryInfo *TLI, 2307 const DominatorTree *DT, CmpInst::Predicate Pred, 2308 AssumptionCache *AC, const Instruction *CxtI, 2309 const InstrInfoQuery &IIQ, Value *LHS, Value *RHS) { 2310 // First, skip past any trivial no-ops. 2311 LHS = LHS->stripPointerCasts(); 2312 RHS = RHS->stripPointerCasts(); 2313 2314 // A non-null pointer is not equal to a null pointer. 2315 if (llvm::isKnownNonZero(LHS, DL, 0, nullptr, nullptr, nullptr, 2316 IIQ.UseInstrInfo) && 2317 isa<ConstantPointerNull>(RHS) && 2318 (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE)) 2319 return ConstantInt::get(GetCompareTy(LHS), 2320 !CmpInst::isTrueWhenEqual(Pred)); 2321 2322 // We can only fold certain predicates on pointer comparisons. 2323 switch (Pred) { 2324 default: 2325 return nullptr; 2326 2327 // Equality comaprisons are easy to fold. 2328 case CmpInst::ICMP_EQ: 2329 case CmpInst::ICMP_NE: 2330 break; 2331 2332 // We can only handle unsigned relational comparisons because 'inbounds' on 2333 // a GEP only protects against unsigned wrapping. 2334 case CmpInst::ICMP_UGT: 2335 case CmpInst::ICMP_UGE: 2336 case CmpInst::ICMP_ULT: 2337 case CmpInst::ICMP_ULE: 2338 // However, we have to switch them to their signed variants to handle 2339 // negative indices from the base pointer. 2340 Pred = ICmpInst::getSignedPredicate(Pred); 2341 break; 2342 } 2343 2344 // Strip off any constant offsets so that we can reason about them. 2345 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets 2346 // here and compare base addresses like AliasAnalysis does, however there are 2347 // numerous hazards. AliasAnalysis and its utilities rely on special rules 2348 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis 2349 // doesn't need to guarantee pointer inequality when it says NoAlias. 2350 Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS); 2351 Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS); 2352 2353 // If LHS and RHS are related via constant offsets to the same base 2354 // value, we can replace it with an icmp which just compares the offsets. 2355 if (LHS == RHS) 2356 return ConstantExpr::getICmp(Pred, LHSOffset, RHSOffset); 2357 2358 // Various optimizations for (in)equality comparisons. 2359 if (Pred == CmpInst::ICMP_EQ || Pred == CmpInst::ICMP_NE) { 2360 // Different non-empty allocations that exist at the same time have 2361 // different addresses (if the program can tell). Global variables always 2362 // exist, so they always exist during the lifetime of each other and all 2363 // allocas. Two different allocas usually have different addresses... 2364 // 2365 // However, if there's an @llvm.stackrestore dynamically in between two 2366 // allocas, they may have the same address. It's tempting to reduce the 2367 // scope of the problem by only looking at *static* allocas here. That would 2368 // cover the majority of allocas while significantly reducing the likelihood 2369 // of having an @llvm.stackrestore pop up in the middle. However, it's not 2370 // actually impossible for an @llvm.stackrestore to pop up in the middle of 2371 // an entry block. Also, if we have a block that's not attached to a 2372 // function, we can't tell if it's "static" under the current definition. 2373 // Theoretically, this problem could be fixed by creating a new kind of 2374 // instruction kind specifically for static allocas. Such a new instruction 2375 // could be required to be at the top of the entry block, thus preventing it 2376 // from being subject to a @llvm.stackrestore. Instcombine could even 2377 // convert regular allocas into these special allocas. It'd be nifty. 2378 // However, until then, this problem remains open. 2379 // 2380 // So, we'll assume that two non-empty allocas have different addresses 2381 // for now. 2382 // 2383 // With all that, if the offsets are within the bounds of their allocations 2384 // (and not one-past-the-end! so we can't use inbounds!), and their 2385 // allocations aren't the same, the pointers are not equal. 2386 // 2387 // Note that it's not necessary to check for LHS being a global variable 2388 // address, due to canonicalization and constant folding. 2389 if (isa<AllocaInst>(LHS) && 2390 (isa<AllocaInst>(RHS) || isa<GlobalVariable>(RHS))) { 2391 ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset); 2392 ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset); 2393 uint64_t LHSSize, RHSSize; 2394 ObjectSizeOpts Opts; 2395 Opts.NullIsUnknownSize = 2396 NullPointerIsDefined(cast<AllocaInst>(LHS)->getFunction()); 2397 if (LHSOffsetCI && RHSOffsetCI && 2398 getObjectSize(LHS, LHSSize, DL, TLI, Opts) && 2399 getObjectSize(RHS, RHSSize, DL, TLI, Opts)) { 2400 const APInt &LHSOffsetValue = LHSOffsetCI->getValue(); 2401 const APInt &RHSOffsetValue = RHSOffsetCI->getValue(); 2402 if (!LHSOffsetValue.isNegative() && 2403 !RHSOffsetValue.isNegative() && 2404 LHSOffsetValue.ult(LHSSize) && 2405 RHSOffsetValue.ult(RHSSize)) { 2406 return ConstantInt::get(GetCompareTy(LHS), 2407 !CmpInst::isTrueWhenEqual(Pred)); 2408 } 2409 } 2410 2411 // Repeat the above check but this time without depending on DataLayout 2412 // or being able to compute a precise size. 2413 if (!cast<PointerType>(LHS->getType())->isEmptyTy() && 2414 !cast<PointerType>(RHS->getType())->isEmptyTy() && 2415 LHSOffset->isNullValue() && 2416 RHSOffset->isNullValue()) 2417 return ConstantInt::get(GetCompareTy(LHS), 2418 !CmpInst::isTrueWhenEqual(Pred)); 2419 } 2420 2421 // Even if an non-inbounds GEP occurs along the path we can still optimize 2422 // equality comparisons concerning the result. We avoid walking the whole 2423 // chain again by starting where the last calls to 2424 // stripAndComputeConstantOffsets left off and accumulate the offsets. 2425 Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true); 2426 Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true); 2427 if (LHS == RHS) 2428 return ConstantExpr::getICmp(Pred, 2429 ConstantExpr::getAdd(LHSOffset, LHSNoBound), 2430 ConstantExpr::getAdd(RHSOffset, RHSNoBound)); 2431 2432 // If one side of the equality comparison must come from a noalias call 2433 // (meaning a system memory allocation function), and the other side must 2434 // come from a pointer that cannot overlap with dynamically-allocated 2435 // memory within the lifetime of the current function (allocas, byval 2436 // arguments, globals), then determine the comparison result here. 2437 SmallVector<const Value *, 8> LHSUObjs, RHSUObjs; 2438 GetUnderlyingObjects(LHS, LHSUObjs, DL); 2439 GetUnderlyingObjects(RHS, RHSUObjs, DL); 2440 2441 // Is the set of underlying objects all noalias calls? 2442 auto IsNAC = [](ArrayRef<const Value *> Objects) { 2443 return all_of(Objects, isNoAliasCall); 2444 }; 2445 2446 // Is the set of underlying objects all things which must be disjoint from 2447 // noalias calls. For allocas, we consider only static ones (dynamic 2448 // allocas might be transformed into calls to malloc not simultaneously 2449 // live with the compared-to allocation). For globals, we exclude symbols 2450 // that might be resolve lazily to symbols in another dynamically-loaded 2451 // library (and, thus, could be malloc'ed by the implementation). 2452 auto IsAllocDisjoint = [](ArrayRef<const Value *> Objects) { 2453 return all_of(Objects, [](const Value *V) { 2454 if (const AllocaInst *AI = dyn_cast<AllocaInst>(V)) 2455 return AI->getParent() && AI->getFunction() && AI->isStaticAlloca(); 2456 if (const GlobalValue *GV = dyn_cast<GlobalValue>(V)) 2457 return (GV->hasLocalLinkage() || GV->hasHiddenVisibility() || 2458 GV->hasProtectedVisibility() || GV->hasGlobalUnnamedAddr()) && 2459 !GV->isThreadLocal(); 2460 if (const Argument *A = dyn_cast<Argument>(V)) 2461 return A->hasByValAttr(); 2462 return false; 2463 }); 2464 }; 2465 2466 if ((IsNAC(LHSUObjs) && IsAllocDisjoint(RHSUObjs)) || 2467 (IsNAC(RHSUObjs) && IsAllocDisjoint(LHSUObjs))) 2468 return ConstantInt::get(GetCompareTy(LHS), 2469 !CmpInst::isTrueWhenEqual(Pred)); 2470 2471 // Fold comparisons for non-escaping pointer even if the allocation call 2472 // cannot be elided. We cannot fold malloc comparison to null. Also, the 2473 // dynamic allocation call could be either of the operands. 2474 Value *MI = nullptr; 2475 if (isAllocLikeFn(LHS, TLI) && 2476 llvm::isKnownNonZero(RHS, DL, 0, nullptr, CxtI, DT)) 2477 MI = LHS; 2478 else if (isAllocLikeFn(RHS, TLI) && 2479 llvm::isKnownNonZero(LHS, DL, 0, nullptr, CxtI, DT)) 2480 MI = RHS; 2481 // FIXME: We should also fold the compare when the pointer escapes, but the 2482 // compare dominates the pointer escape 2483 if (MI && !PointerMayBeCaptured(MI, true, true)) 2484 return ConstantInt::get(GetCompareTy(LHS), 2485 CmpInst::isFalseWhenEqual(Pred)); 2486 } 2487 2488 // Otherwise, fail. 2489 return nullptr; 2490 } 2491 2492 /// Fold an icmp when its operands have i1 scalar type. 2493 static Value *simplifyICmpOfBools(CmpInst::Predicate Pred, Value *LHS, 2494 Value *RHS, const SimplifyQuery &Q) { 2495 Type *ITy = GetCompareTy(LHS); // The return type. 2496 Type *OpTy = LHS->getType(); // The operand type. 2497 if (!OpTy->isIntOrIntVectorTy(1)) 2498 return nullptr; 2499 2500 // A boolean compared to true/false can be simplified in 14 out of the 20 2501 // (10 predicates * 2 constants) possible combinations. Cases not handled here 2502 // require a 'not' of the LHS, so those must be transformed in InstCombine. 2503 if (match(RHS, m_Zero())) { 2504 switch (Pred) { 2505 case CmpInst::ICMP_NE: // X != 0 -> X 2506 case CmpInst::ICMP_UGT: // X >u 0 -> X 2507 case CmpInst::ICMP_SLT: // X <s 0 -> X 2508 return LHS; 2509 2510 case CmpInst::ICMP_ULT: // X <u 0 -> false 2511 case CmpInst::ICMP_SGT: // X >s 0 -> false 2512 return getFalse(ITy); 2513 2514 case CmpInst::ICMP_UGE: // X >=u 0 -> true 2515 case CmpInst::ICMP_SLE: // X <=s 0 -> true 2516 return getTrue(ITy); 2517 2518 default: break; 2519 } 2520 } else if (match(RHS, m_One())) { 2521 switch (Pred) { 2522 case CmpInst::ICMP_EQ: // X == 1 -> X 2523 case CmpInst::ICMP_UGE: // X >=u 1 -> X 2524 case CmpInst::ICMP_SLE: // X <=s -1 -> X 2525 return LHS; 2526 2527 case CmpInst::ICMP_UGT: // X >u 1 -> false 2528 case CmpInst::ICMP_SLT: // X <s -1 -> false 2529 return getFalse(ITy); 2530 2531 case CmpInst::ICMP_ULE: // X <=u 1 -> true 2532 case CmpInst::ICMP_SGE: // X >=s -1 -> true 2533 return getTrue(ITy); 2534 2535 default: break; 2536 } 2537 } 2538 2539 switch (Pred) { 2540 default: 2541 break; 2542 case ICmpInst::ICMP_UGE: 2543 if (isImpliedCondition(RHS, LHS, Q.DL).getValueOr(false)) 2544 return getTrue(ITy); 2545 break; 2546 case ICmpInst::ICMP_SGE: 2547 /// For signed comparison, the values for an i1 are 0 and -1 2548 /// respectively. This maps into a truth table of: 2549 /// LHS | RHS | LHS >=s RHS | LHS implies RHS 2550 /// 0 | 0 | 1 (0 >= 0) | 1 2551 /// 0 | 1 | 1 (0 >= -1) | 1 2552 /// 1 | 0 | 0 (-1 >= 0) | 0 2553 /// 1 | 1 | 1 (-1 >= -1) | 1 2554 if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false)) 2555 return getTrue(ITy); 2556 break; 2557 case ICmpInst::ICMP_ULE: 2558 if (isImpliedCondition(LHS, RHS, Q.DL).getValueOr(false)) 2559 return getTrue(ITy); 2560 break; 2561 } 2562 2563 return nullptr; 2564 } 2565 2566 /// Try hard to fold icmp with zero RHS because this is a common case. 2567 static Value *simplifyICmpWithZero(CmpInst::Predicate Pred, Value *LHS, 2568 Value *RHS, const SimplifyQuery &Q) { 2569 if (!match(RHS, m_Zero())) 2570 return nullptr; 2571 2572 Type *ITy = GetCompareTy(LHS); // The return type. 2573 switch (Pred) { 2574 default: 2575 llvm_unreachable("Unknown ICmp predicate!"); 2576 case ICmpInst::ICMP_ULT: 2577 return getFalse(ITy); 2578 case ICmpInst::ICMP_UGE: 2579 return getTrue(ITy); 2580 case ICmpInst::ICMP_EQ: 2581 case ICmpInst::ICMP_ULE: 2582 if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT, Q.IIQ.UseInstrInfo)) 2583 return getFalse(ITy); 2584 break; 2585 case ICmpInst::ICMP_NE: 2586 case ICmpInst::ICMP_UGT: 2587 if (isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT, Q.IIQ.UseInstrInfo)) 2588 return getTrue(ITy); 2589 break; 2590 case ICmpInst::ICMP_SLT: { 2591 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2592 if (LHSKnown.isNegative()) 2593 return getTrue(ITy); 2594 if (LHSKnown.isNonNegative()) 2595 return getFalse(ITy); 2596 break; 2597 } 2598 case ICmpInst::ICMP_SLE: { 2599 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2600 if (LHSKnown.isNegative()) 2601 return getTrue(ITy); 2602 if (LHSKnown.isNonNegative() && 2603 isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT)) 2604 return getFalse(ITy); 2605 break; 2606 } 2607 case ICmpInst::ICMP_SGE: { 2608 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2609 if (LHSKnown.isNegative()) 2610 return getFalse(ITy); 2611 if (LHSKnown.isNonNegative()) 2612 return getTrue(ITy); 2613 break; 2614 } 2615 case ICmpInst::ICMP_SGT: { 2616 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2617 if (LHSKnown.isNegative()) 2618 return getFalse(ITy); 2619 if (LHSKnown.isNonNegative() && 2620 isKnownNonZero(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT)) 2621 return getTrue(ITy); 2622 break; 2623 } 2624 } 2625 2626 return nullptr; 2627 } 2628 2629 static Value *simplifyICmpWithConstant(CmpInst::Predicate Pred, Value *LHS, 2630 Value *RHS, const InstrInfoQuery &IIQ) { 2631 Type *ITy = GetCompareTy(RHS); // The return type. 2632 2633 Value *X; 2634 // Sign-bit checks can be optimized to true/false after unsigned 2635 // floating-point casts: 2636 // icmp slt (bitcast (uitofp X)), 0 --> false 2637 // icmp sgt (bitcast (uitofp X)), -1 --> true 2638 if (match(LHS, m_BitCast(m_UIToFP(m_Value(X))))) { 2639 if (Pred == ICmpInst::ICMP_SLT && match(RHS, m_Zero())) 2640 return ConstantInt::getFalse(ITy); 2641 if (Pred == ICmpInst::ICMP_SGT && match(RHS, m_AllOnes())) 2642 return ConstantInt::getTrue(ITy); 2643 } 2644 2645 const APInt *C; 2646 if (!match(RHS, m_APInt(C))) 2647 return nullptr; 2648 2649 // Rule out tautological comparisons (eg., ult 0 or uge 0). 2650 ConstantRange RHS_CR = ConstantRange::makeExactICmpRegion(Pred, *C); 2651 if (RHS_CR.isEmptySet()) 2652 return ConstantInt::getFalse(ITy); 2653 if (RHS_CR.isFullSet()) 2654 return ConstantInt::getTrue(ITy); 2655 2656 ConstantRange LHS_CR = computeConstantRange(LHS, IIQ.UseInstrInfo); 2657 if (!LHS_CR.isFullSet()) { 2658 if (RHS_CR.contains(LHS_CR)) 2659 return ConstantInt::getTrue(ITy); 2660 if (RHS_CR.inverse().contains(LHS_CR)) 2661 return ConstantInt::getFalse(ITy); 2662 } 2663 2664 return nullptr; 2665 } 2666 2667 /// TODO: A large part of this logic is duplicated in InstCombine's 2668 /// foldICmpBinOp(). We should be able to share that and avoid the code 2669 /// duplication. 2670 static Value *simplifyICmpWithBinOp(CmpInst::Predicate Pred, Value *LHS, 2671 Value *RHS, const SimplifyQuery &Q, 2672 unsigned MaxRecurse) { 2673 Type *ITy = GetCompareTy(LHS); // The return type. 2674 2675 BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS); 2676 BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS); 2677 if (MaxRecurse && (LBO || RBO)) { 2678 // Analyze the case when either LHS or RHS is an add instruction. 2679 Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr; 2680 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null). 2681 bool NoLHSWrapProblem = false, NoRHSWrapProblem = false; 2682 if (LBO && LBO->getOpcode() == Instruction::Add) { 2683 A = LBO->getOperand(0); 2684 B = LBO->getOperand(1); 2685 NoLHSWrapProblem = 2686 ICmpInst::isEquality(Pred) || 2687 (CmpInst::isUnsigned(Pred) && 2688 Q.IIQ.hasNoUnsignedWrap(cast<OverflowingBinaryOperator>(LBO))) || 2689 (CmpInst::isSigned(Pred) && 2690 Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(LBO))); 2691 } 2692 if (RBO && RBO->getOpcode() == Instruction::Add) { 2693 C = RBO->getOperand(0); 2694 D = RBO->getOperand(1); 2695 NoRHSWrapProblem = 2696 ICmpInst::isEquality(Pred) || 2697 (CmpInst::isUnsigned(Pred) && 2698 Q.IIQ.hasNoUnsignedWrap(cast<OverflowingBinaryOperator>(RBO))) || 2699 (CmpInst::isSigned(Pred) && 2700 Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(RBO))); 2701 } 2702 2703 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow. 2704 if ((A == RHS || B == RHS) && NoLHSWrapProblem) 2705 if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A, 2706 Constant::getNullValue(RHS->getType()), Q, 2707 MaxRecurse - 1)) 2708 return V; 2709 2710 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow. 2711 if ((C == LHS || D == LHS) && NoRHSWrapProblem) 2712 if (Value *V = 2713 SimplifyICmpInst(Pred, Constant::getNullValue(LHS->getType()), 2714 C == LHS ? D : C, Q, MaxRecurse - 1)) 2715 return V; 2716 2717 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow. 2718 if (A && C && (A == C || A == D || B == C || B == D) && NoLHSWrapProblem && 2719 NoRHSWrapProblem) { 2720 // Determine Y and Z in the form icmp (X+Y), (X+Z). 2721 Value *Y, *Z; 2722 if (A == C) { 2723 // C + B == C + D -> B == D 2724 Y = B; 2725 Z = D; 2726 } else if (A == D) { 2727 // D + B == C + D -> B == C 2728 Y = B; 2729 Z = C; 2730 } else if (B == C) { 2731 // A + C == C + D -> A == D 2732 Y = A; 2733 Z = D; 2734 } else { 2735 assert(B == D); 2736 // A + D == C + D -> A == C 2737 Y = A; 2738 Z = C; 2739 } 2740 if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse - 1)) 2741 return V; 2742 } 2743 } 2744 2745 { 2746 Value *Y = nullptr; 2747 // icmp pred (or X, Y), X 2748 if (LBO && match(LBO, m_c_Or(m_Value(Y), m_Specific(RHS)))) { 2749 if (Pred == ICmpInst::ICMP_ULT) 2750 return getFalse(ITy); 2751 if (Pred == ICmpInst::ICMP_UGE) 2752 return getTrue(ITy); 2753 2754 if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SGE) { 2755 KnownBits RHSKnown = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2756 KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2757 if (RHSKnown.isNonNegative() && YKnown.isNegative()) 2758 return Pred == ICmpInst::ICMP_SLT ? getTrue(ITy) : getFalse(ITy); 2759 if (RHSKnown.isNegative() || YKnown.isNonNegative()) 2760 return Pred == ICmpInst::ICMP_SLT ? getFalse(ITy) : getTrue(ITy); 2761 } 2762 } 2763 // icmp pred X, (or X, Y) 2764 if (RBO && match(RBO, m_c_Or(m_Value(Y), m_Specific(LHS)))) { 2765 if (Pred == ICmpInst::ICMP_ULE) 2766 return getTrue(ITy); 2767 if (Pred == ICmpInst::ICMP_UGT) 2768 return getFalse(ITy); 2769 2770 if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SLE) { 2771 KnownBits LHSKnown = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2772 KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2773 if (LHSKnown.isNonNegative() && YKnown.isNegative()) 2774 return Pred == ICmpInst::ICMP_SGT ? getTrue(ITy) : getFalse(ITy); 2775 if (LHSKnown.isNegative() || YKnown.isNonNegative()) 2776 return Pred == ICmpInst::ICMP_SGT ? getFalse(ITy) : getTrue(ITy); 2777 } 2778 } 2779 } 2780 2781 // icmp pred (and X, Y), X 2782 if (LBO && match(LBO, m_c_And(m_Value(), m_Specific(RHS)))) { 2783 if (Pred == ICmpInst::ICMP_UGT) 2784 return getFalse(ITy); 2785 if (Pred == ICmpInst::ICMP_ULE) 2786 return getTrue(ITy); 2787 } 2788 // icmp pred X, (and X, Y) 2789 if (RBO && match(RBO, m_c_And(m_Value(), m_Specific(LHS)))) { 2790 if (Pred == ICmpInst::ICMP_UGE) 2791 return getTrue(ITy); 2792 if (Pred == ICmpInst::ICMP_ULT) 2793 return getFalse(ITy); 2794 } 2795 2796 // 0 - (zext X) pred C 2797 if (!CmpInst::isUnsigned(Pred) && match(LHS, m_Neg(m_ZExt(m_Value())))) { 2798 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(RHS)) { 2799 if (RHSC->getValue().isStrictlyPositive()) { 2800 if (Pred == ICmpInst::ICMP_SLT) 2801 return ConstantInt::getTrue(RHSC->getContext()); 2802 if (Pred == ICmpInst::ICMP_SGE) 2803 return ConstantInt::getFalse(RHSC->getContext()); 2804 if (Pred == ICmpInst::ICMP_EQ) 2805 return ConstantInt::getFalse(RHSC->getContext()); 2806 if (Pred == ICmpInst::ICMP_NE) 2807 return ConstantInt::getTrue(RHSC->getContext()); 2808 } 2809 if (RHSC->getValue().isNonNegative()) { 2810 if (Pred == ICmpInst::ICMP_SLE) 2811 return ConstantInt::getTrue(RHSC->getContext()); 2812 if (Pred == ICmpInst::ICMP_SGT) 2813 return ConstantInt::getFalse(RHSC->getContext()); 2814 } 2815 } 2816 } 2817 2818 // icmp pred (urem X, Y), Y 2819 if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) { 2820 switch (Pred) { 2821 default: 2822 break; 2823 case ICmpInst::ICMP_SGT: 2824 case ICmpInst::ICMP_SGE: { 2825 KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2826 if (!Known.isNonNegative()) 2827 break; 2828 LLVM_FALLTHROUGH; 2829 } 2830 case ICmpInst::ICMP_EQ: 2831 case ICmpInst::ICMP_UGT: 2832 case ICmpInst::ICMP_UGE: 2833 return getFalse(ITy); 2834 case ICmpInst::ICMP_SLT: 2835 case ICmpInst::ICMP_SLE: { 2836 KnownBits Known = computeKnownBits(RHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2837 if (!Known.isNonNegative()) 2838 break; 2839 LLVM_FALLTHROUGH; 2840 } 2841 case ICmpInst::ICMP_NE: 2842 case ICmpInst::ICMP_ULT: 2843 case ICmpInst::ICMP_ULE: 2844 return getTrue(ITy); 2845 } 2846 } 2847 2848 // icmp pred X, (urem Y, X) 2849 if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) { 2850 switch (Pred) { 2851 default: 2852 break; 2853 case ICmpInst::ICMP_SGT: 2854 case ICmpInst::ICMP_SGE: { 2855 KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2856 if (!Known.isNonNegative()) 2857 break; 2858 LLVM_FALLTHROUGH; 2859 } 2860 case ICmpInst::ICMP_NE: 2861 case ICmpInst::ICMP_UGT: 2862 case ICmpInst::ICMP_UGE: 2863 return getTrue(ITy); 2864 case ICmpInst::ICMP_SLT: 2865 case ICmpInst::ICMP_SLE: { 2866 KnownBits Known = computeKnownBits(LHS, Q.DL, 0, Q.AC, Q.CxtI, Q.DT); 2867 if (!Known.isNonNegative()) 2868 break; 2869 LLVM_FALLTHROUGH; 2870 } 2871 case ICmpInst::ICMP_EQ: 2872 case ICmpInst::ICMP_ULT: 2873 case ICmpInst::ICMP_ULE: 2874 return getFalse(ITy); 2875 } 2876 } 2877 2878 // x >> y <=u x 2879 // x udiv y <=u x. 2880 if (LBO && (match(LBO, m_LShr(m_Specific(RHS), m_Value())) || 2881 match(LBO, m_UDiv(m_Specific(RHS), m_Value())))) { 2882 // icmp pred (X op Y), X 2883 if (Pred == ICmpInst::ICMP_UGT) 2884 return getFalse(ITy); 2885 if (Pred == ICmpInst::ICMP_ULE) 2886 return getTrue(ITy); 2887 } 2888 2889 // x >=u x >> y 2890 // x >=u x udiv y. 2891 if (RBO && (match(RBO, m_LShr(m_Specific(LHS), m_Value())) || 2892 match(RBO, m_UDiv(m_Specific(LHS), m_Value())))) { 2893 // icmp pred X, (X op Y) 2894 if (Pred == ICmpInst::ICMP_ULT) 2895 return getFalse(ITy); 2896 if (Pred == ICmpInst::ICMP_UGE) 2897 return getTrue(ITy); 2898 } 2899 2900 // handle: 2901 // CI2 << X == CI 2902 // CI2 << X != CI 2903 // 2904 // where CI2 is a power of 2 and CI isn't 2905 if (auto *CI = dyn_cast<ConstantInt>(RHS)) { 2906 const APInt *CI2Val, *CIVal = &CI->getValue(); 2907 if (LBO && match(LBO, m_Shl(m_APInt(CI2Val), m_Value())) && 2908 CI2Val->isPowerOf2()) { 2909 if (!CIVal->isPowerOf2()) { 2910 // CI2 << X can equal zero in some circumstances, 2911 // this simplification is unsafe if CI is zero. 2912 // 2913 // We know it is safe if: 2914 // - The shift is nsw, we can't shift out the one bit. 2915 // - The shift is nuw, we can't shift out the one bit. 2916 // - CI2 is one 2917 // - CI isn't zero 2918 if (Q.IIQ.hasNoSignedWrap(cast<OverflowingBinaryOperator>(LBO)) || 2919 Q.IIQ.hasNoUnsignedWrap(cast<OverflowingBinaryOperator>(LBO)) || 2920 CI2Val->isOneValue() || !CI->isZero()) { 2921 if (Pred == ICmpInst::ICMP_EQ) 2922 return ConstantInt::getFalse(RHS->getContext()); 2923 if (Pred == ICmpInst::ICMP_NE) 2924 return ConstantInt::getTrue(RHS->getContext()); 2925 } 2926 } 2927 if (CIVal->isSignMask() && CI2Val->isOneValue()) { 2928 if (Pred == ICmpInst::ICMP_UGT) 2929 return ConstantInt::getFalse(RHS->getContext()); 2930 if (Pred == ICmpInst::ICMP_ULE) 2931 return ConstantInt::getTrue(RHS->getContext()); 2932 } 2933 } 2934 } 2935 2936 if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() && 2937 LBO->getOperand(1) == RBO->getOperand(1)) { 2938 switch (LBO->getOpcode()) { 2939 default: 2940 break; 2941 case Instruction::UDiv: 2942 case Instruction::LShr: 2943 if (ICmpInst::isSigned(Pred) || !Q.IIQ.isExact(LBO) || 2944 !Q.IIQ.isExact(RBO)) 2945 break; 2946 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0), 2947 RBO->getOperand(0), Q, MaxRecurse - 1)) 2948 return V; 2949 break; 2950 case Instruction::SDiv: 2951 if (!ICmpInst::isEquality(Pred) || !Q.IIQ.isExact(LBO) || 2952 !Q.IIQ.isExact(RBO)) 2953 break; 2954 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0), 2955 RBO->getOperand(0), Q, MaxRecurse - 1)) 2956 return V; 2957 break; 2958 case Instruction::AShr: 2959 if (!Q.IIQ.isExact(LBO) || !Q.IIQ.isExact(RBO)) 2960 break; 2961 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0), 2962 RBO->getOperand(0), Q, MaxRecurse - 1)) 2963 return V; 2964 break; 2965 case Instruction::Shl: { 2966 bool NUW = Q.IIQ.hasNoUnsignedWrap(LBO) && Q.IIQ.hasNoUnsignedWrap(RBO); 2967 bool NSW = Q.IIQ.hasNoSignedWrap(LBO) && Q.IIQ.hasNoSignedWrap(RBO); 2968 if (!NUW && !NSW) 2969 break; 2970 if (!NSW && ICmpInst::isSigned(Pred)) 2971 break; 2972 if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0), 2973 RBO->getOperand(0), Q, MaxRecurse - 1)) 2974 return V; 2975 break; 2976 } 2977 } 2978 } 2979 return nullptr; 2980 } 2981 2982 /// Simplify integer comparisons where at least one operand of the compare 2983 /// matches an integer min/max idiom. 2984 static Value *simplifyICmpWithMinMax(CmpInst::Predicate Pred, Value *LHS, 2985 Value *RHS, const SimplifyQuery &Q, 2986 unsigned MaxRecurse) { 2987 Type *ITy = GetCompareTy(LHS); // The return type. 2988 Value *A, *B; 2989 CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE; 2990 CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B". 2991 2992 // Signed variants on "max(a,b)>=a -> true". 2993 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) { 2994 if (A != RHS) 2995 std::swap(A, B); // smax(A, B) pred A. 2996 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B". 2997 // We analyze this as smax(A, B) pred A. 2998 P = Pred; 2999 } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) && 3000 (A == LHS || B == LHS)) { 3001 if (A != LHS) 3002 std::swap(A, B); // A pred smax(A, B). 3003 EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B". 3004 // We analyze this as smax(A, B) swapped-pred A. 3005 P = CmpInst::getSwappedPredicate(Pred); 3006 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) && 3007 (A == RHS || B == RHS)) { 3008 if (A != RHS) 3009 std::swap(A, B); // smin(A, B) pred A. 3010 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B". 3011 // We analyze this as smax(-A, -B) swapped-pred -A. 3012 // Note that we do not need to actually form -A or -B thanks to EqP. 3013 P = CmpInst::getSwappedPredicate(Pred); 3014 } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) && 3015 (A == LHS || B == LHS)) { 3016 if (A != LHS) 3017 std::swap(A, B); // A pred smin(A, B). 3018 EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B". 3019 // We analyze this as smax(-A, -B) pred -A. 3020 // Note that we do not need to actually form -A or -B thanks to EqP. 3021 P = Pred; 3022 } 3023 if (P != CmpInst::BAD_ICMP_PREDICATE) { 3024 // Cases correspond to "max(A, B) p A". 3025 switch (P) { 3026 default: 3027 break; 3028 case CmpInst::ICMP_EQ: 3029 case CmpInst::ICMP_SLE: 3030 // Equivalent to "A EqP B". This may be the same as the condition tested 3031 // in the max/min; if so, we can just return that. 3032 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B)) 3033 return V; 3034 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B)) 3035 return V; 3036 // Otherwise, see if "A EqP B" simplifies. 3037 if (MaxRecurse) 3038 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1)) 3039 return V; 3040 break; 3041 case CmpInst::ICMP_NE: 3042 case CmpInst::ICMP_SGT: { 3043 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP); 3044 // Equivalent to "A InvEqP B". This may be the same as the condition 3045 // tested in the max/min; if so, we can just return that. 3046 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B)) 3047 return V; 3048 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B)) 3049 return V; 3050 // Otherwise, see if "A InvEqP B" simplifies. 3051 if (MaxRecurse) 3052 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1)) 3053 return V; 3054 break; 3055 } 3056 case CmpInst::ICMP_SGE: 3057 // Always true. 3058 return getTrue(ITy); 3059 case CmpInst::ICMP_SLT: 3060 // Always false. 3061 return getFalse(ITy); 3062 } 3063 } 3064 3065 // Unsigned variants on "max(a,b)>=a -> true". 3066 P = CmpInst::BAD_ICMP_PREDICATE; 3067 if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) { 3068 if (A != RHS) 3069 std::swap(A, B); // umax(A, B) pred A. 3070 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B". 3071 // We analyze this as umax(A, B) pred A. 3072 P = Pred; 3073 } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) && 3074 (A == LHS || B == LHS)) { 3075 if (A != LHS) 3076 std::swap(A, B); // A pred umax(A, B). 3077 EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B". 3078 // We analyze this as umax(A, B) swapped-pred A. 3079 P = CmpInst::getSwappedPredicate(Pred); 3080 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) && 3081 (A == RHS || B == RHS)) { 3082 if (A != RHS) 3083 std::swap(A, B); // umin(A, B) pred A. 3084 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B". 3085 // We analyze this as umax(-A, -B) swapped-pred -A. 3086 // Note that we do not need to actually form -A or -B thanks to EqP. 3087 P = CmpInst::getSwappedPredicate(Pred); 3088 } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) && 3089 (A == LHS || B == LHS)) { 3090 if (A != LHS) 3091 std::swap(A, B); // A pred umin(A, B). 3092 EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B". 3093 // We analyze this as umax(-A, -B) pred -A. 3094 // Note that we do not need to actually form -A or -B thanks to EqP. 3095 P = Pred; 3096 } 3097 if (P != CmpInst::BAD_ICMP_PREDICATE) { 3098 // Cases correspond to "max(A, B) p A". 3099 switch (P) { 3100 default: 3101 break; 3102 case CmpInst::ICMP_EQ: 3103 case CmpInst::ICMP_ULE: 3104 // Equivalent to "A EqP B". This may be the same as the condition tested 3105 // in the max/min; if so, we can just return that. 3106 if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B)) 3107 return V; 3108 if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B)) 3109 return V; 3110 // Otherwise, see if "A EqP B" simplifies. 3111 if (MaxRecurse) 3112 if (Value *V = SimplifyICmpInst(EqP, A, B, Q, MaxRecurse - 1)) 3113 return V; 3114 break; 3115 case CmpInst::ICMP_NE: 3116 case CmpInst::ICMP_UGT: { 3117 CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP); 3118 // Equivalent to "A InvEqP B". This may be the same as the condition 3119 // tested in the max/min; if so, we can just return that. 3120 if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B)) 3121 return V; 3122 if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B)) 3123 return V; 3124 // Otherwise, see if "A InvEqP B" simplifies. 3125 if (MaxRecurse) 3126 if (Value *V = SimplifyICmpInst(InvEqP, A, B, Q, MaxRecurse - 1)) 3127 return V; 3128 break; 3129 } 3130 case CmpInst::ICMP_UGE: 3131 // Always true. 3132 return getTrue(ITy); 3133 case CmpInst::ICMP_ULT: 3134 // Always false. 3135 return getFalse(ITy); 3136 } 3137 } 3138 3139 // Variants on "max(x,y) >= min(x,z)". 3140 Value *C, *D; 3141 if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && 3142 match(RHS, m_SMin(m_Value(C), m_Value(D))) && 3143 (A == C || A == D || B == C || B == D)) { 3144 // max(x, ?) pred min(x, ?). 3145 if (Pred == CmpInst::ICMP_SGE) 3146 // Always true. 3147 return getTrue(ITy); 3148 if (Pred == CmpInst::ICMP_SLT) 3149 // Always false. 3150 return getFalse(ITy); 3151 } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) && 3152 match(RHS, m_SMax(m_Value(C), m_Value(D))) && 3153 (A == C || A == D || B == C || B == D)) { 3154 // min(x, ?) pred max(x, ?). 3155 if (Pred == CmpInst::ICMP_SLE) 3156 // Always true. 3157 return getTrue(ITy); 3158 if (Pred == CmpInst::ICMP_SGT) 3159 // Always false. 3160 return getFalse(ITy); 3161 } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && 3162 match(RHS, m_UMin(m_Value(C), m_Value(D))) && 3163 (A == C || A == D || B == C || B == D)) { 3164 // max(x, ?) pred min(x, ?). 3165 if (Pred == CmpInst::ICMP_UGE) 3166 // Always true. 3167 return getTrue(ITy); 3168 if (Pred == CmpInst::ICMP_ULT) 3169 // Always false. 3170 return getFalse(ITy); 3171 } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) && 3172 match(RHS, m_UMax(m_Value(C), m_Value(D))) && 3173 (A == C || A == D || B == C || B == D)) { 3174 // min(x, ?) pred max(x, ?). 3175 if (Pred == CmpInst::ICMP_ULE) 3176 // Always true. 3177 return getTrue(ITy); 3178 if (Pred == CmpInst::ICMP_UGT) 3179 // Always false. 3180 return getFalse(ITy); 3181 } 3182 3183 return nullptr; 3184 } 3185 3186 /// Given operands for an ICmpInst, see if we can fold the result. 3187 /// If not, this returns null. 3188 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, 3189 const SimplifyQuery &Q, unsigned MaxRecurse) { 3190 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate; 3191 assert(CmpInst::isIntPredicate(Pred) && "Not an integer compare!"); 3192 3193 if (Constant *CLHS = dyn_cast<Constant>(LHS)) { 3194 if (Constant *CRHS = dyn_cast<Constant>(RHS)) 3195 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI); 3196 3197 // If we have a constant, make sure it is on the RHS. 3198 std::swap(LHS, RHS); 3199 Pred = CmpInst::getSwappedPredicate(Pred); 3200 } 3201 assert(!isa<UndefValue>(LHS) && "Unexpected icmp undef,%X"); 3202 3203 Type *ITy = GetCompareTy(LHS); // The return type. 3204 3205 // For EQ and NE, we can always pick a value for the undef to make the 3206 // predicate pass or fail, so we can return undef. 3207 // Matches behavior in llvm::ConstantFoldCompareInstruction. 3208 if (isa<UndefValue>(RHS) && ICmpInst::isEquality(Pred)) 3209 return UndefValue::get(ITy); 3210 3211 // icmp X, X -> true/false 3212 // icmp X, undef -> true/false because undef could be X. 3213 if (LHS == RHS || isa<UndefValue>(RHS)) 3214 return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred)); 3215 3216 if (Value *V = simplifyICmpOfBools(Pred, LHS, RHS, Q)) 3217 return V; 3218 3219 if (Value *V = simplifyICmpWithZero(Pred, LHS, RHS, Q)) 3220 return V; 3221 3222 if (Value *V = simplifyICmpWithConstant(Pred, LHS, RHS, Q.IIQ)) 3223 return V; 3224 3225 // If both operands have range metadata, use the metadata 3226 // to simplify the comparison. 3227 if (isa<Instruction>(RHS) && isa<Instruction>(LHS)) { 3228 auto RHS_Instr = cast<Instruction>(RHS); 3229 auto LHS_Instr = cast<Instruction>(LHS); 3230 3231 if (Q.IIQ.getMetadata(RHS_Instr, LLVMContext::MD_range) && 3232 Q.IIQ.getMetadata(LHS_Instr, LLVMContext::MD_range)) { 3233 auto RHS_CR = getConstantRangeFromMetadata( 3234 *RHS_Instr->getMetadata(LLVMContext::MD_range)); 3235 auto LHS_CR = getConstantRangeFromMetadata( 3236 *LHS_Instr->getMetadata(LLVMContext::MD_range)); 3237 3238 auto Satisfied_CR = ConstantRange::makeSatisfyingICmpRegion(Pred, RHS_CR); 3239 if (Satisfied_CR.contains(LHS_CR)) 3240 return ConstantInt::getTrue(RHS->getContext()); 3241 3242 auto InversedSatisfied_CR = ConstantRange::makeSatisfyingICmpRegion( 3243 CmpInst::getInversePredicate(Pred), RHS_CR); 3244 if (InversedSatisfied_CR.contains(LHS_CR)) 3245 return ConstantInt::getFalse(RHS->getContext()); 3246 } 3247 } 3248 3249 // Compare of cast, for example (zext X) != 0 -> X != 0 3250 if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) { 3251 Instruction *LI = cast<CastInst>(LHS); 3252 Value *SrcOp = LI->getOperand(0); 3253 Type *SrcTy = SrcOp->getType(); 3254 Type *DstTy = LI->getType(); 3255 3256 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input 3257 // if the integer type is the same size as the pointer type. 3258 if (MaxRecurse && isa<PtrToIntInst>(LI) && 3259 Q.DL.getTypeSizeInBits(SrcTy) == DstTy->getPrimitiveSizeInBits()) { 3260 if (Constant *RHSC = dyn_cast<Constant>(RHS)) { 3261 // Transfer the cast to the constant. 3262 if (Value *V = SimplifyICmpInst(Pred, SrcOp, 3263 ConstantExpr::getIntToPtr(RHSC, SrcTy), 3264 Q, MaxRecurse-1)) 3265 return V; 3266 } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) { 3267 if (RI->getOperand(0)->getType() == SrcTy) 3268 // Compare without the cast. 3269 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0), 3270 Q, MaxRecurse-1)) 3271 return V; 3272 } 3273 } 3274 3275 if (isa<ZExtInst>(LHS)) { 3276 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the 3277 // same type. 3278 if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) { 3279 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType()) 3280 // Compare X and Y. Note that signed predicates become unsigned. 3281 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred), 3282 SrcOp, RI->getOperand(0), Q, 3283 MaxRecurse-1)) 3284 return V; 3285 } 3286 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended 3287 // too. If not, then try to deduce the result of the comparison. 3288 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) { 3289 // Compute the constant that would happen if we truncated to SrcTy then 3290 // reextended to DstTy. 3291 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy); 3292 Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy); 3293 3294 // If the re-extended constant didn't change then this is effectively 3295 // also a case of comparing two zero-extended values. 3296 if (RExt == CI && MaxRecurse) 3297 if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred), 3298 SrcOp, Trunc, Q, MaxRecurse-1)) 3299 return V; 3300 3301 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit 3302 // there. Use this to work out the result of the comparison. 3303 if (RExt != CI) { 3304 switch (Pred) { 3305 default: llvm_unreachable("Unknown ICmp predicate!"); 3306 // LHS <u RHS. 3307 case ICmpInst::ICMP_EQ: 3308 case ICmpInst::ICMP_UGT: 3309 case ICmpInst::ICMP_UGE: 3310 return ConstantInt::getFalse(CI->getContext()); 3311 3312 case ICmpInst::ICMP_NE: 3313 case ICmpInst::ICMP_ULT: 3314 case ICmpInst::ICMP_ULE: 3315 return ConstantInt::getTrue(CI->getContext()); 3316 3317 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS 3318 // is non-negative then LHS <s RHS. 3319 case ICmpInst::ICMP_SGT: 3320 case ICmpInst::ICMP_SGE: 3321 return CI->getValue().isNegative() ? 3322 ConstantInt::getTrue(CI->getContext()) : 3323 ConstantInt::getFalse(CI->getContext()); 3324 3325 case ICmpInst::ICMP_SLT: 3326 case ICmpInst::ICMP_SLE: 3327 return CI->getValue().isNegative() ? 3328 ConstantInt::getFalse(CI->getContext()) : 3329 ConstantInt::getTrue(CI->getContext()); 3330 } 3331 } 3332 } 3333 } 3334 3335 if (isa<SExtInst>(LHS)) { 3336 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the 3337 // same type. 3338 if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) { 3339 if (MaxRecurse && SrcTy == RI->getOperand(0)->getType()) 3340 // Compare X and Y. Note that the predicate does not change. 3341 if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0), 3342 Q, MaxRecurse-1)) 3343 return V; 3344 } 3345 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended 3346 // too. If not, then try to deduce the result of the comparison. 3347 else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) { 3348 // Compute the constant that would happen if we truncated to SrcTy then 3349 // reextended to DstTy. 3350 Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy); 3351 Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy); 3352 3353 // If the re-extended constant didn't change then this is effectively 3354 // also a case of comparing two sign-extended values. 3355 if (RExt == CI && MaxRecurse) 3356 if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, Q, MaxRecurse-1)) 3357 return V; 3358 3359 // Otherwise the upper bits of LHS are all equal, while RHS has varying 3360 // bits there. Use this to work out the result of the comparison. 3361 if (RExt != CI) { 3362 switch (Pred) { 3363 default: llvm_unreachable("Unknown ICmp predicate!"); 3364 case ICmpInst::ICMP_EQ: 3365 return ConstantInt::getFalse(CI->getContext()); 3366 case ICmpInst::ICMP_NE: 3367 return ConstantInt::getTrue(CI->getContext()); 3368 3369 // If RHS is non-negative then LHS <s RHS. If RHS is negative then 3370 // LHS >s RHS. 3371 case ICmpInst::ICMP_SGT: 3372 case ICmpInst::ICMP_SGE: 3373 return CI->getValue().isNegative() ? 3374 ConstantInt::getTrue(CI->getContext()) : 3375 ConstantInt::getFalse(CI->getContext()); 3376 case ICmpInst::ICMP_SLT: 3377 case ICmpInst::ICMP_SLE: 3378 return CI->getValue().isNegative() ? 3379 ConstantInt::getFalse(CI->getContext()) : 3380 ConstantInt::getTrue(CI->getContext()); 3381 3382 // If LHS is non-negative then LHS <u RHS. If LHS is negative then 3383 // LHS >u RHS. 3384 case ICmpInst::ICMP_UGT: 3385 case ICmpInst::ICMP_UGE: 3386 // Comparison is true iff the LHS <s 0. 3387 if (MaxRecurse) 3388 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp, 3389 Constant::getNullValue(SrcTy), 3390 Q, MaxRecurse-1)) 3391 return V; 3392 break; 3393 case ICmpInst::ICMP_ULT: 3394 case ICmpInst::ICMP_ULE: 3395 // Comparison is true iff the LHS >=s 0. 3396 if (MaxRecurse) 3397 if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp, 3398 Constant::getNullValue(SrcTy), 3399 Q, MaxRecurse-1)) 3400 return V; 3401 break; 3402 } 3403 } 3404 } 3405 } 3406 } 3407 3408 // icmp eq|ne X, Y -> false|true if X != Y 3409 if (ICmpInst::isEquality(Pred) && 3410 isKnownNonEqual(LHS, RHS, Q.DL, Q.AC, Q.CxtI, Q.DT, Q.IIQ.UseInstrInfo)) { 3411 return Pred == ICmpInst::ICMP_NE ? getTrue(ITy) : getFalse(ITy); 3412 } 3413 3414 if (Value *V = simplifyICmpWithBinOp(Pred, LHS, RHS, Q, MaxRecurse)) 3415 return V; 3416 3417 if (Value *V = simplifyICmpWithMinMax(Pred, LHS, RHS, Q, MaxRecurse)) 3418 return V; 3419 3420 // Simplify comparisons of related pointers using a powerful, recursive 3421 // GEP-walk when we have target data available.. 3422 if (LHS->getType()->isPointerTy()) 3423 if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI, 3424 Q.IIQ, LHS, RHS)) 3425 return C; 3426 if (auto *CLHS = dyn_cast<PtrToIntOperator>(LHS)) 3427 if (auto *CRHS = dyn_cast<PtrToIntOperator>(RHS)) 3428 if (Q.DL.getTypeSizeInBits(CLHS->getPointerOperandType()) == 3429 Q.DL.getTypeSizeInBits(CLHS->getType()) && 3430 Q.DL.getTypeSizeInBits(CRHS->getPointerOperandType()) == 3431 Q.DL.getTypeSizeInBits(CRHS->getType())) 3432 if (auto *C = computePointerICmp(Q.DL, Q.TLI, Q.DT, Pred, Q.AC, Q.CxtI, 3433 Q.IIQ, CLHS->getPointerOperand(), 3434 CRHS->getPointerOperand())) 3435 return C; 3436 3437 if (GetElementPtrInst *GLHS = dyn_cast<GetElementPtrInst>(LHS)) { 3438 if (GEPOperator *GRHS = dyn_cast<GEPOperator>(RHS)) { 3439 if (GLHS->getPointerOperand() == GRHS->getPointerOperand() && 3440 GLHS->hasAllConstantIndices() && GRHS->hasAllConstantIndices() && 3441 (ICmpInst::isEquality(Pred) || 3442 (GLHS->isInBounds() && GRHS->isInBounds() && 3443 Pred == ICmpInst::getSignedPredicate(Pred)))) { 3444 // The bases are equal and the indices are constant. Build a constant 3445 // expression GEP with the same indices and a null base pointer to see 3446 // what constant folding can make out of it. 3447 Constant *Null = Constant::getNullValue(GLHS->getPointerOperandType()); 3448 SmallVector<Value *, 4> IndicesLHS(GLHS->idx_begin(), GLHS->idx_end()); 3449 Constant *NewLHS = ConstantExpr::getGetElementPtr( 3450 GLHS->getSourceElementType(), Null, IndicesLHS); 3451 3452 SmallVector<Value *, 4> IndicesRHS(GRHS->idx_begin(), GRHS->idx_end()); 3453 Constant *NewRHS = ConstantExpr::getGetElementPtr( 3454 GLHS->getSourceElementType(), Null, IndicesRHS); 3455 return ConstantExpr::getICmp(Pred, NewLHS, NewRHS); 3456 } 3457 } 3458 } 3459 3460 // If the comparison is with the result of a select instruction, check whether 3461 // comparing with either branch of the select always yields the same value. 3462 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS)) 3463 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse)) 3464 return V; 3465 3466 // If the comparison is with the result of a phi instruction, check whether 3467 // doing the compare with each incoming phi value yields a common result. 3468 if (isa<PHINode>(LHS) || isa<PHINode>(RHS)) 3469 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse)) 3470 return V; 3471 3472 return nullptr; 3473 } 3474 3475 Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, 3476 const SimplifyQuery &Q) { 3477 return ::SimplifyICmpInst(Predicate, LHS, RHS, Q, RecursionLimit); 3478 } 3479 3480 /// Given operands for an FCmpInst, see if we can fold the result. 3481 /// If not, this returns null. 3482 static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, 3483 FastMathFlags FMF, const SimplifyQuery &Q, 3484 unsigned MaxRecurse) { 3485 CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate; 3486 assert(CmpInst::isFPPredicate(Pred) && "Not an FP compare!"); 3487 3488 if (Constant *CLHS = dyn_cast<Constant>(LHS)) { 3489 if (Constant *CRHS = dyn_cast<Constant>(RHS)) 3490 return ConstantFoldCompareInstOperands(Pred, CLHS, CRHS, Q.DL, Q.TLI); 3491 3492 // If we have a constant, make sure it is on the RHS. 3493 std::swap(LHS, RHS); 3494 Pred = CmpInst::getSwappedPredicate(Pred); 3495 } 3496 3497 // Fold trivial predicates. 3498 Type *RetTy = GetCompareTy(LHS); 3499 if (Pred == FCmpInst::FCMP_FALSE) 3500 return getFalse(RetTy); 3501 if (Pred == FCmpInst::FCMP_TRUE) 3502 return getTrue(RetTy); 3503 3504 // Fold (un)ordered comparison if we can determine there are no NaNs. 3505 if (Pred == FCmpInst::FCMP_UNO || Pred == FCmpInst::FCMP_ORD) 3506 if (FMF.noNaNs() || 3507 (isKnownNeverNaN(LHS, Q.TLI) && isKnownNeverNaN(RHS, Q.TLI))) 3508 return ConstantInt::get(RetTy, Pred == FCmpInst::FCMP_ORD); 3509 3510 // NaN is unordered; NaN is not ordered. 3511 assert((FCmpInst::isOrdered(Pred) || FCmpInst::isUnordered(Pred)) && 3512 "Comparison must be either ordered or unordered"); 3513 if (match(RHS, m_NaN())) 3514 return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred)); 3515 3516 // fcmp pred x, undef and fcmp pred undef, x 3517 // fold to true if unordered, false if ordered 3518 if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS)) { 3519 // Choosing NaN for the undef will always make unordered comparison succeed 3520 // and ordered comparison fail. 3521 return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred)); 3522 } 3523 3524 // fcmp x,x -> true/false. Not all compares are foldable. 3525 if (LHS == RHS) { 3526 if (CmpInst::isTrueWhenEqual(Pred)) 3527 return getTrue(RetTy); 3528 if (CmpInst::isFalseWhenEqual(Pred)) 3529 return getFalse(RetTy); 3530 } 3531 3532 // Handle fcmp with constant RHS. 3533 // TODO: Use match with a specific FP value, so these work with vectors with 3534 // undef lanes. 3535 const APFloat *C; 3536 if (match(RHS, m_APFloat(C))) { 3537 // Check whether the constant is an infinity. 3538 if (C->isInfinity()) { 3539 if (C->isNegative()) { 3540 switch (Pred) { 3541 case FCmpInst::FCMP_OLT: 3542 // No value is ordered and less than negative infinity. 3543 return getFalse(RetTy); 3544 case FCmpInst::FCMP_UGE: 3545 // All values are unordered with or at least negative infinity. 3546 return getTrue(RetTy); 3547 default: 3548 break; 3549 } 3550 } else { 3551 switch (Pred) { 3552 case FCmpInst::FCMP_OGT: 3553 // No value is ordered and greater than infinity. 3554 return getFalse(RetTy); 3555 case FCmpInst::FCMP_ULE: 3556 // All values are unordered with and at most infinity. 3557 return getTrue(RetTy); 3558 default: 3559 break; 3560 } 3561 } 3562 } 3563 if (C->isNegative() && !C->isNegZero()) { 3564 assert(!C->isNaN() && "Unexpected NaN constant!"); 3565 // TODO: We can catch more cases by using a range check rather than 3566 // relying on CannotBeOrderedLessThanZero. 3567 switch (Pred) { 3568 case FCmpInst::FCMP_UGE: 3569 case FCmpInst::FCMP_UGT: 3570 case FCmpInst::FCMP_UNE: 3571 // (X >= 0) implies (X > C) when (C < 0) 3572 if (CannotBeOrderedLessThanZero(LHS, Q.TLI)) 3573 return getTrue(RetTy); 3574 break; 3575 case FCmpInst::FCMP_OEQ: 3576 case FCmpInst::FCMP_OLE: 3577 case FCmpInst::FCMP_OLT: 3578 // (X >= 0) implies !(X < C) when (C < 0) 3579 if (CannotBeOrderedLessThanZero(LHS, Q.TLI)) 3580 return getFalse(RetTy); 3581 break; 3582 default: 3583 break; 3584 } 3585 } 3586 3587 // Check comparison of [minnum/maxnum with constant] with other constant. 3588 const APFloat *C2; 3589 if ((match(LHS, m_Intrinsic<Intrinsic::minnum>(m_Value(), m_APFloat(C2))) && 3590 C2->compare(*C) == APFloat::cmpLessThan) || 3591 (match(LHS, m_Intrinsic<Intrinsic::maxnum>(m_Value(), m_APFloat(C2))) && 3592 C2->compare(*C) == APFloat::cmpGreaterThan)) { 3593 bool IsMaxNum = 3594 cast<IntrinsicInst>(LHS)->getIntrinsicID() == Intrinsic::maxnum; 3595 // The ordered relationship and minnum/maxnum guarantee that we do not 3596 // have NaN constants, so ordered/unordered preds are handled the same. 3597 switch (Pred) { 3598 case FCmpInst::FCMP_OEQ: case FCmpInst::FCMP_UEQ: 3599 // minnum(X, LesserC) == C --> false 3600 // maxnum(X, GreaterC) == C --> false 3601 return getFalse(RetTy); 3602 case FCmpInst::FCMP_ONE: case FCmpInst::FCMP_UNE: 3603 // minnum(X, LesserC) != C --> true 3604 // maxnum(X, GreaterC) != C --> true 3605 return getTrue(RetTy); 3606 case FCmpInst::FCMP_OGE: case FCmpInst::FCMP_UGE: 3607 case FCmpInst::FCMP_OGT: case FCmpInst::FCMP_UGT: 3608 // minnum(X, LesserC) >= C --> false 3609 // minnum(X, LesserC) > C --> false 3610 // maxnum(X, GreaterC) >= C --> true 3611 // maxnum(X, GreaterC) > C --> true 3612 return ConstantInt::get(RetTy, IsMaxNum); 3613 case FCmpInst::FCMP_OLE: case FCmpInst::FCMP_ULE: 3614 case FCmpInst::FCMP_OLT: case FCmpInst::FCMP_ULT: 3615 // minnum(X, LesserC) <= C --> true 3616 // minnum(X, LesserC) < C --> true 3617 // maxnum(X, GreaterC) <= C --> false 3618 // maxnum(X, GreaterC) < C --> false 3619 return ConstantInt::get(RetTy, !IsMaxNum); 3620 default: 3621 // TRUE/FALSE/ORD/UNO should be handled before this. 3622 llvm_unreachable("Unexpected fcmp predicate"); 3623 } 3624 } 3625 } 3626 3627 if (match(RHS, m_AnyZeroFP())) { 3628 switch (Pred) { 3629 case FCmpInst::FCMP_OGE: 3630 case FCmpInst::FCMP_ULT: 3631 // Positive or zero X >= 0.0 --> true 3632 // Positive or zero X < 0.0 --> false 3633 if ((FMF.noNaNs() || isKnownNeverNaN(LHS, Q.TLI)) && 3634 CannotBeOrderedLessThanZero(LHS, Q.TLI)) 3635 return Pred == FCmpInst::FCMP_OGE ? getTrue(RetTy) : getFalse(RetTy); 3636 break; 3637 case FCmpInst::FCMP_UGE: 3638 case FCmpInst::FCMP_OLT: 3639 // Positive or zero or nan X >= 0.0 --> true 3640 // Positive or zero or nan X < 0.0 --> false 3641 if (CannotBeOrderedLessThanZero(LHS, Q.TLI)) 3642 return Pred == FCmpInst::FCMP_UGE ? getTrue(RetTy) : getFalse(RetTy); 3643 break; 3644 default: 3645 break; 3646 } 3647 } 3648 3649 // If the comparison is with the result of a select instruction, check whether 3650 // comparing with either branch of the select always yields the same value. 3651 if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS)) 3652 if (Value *V = ThreadCmpOverSelect(Pred, LHS, RHS, Q, MaxRecurse)) 3653 return V; 3654 3655 // If the comparison is with the result of a phi instruction, check whether 3656 // doing the compare with each incoming phi value yields a common result. 3657 if (isa<PHINode>(LHS) || isa<PHINode>(RHS)) 3658 if (Value *V = ThreadCmpOverPHI(Pred, LHS, RHS, Q, MaxRecurse)) 3659 return V; 3660 3661 return nullptr; 3662 } 3663 3664 Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, 3665 FastMathFlags FMF, const SimplifyQuery &Q) { 3666 return ::SimplifyFCmpInst(Predicate, LHS, RHS, FMF, Q, RecursionLimit); 3667 } 3668 3669 /// See if V simplifies when its operand Op is replaced with RepOp. 3670 static const Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp, 3671 const SimplifyQuery &Q, 3672 unsigned MaxRecurse) { 3673 // Trivial replacement. 3674 if (V == Op) 3675 return RepOp; 3676 3677 // We cannot replace a constant, and shouldn't even try. 3678 if (isa<Constant>(Op)) 3679 return nullptr; 3680 3681 auto *I = dyn_cast<Instruction>(V); 3682 if (!I) 3683 return nullptr; 3684 3685 // If this is a binary operator, try to simplify it with the replaced op. 3686 if (auto *B = dyn_cast<BinaryOperator>(I)) { 3687 // Consider: 3688 // %cmp = icmp eq i32 %x, 2147483647 3689 // %add = add nsw i32 %x, 1 3690 // %sel = select i1 %cmp, i32 -2147483648, i32 %add 3691 // 3692 // We can't replace %sel with %add unless we strip away the flags. 3693 // TODO: This is an unusual limitation because better analysis results in 3694 // worse simplification. InstCombine can do this fold more generally 3695 // by dropping the flags. Remove this fold to save compile-time? 3696 if (isa<OverflowingBinaryOperator>(B)) 3697 if (Q.IIQ.hasNoSignedWrap(B) || Q.IIQ.hasNoUnsignedWrap(B)) 3698 return nullptr; 3699 if (isa<PossiblyExactOperator>(B) && Q.IIQ.isExact(B)) 3700 return nullptr; 3701 3702 if (MaxRecurse) { 3703 if (B->getOperand(0) == Op) 3704 return SimplifyBinOp(B->getOpcode(), RepOp, B->getOperand(1), Q, 3705 MaxRecurse - 1); 3706 if (B->getOperand(1) == Op) 3707 return SimplifyBinOp(B->getOpcode(), B->getOperand(0), RepOp, Q, 3708 MaxRecurse - 1); 3709 } 3710 } 3711 3712 // Same for CmpInsts. 3713 if (CmpInst *C = dyn_cast<CmpInst>(I)) { 3714 if (MaxRecurse) { 3715 if (C->getOperand(0) == Op) 3716 return SimplifyCmpInst(C->getPredicate(), RepOp, C->getOperand(1), Q, 3717 MaxRecurse - 1); 3718 if (C->getOperand(1) == Op) 3719 return SimplifyCmpInst(C->getPredicate(), C->getOperand(0), RepOp, Q, 3720 MaxRecurse - 1); 3721 } 3722 } 3723 3724 // Same for GEPs. 3725 if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) { 3726 if (MaxRecurse) { 3727 SmallVector<Value *, 8> NewOps(GEP->getNumOperands()); 3728 transform(GEP->operands(), NewOps.begin(), 3729 [&](Value *V) { return V == Op ? RepOp : V; }); 3730 return SimplifyGEPInst(GEP->getSourceElementType(), NewOps, Q, 3731 MaxRecurse - 1); 3732 } 3733 } 3734 3735 // TODO: We could hand off more cases to instsimplify here. 3736 3737 // If all operands are constant after substituting Op for RepOp then we can 3738 // constant fold the instruction. 3739 if (Constant *CRepOp = dyn_cast<Constant>(RepOp)) { 3740 // Build a list of all constant operands. 3741 SmallVector<Constant *, 8> ConstOps; 3742 for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { 3743 if (I->getOperand(i) == Op) 3744 ConstOps.push_back(CRepOp); 3745 else if (Constant *COp = dyn_cast<Constant>(I->getOperand(i))) 3746 ConstOps.push_back(COp); 3747 else 3748 break; 3749 } 3750 3751 // All operands were constants, fold it. 3752 if (ConstOps.size() == I->getNumOperands()) { 3753 if (CmpInst *C = dyn_cast<CmpInst>(I)) 3754 return ConstantFoldCompareInstOperands(C->getPredicate(), ConstOps[0], 3755 ConstOps[1], Q.DL, Q.TLI); 3756 3757 if (LoadInst *LI = dyn_cast<LoadInst>(I)) 3758 if (!LI->isVolatile()) 3759 return ConstantFoldLoadFromConstPtr(ConstOps[0], LI->getType(), Q.DL); 3760 3761 return ConstantFoldInstOperands(I, ConstOps, Q.DL, Q.TLI); 3762 } 3763 } 3764 3765 return nullptr; 3766 } 3767 3768 /// Try to simplify a select instruction when its condition operand is an 3769 /// integer comparison where one operand of the compare is a constant. 3770 static Value *simplifySelectBitTest(Value *TrueVal, Value *FalseVal, Value *X, 3771 const APInt *Y, bool TrueWhenUnset) { 3772 const APInt *C; 3773 3774 // (X & Y) == 0 ? X & ~Y : X --> X 3775 // (X & Y) != 0 ? X & ~Y : X --> X & ~Y 3776 if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) && 3777 *Y == ~*C) 3778 return TrueWhenUnset ? FalseVal : TrueVal; 3779 3780 // (X & Y) == 0 ? X : X & ~Y --> X & ~Y 3781 // (X & Y) != 0 ? X : X & ~Y --> X 3782 if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) && 3783 *Y == ~*C) 3784 return TrueWhenUnset ? FalseVal : TrueVal; 3785 3786 if (Y->isPowerOf2()) { 3787 // (X & Y) == 0 ? X | Y : X --> X | Y 3788 // (X & Y) != 0 ? X | Y : X --> X 3789 if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) && 3790 *Y == *C) 3791 return TrueWhenUnset ? TrueVal : FalseVal; 3792 3793 // (X & Y) == 0 ? X : X | Y --> X 3794 // (X & Y) != 0 ? X : X | Y --> X | Y 3795 if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) && 3796 *Y == *C) 3797 return TrueWhenUnset ? TrueVal : FalseVal; 3798 } 3799 3800 return nullptr; 3801 } 3802 3803 /// An alternative way to test if a bit is set or not uses sgt/slt instead of 3804 /// eq/ne. 3805 static Value *simplifySelectWithFakeICmpEq(Value *CmpLHS, Value *CmpRHS, 3806 ICmpInst::Predicate Pred, 3807 Value *TrueVal, Value *FalseVal) { 3808 Value *X; 3809 APInt Mask; 3810 if (!decomposeBitTestICmp(CmpLHS, CmpRHS, Pred, X, Mask)) 3811 return nullptr; 3812 3813 return simplifySelectBitTest(TrueVal, FalseVal, X, &Mask, 3814 Pred == ICmpInst::ICMP_EQ); 3815 } 3816 3817 /// Try to simplify a select instruction when its condition operand is an 3818 /// integer comparison. 3819 static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal, 3820 Value *FalseVal, const SimplifyQuery &Q, 3821 unsigned MaxRecurse) { 3822 ICmpInst::Predicate Pred; 3823 Value *CmpLHS, *CmpRHS; 3824 if (!match(CondVal, m_ICmp(Pred, m_Value(CmpLHS), m_Value(CmpRHS)))) 3825 return nullptr; 3826 3827 if (ICmpInst::isEquality(Pred) && match(CmpRHS, m_Zero())) { 3828 Value *X; 3829 const APInt *Y; 3830 if (match(CmpLHS, m_And(m_Value(X), m_APInt(Y)))) 3831 if (Value *V = simplifySelectBitTest(TrueVal, FalseVal, X, Y, 3832 Pred == ICmpInst::ICMP_EQ)) 3833 return V; 3834 3835 // Test for a bogus zero-shift-guard-op around funnel-shift or rotate. 3836 Value *ShAmt; 3837 auto isFsh = m_CombineOr(m_Intrinsic<Intrinsic::fshl>(m_Value(X), m_Value(), 3838 m_Value(ShAmt)), 3839 m_Intrinsic<Intrinsic::fshr>(m_Value(), m_Value(X), 3840 m_Value(ShAmt))); 3841 // (ShAmt == 0) ? fshl(X, *, ShAmt) : X --> X 3842 // (ShAmt == 0) ? fshr(*, X, ShAmt) : X --> X 3843 if (match(TrueVal, isFsh) && FalseVal == X && CmpLHS == ShAmt && 3844 Pred == ICmpInst::ICMP_EQ) 3845 return X; 3846 // (ShAmt != 0) ? X : fshl(X, *, ShAmt) --> X 3847 // (ShAmt != 0) ? X : fshr(*, X, ShAmt) --> X 3848 if (match(FalseVal, isFsh) && TrueVal == X && CmpLHS == ShAmt && 3849 Pred == ICmpInst::ICMP_NE) 3850 return X; 3851 3852 // Test for a zero-shift-guard-op around rotates. These are used to 3853 // avoid UB from oversized shifts in raw IR rotate patterns, but the 3854 // intrinsics do not have that problem. 3855 // We do not allow this transform for the general funnel shift case because 3856 // that would not preserve the poison safety of the original code. 3857 auto isRotate = m_CombineOr(m_Intrinsic<Intrinsic::fshl>(m_Value(X), 3858 m_Deferred(X), 3859 m_Value(ShAmt)), 3860 m_Intrinsic<Intrinsic::fshr>(m_Value(X), 3861 m_Deferred(X), 3862 m_Value(ShAmt))); 3863 // (ShAmt != 0) ? fshl(X, X, ShAmt) : X --> fshl(X, X, ShAmt) 3864 // (ShAmt != 0) ? fshr(X, X, ShAmt) : X --> fshr(X, X, ShAmt) 3865 if (match(TrueVal, isRotate) && FalseVal == X && CmpLHS == ShAmt && 3866 Pred == ICmpInst::ICMP_NE) 3867 return TrueVal; 3868 // (ShAmt == 0) ? X : fshl(X, X, ShAmt) --> fshl(X, X, ShAmt) 3869 // (ShAmt == 0) ? X : fshr(X, X, ShAmt) --> fshr(X, X, ShAmt) 3870 if (match(FalseVal, isRotate) && TrueVal == X && CmpLHS == ShAmt && 3871 Pred == ICmpInst::ICMP_EQ) 3872 return FalseVal; 3873 } 3874 3875 // Check for other compares that behave like bit test. 3876 if (Value *V = simplifySelectWithFakeICmpEq(CmpLHS, CmpRHS, Pred, 3877 TrueVal, FalseVal)) 3878 return V; 3879 3880 // If we have an equality comparison, then we know the value in one of the 3881 // arms of the select. See if substituting this value into the arm and 3882 // simplifying the result yields the same value as the other arm. 3883 if (Pred == ICmpInst::ICMP_EQ) { 3884 if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) == 3885 TrueVal || 3886 SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) == 3887 TrueVal) 3888 return FalseVal; 3889 if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) == 3890 FalseVal || 3891 SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) == 3892 FalseVal) 3893 return FalseVal; 3894 } else if (Pred == ICmpInst::ICMP_NE) { 3895 if (SimplifyWithOpReplaced(TrueVal, CmpLHS, CmpRHS, Q, MaxRecurse) == 3896 FalseVal || 3897 SimplifyWithOpReplaced(TrueVal, CmpRHS, CmpLHS, Q, MaxRecurse) == 3898 FalseVal) 3899 return TrueVal; 3900 if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q, MaxRecurse) == 3901 TrueVal || 3902 SimplifyWithOpReplaced(FalseVal, CmpRHS, CmpLHS, Q, MaxRecurse) == 3903 TrueVal) 3904 return TrueVal; 3905 } 3906 3907 return nullptr; 3908 } 3909 3910 /// Try to simplify a select instruction when its condition operand is a 3911 /// floating-point comparison. 3912 static Value *simplifySelectWithFCmp(Value *Cond, Value *T, Value *F, 3913 const SimplifyQuery &Q) { 3914 FCmpInst::Predicate Pred; 3915 if (!match(Cond, m_FCmp(Pred, m_Specific(T), m_Specific(F))) && 3916 !match(Cond, m_FCmp(Pred, m_Specific(F), m_Specific(T)))) 3917 return nullptr; 3918 3919 // This transform is safe if we do not have (do not care about) -0.0 or if 3920 // at least one operand is known to not be -0.0. Otherwise, the select can 3921 // change the sign of a zero operand. 3922 bool HasNoSignedZeros = Q.CxtI && isa<FPMathOperator>(Q.CxtI) && 3923 Q.CxtI->hasNoSignedZeros(); 3924 const APFloat *C; 3925 if (HasNoSignedZeros || (match(T, m_APFloat(C)) && C->isNonZero()) || 3926 (match(F, m_APFloat(C)) && C->isNonZero())) { 3927 // (T == F) ? T : F --> F 3928 // (F == T) ? T : F --> F 3929 if (Pred == FCmpInst::FCMP_OEQ) 3930 return F; 3931 3932 // (T != F) ? T : F --> T 3933 // (F != T) ? T : F --> T 3934 if (Pred == FCmpInst::FCMP_UNE) 3935 return T; 3936 } 3937 3938 return nullptr; 3939 } 3940 3941 /// Given operands for a SelectInst, see if we can fold the result. 3942 /// If not, this returns null. 3943 static Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal, 3944 const SimplifyQuery &Q, unsigned MaxRecurse) { 3945 if (auto *CondC = dyn_cast<Constant>(Cond)) { 3946 if (auto *TrueC = dyn_cast<Constant>(TrueVal)) 3947 if (auto *FalseC = dyn_cast<Constant>(FalseVal)) 3948 return ConstantFoldSelectInstruction(CondC, TrueC, FalseC); 3949 3950 // select undef, X, Y -> X or Y 3951 if (isa<UndefValue>(CondC)) 3952 return isa<Constant>(FalseVal) ? FalseVal : TrueVal; 3953 3954 // TODO: Vector constants with undef elements don't simplify. 3955 3956 // select true, X, Y -> X 3957 if (CondC->isAllOnesValue()) 3958 return TrueVal; 3959 // select false, X, Y -> Y 3960 if (CondC->isNullValue()) 3961 return FalseVal; 3962 } 3963 3964 // select ?, X, X -> X 3965 if (TrueVal == FalseVal) 3966 return TrueVal; 3967 3968 if (isa<UndefValue>(TrueVal)) // select ?, undef, X -> X 3969 return FalseVal; 3970 if (isa<UndefValue>(FalseVal)) // select ?, X, undef -> X 3971 return TrueVal; 3972 3973 if (Value *V = 3974 simplifySelectWithICmpCond(Cond, TrueVal, FalseVal, Q, MaxRecurse)) 3975 return V; 3976 3977 if (Value *V = simplifySelectWithFCmp(Cond, TrueVal, FalseVal, Q)) 3978 return V; 3979 3980 if (Value *V = foldSelectWithBinaryOp(Cond, TrueVal, FalseVal)) 3981 return V; 3982 3983 Optional<bool> Imp = isImpliedByDomCondition(Cond, Q.CxtI, Q.DL); 3984 if (Imp) 3985 return *Imp ? TrueVal : FalseVal; 3986 3987 return nullptr; 3988 } 3989 3990 Value *llvm::SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal, 3991 const SimplifyQuery &Q) { 3992 return ::SimplifySelectInst(Cond, TrueVal, FalseVal, Q, RecursionLimit); 3993 } 3994 3995 /// Given operands for an GetElementPtrInst, see if we can fold the result. 3996 /// If not, this returns null. 3997 static Value *SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops, 3998 const SimplifyQuery &Q, unsigned) { 3999 // The type of the GEP pointer operand. 4000 unsigned AS = 4001 cast<PointerType>(Ops[0]->getType()->getScalarType())->getAddressSpace(); 4002 4003 // getelementptr P -> P. 4004 if (Ops.size() == 1) 4005 return Ops[0]; 4006 4007 // Compute the (pointer) type returned by the GEP instruction. 4008 Type *LastType = GetElementPtrInst::getIndexedType(SrcTy, Ops.slice(1)); 4009 Type *GEPTy = PointerType::get(LastType, AS); 4010 if (VectorType *VT = dyn_cast<VectorType>(Ops[0]->getType())) 4011 GEPTy = VectorType::get(GEPTy, VT->getNumElements()); 4012 else if (VectorType *VT = dyn_cast<VectorType>(Ops[1]->getType())) 4013 GEPTy = VectorType::get(GEPTy, VT->getNumElements()); 4014 4015 if (isa<UndefValue>(Ops[0])) 4016 return UndefValue::get(GEPTy); 4017 4018 if (Ops.size() == 2) { 4019 // getelementptr P, 0 -> P. 4020 if (match(Ops[1], m_Zero()) && Ops[0]->getType() == GEPTy) 4021 return Ops[0]; 4022 4023 Type *Ty = SrcTy; 4024 if (Ty->isSized()) { 4025 Value *P; 4026 uint64_t C; 4027 uint64_t TyAllocSize = Q.DL.getTypeAllocSize(Ty); 4028 // getelementptr P, N -> P if P points to a type of zero size. 4029 if (TyAllocSize == 0 && Ops[0]->getType() == GEPTy) 4030 return Ops[0]; 4031 4032 // The following transforms are only safe if the ptrtoint cast 4033 // doesn't truncate the pointers. 4034 if (Ops[1]->getType()->getScalarSizeInBits() == 4035 Q.DL.getIndexSizeInBits(AS)) { 4036 auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * { 4037 if (match(P, m_Zero())) 4038 return Constant::getNullValue(GEPTy); 4039 Value *Temp; 4040 if (match(P, m_PtrToInt(m_Value(Temp)))) 4041 if (Temp->getType() == GEPTy) 4042 return Temp; 4043 return nullptr; 4044 }; 4045 4046 // getelementptr V, (sub P, V) -> P if P points to a type of size 1. 4047 if (TyAllocSize == 1 && 4048 match(Ops[1], m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))))) 4049 if (Value *R = PtrToIntOrZero(P)) 4050 return R; 4051 4052 // getelementptr V, (ashr (sub P, V), C) -> Q 4053 // if P points to a type of size 1 << C. 4054 if (match(Ops[1], 4055 m_AShr(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))), 4056 m_ConstantInt(C))) && 4057 TyAllocSize == 1ULL << C) 4058 if (Value *R = PtrToIntOrZero(P)) 4059 return R; 4060 4061 // getelementptr V, (sdiv (sub P, V), C) -> Q 4062 // if P points to a type of size C. 4063 if (match(Ops[1], 4064 m_SDiv(m_Sub(m_Value(P), m_PtrToInt(m_Specific(Ops[0]))), 4065 m_SpecificInt(TyAllocSize)))) 4066 if (Value *R = PtrToIntOrZero(P)) 4067 return R; 4068 } 4069 } 4070 } 4071 4072 if (Q.DL.getTypeAllocSize(LastType) == 1 && 4073 all_of(Ops.slice(1).drop_back(1), 4074 [](Value *Idx) { return match(Idx, m_Zero()); })) { 4075 unsigned IdxWidth = 4076 Q.DL.getIndexSizeInBits(Ops[0]->getType()->getPointerAddressSpace()); 4077 if (Q.DL.getTypeSizeInBits(Ops.back()->getType()) == IdxWidth) { 4078 APInt BasePtrOffset(IdxWidth, 0); 4079 Value *StrippedBasePtr = 4080 Ops[0]->stripAndAccumulateInBoundsConstantOffsets(Q.DL, 4081 BasePtrOffset); 4082 4083 // gep (gep V, C), (sub 0, V) -> C 4084 if (match(Ops.back(), 4085 m_Sub(m_Zero(), m_PtrToInt(m_Specific(StrippedBasePtr))))) { 4086 auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset); 4087 return ConstantExpr::getIntToPtr(CI, GEPTy); 4088 } 4089 // gep (gep V, C), (xor V, -1) -> C-1 4090 if (match(Ops.back(), 4091 m_Xor(m_PtrToInt(m_Specific(StrippedBasePtr)), m_AllOnes()))) { 4092 auto *CI = ConstantInt::get(GEPTy->getContext(), BasePtrOffset - 1); 4093 return ConstantExpr::getIntToPtr(CI, GEPTy); 4094 } 4095 } 4096 } 4097 4098 // Check to see if this is constant foldable. 4099 if (!all_of(Ops, [](Value *V) { return isa<Constant>(V); })) 4100 return nullptr; 4101 4102 auto *CE = ConstantExpr::getGetElementPtr(SrcTy, cast<Constant>(Ops[0]), 4103 Ops.slice(1)); 4104 if (auto *CEFolded = ConstantFoldConstant(CE, Q.DL)) 4105 return CEFolded; 4106 return CE; 4107 } 4108 4109 Value *llvm::SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops, 4110 const SimplifyQuery &Q) { 4111 return ::SimplifyGEPInst(SrcTy, Ops, Q, RecursionLimit); 4112 } 4113 4114 /// Given operands for an InsertValueInst, see if we can fold the result. 4115 /// If not, this returns null. 4116 static Value *SimplifyInsertValueInst(Value *Agg, Value *Val, 4117 ArrayRef<unsigned> Idxs, const SimplifyQuery &Q, 4118 unsigned) { 4119 if (Constant *CAgg = dyn_cast<Constant>(Agg)) 4120 if (Constant *CVal = dyn_cast<Constant>(Val)) 4121 return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs); 4122 4123 // insertvalue x, undef, n -> x 4124 if (match(Val, m_Undef())) 4125 return Agg; 4126 4127 // insertvalue x, (extractvalue y, n), n 4128 if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val)) 4129 if (EV->getAggregateOperand()->getType() == Agg->getType() && 4130 EV->getIndices() == Idxs) { 4131 // insertvalue undef, (extractvalue y, n), n -> y 4132 if (match(Agg, m_Undef())) 4133 return EV->getAggregateOperand(); 4134 4135 // insertvalue y, (extractvalue y, n), n -> y 4136 if (Agg == EV->getAggregateOperand()) 4137 return Agg; 4138 } 4139 4140 return nullptr; 4141 } 4142 4143 Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val, 4144 ArrayRef<unsigned> Idxs, 4145 const SimplifyQuery &Q) { 4146 return ::SimplifyInsertValueInst(Agg, Val, Idxs, Q, RecursionLimit); 4147 } 4148 4149 Value *llvm::SimplifyInsertElementInst(Value *Vec, Value *Val, Value *Idx, 4150 const SimplifyQuery &Q) { 4151 // Try to constant fold. 4152 auto *VecC = dyn_cast<Constant>(Vec); 4153 auto *ValC = dyn_cast<Constant>(Val); 4154 auto *IdxC = dyn_cast<Constant>(Idx); 4155 if (VecC && ValC && IdxC) 4156 return ConstantFoldInsertElementInstruction(VecC, ValC, IdxC); 4157 4158 // Fold into undef if index is out of bounds. 4159 if (auto *CI = dyn_cast<ConstantInt>(Idx)) { 4160 uint64_t NumElements = cast<VectorType>(Vec->getType())->getNumElements(); 4161 if (CI->uge(NumElements)) 4162 return UndefValue::get(Vec->getType()); 4163 } 4164 4165 // If index is undef, it might be out of bounds (see above case) 4166 if (isa<UndefValue>(Idx)) 4167 return UndefValue::get(Vec->getType()); 4168 4169 // Inserting an undef scalar? Assume it is the same value as the existing 4170 // vector element. 4171 if (isa<UndefValue>(Val)) 4172 return Vec; 4173 4174 // If we are extracting a value from a vector, then inserting it into the same 4175 // place, that's the input vector: 4176 // insertelt Vec, (extractelt Vec, Idx), Idx --> Vec 4177 if (match(Val, m_ExtractElement(m_Specific(Vec), m_Specific(Idx)))) 4178 return Vec; 4179 4180 return nullptr; 4181 } 4182 4183 /// Given operands for an ExtractValueInst, see if we can fold the result. 4184 /// If not, this returns null. 4185 static Value *SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs, 4186 const SimplifyQuery &, unsigned) { 4187 if (auto *CAgg = dyn_cast<Constant>(Agg)) 4188 return ConstantFoldExtractValueInstruction(CAgg, Idxs); 4189 4190 // extractvalue x, (insertvalue y, elt, n), n -> elt 4191 unsigned NumIdxs = Idxs.size(); 4192 for (auto *IVI = dyn_cast<InsertValueInst>(Agg); IVI != nullptr; 4193 IVI = dyn_cast<InsertValueInst>(IVI->getAggregateOperand())) { 4194 ArrayRef<unsigned> InsertValueIdxs = IVI->getIndices(); 4195 unsigned NumInsertValueIdxs = InsertValueIdxs.size(); 4196 unsigned NumCommonIdxs = std::min(NumInsertValueIdxs, NumIdxs); 4197 if (InsertValueIdxs.slice(0, NumCommonIdxs) == 4198 Idxs.slice(0, NumCommonIdxs)) { 4199 if (NumIdxs == NumInsertValueIdxs) 4200 return IVI->getInsertedValueOperand(); 4201 break; 4202 } 4203 } 4204 4205 return nullptr; 4206 } 4207 4208 Value *llvm::SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs, 4209 const SimplifyQuery &Q) { 4210 return ::SimplifyExtractValueInst(Agg, Idxs, Q, RecursionLimit); 4211 } 4212 4213 /// Given operands for an ExtractElementInst, see if we can fold the result. 4214 /// If not, this returns null. 4215 static Value *SimplifyExtractElementInst(Value *Vec, Value *Idx, const SimplifyQuery &, 4216 unsigned) { 4217 if (auto *CVec = dyn_cast<Constant>(Vec)) { 4218 if (auto *CIdx = dyn_cast<Constant>(Idx)) 4219 return ConstantFoldExtractElementInstruction(CVec, CIdx); 4220 4221 // The index is not relevant if our vector is a splat. 4222 if (auto *Splat = CVec->getSplatValue()) 4223 return Splat; 4224 4225 if (isa<UndefValue>(Vec)) 4226 return UndefValue::get(Vec->getType()->getVectorElementType()); 4227 } 4228 4229 // If extracting a specified index from the vector, see if we can recursively 4230 // find a previously computed scalar that was inserted into the vector. 4231 if (auto *IdxC = dyn_cast<ConstantInt>(Idx)) { 4232 if (IdxC->getValue().uge(Vec->getType()->getVectorNumElements())) 4233 // definitely out of bounds, thus undefined result 4234 return UndefValue::get(Vec->getType()->getVectorElementType()); 4235 if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue())) 4236 return Elt; 4237 } 4238 4239 // An undef extract index can be arbitrarily chosen to be an out-of-range 4240 // index value, which would result in the instruction being undef. 4241 if (isa<UndefValue>(Idx)) 4242 return UndefValue::get(Vec->getType()->getVectorElementType()); 4243 4244 return nullptr; 4245 } 4246 4247 Value *llvm::SimplifyExtractElementInst(Value *Vec, Value *Idx, 4248 const SimplifyQuery &Q) { 4249 return ::SimplifyExtractElementInst(Vec, Idx, Q, RecursionLimit); 4250 } 4251 4252 /// See if we can fold the given phi. If not, returns null. 4253 static Value *SimplifyPHINode(PHINode *PN, const SimplifyQuery &Q) { 4254 // If all of the PHI's incoming values are the same then replace the PHI node 4255 // with the common value. 4256 Value *CommonValue = nullptr; 4257 bool HasUndefInput = false; 4258 for (Value *Incoming : PN->incoming_values()) { 4259 // If the incoming value is the phi node itself, it can safely be skipped. 4260 if (Incoming == PN) continue; 4261 if (isa<UndefValue>(Incoming)) { 4262 // Remember that we saw an undef value, but otherwise ignore them. 4263 HasUndefInput = true; 4264 continue; 4265 } 4266 if (CommonValue && Incoming != CommonValue) 4267 return nullptr; // Not the same, bail out. 4268 CommonValue = Incoming; 4269 } 4270 4271 // If CommonValue is null then all of the incoming values were either undef or 4272 // equal to the phi node itself. 4273 if (!CommonValue) 4274 return UndefValue::get(PN->getType()); 4275 4276 // If we have a PHI node like phi(X, undef, X), where X is defined by some 4277 // instruction, we cannot return X as the result of the PHI node unless it 4278 // dominates the PHI block. 4279 if (HasUndefInput) 4280 return valueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr; 4281 4282 return CommonValue; 4283 } 4284 4285 static Value *SimplifyCastInst(unsigned CastOpc, Value *Op, 4286 Type *Ty, const SimplifyQuery &Q, unsigned MaxRecurse) { 4287 if (auto *C = dyn_cast<Constant>(Op)) 4288 return ConstantFoldCastOperand(CastOpc, C, Ty, Q.DL); 4289 4290 if (auto *CI = dyn_cast<CastInst>(Op)) { 4291 auto *Src = CI->getOperand(0); 4292 Type *SrcTy = Src->getType(); 4293 Type *MidTy = CI->getType(); 4294 Type *DstTy = Ty; 4295 if (Src->getType() == Ty) { 4296 auto FirstOp = static_cast<Instruction::CastOps>(CI->getOpcode()); 4297 auto SecondOp = static_cast<Instruction::CastOps>(CastOpc); 4298 Type *SrcIntPtrTy = 4299 SrcTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(SrcTy) : nullptr; 4300 Type *MidIntPtrTy = 4301 MidTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(MidTy) : nullptr; 4302 Type *DstIntPtrTy = 4303 DstTy->isPtrOrPtrVectorTy() ? Q.DL.getIntPtrType(DstTy) : nullptr; 4304 if (CastInst::isEliminableCastPair(FirstOp, SecondOp, SrcTy, MidTy, DstTy, 4305 SrcIntPtrTy, MidIntPtrTy, 4306 DstIntPtrTy) == Instruction::BitCast) 4307 return Src; 4308 } 4309 } 4310 4311 // bitcast x -> x 4312 if (CastOpc == Instruction::BitCast) 4313 if (Op->getType() == Ty) 4314 return Op; 4315 4316 return nullptr; 4317 } 4318 4319 Value *llvm::SimplifyCastInst(unsigned CastOpc, Value *Op, Type *Ty, 4320 const SimplifyQuery &Q) { 4321 return ::SimplifyCastInst(CastOpc, Op, Ty, Q, RecursionLimit); 4322 } 4323 4324 /// For the given destination element of a shuffle, peek through shuffles to 4325 /// match a root vector source operand that contains that element in the same 4326 /// vector lane (ie, the same mask index), so we can eliminate the shuffle(s). 4327 static Value *foldIdentityShuffles(int DestElt, Value *Op0, Value *Op1, 4328 int MaskVal, Value *RootVec, 4329 unsigned MaxRecurse) { 4330 if (!MaxRecurse--) 4331 return nullptr; 4332 4333 // Bail out if any mask value is undefined. That kind of shuffle may be 4334 // simplified further based on demanded bits or other folds. 4335 if (MaskVal == -1) 4336 return nullptr; 4337 4338 // The mask value chooses which source operand we need to look at next. 4339 int InVecNumElts = Op0->getType()->getVectorNumElements(); 4340 int RootElt = MaskVal; 4341 Value *SourceOp = Op0; 4342 if (MaskVal >= InVecNumElts) { 4343 RootElt = MaskVal - InVecNumElts; 4344 SourceOp = Op1; 4345 } 4346 4347 // If the source operand is a shuffle itself, look through it to find the 4348 // matching root vector. 4349 if (auto *SourceShuf = dyn_cast<ShuffleVectorInst>(SourceOp)) { 4350 return foldIdentityShuffles( 4351 DestElt, SourceShuf->getOperand(0), SourceShuf->getOperand(1), 4352 SourceShuf->getMaskValue(RootElt), RootVec, MaxRecurse); 4353 } 4354 4355 // TODO: Look through bitcasts? What if the bitcast changes the vector element 4356 // size? 4357 4358 // The source operand is not a shuffle. Initialize the root vector value for 4359 // this shuffle if that has not been done yet. 4360 if (!RootVec) 4361 RootVec = SourceOp; 4362 4363 // Give up as soon as a source operand does not match the existing root value. 4364 if (RootVec != SourceOp) 4365 return nullptr; 4366 4367 // The element must be coming from the same lane in the source vector 4368 // (although it may have crossed lanes in intermediate shuffles). 4369 if (RootElt != DestElt) 4370 return nullptr; 4371 4372 return RootVec; 4373 } 4374 4375 static Value *SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask, 4376 Type *RetTy, const SimplifyQuery &Q, 4377 unsigned MaxRecurse) { 4378 if (isa<UndefValue>(Mask)) 4379 return UndefValue::get(RetTy); 4380 4381 Type *InVecTy = Op0->getType(); 4382 unsigned MaskNumElts = Mask->getType()->getVectorNumElements(); 4383 unsigned InVecNumElts = InVecTy->getVectorNumElements(); 4384 4385 SmallVector<int, 32> Indices; 4386 ShuffleVectorInst::getShuffleMask(Mask, Indices); 4387 assert(MaskNumElts == Indices.size() && 4388 "Size of Indices not same as number of mask elements?"); 4389 4390 // Canonicalization: If mask does not select elements from an input vector, 4391 // replace that input vector with undef. 4392 bool MaskSelects0 = false, MaskSelects1 = false; 4393 for (unsigned i = 0; i != MaskNumElts; ++i) { 4394 if (Indices[i] == -1) 4395 continue; 4396 if ((unsigned)Indices[i] < InVecNumElts) 4397 MaskSelects0 = true; 4398 else 4399 MaskSelects1 = true; 4400 } 4401 if (!MaskSelects0) 4402 Op0 = UndefValue::get(InVecTy); 4403 if (!MaskSelects1) 4404 Op1 = UndefValue::get(InVecTy); 4405 4406 auto *Op0Const = dyn_cast<Constant>(Op0); 4407 auto *Op1Const = dyn_cast<Constant>(Op1); 4408 4409 // If all operands are constant, constant fold the shuffle. 4410 if (Op0Const && Op1Const) 4411 return ConstantFoldShuffleVectorInstruction(Op0Const, Op1Const, Mask); 4412 4413 // Canonicalization: if only one input vector is constant, it shall be the 4414 // second one. 4415 if (Op0Const && !Op1Const) { 4416 std::swap(Op0, Op1); 4417 ShuffleVectorInst::commuteShuffleMask(Indices, InVecNumElts); 4418 } 4419 4420 // A shuffle of a splat is always the splat itself. Legal if the shuffle's 4421 // value type is same as the input vectors' type. 4422 if (auto *OpShuf = dyn_cast<ShuffleVectorInst>(Op0)) 4423 if (isa<UndefValue>(Op1) && RetTy == InVecTy && 4424 OpShuf->getMask()->getSplatValue()) 4425 return Op0; 4426 4427 // Don't fold a shuffle with undef mask elements. This may get folded in a 4428 // better way using demanded bits or other analysis. 4429 // TODO: Should we allow this? 4430 if (find(Indices, -1) != Indices.end()) 4431 return nullptr; 4432 4433 // Check if every element of this shuffle can be mapped back to the 4434 // corresponding element of a single root vector. If so, we don't need this 4435 // shuffle. This handles simple identity shuffles as well as chains of 4436 // shuffles that may widen/narrow and/or move elements across lanes and back. 4437 Value *RootVec = nullptr; 4438 for (unsigned i = 0; i != MaskNumElts; ++i) { 4439 // Note that recursion is limited for each vector element, so if any element 4440 // exceeds the limit, this will fail to simplify. 4441 RootVec = 4442 foldIdentityShuffles(i, Op0, Op1, Indices[i], RootVec, MaxRecurse); 4443 4444 // We can't replace a widening/narrowing shuffle with one of its operands. 4445 if (!RootVec || RootVec->getType() != RetTy) 4446 return nullptr; 4447 } 4448 return RootVec; 4449 } 4450 4451 /// Given operands for a ShuffleVectorInst, fold the result or return null. 4452 Value *llvm::SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask, 4453 Type *RetTy, const SimplifyQuery &Q) { 4454 return ::SimplifyShuffleVectorInst(Op0, Op1, Mask, RetTy, Q, RecursionLimit); 4455 } 4456 4457 static Constant *foldConstant(Instruction::UnaryOps Opcode, 4458 Value *&Op, const SimplifyQuery &Q) { 4459 if (auto *C = dyn_cast<Constant>(Op)) 4460 return ConstantFoldUnaryOpOperand(Opcode, C, Q.DL); 4461 return nullptr; 4462 } 4463 4464 /// Given the operand for an FNeg, see if we can fold the result. If not, this 4465 /// returns null. 4466 static Value *simplifyFNegInst(Value *Op, FastMathFlags FMF, 4467 const SimplifyQuery &Q, unsigned MaxRecurse) { 4468 if (Constant *C = foldConstant(Instruction::FNeg, Op, Q)) 4469 return C; 4470 4471 Value *X; 4472 // fneg (fneg X) ==> X 4473 if (match(Op, m_FNeg(m_Value(X)))) 4474 return X; 4475 4476 return nullptr; 4477 } 4478 4479 Value *llvm::SimplifyFNegInst(Value *Op, FastMathFlags FMF, 4480 const SimplifyQuery &Q) { 4481 return ::simplifyFNegInst(Op, FMF, Q, RecursionLimit); 4482 } 4483 4484 static Constant *propagateNaN(Constant *In) { 4485 // If the input is a vector with undef elements, just return a default NaN. 4486 if (!In->isNaN()) 4487 return ConstantFP::getNaN(In->getType()); 4488 4489 // Propagate the existing NaN constant when possible. 4490 // TODO: Should we quiet a signaling NaN? 4491 return In; 4492 } 4493 4494 /// Perform folds that are common to any floating-point operation. This implies 4495 /// transforms based on undef/NaN because the operation itself makes no 4496 /// difference to the result. 4497 static Constant *simplifyFPOp(ArrayRef<Value *> Ops) { 4498 if (any_of(Ops, [](Value *V) { return isa<UndefValue>(V); })) 4499 return ConstantFP::getNaN(Ops[0]->getType()); 4500 4501 for (Value *V : Ops) 4502 if (match(V, m_NaN())) 4503 return propagateNaN(cast<Constant>(V)); 4504 4505 return nullptr; 4506 } 4507 4508 /// Given operands for an FAdd, see if we can fold the result. If not, this 4509 /// returns null. 4510 static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF, 4511 const SimplifyQuery &Q, unsigned MaxRecurse) { 4512 if (Constant *C = foldOrCommuteConstant(Instruction::FAdd, Op0, Op1, Q)) 4513 return C; 4514 4515 if (Constant *C = simplifyFPOp({Op0, Op1})) 4516 return C; 4517 4518 // fadd X, -0 ==> X 4519 if (match(Op1, m_NegZeroFP())) 4520 return Op0; 4521 4522 // fadd X, 0 ==> X, when we know X is not -0 4523 if (match(Op1, m_PosZeroFP()) && 4524 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI))) 4525 return Op0; 4526 4527 // With nnan: -X + X --> 0.0 (and commuted variant) 4528 // We don't have to explicitly exclude infinities (ninf): INF + -INF == NaN. 4529 // Negative zeros are allowed because we always end up with positive zero: 4530 // X = -0.0: (-0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0 4531 // X = -0.0: ( 0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0 4532 // X = 0.0: (-0.0 - ( 0.0)) + ( 0.0) == (-0.0) + ( 0.0) == 0.0 4533 // X = 0.0: ( 0.0 - ( 0.0)) + ( 0.0) == ( 0.0) + ( 0.0) == 0.0 4534 if (FMF.noNaNs()) { 4535 if (match(Op0, m_FSub(m_AnyZeroFP(), m_Specific(Op1))) || 4536 match(Op1, m_FSub(m_AnyZeroFP(), m_Specific(Op0)))) 4537 return ConstantFP::getNullValue(Op0->getType()); 4538 4539 if (match(Op0, m_FNeg(m_Specific(Op1))) || 4540 match(Op1, m_FNeg(m_Specific(Op0)))) 4541 return ConstantFP::getNullValue(Op0->getType()); 4542 } 4543 4544 // (X - Y) + Y --> X 4545 // Y + (X - Y) --> X 4546 Value *X; 4547 if (FMF.noSignedZeros() && FMF.allowReassoc() && 4548 (match(Op0, m_FSub(m_Value(X), m_Specific(Op1))) || 4549 match(Op1, m_FSub(m_Value(X), m_Specific(Op0))))) 4550 return X; 4551 4552 return nullptr; 4553 } 4554 4555 /// Given operands for an FSub, see if we can fold the result. If not, this 4556 /// returns null. 4557 static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF, 4558 const SimplifyQuery &Q, unsigned MaxRecurse) { 4559 if (Constant *C = foldOrCommuteConstant(Instruction::FSub, Op0, Op1, Q)) 4560 return C; 4561 4562 if (Constant *C = simplifyFPOp({Op0, Op1})) 4563 return C; 4564 4565 // fsub X, +0 ==> X 4566 if (match(Op1, m_PosZeroFP())) 4567 return Op0; 4568 4569 // fsub X, -0 ==> X, when we know X is not -0 4570 if (match(Op1, m_NegZeroFP()) && 4571 (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI))) 4572 return Op0; 4573 4574 // fsub -0.0, (fsub -0.0, X) ==> X 4575 // fsub -0.0, (fneg X) ==> X 4576 Value *X; 4577 if (match(Op0, m_NegZeroFP()) && 4578 match(Op1, m_FNeg(m_Value(X)))) 4579 return X; 4580 4581 // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored. 4582 // fsub 0.0, (fneg X) ==> X if signed zeros are ignored. 4583 if (FMF.noSignedZeros() && match(Op0, m_AnyZeroFP()) && 4584 (match(Op1, m_FSub(m_AnyZeroFP(), m_Value(X))) || 4585 match(Op1, m_FNeg(m_Value(X))))) 4586 return X; 4587 4588 // fsub nnan x, x ==> 0.0 4589 if (FMF.noNaNs() && Op0 == Op1) 4590 return Constant::getNullValue(Op0->getType()); 4591 4592 // Y - (Y - X) --> X 4593 // (X + Y) - Y --> X 4594 if (FMF.noSignedZeros() && FMF.allowReassoc() && 4595 (match(Op1, m_FSub(m_Specific(Op0), m_Value(X))) || 4596 match(Op0, m_c_FAdd(m_Specific(Op1), m_Value(X))))) 4597 return X; 4598 4599 return nullptr; 4600 } 4601 4602 static Value *SimplifyFMAFMul(Value *Op0, Value *Op1, FastMathFlags FMF, 4603 const SimplifyQuery &Q, unsigned MaxRecurse) { 4604 if (Constant *C = simplifyFPOp({Op0, Op1})) 4605 return C; 4606 4607 // fmul X, 1.0 ==> X 4608 if (match(Op1, m_FPOne())) 4609 return Op0; 4610 4611 // fmul 1.0, X ==> X 4612 if (match(Op0, m_FPOne())) 4613 return Op1; 4614 4615 // fmul nnan nsz X, 0 ==> 0 4616 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZeroFP())) 4617 return ConstantFP::getNullValue(Op0->getType()); 4618 4619 // fmul nnan nsz 0, X ==> 0 4620 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZeroFP())) 4621 return ConstantFP::getNullValue(Op1->getType()); 4622 4623 // sqrt(X) * sqrt(X) --> X, if we can: 4624 // 1. Remove the intermediate rounding (reassociate). 4625 // 2. Ignore non-zero negative numbers because sqrt would produce NAN. 4626 // 3. Ignore -0.0 because sqrt(-0.0) == -0.0, but -0.0 * -0.0 == 0.0. 4627 Value *X; 4628 if (Op0 == Op1 && match(Op0, m_Intrinsic<Intrinsic::sqrt>(m_Value(X))) && 4629 FMF.allowReassoc() && FMF.noNaNs() && FMF.noSignedZeros()) 4630 return X; 4631 4632 return nullptr; 4633 } 4634 4635 /// Given the operands for an FMul, see if we can fold the result 4636 static Value *SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF, 4637 const SimplifyQuery &Q, unsigned MaxRecurse) { 4638 if (Constant *C = foldOrCommuteConstant(Instruction::FMul, Op0, Op1, Q)) 4639 return C; 4640 4641 // Now apply simplifications that do not require rounding. 4642 return SimplifyFMAFMul(Op0, Op1, FMF, Q, MaxRecurse); 4643 } 4644 4645 Value *llvm::SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF, 4646 const SimplifyQuery &Q) { 4647 return ::SimplifyFAddInst(Op0, Op1, FMF, Q, RecursionLimit); 4648 } 4649 4650 4651 Value *llvm::SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF, 4652 const SimplifyQuery &Q) { 4653 return ::SimplifyFSubInst(Op0, Op1, FMF, Q, RecursionLimit); 4654 } 4655 4656 Value *llvm::SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF, 4657 const SimplifyQuery &Q) { 4658 return ::SimplifyFMulInst(Op0, Op1, FMF, Q, RecursionLimit); 4659 } 4660 4661 Value *llvm::SimplifyFMAFMul(Value *Op0, Value *Op1, FastMathFlags FMF, 4662 const SimplifyQuery &Q) { 4663 return ::SimplifyFMAFMul(Op0, Op1, FMF, Q, RecursionLimit); 4664 } 4665 4666 static Value *SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF, 4667 const SimplifyQuery &Q, unsigned) { 4668 if (Constant *C = foldOrCommuteConstant(Instruction::FDiv, Op0, Op1, Q)) 4669 return C; 4670 4671 if (Constant *C = simplifyFPOp({Op0, Op1})) 4672 return C; 4673 4674 // X / 1.0 -> X 4675 if (match(Op1, m_FPOne())) 4676 return Op0; 4677 4678 // 0 / X -> 0 4679 // Requires that NaNs are off (X could be zero) and signed zeroes are 4680 // ignored (X could be positive or negative, so the output sign is unknown). 4681 if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZeroFP())) 4682 return ConstantFP::getNullValue(Op0->getType()); 4683 4684 if (FMF.noNaNs()) { 4685 // X / X -> 1.0 is legal when NaNs are ignored. 4686 // We can ignore infinities because INF/INF is NaN. 4687 if (Op0 == Op1) 4688 return ConstantFP::get(Op0->getType(), 1.0); 4689 4690 // (X * Y) / Y --> X if we can reassociate to the above form. 4691 Value *X; 4692 if (FMF.allowReassoc() && match(Op0, m_c_FMul(m_Value(X), m_Specific(Op1)))) 4693 return X; 4694 4695 // -X / X -> -1.0 and 4696 // X / -X -> -1.0 are legal when NaNs are ignored. 4697 // We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored. 4698 if (match(Op0, m_FNegNSZ(m_Specific(Op1))) || 4699 match(Op1, m_FNegNSZ(m_Specific(Op0)))) 4700 return ConstantFP::get(Op0->getType(), -1.0); 4701 } 4702 4703 return nullptr; 4704 } 4705 4706 Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF, 4707 const SimplifyQuery &Q) { 4708 return ::SimplifyFDivInst(Op0, Op1, FMF, Q, RecursionLimit); 4709 } 4710 4711 static Value *SimplifyFRemInst(Value *Op0, Value *Op1, FastMathFlags FMF, 4712 const SimplifyQuery &Q, unsigned) { 4713 if (Constant *C = foldOrCommuteConstant(Instruction::FRem, Op0, Op1, Q)) 4714 return C; 4715 4716 if (Constant *C = simplifyFPOp({Op0, Op1})) 4717 return C; 4718 4719 // Unlike fdiv, the result of frem always matches the sign of the dividend. 4720 // The constant match may include undef elements in a vector, so return a full 4721 // zero constant as the result. 4722 if (FMF.noNaNs()) { 4723 // +0 % X -> 0 4724 if (match(Op0, m_PosZeroFP())) 4725 return ConstantFP::getNullValue(Op0->getType()); 4726 // -0 % X -> -0 4727 if (match(Op0, m_NegZeroFP())) 4728 return ConstantFP::getNegativeZero(Op0->getType()); 4729 } 4730 4731 return nullptr; 4732 } 4733 4734 Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, FastMathFlags FMF, 4735 const SimplifyQuery &Q) { 4736 return ::SimplifyFRemInst(Op0, Op1, FMF, Q, RecursionLimit); 4737 } 4738 4739 //=== Helper functions for higher up the class hierarchy. 4740 4741 /// Given the operand for a UnaryOperator, see if we can fold the result. 4742 /// If not, this returns null. 4743 static Value *simplifyUnOp(unsigned Opcode, Value *Op, const SimplifyQuery &Q, 4744 unsigned MaxRecurse) { 4745 switch (Opcode) { 4746 case Instruction::FNeg: 4747 return simplifyFNegInst(Op, FastMathFlags(), Q, MaxRecurse); 4748 default: 4749 llvm_unreachable("Unexpected opcode"); 4750 } 4751 } 4752 4753 /// Given the operand for a UnaryOperator, see if we can fold the result. 4754 /// If not, this returns null. 4755 /// Try to use FastMathFlags when folding the result. 4756 static Value *simplifyFPUnOp(unsigned Opcode, Value *Op, 4757 const FastMathFlags &FMF, 4758 const SimplifyQuery &Q, unsigned MaxRecurse) { 4759 switch (Opcode) { 4760 case Instruction::FNeg: 4761 return simplifyFNegInst(Op, FMF, Q, MaxRecurse); 4762 default: 4763 return simplifyUnOp(Opcode, Op, Q, MaxRecurse); 4764 } 4765 } 4766 4767 Value *llvm::SimplifyUnOp(unsigned Opcode, Value *Op, const SimplifyQuery &Q) { 4768 return ::simplifyUnOp(Opcode, Op, Q, RecursionLimit); 4769 } 4770 4771 Value *llvm::SimplifyUnOp(unsigned Opcode, Value *Op, FastMathFlags FMF, 4772 const SimplifyQuery &Q) { 4773 return ::simplifyFPUnOp(Opcode, Op, FMF, Q, RecursionLimit); 4774 } 4775 4776 /// Given operands for a BinaryOperator, see if we can fold the result. 4777 /// If not, this returns null. 4778 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, 4779 const SimplifyQuery &Q, unsigned MaxRecurse) { 4780 switch (Opcode) { 4781 case Instruction::Add: 4782 return SimplifyAddInst(LHS, RHS, false, false, Q, MaxRecurse); 4783 case Instruction::Sub: 4784 return SimplifySubInst(LHS, RHS, false, false, Q, MaxRecurse); 4785 case Instruction::Mul: 4786 return SimplifyMulInst(LHS, RHS, Q, MaxRecurse); 4787 case Instruction::SDiv: 4788 return SimplifySDivInst(LHS, RHS, Q, MaxRecurse); 4789 case Instruction::UDiv: 4790 return SimplifyUDivInst(LHS, RHS, Q, MaxRecurse); 4791 case Instruction::SRem: 4792 return SimplifySRemInst(LHS, RHS, Q, MaxRecurse); 4793 case Instruction::URem: 4794 return SimplifyURemInst(LHS, RHS, Q, MaxRecurse); 4795 case Instruction::Shl: 4796 return SimplifyShlInst(LHS, RHS, false, false, Q, MaxRecurse); 4797 case Instruction::LShr: 4798 return SimplifyLShrInst(LHS, RHS, false, Q, MaxRecurse); 4799 case Instruction::AShr: 4800 return SimplifyAShrInst(LHS, RHS, false, Q, MaxRecurse); 4801 case Instruction::And: 4802 return SimplifyAndInst(LHS, RHS, Q, MaxRecurse); 4803 case Instruction::Or: 4804 return SimplifyOrInst(LHS, RHS, Q, MaxRecurse); 4805 case Instruction::Xor: 4806 return SimplifyXorInst(LHS, RHS, Q, MaxRecurse); 4807 case Instruction::FAdd: 4808 return SimplifyFAddInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse); 4809 case Instruction::FSub: 4810 return SimplifyFSubInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse); 4811 case Instruction::FMul: 4812 return SimplifyFMulInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse); 4813 case Instruction::FDiv: 4814 return SimplifyFDivInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse); 4815 case Instruction::FRem: 4816 return SimplifyFRemInst(LHS, RHS, FastMathFlags(), Q, MaxRecurse); 4817 default: 4818 llvm_unreachable("Unexpected opcode"); 4819 } 4820 } 4821 4822 /// Given operands for a BinaryOperator, see if we can fold the result. 4823 /// If not, this returns null. 4824 /// Try to use FastMathFlags when folding the result. 4825 static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, 4826 const FastMathFlags &FMF, const SimplifyQuery &Q, 4827 unsigned MaxRecurse) { 4828 switch (Opcode) { 4829 case Instruction::FAdd: 4830 return SimplifyFAddInst(LHS, RHS, FMF, Q, MaxRecurse); 4831 case Instruction::FSub: 4832 return SimplifyFSubInst(LHS, RHS, FMF, Q, MaxRecurse); 4833 case Instruction::FMul: 4834 return SimplifyFMulInst(LHS, RHS, FMF, Q, MaxRecurse); 4835 case Instruction::FDiv: 4836 return SimplifyFDivInst(LHS, RHS, FMF, Q, MaxRecurse); 4837 default: 4838 return SimplifyBinOp(Opcode, LHS, RHS, Q, MaxRecurse); 4839 } 4840 } 4841 4842 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, 4843 const SimplifyQuery &Q) { 4844 return ::SimplifyBinOp(Opcode, LHS, RHS, Q, RecursionLimit); 4845 } 4846 4847 Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, 4848 FastMathFlags FMF, const SimplifyQuery &Q) { 4849 return ::SimplifyBinOp(Opcode, LHS, RHS, FMF, Q, RecursionLimit); 4850 } 4851 4852 /// Given operands for a CmpInst, see if we can fold the result. 4853 static Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS, 4854 const SimplifyQuery &Q, unsigned MaxRecurse) { 4855 if (CmpInst::isIntPredicate((CmpInst::Predicate)Predicate)) 4856 return SimplifyICmpInst(Predicate, LHS, RHS, Q, MaxRecurse); 4857 return SimplifyFCmpInst(Predicate, LHS, RHS, FastMathFlags(), Q, MaxRecurse); 4858 } 4859 4860 Value *llvm::SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS, 4861 const SimplifyQuery &Q) { 4862 return ::SimplifyCmpInst(Predicate, LHS, RHS, Q, RecursionLimit); 4863 } 4864 4865 static bool IsIdempotent(Intrinsic::ID ID) { 4866 switch (ID) { 4867 default: return false; 4868 4869 // Unary idempotent: f(f(x)) = f(x) 4870 case Intrinsic::fabs: 4871 case Intrinsic::floor: 4872 case Intrinsic::ceil: 4873 case Intrinsic::trunc: 4874 case Intrinsic::rint: 4875 case Intrinsic::nearbyint: 4876 case Intrinsic::round: 4877 case Intrinsic::canonicalize: 4878 return true; 4879 } 4880 } 4881 4882 static Value *SimplifyRelativeLoad(Constant *Ptr, Constant *Offset, 4883 const DataLayout &DL) { 4884 GlobalValue *PtrSym; 4885 APInt PtrOffset; 4886 if (!IsConstantOffsetFromGlobal(Ptr, PtrSym, PtrOffset, DL)) 4887 return nullptr; 4888 4889 Type *Int8PtrTy = Type::getInt8PtrTy(Ptr->getContext()); 4890 Type *Int32Ty = Type::getInt32Ty(Ptr->getContext()); 4891 Type *Int32PtrTy = Int32Ty->getPointerTo(); 4892 Type *Int64Ty = Type::getInt64Ty(Ptr->getContext()); 4893 4894 auto *OffsetConstInt = dyn_cast<ConstantInt>(Offset); 4895 if (!OffsetConstInt || OffsetConstInt->getType()->getBitWidth() > 64) 4896 return nullptr; 4897 4898 uint64_t OffsetInt = OffsetConstInt->getSExtValue(); 4899 if (OffsetInt % 4 != 0) 4900 return nullptr; 4901 4902 Constant *C = ConstantExpr::getGetElementPtr( 4903 Int32Ty, ConstantExpr::getBitCast(Ptr, Int32PtrTy), 4904 ConstantInt::get(Int64Ty, OffsetInt / 4)); 4905 Constant *Loaded = ConstantFoldLoadFromConstPtr(C, Int32Ty, DL); 4906 if (!Loaded) 4907 return nullptr; 4908 4909 auto *LoadedCE = dyn_cast<ConstantExpr>(Loaded); 4910 if (!LoadedCE) 4911 return nullptr; 4912 4913 if (LoadedCE->getOpcode() == Instruction::Trunc) { 4914 LoadedCE = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0)); 4915 if (!LoadedCE) 4916 return nullptr; 4917 } 4918 4919 if (LoadedCE->getOpcode() != Instruction::Sub) 4920 return nullptr; 4921 4922 auto *LoadedLHS = dyn_cast<ConstantExpr>(LoadedCE->getOperand(0)); 4923 if (!LoadedLHS || LoadedLHS->getOpcode() != Instruction::PtrToInt) 4924 return nullptr; 4925 auto *LoadedLHSPtr = LoadedLHS->getOperand(0); 4926 4927 Constant *LoadedRHS = LoadedCE->getOperand(1); 4928 GlobalValue *LoadedRHSSym; 4929 APInt LoadedRHSOffset; 4930 if (!IsConstantOffsetFromGlobal(LoadedRHS, LoadedRHSSym, LoadedRHSOffset, 4931 DL) || 4932 PtrSym != LoadedRHSSym || PtrOffset != LoadedRHSOffset) 4933 return nullptr; 4934 4935 return ConstantExpr::getBitCast(LoadedLHSPtr, Int8PtrTy); 4936 } 4937 4938 static Value *simplifyUnaryIntrinsic(Function *F, Value *Op0, 4939 const SimplifyQuery &Q) { 4940 // Idempotent functions return the same result when called repeatedly. 4941 Intrinsic::ID IID = F->getIntrinsicID(); 4942 if (IsIdempotent(IID)) 4943 if (auto *II = dyn_cast<IntrinsicInst>(Op0)) 4944 if (II->getIntrinsicID() == IID) 4945 return II; 4946 4947 Value *X; 4948 switch (IID) { 4949 case Intrinsic::fabs: 4950 if (SignBitMustBeZero(Op0, Q.TLI)) return Op0; 4951 break; 4952 case Intrinsic::bswap: 4953 // bswap(bswap(x)) -> x 4954 if (match(Op0, m_BSwap(m_Value(X)))) return X; 4955 break; 4956 case Intrinsic::bitreverse: 4957 // bitreverse(bitreverse(x)) -> x 4958 if (match(Op0, m_BitReverse(m_Value(X)))) return X; 4959 break; 4960 case Intrinsic::exp: 4961 // exp(log(x)) -> x 4962 if (Q.CxtI->hasAllowReassoc() && 4963 match(Op0, m_Intrinsic<Intrinsic::log>(m_Value(X)))) return X; 4964 break; 4965 case Intrinsic::exp2: 4966 // exp2(log2(x)) -> x 4967 if (Q.CxtI->hasAllowReassoc() && 4968 match(Op0, m_Intrinsic<Intrinsic::log2>(m_Value(X)))) return X; 4969 break; 4970 case Intrinsic::log: 4971 // log(exp(x)) -> x 4972 if (Q.CxtI->hasAllowReassoc() && 4973 match(Op0, m_Intrinsic<Intrinsic::exp>(m_Value(X)))) return X; 4974 break; 4975 case Intrinsic::log2: 4976 // log2(exp2(x)) -> x 4977 if (Q.CxtI->hasAllowReassoc() && 4978 (match(Op0, m_Intrinsic<Intrinsic::exp2>(m_Value(X))) || 4979 match(Op0, m_Intrinsic<Intrinsic::pow>(m_SpecificFP(2.0), 4980 m_Value(X))))) return X; 4981 break; 4982 case Intrinsic::log10: 4983 // log10(pow(10.0, x)) -> x 4984 if (Q.CxtI->hasAllowReassoc() && 4985 match(Op0, m_Intrinsic<Intrinsic::pow>(m_SpecificFP(10.0), 4986 m_Value(X)))) return X; 4987 break; 4988 case Intrinsic::floor: 4989 case Intrinsic::trunc: 4990 case Intrinsic::ceil: 4991 case Intrinsic::round: 4992 case Intrinsic::nearbyint: 4993 case Intrinsic::rint: { 4994 // floor (sitofp x) -> sitofp x 4995 // floor (uitofp x) -> uitofp x 4996 // 4997 // Converting from int always results in a finite integral number or 4998 // infinity. For either of those inputs, these rounding functions always 4999 // return the same value, so the rounding can be eliminated. 5000 if (match(Op0, m_SIToFP(m_Value())) || match(Op0, m_UIToFP(m_Value()))) 5001 return Op0; 5002 break; 5003 } 5004 default: 5005 break; 5006 } 5007 5008 return nullptr; 5009 } 5010 5011 static Value *simplifyBinaryIntrinsic(Function *F, Value *Op0, Value *Op1, 5012 const SimplifyQuery &Q) { 5013 Intrinsic::ID IID = F->getIntrinsicID(); 5014 Type *ReturnType = F->getReturnType(); 5015 switch (IID) { 5016 case Intrinsic::usub_with_overflow: 5017 case Intrinsic::ssub_with_overflow: 5018 // X - X -> { 0, false } 5019 if (Op0 == Op1) 5020 return Constant::getNullValue(ReturnType); 5021 LLVM_FALLTHROUGH; 5022 case Intrinsic::uadd_with_overflow: 5023 case Intrinsic::sadd_with_overflow: 5024 // X - undef -> { undef, false } 5025 // undef - X -> { undef, false } 5026 // X + undef -> { undef, false } 5027 // undef + x -> { undef, false } 5028 if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1)) { 5029 return ConstantStruct::get( 5030 cast<StructType>(ReturnType), 5031 {UndefValue::get(ReturnType->getStructElementType(0)), 5032 Constant::getNullValue(ReturnType->getStructElementType(1))}); 5033 } 5034 break; 5035 case Intrinsic::umul_with_overflow: 5036 case Intrinsic::smul_with_overflow: 5037 // 0 * X -> { 0, false } 5038 // X * 0 -> { 0, false } 5039 if (match(Op0, m_Zero()) || match(Op1, m_Zero())) 5040 return Constant::getNullValue(ReturnType); 5041 // undef * X -> { 0, false } 5042 // X * undef -> { 0, false } 5043 if (match(Op0, m_Undef()) || match(Op1, m_Undef())) 5044 return Constant::getNullValue(ReturnType); 5045 break; 5046 case Intrinsic::uadd_sat: 5047 // sat(MAX + X) -> MAX 5048 // sat(X + MAX) -> MAX 5049 if (match(Op0, m_AllOnes()) || match(Op1, m_AllOnes())) 5050 return Constant::getAllOnesValue(ReturnType); 5051 LLVM_FALLTHROUGH; 5052 case Intrinsic::sadd_sat: 5053 // sat(X + undef) -> -1 5054 // sat(undef + X) -> -1 5055 // For unsigned: Assume undef is MAX, thus we saturate to MAX (-1). 5056 // For signed: Assume undef is ~X, in which case X + ~X = -1. 5057 if (match(Op0, m_Undef()) || match(Op1, m_Undef())) 5058 return Constant::getAllOnesValue(ReturnType); 5059 5060 // X + 0 -> X 5061 if (match(Op1, m_Zero())) 5062 return Op0; 5063 // 0 + X -> X 5064 if (match(Op0, m_Zero())) 5065 return Op1; 5066 break; 5067 case Intrinsic::usub_sat: 5068 // sat(0 - X) -> 0, sat(X - MAX) -> 0 5069 if (match(Op0, m_Zero()) || match(Op1, m_AllOnes())) 5070 return Constant::getNullValue(ReturnType); 5071 LLVM_FALLTHROUGH; 5072 case Intrinsic::ssub_sat: 5073 // X - X -> 0, X - undef -> 0, undef - X -> 0 5074 if (Op0 == Op1 || match(Op0, m_Undef()) || match(Op1, m_Undef())) 5075 return Constant::getNullValue(ReturnType); 5076 // X - 0 -> X 5077 if (match(Op1, m_Zero())) 5078 return Op0; 5079 break; 5080 case Intrinsic::load_relative: 5081 if (auto *C0 = dyn_cast<Constant>(Op0)) 5082 if (auto *C1 = dyn_cast<Constant>(Op1)) 5083 return SimplifyRelativeLoad(C0, C1, Q.DL); 5084 break; 5085 case Intrinsic::powi: 5086 if (auto *Power = dyn_cast<ConstantInt>(Op1)) { 5087 // powi(x, 0) -> 1.0 5088 if (Power->isZero()) 5089 return ConstantFP::get(Op0->getType(), 1.0); 5090 // powi(x, 1) -> x 5091 if (Power->isOne()) 5092 return Op0; 5093 } 5094 break; 5095 case Intrinsic::maxnum: 5096 case Intrinsic::minnum: 5097 case Intrinsic::maximum: 5098 case Intrinsic::minimum: { 5099 // If the arguments are the same, this is a no-op. 5100 if (Op0 == Op1) return Op0; 5101 5102 // If one argument is undef, return the other argument. 5103 if (match(Op0, m_Undef())) 5104 return Op1; 5105 if (match(Op1, m_Undef())) 5106 return Op0; 5107 5108 // If one argument is NaN, return other or NaN appropriately. 5109 bool PropagateNaN = IID == Intrinsic::minimum || IID == Intrinsic::maximum; 5110 if (match(Op0, m_NaN())) 5111 return PropagateNaN ? Op0 : Op1; 5112 if (match(Op1, m_NaN())) 5113 return PropagateNaN ? Op1 : Op0; 5114 5115 // Min/max of the same operation with common operand: 5116 // m(m(X, Y)), X --> m(X, Y) (4 commuted variants) 5117 if (auto *M0 = dyn_cast<IntrinsicInst>(Op0)) 5118 if (M0->getIntrinsicID() == IID && 5119 (M0->getOperand(0) == Op1 || M0->getOperand(1) == Op1)) 5120 return Op0; 5121 if (auto *M1 = dyn_cast<IntrinsicInst>(Op1)) 5122 if (M1->getIntrinsicID() == IID && 5123 (M1->getOperand(0) == Op0 || M1->getOperand(1) == Op0)) 5124 return Op1; 5125 5126 // min(X, -Inf) --> -Inf (and commuted variant) 5127 // max(X, +Inf) --> +Inf (and commuted variant) 5128 bool UseNegInf = IID == Intrinsic::minnum || IID == Intrinsic::minimum; 5129 const APFloat *C; 5130 if ((match(Op0, m_APFloat(C)) && C->isInfinity() && 5131 C->isNegative() == UseNegInf) || 5132 (match(Op1, m_APFloat(C)) && C->isInfinity() && 5133 C->isNegative() == UseNegInf)) 5134 return ConstantFP::getInfinity(ReturnType, UseNegInf); 5135 5136 // TODO: minnum(nnan x, inf) -> x 5137 // TODO: minnum(nnan ninf x, flt_max) -> x 5138 // TODO: maxnum(nnan x, -inf) -> x 5139 // TODO: maxnum(nnan ninf x, -flt_max) -> x 5140 break; 5141 } 5142 default: 5143 break; 5144 } 5145 5146 return nullptr; 5147 } 5148 5149 static Value *simplifyIntrinsic(CallBase *Call, const SimplifyQuery &Q) { 5150 5151 // Intrinsics with no operands have some kind of side effect. Don't simplify. 5152 unsigned NumOperands = Call->getNumArgOperands(); 5153 if (!NumOperands) 5154 return nullptr; 5155 5156 Function *F = cast<Function>(Call->getCalledFunction()); 5157 Intrinsic::ID IID = F->getIntrinsicID(); 5158 if (NumOperands == 1) 5159 return simplifyUnaryIntrinsic(F, Call->getArgOperand(0), Q); 5160 5161 if (NumOperands == 2) 5162 return simplifyBinaryIntrinsic(F, Call->getArgOperand(0), 5163 Call->getArgOperand(1), Q); 5164 5165 // Handle intrinsics with 3 or more arguments. 5166 switch (IID) { 5167 case Intrinsic::masked_load: 5168 case Intrinsic::masked_gather: { 5169 Value *MaskArg = Call->getArgOperand(2); 5170 Value *PassthruArg = Call->getArgOperand(3); 5171 // If the mask is all zeros or undef, the "passthru" argument is the result. 5172 if (maskIsAllZeroOrUndef(MaskArg)) 5173 return PassthruArg; 5174 return nullptr; 5175 } 5176 case Intrinsic::fshl: 5177 case Intrinsic::fshr: { 5178 Value *Op0 = Call->getArgOperand(0), *Op1 = Call->getArgOperand(1), 5179 *ShAmtArg = Call->getArgOperand(2); 5180 5181 // If both operands are undef, the result is undef. 5182 if (match(Op0, m_Undef()) && match(Op1, m_Undef())) 5183 return UndefValue::get(F->getReturnType()); 5184 5185 // If shift amount is undef, assume it is zero. 5186 if (match(ShAmtArg, m_Undef())) 5187 return Call->getArgOperand(IID == Intrinsic::fshl ? 0 : 1); 5188 5189 const APInt *ShAmtC; 5190 if (match(ShAmtArg, m_APInt(ShAmtC))) { 5191 // If there's effectively no shift, return the 1st arg or 2nd arg. 5192 APInt BitWidth = APInt(ShAmtC->getBitWidth(), ShAmtC->getBitWidth()); 5193 if (ShAmtC->urem(BitWidth).isNullValue()) 5194 return Call->getArgOperand(IID == Intrinsic::fshl ? 0 : 1); 5195 } 5196 return nullptr; 5197 } 5198 case Intrinsic::fma: 5199 case Intrinsic::fmuladd: { 5200 Value *Op0 = Call->getArgOperand(0); 5201 Value *Op1 = Call->getArgOperand(1); 5202 Value *Op2 = Call->getArgOperand(2); 5203 if (Value *V = simplifyFPOp({ Op0, Op1, Op2 })) 5204 return V; 5205 return nullptr; 5206 } 5207 default: 5208 return nullptr; 5209 } 5210 } 5211 5212 Value *llvm::SimplifyCall(CallBase *Call, const SimplifyQuery &Q) { 5213 Value *Callee = Call->getCalledValue(); 5214 5215 // call undef -> undef 5216 // call null -> undef 5217 if (isa<UndefValue>(Callee) || isa<ConstantPointerNull>(Callee)) 5218 return UndefValue::get(Call->getType()); 5219 5220 Function *F = dyn_cast<Function>(Callee); 5221 if (!F) 5222 return nullptr; 5223 5224 if (F->isIntrinsic()) 5225 if (Value *Ret = simplifyIntrinsic(Call, Q)) 5226 return Ret; 5227 5228 if (!canConstantFoldCallTo(Call, F)) 5229 return nullptr; 5230 5231 SmallVector<Constant *, 4> ConstantArgs; 5232 unsigned NumArgs = Call->getNumArgOperands(); 5233 ConstantArgs.reserve(NumArgs); 5234 for (auto &Arg : Call->args()) { 5235 Constant *C = dyn_cast<Constant>(&Arg); 5236 if (!C) 5237 return nullptr; 5238 ConstantArgs.push_back(C); 5239 } 5240 5241 return ConstantFoldCall(Call, F, ConstantArgs, Q.TLI); 5242 } 5243 5244 /// See if we can compute a simplified version of this instruction. 5245 /// If not, this returns null. 5246 5247 Value *llvm::SimplifyInstruction(Instruction *I, const SimplifyQuery &SQ, 5248 OptimizationRemarkEmitter *ORE) { 5249 const SimplifyQuery Q = SQ.CxtI ? SQ : SQ.getWithInstruction(I); 5250 Value *Result; 5251 5252 switch (I->getOpcode()) { 5253 default: 5254 Result = ConstantFoldInstruction(I, Q.DL, Q.TLI); 5255 break; 5256 case Instruction::FNeg: 5257 Result = SimplifyFNegInst(I->getOperand(0), I->getFastMathFlags(), Q); 5258 break; 5259 case Instruction::FAdd: 5260 Result = SimplifyFAddInst(I->getOperand(0), I->getOperand(1), 5261 I->getFastMathFlags(), Q); 5262 break; 5263 case Instruction::Add: 5264 Result = 5265 SimplifyAddInst(I->getOperand(0), I->getOperand(1), 5266 Q.IIQ.hasNoSignedWrap(cast<BinaryOperator>(I)), 5267 Q.IIQ.hasNoUnsignedWrap(cast<BinaryOperator>(I)), Q); 5268 break; 5269 case Instruction::FSub: 5270 Result = SimplifyFSubInst(I->getOperand(0), I->getOperand(1), 5271 I->getFastMathFlags(), Q); 5272 break; 5273 case Instruction::Sub: 5274 Result = 5275 SimplifySubInst(I->getOperand(0), I->getOperand(1), 5276 Q.IIQ.hasNoSignedWrap(cast<BinaryOperator>(I)), 5277 Q.IIQ.hasNoUnsignedWrap(cast<BinaryOperator>(I)), Q); 5278 break; 5279 case Instruction::FMul: 5280 Result = SimplifyFMulInst(I->getOperand(0), I->getOperand(1), 5281 I->getFastMathFlags(), Q); 5282 break; 5283 case Instruction::Mul: 5284 Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), Q); 5285 break; 5286 case Instruction::SDiv: 5287 Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), Q); 5288 break; 5289 case Instruction::UDiv: 5290 Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), Q); 5291 break; 5292 case Instruction::FDiv: 5293 Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), 5294 I->getFastMathFlags(), Q); 5295 break; 5296 case Instruction::SRem: 5297 Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), Q); 5298 break; 5299 case Instruction::URem: 5300 Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), Q); 5301 break; 5302 case Instruction::FRem: 5303 Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), 5304 I->getFastMathFlags(), Q); 5305 break; 5306 case Instruction::Shl: 5307 Result = 5308 SimplifyShlInst(I->getOperand(0), I->getOperand(1), 5309 Q.IIQ.hasNoSignedWrap(cast<BinaryOperator>(I)), 5310 Q.IIQ.hasNoUnsignedWrap(cast<BinaryOperator>(I)), Q); 5311 break; 5312 case Instruction::LShr: 5313 Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1), 5314 Q.IIQ.isExact(cast<BinaryOperator>(I)), Q); 5315 break; 5316 case Instruction::AShr: 5317 Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1), 5318 Q.IIQ.isExact(cast<BinaryOperator>(I)), Q); 5319 break; 5320 case Instruction::And: 5321 Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), Q); 5322 break; 5323 case Instruction::Or: 5324 Result = SimplifyOrInst(I->getOperand(0), I->getOperand(1), Q); 5325 break; 5326 case Instruction::Xor: 5327 Result = SimplifyXorInst(I->getOperand(0), I->getOperand(1), Q); 5328 break; 5329 case Instruction::ICmp: 5330 Result = SimplifyICmpInst(cast<ICmpInst>(I)->getPredicate(), 5331 I->getOperand(0), I->getOperand(1), Q); 5332 break; 5333 case Instruction::FCmp: 5334 Result = 5335 SimplifyFCmpInst(cast<FCmpInst>(I)->getPredicate(), I->getOperand(0), 5336 I->getOperand(1), I->getFastMathFlags(), Q); 5337 break; 5338 case Instruction::Select: 5339 Result = SimplifySelectInst(I->getOperand(0), I->getOperand(1), 5340 I->getOperand(2), Q); 5341 break; 5342 case Instruction::GetElementPtr: { 5343 SmallVector<Value *, 8> Ops(I->op_begin(), I->op_end()); 5344 Result = SimplifyGEPInst(cast<GetElementPtrInst>(I)->getSourceElementType(), 5345 Ops, Q); 5346 break; 5347 } 5348 case Instruction::InsertValue: { 5349 InsertValueInst *IV = cast<InsertValueInst>(I); 5350 Result = SimplifyInsertValueInst(IV->getAggregateOperand(), 5351 IV->getInsertedValueOperand(), 5352 IV->getIndices(), Q); 5353 break; 5354 } 5355 case Instruction::InsertElement: { 5356 auto *IE = cast<InsertElementInst>(I); 5357 Result = SimplifyInsertElementInst(IE->getOperand(0), IE->getOperand(1), 5358 IE->getOperand(2), Q); 5359 break; 5360 } 5361 case Instruction::ExtractValue: { 5362 auto *EVI = cast<ExtractValueInst>(I); 5363 Result = SimplifyExtractValueInst(EVI->getAggregateOperand(), 5364 EVI->getIndices(), Q); 5365 break; 5366 } 5367 case Instruction::ExtractElement: { 5368 auto *EEI = cast<ExtractElementInst>(I); 5369 Result = SimplifyExtractElementInst(EEI->getVectorOperand(), 5370 EEI->getIndexOperand(), Q); 5371 break; 5372 } 5373 case Instruction::ShuffleVector: { 5374 auto *SVI = cast<ShuffleVectorInst>(I); 5375 Result = SimplifyShuffleVectorInst(SVI->getOperand(0), SVI->getOperand(1), 5376 SVI->getMask(), SVI->getType(), Q); 5377 break; 5378 } 5379 case Instruction::PHI: 5380 Result = SimplifyPHINode(cast<PHINode>(I), Q); 5381 break; 5382 case Instruction::Call: { 5383 Result = SimplifyCall(cast<CallInst>(I), Q); 5384 break; 5385 } 5386 #define HANDLE_CAST_INST(num, opc, clas) case Instruction::opc: 5387 #include "llvm/IR/Instruction.def" 5388 #undef HANDLE_CAST_INST 5389 Result = 5390 SimplifyCastInst(I->getOpcode(), I->getOperand(0), I->getType(), Q); 5391 break; 5392 case Instruction::Alloca: 5393 // No simplifications for Alloca and it can't be constant folded. 5394 Result = nullptr; 5395 break; 5396 } 5397 5398 // In general, it is possible for computeKnownBits to determine all bits in a 5399 // value even when the operands are not all constants. 5400 if (!Result && I->getType()->isIntOrIntVectorTy()) { 5401 KnownBits Known = computeKnownBits(I, Q.DL, /*Depth*/ 0, Q.AC, I, Q.DT, ORE); 5402 if (Known.isConstant()) 5403 Result = ConstantInt::get(I->getType(), Known.getConstant()); 5404 } 5405 5406 /// If called on unreachable code, the above logic may report that the 5407 /// instruction simplified to itself. Make life easier for users by 5408 /// detecting that case here, returning a safe value instead. 5409 return Result == I ? UndefValue::get(I->getType()) : Result; 5410 } 5411 5412 /// Implementation of recursive simplification through an instruction's 5413 /// uses. 5414 /// 5415 /// This is the common implementation of the recursive simplification routines. 5416 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to 5417 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of 5418 /// instructions to process and attempt to simplify it using 5419 /// InstructionSimplify. Recursively visited users which could not be 5420 /// simplified themselves are to the optional UnsimplifiedUsers set for 5421 /// further processing by the caller. 5422 /// 5423 /// This routine returns 'true' only when *it* simplifies something. The passed 5424 /// in simplified value does not count toward this. 5425 static bool replaceAndRecursivelySimplifyImpl( 5426 Instruction *I, Value *SimpleV, const TargetLibraryInfo *TLI, 5427 const DominatorTree *DT, AssumptionCache *AC, 5428 SmallSetVector<Instruction *, 8> *UnsimplifiedUsers = nullptr) { 5429 bool Simplified = false; 5430 SmallSetVector<Instruction *, 8> Worklist; 5431 const DataLayout &DL = I->getModule()->getDataLayout(); 5432 5433 // If we have an explicit value to collapse to, do that round of the 5434 // simplification loop by hand initially. 5435 if (SimpleV) { 5436 for (User *U : I->users()) 5437 if (U != I) 5438 Worklist.insert(cast<Instruction>(U)); 5439 5440 // Replace the instruction with its simplified value. 5441 I->replaceAllUsesWith(SimpleV); 5442 5443 // Gracefully handle edge cases where the instruction is not wired into any 5444 // parent block. 5445 if (I->getParent() && !I->isEHPad() && !I->isTerminator() && 5446 !I->mayHaveSideEffects()) 5447 I->eraseFromParent(); 5448 } else { 5449 Worklist.insert(I); 5450 } 5451 5452 // Note that we must test the size on each iteration, the worklist can grow. 5453 for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) { 5454 I = Worklist[Idx]; 5455 5456 // See if this instruction simplifies. 5457 SimpleV = SimplifyInstruction(I, {DL, TLI, DT, AC}); 5458 if (!SimpleV) { 5459 if (UnsimplifiedUsers) 5460 UnsimplifiedUsers->insert(I); 5461 continue; 5462 } 5463 5464 Simplified = true; 5465 5466 // Stash away all the uses of the old instruction so we can check them for 5467 // recursive simplifications after a RAUW. This is cheaper than checking all 5468 // uses of To on the recursive step in most cases. 5469 for (User *U : I->users()) 5470 Worklist.insert(cast<Instruction>(U)); 5471 5472 // Replace the instruction with its simplified value. 5473 I->replaceAllUsesWith(SimpleV); 5474 5475 // Gracefully handle edge cases where the instruction is not wired into any 5476 // parent block. 5477 if (I->getParent() && !I->isEHPad() && !I->isTerminator() && 5478 !I->mayHaveSideEffects()) 5479 I->eraseFromParent(); 5480 } 5481 return Simplified; 5482 } 5483 5484 bool llvm::recursivelySimplifyInstruction(Instruction *I, 5485 const TargetLibraryInfo *TLI, 5486 const DominatorTree *DT, 5487 AssumptionCache *AC) { 5488 return replaceAndRecursivelySimplifyImpl(I, nullptr, TLI, DT, AC, nullptr); 5489 } 5490 5491 bool llvm::replaceAndRecursivelySimplify( 5492 Instruction *I, Value *SimpleV, const TargetLibraryInfo *TLI, 5493 const DominatorTree *DT, AssumptionCache *AC, 5494 SmallSetVector<Instruction *, 8> *UnsimplifiedUsers) { 5495 assert(I != SimpleV && "replaceAndRecursivelySimplify(X,X) is not valid!"); 5496 assert(SimpleV && "Must provide a simplified value."); 5497 return replaceAndRecursivelySimplifyImpl(I, SimpleV, TLI, DT, AC, 5498 UnsimplifiedUsers); 5499 } 5500 5501 namespace llvm { 5502 const SimplifyQuery getBestSimplifyQuery(Pass &P, Function &F) { 5503 auto *DTWP = P.getAnalysisIfAvailable<DominatorTreeWrapperPass>(); 5504 auto *DT = DTWP ? &DTWP->getDomTree() : nullptr; 5505 auto *TLIWP = P.getAnalysisIfAvailable<TargetLibraryInfoWrapperPass>(); 5506 auto *TLI = TLIWP ? &TLIWP->getTLI(F) : nullptr; 5507 auto *ACWP = P.getAnalysisIfAvailable<AssumptionCacheTracker>(); 5508 auto *AC = ACWP ? &ACWP->getAssumptionCache(F) : nullptr; 5509 return {F.getParent()->getDataLayout(), TLI, DT, AC}; 5510 } 5511 5512 const SimplifyQuery getBestSimplifyQuery(LoopStandardAnalysisResults &AR, 5513 const DataLayout &DL) { 5514 return {DL, &AR.TLI, &AR.DT, &AR.AC}; 5515 } 5516 5517 template <class T, class... TArgs> 5518 const SimplifyQuery getBestSimplifyQuery(AnalysisManager<T, TArgs...> &AM, 5519 Function &F) { 5520 auto *DT = AM.template getCachedResult<DominatorTreeAnalysis>(F); 5521 auto *TLI = AM.template getCachedResult<TargetLibraryAnalysis>(F); 5522 auto *AC = AM.template getCachedResult<AssumptionAnalysis>(F); 5523 return {F.getParent()->getDataLayout(), TLI, DT, AC}; 5524 } 5525 template const SimplifyQuery getBestSimplifyQuery(AnalysisManager<Function> &, 5526 Function &); 5527 } 5528