//===- InstCombineAndOrXor.cpp --------------------------------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements the visitAnd, visitOr, and visitXor functions. // //===----------------------------------------------------------------------===// #include "InstCombineInternal.h" #include "llvm/Analysis/InstructionSimplify.h" #include "llvm/IR/ConstantRange.h" #include "llvm/IR/Intrinsics.h" #include "llvm/IR/PatternMatch.h" #include "llvm/Transforms/Utils/CmpInstAnalysis.h" using namespace llvm; using namespace PatternMatch; #define DEBUG_TYPE "instcombine" static inline Value *dyn_castNotVal(Value *V) { // If this is not(not(x)) don't return that this is a not: we want the two // not's to be folded first. if (BinaryOperator::isNot(V)) { Value *Operand = BinaryOperator::getNotArgument(V); if (!IsFreeToInvert(Operand, Operand->hasOneUse())) return Operand; } // Constants can be considered to be not'ed values... if (ConstantInt *C = dyn_cast(V)) return ConstantInt::get(C->getType(), ~C->getValue()); return nullptr; } /// Similar to getICmpCode but for FCmpInst. This encodes a fcmp predicate into /// a three bit mask. It also returns whether it is an ordered predicate by /// reference. static unsigned getFCmpCode(FCmpInst::Predicate CC, bool &isOrdered) { isOrdered = false; switch (CC) { case FCmpInst::FCMP_ORD: isOrdered = true; return 0; // 000 case FCmpInst::FCMP_UNO: return 0; // 000 case FCmpInst::FCMP_OGT: isOrdered = true; return 1; // 001 case FCmpInst::FCMP_UGT: return 1; // 001 case FCmpInst::FCMP_OEQ: isOrdered = true; return 2; // 010 case FCmpInst::FCMP_UEQ: return 2; // 010 case FCmpInst::FCMP_OGE: isOrdered = true; return 3; // 011 case FCmpInst::FCMP_UGE: return 3; // 011 case FCmpInst::FCMP_OLT: isOrdered = true; return 4; // 100 case FCmpInst::FCMP_ULT: return 4; // 100 case FCmpInst::FCMP_ONE: isOrdered = true; return 5; // 101 case FCmpInst::FCMP_UNE: return 5; // 101 case FCmpInst::FCMP_OLE: isOrdered = true; return 6; // 110 case FCmpInst::FCMP_ULE: return 6; // 110 // True -> 7 default: // Not expecting FCMP_FALSE and FCMP_TRUE; llvm_unreachable("Unexpected FCmp predicate!"); } } /// This is the complement of getICmpCode, which turns an opcode and two /// operands into either a constant true or false, or a brand new ICmp /// instruction. The sign is passed in to determine which kind of predicate to /// use in the new icmp instruction. static Value *getNewICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS, InstCombiner::BuilderTy *Builder) { ICmpInst::Predicate NewPred; if (Value *NewConstant = getICmpValue(Sign, Code, LHS, RHS, NewPred)) return NewConstant; return Builder->CreateICmp(NewPred, LHS, RHS); } /// This is the complement of getFCmpCode, which turns an opcode and two /// operands into either a FCmp instruction. isordered is passed in to determine /// which kind of predicate to use in the new fcmp instruction. static Value *getFCmpValue(bool isordered, unsigned code, Value *LHS, Value *RHS, InstCombiner::BuilderTy *Builder) { CmpInst::Predicate Pred; switch (code) { default: llvm_unreachable("Illegal FCmp code!"); case 0: Pred = isordered ? FCmpInst::FCMP_ORD : FCmpInst::FCMP_UNO; break; case 1: Pred = isordered ? FCmpInst::FCMP_OGT : FCmpInst::FCMP_UGT; break; case 2: Pred = isordered ? FCmpInst::FCMP_OEQ : FCmpInst::FCMP_UEQ; break; case 3: Pred = isordered ? FCmpInst::FCMP_OGE : FCmpInst::FCMP_UGE; break; case 4: Pred = isordered ? FCmpInst::FCMP_OLT : FCmpInst::FCMP_ULT; break; case 5: Pred = isordered ? FCmpInst::FCMP_ONE : FCmpInst::FCMP_UNE; break; case 6: Pred = isordered ? FCmpInst::FCMP_OLE : FCmpInst::FCMP_ULE; break; case 7: if (!isordered) return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1); Pred = FCmpInst::FCMP_ORD; break; } return Builder->CreateFCmp(Pred, LHS, RHS); } /// \brief Transform BITWISE_OP(BSWAP(A),BSWAP(B)) to BSWAP(BITWISE_OP(A, B)) /// \param I Binary operator to transform. /// \return Pointer to node that must replace the original binary operator, or /// null pointer if no transformation was made. Value *InstCombiner::SimplifyBSwap(BinaryOperator &I) { IntegerType *ITy = dyn_cast(I.getType()); // Can't do vectors. if (I.getType()->isVectorTy()) return nullptr; // Can only do bitwise ops. unsigned Op = I.getOpcode(); if (Op != Instruction::And && Op != Instruction::Or && Op != Instruction::Xor) return nullptr; Value *OldLHS = I.getOperand(0); Value *OldRHS = I.getOperand(1); ConstantInt *ConstLHS = dyn_cast(OldLHS); ConstantInt *ConstRHS = dyn_cast(OldRHS); IntrinsicInst *IntrLHS = dyn_cast(OldLHS); IntrinsicInst *IntrRHS = dyn_cast(OldRHS); bool IsBswapLHS = (IntrLHS && IntrLHS->getIntrinsicID() == Intrinsic::bswap); bool IsBswapRHS = (IntrRHS && IntrRHS->getIntrinsicID() == Intrinsic::bswap); if (!IsBswapLHS && !IsBswapRHS) return nullptr; if (!IsBswapLHS && !ConstLHS) return nullptr; if (!IsBswapRHS && !ConstRHS) return nullptr; /// OP( BSWAP(x), BSWAP(y) ) -> BSWAP( OP(x, y) ) /// OP( BSWAP(x), CONSTANT ) -> BSWAP( OP(x, BSWAP(CONSTANT) ) ) Value *NewLHS = IsBswapLHS ? IntrLHS->getOperand(0) : Builder->getInt(ConstLHS->getValue().byteSwap()); Value *NewRHS = IsBswapRHS ? IntrRHS->getOperand(0) : Builder->getInt(ConstRHS->getValue().byteSwap()); Value *BinOp = nullptr; if (Op == Instruction::And) BinOp = Builder->CreateAnd(NewLHS, NewRHS); else if (Op == Instruction::Or) BinOp = Builder->CreateOr(NewLHS, NewRHS); else //if (Op == Instruction::Xor) BinOp = Builder->CreateXor(NewLHS, NewRHS); Function *F = Intrinsic::getDeclaration(I.getModule(), Intrinsic::bswap, ITy); return Builder->CreateCall(F, BinOp); } /// This handles expressions of the form ((val OP C1) & C2). Where /// the Op parameter is 'OP', OpRHS is 'C1', and AndRHS is 'C2'. Op is /// guaranteed to be a binary operator. Instruction *InstCombiner::OptAndOp(Instruction *Op, ConstantInt *OpRHS, ConstantInt *AndRHS, BinaryOperator &TheAnd) { Value *X = Op->getOperand(0); Constant *Together = nullptr; if (!Op->isShift()) Together = ConstantExpr::getAnd(AndRHS, OpRHS); switch (Op->getOpcode()) { case Instruction::Xor: if (Op->hasOneUse()) { // (X ^ C1) & C2 --> (X & C2) ^ (C1&C2) Value *And = Builder->CreateAnd(X, AndRHS); And->takeName(Op); return BinaryOperator::CreateXor(And, Together); } break; case Instruction::Or: if (Op->hasOneUse()){ if (Together != OpRHS) { // (X | C1) & C2 --> (X | (C1&C2)) & C2 Value *Or = Builder->CreateOr(X, Together); Or->takeName(Op); return BinaryOperator::CreateAnd(Or, AndRHS); } ConstantInt *TogetherCI = dyn_cast(Together); if (TogetherCI && !TogetherCI->isZero()){ // (X | C1) & C2 --> (X & (C2^(C1&C2))) | C1 // NOTE: This reduces the number of bits set in the & mask, which // can expose opportunities for store narrowing. Together = ConstantExpr::getXor(AndRHS, Together); Value *And = Builder->CreateAnd(X, Together); And->takeName(Op); return BinaryOperator::CreateOr(And, OpRHS); } } break; case Instruction::Add: if (Op->hasOneUse()) { // Adding a one to a single bit bit-field should be turned into an XOR // of the bit. First thing to check is to see if this AND is with a // single bit constant. const APInt &AndRHSV = AndRHS->getValue(); // If there is only one bit set. if (AndRHSV.isPowerOf2()) { // Ok, at this point, we know that we are masking the result of the // ADD down to exactly one bit. If the constant we are adding has // no bits set below this bit, then we can eliminate the ADD. const APInt& AddRHS = OpRHS->getValue(); // Check to see if any bits below the one bit set in AndRHSV are set. if ((AddRHS & (AndRHSV-1)) == 0) { // If not, the only thing that can effect the output of the AND is // the bit specified by AndRHSV. If that bit is set, the effect of // the XOR is to toggle the bit. If it is clear, then the ADD has // no effect. if ((AddRHS & AndRHSV) == 0) { // Bit is not set, noop TheAnd.setOperand(0, X); return &TheAnd; } else { // Pull the XOR out of the AND. Value *NewAnd = Builder->CreateAnd(X, AndRHS); NewAnd->takeName(Op); return BinaryOperator::CreateXor(NewAnd, AndRHS); } } } } break; case Instruction::Shl: { // We know that the AND will not produce any of the bits shifted in, so if // the anded constant includes them, clear them now! // uint32_t BitWidth = AndRHS->getType()->getBitWidth(); uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth); APInt ShlMask(APInt::getHighBitsSet(BitWidth, BitWidth-OpRHSVal)); ConstantInt *CI = Builder->getInt(AndRHS->getValue() & ShlMask); if (CI->getValue() == ShlMask) // Masking out bits that the shift already masks. return ReplaceInstUsesWith(TheAnd, Op); // No need for the and. if (CI != AndRHS) { // Reducing bits set in and. TheAnd.setOperand(1, CI); return &TheAnd; } break; } case Instruction::LShr: { // We know that the AND will not produce any of the bits shifted in, so if // the anded constant includes them, clear them now! This only applies to // unsigned shifts, because a signed shr may bring in set bits! // uint32_t BitWidth = AndRHS->getType()->getBitWidth(); uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth); APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal)); ConstantInt *CI = Builder->getInt(AndRHS->getValue() & ShrMask); if (CI->getValue() == ShrMask) // Masking out bits that the shift already masks. return ReplaceInstUsesWith(TheAnd, Op); if (CI != AndRHS) { TheAnd.setOperand(1, CI); // Reduce bits set in and cst. return &TheAnd; } break; } case Instruction::AShr: // Signed shr. // See if this is shifting in some sign extension, then masking it out // with an and. if (Op->hasOneUse()) { uint32_t BitWidth = AndRHS->getType()->getBitWidth(); uint32_t OpRHSVal = OpRHS->getLimitedValue(BitWidth); APInt ShrMask(APInt::getLowBitsSet(BitWidth, BitWidth - OpRHSVal)); Constant *C = Builder->getInt(AndRHS->getValue() & ShrMask); if (C == AndRHS) { // Masking out bits shifted in. // (Val ashr C1) & C2 -> (Val lshr C1) & C2 // Make the argument unsigned. Value *ShVal = Op->getOperand(0); ShVal = Builder->CreateLShr(ShVal, OpRHS, Op->getName()); return BinaryOperator::CreateAnd(ShVal, AndRHS, TheAnd.getName()); } } break; } return nullptr; } /// Emit a computation of: (V >= Lo && V < Hi) if Inside is true, otherwise /// (V < Lo || V >= Hi). In practice, we emit the more efficient /// (V-Lo) \(ConstantExpr::getICmp((isSigned ? ICmpInst::ICMP_SLE:ICmpInst::ICMP_ULE), Lo, Hi))->getZExtValue() && "Lo is not <= Hi in range emission code!"); if (Inside) { if (Lo == Hi) // Trivially false. return Builder->getFalse(); // V >= Min && V < Hi --> V < Hi if (cast(Lo)->isMinValue(isSigned)) { ICmpInst::Predicate pred = (isSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT); return Builder->CreateICmp(pred, V, Hi); } // Emit V-Lo CreateAdd(V, NegLo, V->getName()+".off"); Constant *UpperBound = ConstantExpr::getAdd(NegLo, Hi); return Builder->CreateICmpULT(Add, UpperBound); } if (Lo == Hi) // Trivially true. return Builder->getTrue(); // V < Min || V >= Hi -> V > Hi-1 Hi = SubOne(cast(Hi)); if (cast(Lo)->isMinValue(isSigned)) { ICmpInst::Predicate pred = (isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT); return Builder->CreateICmp(pred, V, Hi); } // Emit V-Lo >u Hi-1-Lo // Note that Hi has already had one subtracted from it, above. ConstantInt *NegLo = cast(ConstantExpr::getNeg(Lo)); Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off"); Constant *LowerBound = ConstantExpr::getAdd(NegLo, Hi); return Builder->CreateICmpUGT(Add, LowerBound); } /// Returns true iff Val consists of one contiguous run of 1s with any number /// of 0s on either side. The 1s are allowed to wrap from LSB to MSB, /// so 0x000FFF0, 0x0000FFFF, and 0xFF0000FF are all runs. 0x0F0F0000 is /// not, since all 1s are not contiguous. static bool isRunOfOnes(ConstantInt *Val, uint32_t &MB, uint32_t &ME) { const APInt& V = Val->getValue(); uint32_t BitWidth = Val->getType()->getBitWidth(); if (!APIntOps::isShiftedMask(BitWidth, V)) return false; // look for the first zero bit after the run of ones MB = BitWidth - ((V - 1) ^ V).countLeadingZeros(); // look for the first non-zero bit ME = V.getActiveBits(); return true; } /// This is part of an expression (LHS +/- RHS) & Mask, where isSub determines /// whether the operator is a sub. If we can fold one of the following xforms: /// /// ((A & N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == Mask /// ((A | N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == 0 /// ((A ^ N) +/- B) & Mask -> (A +/- B) & Mask iff N&Mask == 0 /// /// return (A +/- B). /// Value *InstCombiner::FoldLogicalPlusAnd(Value *LHS, Value *RHS, ConstantInt *Mask, bool isSub, Instruction &I) { Instruction *LHSI = dyn_cast(LHS); if (!LHSI || LHSI->getNumOperands() != 2 || !isa(LHSI->getOperand(1))) return nullptr; ConstantInt *N = cast(LHSI->getOperand(1)); switch (LHSI->getOpcode()) { default: return nullptr; case Instruction::And: if (ConstantExpr::getAnd(N, Mask) == Mask) { // If the AndRHS is a power of two minus one (0+1+), this is simple. if ((Mask->getValue().countLeadingZeros() + Mask->getValue().countPopulation()) == Mask->getValue().getBitWidth()) break; // Otherwise, if Mask is 0+1+0+, and if B is known to have the low 0+ // part, we don't need any explicit masks to take them out of A. If that // is all N is, ignore it. uint32_t MB = 0, ME = 0; if (isRunOfOnes(Mask, MB, ME)) { // begin/end bit of run, inclusive uint32_t BitWidth = cast(RHS->getType())->getBitWidth(); APInt Mask(APInt::getLowBitsSet(BitWidth, MB-1)); if (MaskedValueIsZero(RHS, Mask, 0, &I)) break; } } return nullptr; case Instruction::Or: case Instruction::Xor: // If the AndRHS is a power of two minus one (0+1+), and N&Mask == 0 if ((Mask->getValue().countLeadingZeros() + Mask->getValue().countPopulation()) == Mask->getValue().getBitWidth() && ConstantExpr::getAnd(N, Mask)->isNullValue()) break; return nullptr; } if (isSub) return Builder->CreateSub(LHSI->getOperand(0), RHS, "fold"); return Builder->CreateAdd(LHSI->getOperand(0), RHS, "fold"); } /// enum for classifying (icmp eq (A & B), C) and (icmp ne (A & B), C) /// One of A and B is considered the mask, the other the value. This is /// described as the "AMask" or "BMask" part of the enum. If the enum /// contains only "Mask", then both A and B can be considered masks. /// If A is the mask, then it was proven, that (A & C) == C. This /// is trivial if C == A, or C == 0. If both A and C are constants, this /// proof is also easy. /// For the following explanations we assume that A is the mask. /// The part "AllOnes" declares, that the comparison is true only /// if (A & B) == A, or all bits of A are set in B. /// Example: (icmp eq (A & 3), 3) -> FoldMskICmp_AMask_AllOnes /// The part "AllZeroes" declares, that the comparison is true only /// if (A & B) == 0, or all bits of A are cleared in B. /// Example: (icmp eq (A & 3), 0) -> FoldMskICmp_Mask_AllZeroes /// The part "Mixed" declares, that (A & B) == C and C might or might not /// contain any number of one bits and zero bits. /// Example: (icmp eq (A & 3), 1) -> FoldMskICmp_AMask_Mixed /// The Part "Not" means, that in above descriptions "==" should be replaced /// by "!=". /// Example: (icmp ne (A & 3), 3) -> FoldMskICmp_AMask_NotAllOnes /// If the mask A contains a single bit, then the following is equivalent: /// (icmp eq (A & B), A) equals (icmp ne (A & B), 0) /// (icmp ne (A & B), A) equals (icmp eq (A & B), 0) enum MaskedICmpType { FoldMskICmp_AMask_AllOnes = 1, FoldMskICmp_AMask_NotAllOnes = 2, FoldMskICmp_BMask_AllOnes = 4, FoldMskICmp_BMask_NotAllOnes = 8, FoldMskICmp_Mask_AllZeroes = 16, FoldMskICmp_Mask_NotAllZeroes = 32, FoldMskICmp_AMask_Mixed = 64, FoldMskICmp_AMask_NotMixed = 128, FoldMskICmp_BMask_Mixed = 256, FoldMskICmp_BMask_NotMixed = 512 }; /// Return the set of pattern classes (from MaskedICmpType) /// that (icmp SCC (A & B), C) satisfies. static unsigned getTypeOfMaskedICmp(Value* A, Value* B, Value* C, ICmpInst::Predicate SCC) { ConstantInt *ACst = dyn_cast(A); ConstantInt *BCst = dyn_cast(B); ConstantInt *CCst = dyn_cast(C); bool icmp_eq = (SCC == ICmpInst::ICMP_EQ); bool icmp_abit = (ACst && !ACst->isZero() && ACst->getValue().isPowerOf2()); bool icmp_bbit = (BCst && !BCst->isZero() && BCst->getValue().isPowerOf2()); unsigned result = 0; if (CCst && CCst->isZero()) { // if C is zero, then both A and B qualify as mask result |= (icmp_eq ? (FoldMskICmp_Mask_AllZeroes | FoldMskICmp_Mask_AllZeroes | FoldMskICmp_AMask_Mixed | FoldMskICmp_BMask_Mixed) : (FoldMskICmp_Mask_NotAllZeroes | FoldMskICmp_Mask_NotAllZeroes | FoldMskICmp_AMask_NotMixed | FoldMskICmp_BMask_NotMixed)); if (icmp_abit) result |= (icmp_eq ? (FoldMskICmp_AMask_NotAllOnes | FoldMskICmp_AMask_NotMixed) : (FoldMskICmp_AMask_AllOnes | FoldMskICmp_AMask_Mixed)); if (icmp_bbit) result |= (icmp_eq ? (FoldMskICmp_BMask_NotAllOnes | FoldMskICmp_BMask_NotMixed) : (FoldMskICmp_BMask_AllOnes | FoldMskICmp_BMask_Mixed)); return result; } if (A == C) { result |= (icmp_eq ? (FoldMskICmp_AMask_AllOnes | FoldMskICmp_AMask_Mixed) : (FoldMskICmp_AMask_NotAllOnes | FoldMskICmp_AMask_NotMixed)); if (icmp_abit) result |= (icmp_eq ? (FoldMskICmp_Mask_NotAllZeroes | FoldMskICmp_AMask_NotMixed) : (FoldMskICmp_Mask_AllZeroes | FoldMskICmp_AMask_Mixed)); } else if (ACst && CCst && ConstantExpr::getAnd(ACst, CCst) == CCst) { result |= (icmp_eq ? FoldMskICmp_AMask_Mixed : FoldMskICmp_AMask_NotMixed); } if (B == C) { result |= (icmp_eq ? (FoldMskICmp_BMask_AllOnes | FoldMskICmp_BMask_Mixed) : (FoldMskICmp_BMask_NotAllOnes | FoldMskICmp_BMask_NotMixed)); if (icmp_bbit) result |= (icmp_eq ? (FoldMskICmp_Mask_NotAllZeroes | FoldMskICmp_BMask_NotMixed) : (FoldMskICmp_Mask_AllZeroes | FoldMskICmp_BMask_Mixed)); } else if (BCst && CCst && ConstantExpr::getAnd(BCst, CCst) == CCst) { result |= (icmp_eq ? FoldMskICmp_BMask_Mixed : FoldMskICmp_BMask_NotMixed); } return result; } /// Convert an analysis of a masked ICmp into its equivalent if all boolean /// operations had the opposite sense. Since each "NotXXX" flag (recording !=) /// is adjacent to the corresponding normal flag (recording ==), this just /// involves swapping those bits over. static unsigned conjugateICmpMask(unsigned Mask) { unsigned NewMask; NewMask = (Mask & (FoldMskICmp_AMask_AllOnes | FoldMskICmp_BMask_AllOnes | FoldMskICmp_Mask_AllZeroes | FoldMskICmp_AMask_Mixed | FoldMskICmp_BMask_Mixed)) << 1; NewMask |= (Mask & (FoldMskICmp_AMask_NotAllOnes | FoldMskICmp_BMask_NotAllOnes | FoldMskICmp_Mask_NotAllZeroes | FoldMskICmp_AMask_NotMixed | FoldMskICmp_BMask_NotMixed)) >> 1; return NewMask; } /// Decompose an icmp into the form ((X & Y) pred Z) if possible. /// The returned predicate is either == or !=. Returns false if /// decomposition fails. static bool decomposeBitTestICmp(const ICmpInst *I, ICmpInst::Predicate &Pred, Value *&X, Value *&Y, Value *&Z) { ConstantInt *C = dyn_cast(I->getOperand(1)); if (!C) return false; switch (I->getPredicate()) { default: return false; case ICmpInst::ICMP_SLT: // X < 0 is equivalent to (X & SignBit) != 0. if (!C->isZero()) return false; Y = ConstantInt::get(I->getContext(), APInt::getSignBit(C->getBitWidth())); Pred = ICmpInst::ICMP_NE; break; case ICmpInst::ICMP_SGT: // X > -1 is equivalent to (X & SignBit) == 0. if (!C->isAllOnesValue()) return false; Y = ConstantInt::get(I->getContext(), APInt::getSignBit(C->getBitWidth())); Pred = ICmpInst::ICMP_EQ; break; case ICmpInst::ICMP_ULT: // X getValue().isPowerOf2()) return false; Y = ConstantInt::get(I->getContext(), -C->getValue()); Pred = ICmpInst::ICMP_EQ; break; case ICmpInst::ICMP_UGT: // X >u 2^n-1 is equivalent to (X & ~(2^n-1)) != 0. if (!(C->getValue() + 1).isPowerOf2()) return false; Y = ConstantInt::get(I->getContext(), ~C->getValue()); Pred = ICmpInst::ICMP_NE; break; } X = I->getOperand(0); Z = ConstantInt::getNullValue(C->getType()); return true; } /// Handle (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E) /// Return the set of pattern classes (from MaskedICmpType) /// that both LHS and RHS satisfy. static unsigned foldLogOpOfMaskedICmpsHelper(Value*& A, Value*& B, Value*& C, Value*& D, Value*& E, ICmpInst *LHS, ICmpInst *RHS, ICmpInst::Predicate &LHSCC, ICmpInst::Predicate &RHSCC) { if (LHS->getOperand(0)->getType() != RHS->getOperand(0)->getType()) return 0; // vectors are not (yet?) supported if (LHS->getOperand(0)->getType()->isVectorTy()) return 0; // Here comes the tricky part: // LHS might be of the form L11 & L12 == X, X == L21 & L22, // and L11 & L12 == L21 & L22. The same goes for RHS. // Now we must find those components L** and R**, that are equal, so // that we can extract the parameters A, B, C, D, and E for the canonical // above. Value *L1 = LHS->getOperand(0); Value *L2 = LHS->getOperand(1); Value *L11,*L12,*L21,*L22; // Check whether the icmp can be decomposed into a bit test. if (decomposeBitTestICmp(LHS, LHSCC, L11, L12, L2)) { L21 = L22 = L1 = nullptr; } else { // Look for ANDs in the LHS icmp. if (!L1->getType()->isIntegerTy()) { // You can icmp pointers, for example. They really aren't masks. L11 = L12 = nullptr; } else if (!match(L1, m_And(m_Value(L11), m_Value(L12)))) { // Any icmp can be viewed as being trivially masked; if it allows us to // remove one, it's worth it. L11 = L1; L12 = Constant::getAllOnesValue(L1->getType()); } if (!L2->getType()->isIntegerTy()) { // You can icmp pointers, for example. They really aren't masks. L21 = L22 = nullptr; } else if (!match(L2, m_And(m_Value(L21), m_Value(L22)))) { L21 = L2; L22 = Constant::getAllOnesValue(L2->getType()); } } // Bail if LHS was a icmp that can't be decomposed into an equality. if (!ICmpInst::isEquality(LHSCC)) return 0; Value *R1 = RHS->getOperand(0); Value *R2 = RHS->getOperand(1); Value *R11,*R12; bool ok = false; if (decomposeBitTestICmp(RHS, RHSCC, R11, R12, R2)) { if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) { A = R11; D = R12; } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) { A = R12; D = R11; } else { return 0; } E = R2; R1 = nullptr; ok = true; } else if (R1->getType()->isIntegerTy()) { if (!match(R1, m_And(m_Value(R11), m_Value(R12)))) { // As before, model no mask as a trivial mask if it'll let us do an // optimization. R11 = R1; R12 = Constant::getAllOnesValue(R1->getType()); } if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) { A = R11; D = R12; E = R2; ok = true; } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) { A = R12; D = R11; E = R2; ok = true; } } // Bail if RHS was a icmp that can't be decomposed into an equality. if (!ICmpInst::isEquality(RHSCC)) return 0; // Look for ANDs in on the right side of the RHS icmp. if (!ok && R2->getType()->isIntegerTy()) { if (!match(R2, m_And(m_Value(R11), m_Value(R12)))) { R11 = R2; R12 = Constant::getAllOnesValue(R2->getType()); } if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) { A = R11; D = R12; E = R1; ok = true; } else if (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22) { A = R12; D = R11; E = R1; ok = true; } else { return 0; } } if (!ok) return 0; if (L11 == A) { B = L12; C = L2; } else if (L12 == A) { B = L11; C = L2; } else if (L21 == A) { B = L22; C = L1; } else if (L22 == A) { B = L21; C = L1; } unsigned left_type = getTypeOfMaskedICmp(A, B, C, LHSCC); unsigned right_type = getTypeOfMaskedICmp(A, D, E, RHSCC); return left_type & right_type; } /// Try to fold (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E) /// into a single (icmp(A & X) ==/!= Y). static Value *foldLogOpOfMaskedICmps(ICmpInst *LHS, ICmpInst *RHS, bool IsAnd, llvm::InstCombiner::BuilderTy *Builder) { Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr, *E = nullptr; ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate(); unsigned mask = foldLogOpOfMaskedICmpsHelper(A, B, C, D, E, LHS, RHS, LHSCC, RHSCC); if (mask == 0) return nullptr; assert(ICmpInst::isEquality(LHSCC) && ICmpInst::isEquality(RHSCC) && "foldLogOpOfMaskedICmpsHelper must return an equality predicate."); // In full generality: // (icmp (A & B) Op C) | (icmp (A & D) Op E) // == ![ (icmp (A & B) !Op C) & (icmp (A & D) !Op E) ] // // If the latter can be converted into (icmp (A & X) Op Y) then the former is // equivalent to (icmp (A & X) !Op Y). // // Therefore, we can pretend for the rest of this function that we're dealing // with the conjunction, provided we flip the sense of any comparisons (both // input and output). // In most cases we're going to produce an EQ for the "&&" case. ICmpInst::Predicate NEWCC = IsAnd ? ICmpInst::ICMP_EQ : ICmpInst::ICMP_NE; if (!IsAnd) { // Convert the masking analysis into its equivalent with negated // comparisons. mask = conjugateICmpMask(mask); } if (mask & FoldMskICmp_Mask_AllZeroes) { // (icmp eq (A & B), 0) & (icmp eq (A & D), 0) // -> (icmp eq (A & (B|D)), 0) Value *newOr = Builder->CreateOr(B, D); Value *newAnd = Builder->CreateAnd(A, newOr); // we can't use C as zero, because we might actually handle // (icmp ne (A & B), B) & (icmp ne (A & D), D) // with B and D, having a single bit set Value *zero = Constant::getNullValue(A->getType()); return Builder->CreateICmp(NEWCC, newAnd, zero); } if (mask & FoldMskICmp_BMask_AllOnes) { // (icmp eq (A & B), B) & (icmp eq (A & D), D) // -> (icmp eq (A & (B|D)), (B|D)) Value *newOr = Builder->CreateOr(B, D); Value *newAnd = Builder->CreateAnd(A, newOr); return Builder->CreateICmp(NEWCC, newAnd, newOr); } if (mask & FoldMskICmp_AMask_AllOnes) { // (icmp eq (A & B), A) & (icmp eq (A & D), A) // -> (icmp eq (A & (B&D)), A) Value *newAnd1 = Builder->CreateAnd(B, D); Value *newAnd = Builder->CreateAnd(A, newAnd1); return Builder->CreateICmp(NEWCC, newAnd, A); } // Remaining cases assume at least that B and D are constant, and depend on // their actual values. This isn't strictly, necessary, just a "handle the // easy cases for now" decision. ConstantInt *BCst = dyn_cast(B); if (!BCst) return nullptr; ConstantInt *DCst = dyn_cast(D); if (!DCst) return nullptr; if (mask & (FoldMskICmp_Mask_NotAllZeroes | FoldMskICmp_BMask_NotAllOnes)) { // (icmp ne (A & B), 0) & (icmp ne (A & D), 0) and // (icmp ne (A & B), B) & (icmp ne (A & D), D) // -> (icmp ne (A & B), 0) or (icmp ne (A & D), 0) // Only valid if one of the masks is a superset of the other (check "B&D" is // the same as either B or D). APInt NewMask = BCst->getValue() & DCst->getValue(); if (NewMask == BCst->getValue()) return LHS; else if (NewMask == DCst->getValue()) return RHS; } if (mask & FoldMskICmp_AMask_NotAllOnes) { // (icmp ne (A & B), B) & (icmp ne (A & D), D) // -> (icmp ne (A & B), A) or (icmp ne (A & D), A) // Only valid if one of the masks is a superset of the other (check "B|D" is // the same as either B or D). APInt NewMask = BCst->getValue() | DCst->getValue(); if (NewMask == BCst->getValue()) return LHS; else if (NewMask == DCst->getValue()) return RHS; } if (mask & FoldMskICmp_BMask_Mixed) { // (icmp eq (A & B), C) & (icmp eq (A & D), E) // We already know that B & C == C && D & E == E. // If we can prove that (B & D) & (C ^ E) == 0, that is, the bits of // C and E, which are shared by both the mask B and the mask D, don't // contradict, then we can transform to // -> (icmp eq (A & (B|D)), (C|E)) // Currently, we only handle the case of B, C, D, and E being constant. // we can't simply use C and E, because we might actually handle // (icmp ne (A & B), B) & (icmp eq (A & D), D) // with B and D, having a single bit set ConstantInt *CCst = dyn_cast(C); if (!CCst) return nullptr; ConstantInt *ECst = dyn_cast(E); if (!ECst) return nullptr; if (LHSCC != NEWCC) CCst = cast(ConstantExpr::getXor(BCst, CCst)); if (RHSCC != NEWCC) ECst = cast(ConstantExpr::getXor(DCst, ECst)); // if there is a conflict we should actually return a false for the // whole construct if (((BCst->getValue() & DCst->getValue()) & (CCst->getValue() ^ ECst->getValue())) != 0) return ConstantInt::get(LHS->getType(), !IsAnd); Value *newOr1 = Builder->CreateOr(B, D); Value *newOr2 = ConstantExpr::getOr(CCst, ECst); Value *newAnd = Builder->CreateAnd(A, newOr1); return Builder->CreateICmp(NEWCC, newAnd, newOr2); } return nullptr; } /// Try to fold a signed range checked with lower bound 0 to an unsigned icmp. /// Example: (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n /// If \p Inverted is true then the check is for the inverted range, e.g. /// (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n Value *InstCombiner::simplifyRangeCheck(ICmpInst *Cmp0, ICmpInst *Cmp1, bool Inverted) { // Check the lower range comparison, e.g. x >= 0 // InstCombine already ensured that if there is a constant it's on the RHS. ConstantInt *RangeStart = dyn_cast(Cmp0->getOperand(1)); if (!RangeStart) return nullptr; ICmpInst::Predicate Pred0 = (Inverted ? Cmp0->getInversePredicate() : Cmp0->getPredicate()); // Accept x > -1 or x >= 0 (after potentially inverting the predicate). if (!((Pred0 == ICmpInst::ICMP_SGT && RangeStart->isMinusOne()) || (Pred0 == ICmpInst::ICMP_SGE && RangeStart->isZero()))) return nullptr; ICmpInst::Predicate Pred1 = (Inverted ? Cmp1->getInversePredicate() : Cmp1->getPredicate()); Value *Input = Cmp0->getOperand(0); Value *RangeEnd; if (Cmp1->getOperand(0) == Input) { // For the upper range compare we have: icmp x, n RangeEnd = Cmp1->getOperand(1); } else if (Cmp1->getOperand(1) == Input) { // For the upper range compare we have: icmp n, x RangeEnd = Cmp1->getOperand(0); Pred1 = ICmpInst::getSwappedPredicate(Pred1); } else { return nullptr; } // Check the upper range comparison, e.g. x < n ICmpInst::Predicate NewPred; switch (Pred1) { case ICmpInst::ICMP_SLT: NewPred = ICmpInst::ICMP_ULT; break; case ICmpInst::ICMP_SLE: NewPred = ICmpInst::ICMP_ULE; break; default: return nullptr; } // This simplification is only valid if the upper range is not negative. bool IsNegative, IsNotNegative; ComputeSignBit(RangeEnd, IsNotNegative, IsNegative, /*Depth=*/0, Cmp1); if (!IsNotNegative) return nullptr; if (Inverted) NewPred = ICmpInst::getInversePredicate(NewPred); return Builder->CreateICmp(NewPred, Input, RangeEnd); } /// Fold (icmp)&(icmp) if possible. Value *InstCombiner::FoldAndOfICmps(ICmpInst *LHS, ICmpInst *RHS) { ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate(); // (icmp1 A, B) & (icmp2 A, B) --> (icmp3 A, B) if (PredicatesFoldable(LHSCC, RHSCC)) { if (LHS->getOperand(0) == RHS->getOperand(1) && LHS->getOperand(1) == RHS->getOperand(0)) LHS->swapOperands(); if (LHS->getOperand(0) == RHS->getOperand(0) && LHS->getOperand(1) == RHS->getOperand(1)) { Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1); unsigned Code = getICmpCode(LHS) & getICmpCode(RHS); bool isSigned = LHS->isSigned() || RHS->isSigned(); return getNewICmpValue(isSigned, Code, Op0, Op1, Builder); } } // handle (roughly): (icmp eq (A & B), C) & (icmp eq (A & D), E) if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, true, Builder)) return V; // E.g. (icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n if (Value *V = simplifyRangeCheck(LHS, RHS, /*Inverted=*/false)) return V; // E.g. (icmp slt x, n) & (icmp sge x, 0) --> icmp ult x, n if (Value *V = simplifyRangeCheck(RHS, LHS, /*Inverted=*/false)) return V; // This only handles icmp of constants: (icmp1 A, C1) & (icmp2 B, C2). Value *Val = LHS->getOperand(0), *Val2 = RHS->getOperand(0); ConstantInt *LHSCst = dyn_cast(LHS->getOperand(1)); ConstantInt *RHSCst = dyn_cast(RHS->getOperand(1)); if (!LHSCst || !RHSCst) return nullptr; if (LHSCst == RHSCst && LHSCC == RHSCC) { // (icmp ult A, C) & (icmp ult B, C) --> (icmp ult (A|B), C) // where C is a power of 2 if (LHSCC == ICmpInst::ICMP_ULT && LHSCst->getValue().isPowerOf2()) { Value *NewOr = Builder->CreateOr(Val, Val2); return Builder->CreateICmp(LHSCC, NewOr, LHSCst); } // (icmp eq A, 0) & (icmp eq B, 0) --> (icmp eq (A|B), 0) if (LHSCC == ICmpInst::ICMP_EQ && LHSCst->isZero()) { Value *NewOr = Builder->CreateOr(Val, Val2); return Builder->CreateICmp(LHSCC, NewOr, LHSCst); } } // (trunc x) == C1 & (and x, CA) == C2 -> (and x, CA|CMAX) == C1|C2 // where CMAX is the all ones value for the truncated type, // iff the lower bits of C2 and CA are zero. if (LHSCC == ICmpInst::ICMP_EQ && LHSCC == RHSCC && LHS->hasOneUse() && RHS->hasOneUse()) { Value *V; ConstantInt *AndCst, *SmallCst = nullptr, *BigCst = nullptr; // (trunc x) == C1 & (and x, CA) == C2 // (and x, CA) == C2 & (trunc x) == C1 if (match(Val2, m_Trunc(m_Value(V))) && match(Val, m_And(m_Specific(V), m_ConstantInt(AndCst)))) { SmallCst = RHSCst; BigCst = LHSCst; } else if (match(Val, m_Trunc(m_Value(V))) && match(Val2, m_And(m_Specific(V), m_ConstantInt(AndCst)))) { SmallCst = LHSCst; BigCst = RHSCst; } if (SmallCst && BigCst) { unsigned BigBitSize = BigCst->getType()->getBitWidth(); unsigned SmallBitSize = SmallCst->getType()->getBitWidth(); // Check that the low bits are zero. APInt Low = APInt::getLowBitsSet(BigBitSize, SmallBitSize); if ((Low & AndCst->getValue()) == 0 && (Low & BigCst->getValue()) == 0) { Value *NewAnd = Builder->CreateAnd(V, Low | AndCst->getValue()); APInt N = SmallCst->getValue().zext(BigBitSize) | BigCst->getValue(); Value *NewVal = ConstantInt::get(AndCst->getType()->getContext(), N); return Builder->CreateICmp(LHSCC, NewAnd, NewVal); } } } // From here on, we only handle: // (icmp1 A, C1) & (icmp2 A, C2) --> something simpler. if (Val != Val2) return nullptr; // ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere. if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE || RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE || LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE || RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE) return nullptr; // Make a constant range that's the intersection of the two icmp ranges. // If the intersection is empty, we know that the result is false. ConstantRange LHSRange = ConstantRange::makeAllowedICmpRegion(LHSCC, LHSCst->getValue()); ConstantRange RHSRange = ConstantRange::makeAllowedICmpRegion(RHSCC, RHSCst->getValue()); if (LHSRange.intersectWith(RHSRange).isEmptySet()) return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0); // We can't fold (ugt x, C) & (sgt x, C2). if (!PredicatesFoldable(LHSCC, RHSCC)) return nullptr; // Ensure that the larger constant is on the RHS. bool ShouldSwap; if (CmpInst::isSigned(LHSCC) || (ICmpInst::isEquality(LHSCC) && CmpInst::isSigned(RHSCC))) ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue()); else ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue()); if (ShouldSwap) { std::swap(LHS, RHS); std::swap(LHSCst, RHSCst); std::swap(LHSCC, RHSCC); } // At this point, we know we have two icmp instructions // comparing a value against two constants and and'ing the result // together. Because of the above check, we know that we only have // icmp eq, icmp ne, icmp [su]lt, and icmp [SU]gt here. We also know // (from the icmp folding check above), that the two constants // are not equal and that the larger constant is on the RHS assert(LHSCst != RHSCst && "Compares not folded above?"); switch (LHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_EQ: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_NE: // (X == 13 & X != 15) -> X == 13 case ICmpInst::ICMP_ULT: // (X == 13 & X < 15) -> X == 13 case ICmpInst::ICMP_SLT: // (X == 13 & X < 15) -> X == 13 return LHS; } case ICmpInst::ICMP_NE: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_ULT: if (LHSCst == SubOne(RHSCst)) // (X != 13 & X u< 14) -> X < 13 return Builder->CreateICmpULT(Val, LHSCst); if (LHSCst->isNullValue()) // (X != 0 & X u< 14) -> X-1 u< 13 return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, false, true); break; // (X != 13 & X u< 15) -> no change case ICmpInst::ICMP_SLT: if (LHSCst == SubOne(RHSCst)) // (X != 13 & X s< 14) -> X < 13 return Builder->CreateICmpSLT(Val, LHSCst); break; // (X != 13 & X s< 15) -> no change case ICmpInst::ICMP_EQ: // (X != 13 & X == 15) -> X == 15 case ICmpInst::ICMP_UGT: // (X != 13 & X u> 15) -> X u> 15 case ICmpInst::ICMP_SGT: // (X != 13 & X s> 15) -> X s> 15 return RHS; case ICmpInst::ICMP_NE: // Special case to get the ordering right when the values wrap around // zero. if (LHSCst->getValue() == 0 && RHSCst->getValue().isAllOnesValue()) std::swap(LHSCst, RHSCst); if (LHSCst == SubOne(RHSCst)){// (X != 13 & X != 14) -> X-13 >u 1 Constant *AddCST = ConstantExpr::getNeg(LHSCst); Value *Add = Builder->CreateAdd(Val, AddCST, Val->getName()+".off"); return Builder->CreateICmpUGT(Add, ConstantInt::get(Add->getType(), 1), Val->getName()+".cmp"); } break; // (X != 13 & X != 15) -> no change } break; case ICmpInst::ICMP_ULT: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_EQ: // (X u< 13 & X == 15) -> false case ICmpInst::ICMP_UGT: // (X u< 13 & X u> 15) -> false return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0); case ICmpInst::ICMP_SGT: // (X u< 13 & X s> 15) -> no change break; case ICmpInst::ICMP_NE: // (X u< 13 & X != 15) -> X u< 13 case ICmpInst::ICMP_ULT: // (X u< 13 & X u< 15) -> X u< 13 return LHS; case ICmpInst::ICMP_SLT: // (X u< 13 & X s< 15) -> no change break; } break; case ICmpInst::ICMP_SLT: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_UGT: // (X s< 13 & X u> 15) -> no change break; case ICmpInst::ICMP_NE: // (X s< 13 & X != 15) -> X < 13 case ICmpInst::ICMP_SLT: // (X s< 13 & X s< 15) -> X < 13 return LHS; case ICmpInst::ICMP_ULT: // (X s< 13 & X u< 15) -> no change break; } break; case ICmpInst::ICMP_UGT: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_EQ: // (X u> 13 & X == 15) -> X == 15 case ICmpInst::ICMP_UGT: // (X u> 13 & X u> 15) -> X u> 15 return RHS; case ICmpInst::ICMP_SGT: // (X u> 13 & X s> 15) -> no change break; case ICmpInst::ICMP_NE: if (RHSCst == AddOne(LHSCst)) // (X u> 13 & X != 14) -> X u> 14 return Builder->CreateICmp(LHSCC, Val, RHSCst); break; // (X u> 13 & X != 15) -> no change case ICmpInst::ICMP_ULT: // (X u> 13 & X u< 15) -> (X-14) 13 & X s< 15) -> no change break; } break; case ICmpInst::ICMP_SGT: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_EQ: // (X s> 13 & X == 15) -> X == 15 case ICmpInst::ICMP_SGT: // (X s> 13 & X s> 15) -> X s> 15 return RHS; case ICmpInst::ICMP_UGT: // (X s> 13 & X u> 15) -> no change break; case ICmpInst::ICMP_NE: if (RHSCst == AddOne(LHSCst)) // (X s> 13 & X != 14) -> X s> 14 return Builder->CreateICmp(LHSCC, Val, RHSCst); break; // (X s> 13 & X != 15) -> no change case ICmpInst::ICMP_SLT: // (X s> 13 & X s< 15) -> (X-14) s< 1 return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, true, true); case ICmpInst::ICMP_ULT: // (X s> 13 & X u< 15) -> no change break; } break; } return nullptr; } /// Optimize (fcmp)&(fcmp). NOTE: Unlike the rest of instcombine, this returns /// a Value which should already be inserted into the function. Value *InstCombiner::FoldAndOfFCmps(FCmpInst *LHS, FCmpInst *RHS) { if (LHS->getPredicate() == FCmpInst::FCMP_ORD && RHS->getPredicate() == FCmpInst::FCMP_ORD) { if (LHS->getOperand(0)->getType() != RHS->getOperand(0)->getType()) return nullptr; // (fcmp ord x, c) & (fcmp ord y, c) -> (fcmp ord x, y) if (ConstantFP *LHSC = dyn_cast(LHS->getOperand(1))) if (ConstantFP *RHSC = dyn_cast(RHS->getOperand(1))) { // If either of the constants are nans, then the whole thing returns // false. if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN()) return Builder->getFalse(); return Builder->CreateFCmpORD(LHS->getOperand(0), RHS->getOperand(0)); } // Handle vector zeros. This occurs because the canonical form of // "fcmp ord x,x" is "fcmp ord x, 0". if (isa(LHS->getOperand(1)) && isa(RHS->getOperand(1))) return Builder->CreateFCmpORD(LHS->getOperand(0), RHS->getOperand(0)); return nullptr; } Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1); Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1); FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate(); if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) { // Swap RHS operands to match LHS. Op1CC = FCmpInst::getSwappedPredicate(Op1CC); std::swap(Op1LHS, Op1RHS); } if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) { // Simplify (fcmp cc0 x, y) & (fcmp cc1 x, y). if (Op0CC == Op1CC) return Builder->CreateFCmp((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS); if (Op0CC == FCmpInst::FCMP_FALSE || Op1CC == FCmpInst::FCMP_FALSE) return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0); if (Op0CC == FCmpInst::FCMP_TRUE) return RHS; if (Op1CC == FCmpInst::FCMP_TRUE) return LHS; bool Op0Ordered; bool Op1Ordered; unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered); unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered); // uno && ord -> false if (Op0Pred == 0 && Op1Pred == 0 && Op0Ordered != Op1Ordered) return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0); if (Op1Pred == 0) { std::swap(LHS, RHS); std::swap(Op0Pred, Op1Pred); std::swap(Op0Ordered, Op1Ordered); } if (Op0Pred == 0) { // uno && ueq -> uno && (uno || eq) -> uno // ord && olt -> ord && (ord && lt) -> olt if (!Op0Ordered && (Op0Ordered == Op1Ordered)) return LHS; if (Op0Ordered && (Op0Ordered == Op1Ordered)) return RHS; // uno && oeq -> uno && (ord && eq) -> false if (!Op0Ordered) return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0); // ord && ueq -> ord && (uno || eq) -> oeq return getFCmpValue(true, Op1Pred, Op0LHS, Op0RHS, Builder); } } return nullptr; } /// Match De Morgan's Laws: /// (~A & ~B) == (~(A | B)) /// (~A | ~B) == (~(A & B)) static Instruction *matchDeMorgansLaws(BinaryOperator &I, InstCombiner::BuilderTy *Builder) { auto Opcode = I.getOpcode(); assert((Opcode == Instruction::And || Opcode == Instruction::Or) && "Trying to match De Morgan's Laws with something other than and/or"); // Flip the logic operation. if (Opcode == Instruction::And) Opcode = Instruction::Or; else Opcode = Instruction::And; Value *Op0 = I.getOperand(0); Value *Op1 = I.getOperand(1); // TODO: Use pattern matchers instead of dyn_cast. if (Value *Op0NotVal = dyn_castNotVal(Op0)) if (Value *Op1NotVal = dyn_castNotVal(Op1)) if (Op0->hasOneUse() && Op1->hasOneUse()) { Value *LogicOp = Builder->CreateBinOp(Opcode, Op0NotVal, Op1NotVal, I.getName() + ".demorgan"); return BinaryOperator::CreateNot(LogicOp); } // De Morgan's Law in disguise: // (zext(bool A) ^ 1) & (zext(bool B) ^ 1) -> zext(~(A | B)) // (zext(bool A) ^ 1) | (zext(bool B) ^ 1) -> zext(~(A & B)) Value *A = nullptr; Value *B = nullptr; ConstantInt *C1 = nullptr; if (match(Op0, m_OneUse(m_Xor(m_ZExt(m_Value(A)), m_ConstantInt(C1)))) && match(Op1, m_OneUse(m_Xor(m_ZExt(m_Value(B)), m_Specific(C1))))) { // TODO: This check could be loosened to handle different type sizes. // Alternatively, we could fix the definition of m_Not to recognize a not // operation hidden by a zext? if (A->getType()->isIntegerTy(1) && B->getType()->isIntegerTy(1) && C1->isOne()) { Value *LogicOp = Builder->CreateBinOp(Opcode, A, B, I.getName() + ".demorgan"); Value *Not = Builder->CreateNot(LogicOp); return CastInst::CreateZExtOrBitCast(Not, I.getType()); } } return nullptr; } Instruction *InstCombiner::visitAnd(BinaryOperator &I) { bool Changed = SimplifyAssociativeOrCommutative(I); Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); if (Value *V = SimplifyVectorOp(I)) return ReplaceInstUsesWith(I, V); if (Value *V = SimplifyAndInst(Op0, Op1, DL, TLI, DT, AC)) return ReplaceInstUsesWith(I, V); // (A|B)&(A|C) -> A|(B&C) etc if (Value *V = SimplifyUsingDistributiveLaws(I)) return ReplaceInstUsesWith(I, V); // See if we can simplify any instructions used by the instruction whose sole // purpose is to compute bits we don't care about. if (SimplifyDemandedInstructionBits(I)) return &I; if (Value *V = SimplifyBSwap(I)) return ReplaceInstUsesWith(I, V); if (ConstantInt *AndRHS = dyn_cast(Op1)) { const APInt &AndRHSMask = AndRHS->getValue(); // Optimize a variety of ((val OP C1) & C2) combinations... if (BinaryOperator *Op0I = dyn_cast(Op0)) { Value *Op0LHS = Op0I->getOperand(0); Value *Op0RHS = Op0I->getOperand(1); switch (Op0I->getOpcode()) { default: break; case Instruction::Xor: case Instruction::Or: { // If the mask is only needed on one incoming arm, push it up. if (!Op0I->hasOneUse()) break; APInt NotAndRHS(~AndRHSMask); if (MaskedValueIsZero(Op0LHS, NotAndRHS, 0, &I)) { // Not masking anything out for the LHS, move to RHS. Value *NewRHS = Builder->CreateAnd(Op0RHS, AndRHS, Op0RHS->getName()+".masked"); return BinaryOperator::Create(Op0I->getOpcode(), Op0LHS, NewRHS); } if (!isa(Op0RHS) && MaskedValueIsZero(Op0RHS, NotAndRHS, 0, &I)) { // Not masking anything out for the RHS, move to LHS. Value *NewLHS = Builder->CreateAnd(Op0LHS, AndRHS, Op0LHS->getName()+".masked"); return BinaryOperator::Create(Op0I->getOpcode(), NewLHS, Op0RHS); } break; } case Instruction::Add: // ((A & N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == AndRHS. // ((A | N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == 0 // ((A ^ N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == 0 if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, false, I)) return BinaryOperator::CreateAnd(V, AndRHS); if (Value *V = FoldLogicalPlusAnd(Op0RHS, Op0LHS, AndRHS, false, I)) return BinaryOperator::CreateAnd(V, AndRHS); // Add commutes break; case Instruction::Sub: // ((A & N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == AndRHS. // ((A | N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0 // ((A ^ N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0 if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, true, I)) return BinaryOperator::CreateAnd(V, AndRHS); // -x & 1 -> x & 1 if (AndRHSMask == 1 && match(Op0LHS, m_Zero())) return BinaryOperator::CreateAnd(Op0RHS, AndRHS); // (A - N) & AndRHS -> -N & AndRHS iff A&AndRHS==0 and AndRHS // has 1's for all bits that the subtraction with A might affect. if (Op0I->hasOneUse() && !match(Op0LHS, m_Zero())) { uint32_t BitWidth = AndRHSMask.getBitWidth(); uint32_t Zeros = AndRHSMask.countLeadingZeros(); APInt Mask = APInt::getLowBitsSet(BitWidth, BitWidth - Zeros); if (MaskedValueIsZero(Op0LHS, Mask, 0, &I)) { Value *NewNeg = Builder->CreateNeg(Op0RHS); return BinaryOperator::CreateAnd(NewNeg, AndRHS); } } break; case Instruction::Shl: case Instruction::LShr: // (1 << x) & 1 --> zext(x == 0) // (1 >> x) & 1 --> zext(x == 0) if (AndRHSMask == 1 && Op0LHS == AndRHS) { Value *NewICmp = Builder->CreateICmpEQ(Op0RHS, Constant::getNullValue(I.getType())); return new ZExtInst(NewICmp, I.getType()); } break; } if (ConstantInt *Op0CI = dyn_cast(Op0I->getOperand(1))) if (Instruction *Res = OptAndOp(Op0I, Op0CI, AndRHS, I)) return Res; } // If this is an integer truncation, and if the source is an 'and' with // immediate, transform it. This frequently occurs for bitfield accesses. { Value *X = nullptr; ConstantInt *YC = nullptr; if (match(Op0, m_Trunc(m_And(m_Value(X), m_ConstantInt(YC))))) { // Change: and (trunc (and X, YC) to T), C2 // into : and (trunc X to T), trunc(YC) & C2 // This will fold the two constants together, which may allow // other simplifications. Value *NewCast = Builder->CreateTrunc(X, I.getType(), "and.shrunk"); Constant *C3 = ConstantExpr::getTrunc(YC, I.getType()); C3 = ConstantExpr::getAnd(C3, AndRHS); return BinaryOperator::CreateAnd(NewCast, C3); } } // Try to fold constant and into select arguments. if (SelectInst *SI = dyn_cast(Op0)) if (Instruction *R = FoldOpIntoSelect(I, SI)) return R; if (isa(Op0)) if (Instruction *NV = FoldOpIntoPhi(I)) return NV; } if (Instruction *DeMorgan = matchDeMorgansLaws(I, Builder)) return DeMorgan; { Value *A = nullptr, *B = nullptr, *C = nullptr, *D = nullptr; // (A|B) & ~(A&B) -> A^B if (match(Op0, m_Or(m_Value(A), m_Value(B))) && match(Op1, m_Not(m_And(m_Value(C), m_Value(D)))) && ((A == C && B == D) || (A == D && B == C))) return BinaryOperator::CreateXor(A, B); // ~(A&B) & (A|B) -> A^B if (match(Op1, m_Or(m_Value(A), m_Value(B))) && match(Op0, m_Not(m_And(m_Value(C), m_Value(D)))) && ((A == C && B == D) || (A == D && B == C))) return BinaryOperator::CreateXor(A, B); // A&(A^B) => A & ~B { Value *tmpOp0 = Op0; Value *tmpOp1 = Op1; if (Op0->hasOneUse() && match(Op0, m_Xor(m_Value(A), m_Value(B)))) { if (A == Op1 || B == Op1 ) { tmpOp1 = Op0; tmpOp0 = Op1; // Simplify below } } if (tmpOp1->hasOneUse() && match(tmpOp1, m_Xor(m_Value(A), m_Value(B)))) { if (B == tmpOp0) { std::swap(A, B); } // Notice that the patten (A&(~B)) is actually (A&(-1^B)), so if // A is originally -1 (or a vector of -1 and undefs), then we enter // an endless loop. By checking that A is non-constant we ensure that // we will never get to the loop. if (A == tmpOp0 && !isa(A)) // A&(A^B) -> A & ~B return BinaryOperator::CreateAnd(A, Builder->CreateNot(B)); } } // (A&((~A)|B)) -> A&B if (match(Op0, m_Or(m_Not(m_Specific(Op1)), m_Value(A))) || match(Op0, m_Or(m_Value(A), m_Not(m_Specific(Op1))))) return BinaryOperator::CreateAnd(A, Op1); if (match(Op1, m_Or(m_Not(m_Specific(Op0)), m_Value(A))) || match(Op1, m_Or(m_Value(A), m_Not(m_Specific(Op0))))) return BinaryOperator::CreateAnd(A, Op0); // (A ^ B) & ((B ^ C) ^ A) -> (A ^ B) & ~C if (match(Op0, m_Xor(m_Value(A), m_Value(B)))) if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A)))) if (Op1->hasOneUse() || cast(Op1)->hasOneUse()) return BinaryOperator::CreateAnd(Op0, Builder->CreateNot(C)); // ((A ^ C) ^ B) & (B ^ A) -> (B ^ A) & ~C if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B)))) if (match(Op1, m_Xor(m_Specific(B), m_Specific(A)))) if (Op0->hasOneUse() || cast(Op0)->hasOneUse()) return BinaryOperator::CreateAnd(Op1, Builder->CreateNot(C)); // (A | B) & ((~A) ^ B) -> (A & B) if (match(Op0, m_Or(m_Value(A), m_Value(B))) && match(Op1, m_Xor(m_Not(m_Specific(A)), m_Specific(B)))) return BinaryOperator::CreateAnd(A, B); // ((~A) ^ B) & (A | B) -> (A & B) if (match(Op0, m_Xor(m_Not(m_Value(A)), m_Value(B))) && match(Op1, m_Or(m_Specific(A), m_Specific(B)))) return BinaryOperator::CreateAnd(A, B); } { ICmpInst *LHS = dyn_cast(Op0); ICmpInst *RHS = dyn_cast(Op1); if (LHS && RHS) if (Value *Res = FoldAndOfICmps(LHS, RHS)) return ReplaceInstUsesWith(I, Res); // TODO: Make this recursive; it's a little tricky because an arbitrary // number of 'and' instructions might have to be created. Value *X, *Y; if (LHS && match(Op1, m_OneUse(m_And(m_Value(X), m_Value(Y))))) { if (auto *Cmp = dyn_cast(X)) if (Value *Res = FoldAndOfICmps(LHS, Cmp)) return ReplaceInstUsesWith(I, Builder->CreateAnd(Res, Y)); if (auto *Cmp = dyn_cast(Y)) if (Value *Res = FoldAndOfICmps(LHS, Cmp)) return ReplaceInstUsesWith(I, Builder->CreateAnd(Res, X)); } if (RHS && match(Op0, m_OneUse(m_And(m_Value(X), m_Value(Y))))) { if (auto *Cmp = dyn_cast(X)) if (Value *Res = FoldAndOfICmps(Cmp, RHS)) return ReplaceInstUsesWith(I, Builder->CreateAnd(Res, Y)); if (auto *Cmp = dyn_cast(Y)) if (Value *Res = FoldAndOfICmps(Cmp, RHS)) return ReplaceInstUsesWith(I, Builder->CreateAnd(Res, X)); } } // If and'ing two fcmp, try combine them into one. if (FCmpInst *LHS = dyn_cast(I.getOperand(0))) if (FCmpInst *RHS = dyn_cast(I.getOperand(1))) if (Value *Res = FoldAndOfFCmps(LHS, RHS)) return ReplaceInstUsesWith(I, Res); if (CastInst *Op0C = dyn_cast(Op0)) { Value *Op0COp = Op0C->getOperand(0); Type *SrcTy = Op0COp->getType(); // fold (and (cast A), (cast B)) -> (cast (and A, B)) if (CastInst *Op1C = dyn_cast(Op1)) { if (Op0C->getOpcode() == Op1C->getOpcode() && // same cast kind ? SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntOrIntVectorTy()) { Value *Op1COp = Op1C->getOperand(0); // Only do this if the casts both really cause code to be generated. if (ShouldOptimizeCast(Op0C->getOpcode(), Op0COp, I.getType()) && ShouldOptimizeCast(Op1C->getOpcode(), Op1COp, I.getType())) { Value *NewOp = Builder->CreateAnd(Op0COp, Op1COp, I.getName()); return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType()); } // If this is and(cast(icmp), cast(icmp)), try to fold this even if the // cast is otherwise not optimizable. This happens for vector sexts. if (ICmpInst *RHS = dyn_cast(Op1COp)) if (ICmpInst *LHS = dyn_cast(Op0COp)) if (Value *Res = FoldAndOfICmps(LHS, RHS)) return CastInst::Create(Op0C->getOpcode(), Res, I.getType()); // If this is and(cast(fcmp), cast(fcmp)), try to fold this even if the // cast is otherwise not optimizable. This happens for vector sexts. if (FCmpInst *RHS = dyn_cast(Op1COp)) if (FCmpInst *LHS = dyn_cast(Op0COp)) if (Value *Res = FoldAndOfFCmps(LHS, RHS)) return CastInst::Create(Op0C->getOpcode(), Res, I.getType()); } } // If we are masking off the sign bit of a floating-point value, convert // this to the canonical fabs intrinsic call and cast back to integer. // The backend should know how to optimize fabs(). // TODO: This transform should also apply to vectors. ConstantInt *CI; if (isa(Op0C) && SrcTy->isFloatingPointTy() && match(Op1, m_ConstantInt(CI)) && CI->isMaxValue(true)) { Module *M = I.getModule(); Function *Fabs = Intrinsic::getDeclaration(M, Intrinsic::fabs, SrcTy); Value *Call = Builder->CreateCall(Fabs, Op0COp, "fabs"); return CastInst::CreateBitOrPointerCast(Call, I.getType()); } } { Value *X = nullptr; bool OpsSwapped = false; // Canonicalize SExt or Not to the LHS if (match(Op1, m_SExt(m_Value())) || match(Op1, m_Not(m_Value()))) { std::swap(Op0, Op1); OpsSwapped = true; } // Fold (and (sext bool to A), B) --> (select bool, B, 0) if (match(Op0, m_SExt(m_Value(X))) && X->getType()->getScalarType()->isIntegerTy(1)) { Value *Zero = Constant::getNullValue(Op1->getType()); return SelectInst::Create(X, Op1, Zero); } // Fold (and ~(sext bool to A), B) --> (select bool, 0, B) if (match(Op0, m_Not(m_SExt(m_Value(X)))) && X->getType()->getScalarType()->isIntegerTy(1)) { Value *Zero = Constant::getNullValue(Op0->getType()); return SelectInst::Create(X, Zero, Op1); } if (OpsSwapped) std::swap(Op0, Op1); } return Changed ? &I : nullptr; } /// Analyze the specified subexpression and see if it is capable of providing /// pieces of a bswap or bitreverse. The subexpression provides a potential /// piece of a bswap or bitreverse if it can be proven that each non-zero bit in /// the output of the expression came from a corresponding bit in some other /// value. This function is recursive, and the end result is a mapping of /// (value, bitnumber) to bitnumber. It is the caller's responsibility to /// validate that all `value`s are identical and that the bitnumber to bitnumber /// mapping is correct for a bswap or bitreverse. /// /// For example, if the current subexpression if "(shl i32 %X, 24)" then we know /// that the expression deposits the low byte of %X into the high byte of the /// result and that all other bits are zero. This expression is accepted, /// BitValues[24-31] are set to %X and BitProvenance[24-31] are set to [0-7]. /// /// This function returns true if the match was unsuccessful and false if so. /// On entry to the function the "OverallLeftShift" is a signed integer value /// indicating the number of bits that the subexpression is later shifted. For /// example, if the expression is later right shifted by 16 bits, the /// OverallLeftShift value would be -16 on entry. This is used to specify which /// bits of BitValues are actually being set. /// /// Similarly, BitMask is a bitmask where a bit is clear if its corresponding /// bit is masked to zero by a user. For example, in (X & 255), X will be /// processed with a bytemask of 255. BitMask is always in the local /// (OverallLeftShift) coordinate space. /// static bool CollectBitParts(Value *V, int OverallLeftShift, APInt BitMask, SmallVectorImpl &BitValues, SmallVectorImpl &BitProvenance) { if (Instruction *I = dyn_cast(V)) { // If this is an or instruction, it may be an inner node of the bswap. if (I->getOpcode() == Instruction::Or) return CollectBitParts(I->getOperand(0), OverallLeftShift, BitMask, BitValues, BitProvenance) || CollectBitParts(I->getOperand(1), OverallLeftShift, BitMask, BitValues, BitProvenance); // If this is a logical shift by a constant, recurse with OverallLeftShift // and BitMask adjusted. if (I->isLogicalShift() && isa(I->getOperand(1))) { unsigned ShAmt = cast(I->getOperand(1))->getLimitedValue(~0U); // Ensure the shift amount is defined. if (ShAmt > BitValues.size()) return true; unsigned BitShift = ShAmt; if (I->getOpcode() == Instruction::Shl) { // X << C -> collect(X, +C) OverallLeftShift += BitShift; BitMask = BitMask.lshr(BitShift); } else { // X >>u C -> collect(X, -C) OverallLeftShift -= BitShift; BitMask = BitMask.shl(BitShift); } if (OverallLeftShift >= (int)BitValues.size()) return true; if (OverallLeftShift <= -(int)BitValues.size()) return true; return CollectBitParts(I->getOperand(0), OverallLeftShift, BitMask, BitValues, BitProvenance); } // If this is a logical 'and' with a mask that clears bits, clear the // corresponding bits in BitMask. if (I->getOpcode() == Instruction::And && isa(I->getOperand(1))) { unsigned NumBits = BitValues.size(); APInt Bit(I->getType()->getPrimitiveSizeInBits(), 1); const APInt &AndMask = cast(I->getOperand(1))->getValue(); for (unsigned i = 0; i != NumBits; ++i, Bit <<= 1) { // If this bit is masked out by a later operation, we don't care what // the and mask is. if (BitMask[i] == 0) continue; // If the AndMask is zero for this bit, clear the bit. APInt MaskB = AndMask & Bit; if (MaskB == 0) { BitMask.clearBit(i); continue; } // Otherwise, this bit is kept. } return CollectBitParts(I->getOperand(0), OverallLeftShift, BitMask, BitValues, BitProvenance); } } // Okay, we got to something that isn't a shift, 'or' or 'and'. This must be // the input value to the bswap/bitreverse. To be part of a bswap or // bitreverse we must be demanding a contiguous range of bits from it. unsigned InputBitLen = BitMask.countPopulation(); unsigned InputBitNo = BitMask.countTrailingZeros(); if (BitMask.getBitWidth() - BitMask.countLeadingZeros() - InputBitNo != InputBitLen) // Not a contiguous set range of bits! return true; // We know we're moving a contiguous range of bits from the input to the // output. Record which bits in the output came from which bits in the input. unsigned DestBitNo = InputBitNo + OverallLeftShift; for (unsigned I = 0; I < InputBitLen; ++I) BitProvenance[DestBitNo + I] = InputBitNo + I; // If the destination bit value is already defined, the values are or'd // together, which isn't a bswap/bitreverse (unless it's an or of the same // bits). if (BitValues[DestBitNo] && BitValues[DestBitNo] != V) return true; for (unsigned I = 0; I < InputBitLen; ++I) BitValues[DestBitNo + I] = V; return false; } static bool bitTransformIsCorrectForBSwap(unsigned From, unsigned To, unsigned BitWidth) { if (From % 8 != To % 8) return false; // Convert from bit indices to byte indices and check for a byte reversal. From >>= 3; To >>= 3; BitWidth >>= 3; return From == BitWidth - To - 1; } static bool bitTransformIsCorrectForBitReverse(unsigned From, unsigned To, unsigned BitWidth) { return From == BitWidth - To - 1; } /// Given an OR instruction, check to see if this is a bswap or bitreverse /// idiom. If so, insert the new intrinsic and return it. Instruction *InstCombiner::MatchBSwapOrBitReverse(BinaryOperator &I) { IntegerType *ITy = dyn_cast(I.getType()); if (!ITy) return nullptr; // Can't do vectors. unsigned BW = ITy->getBitWidth(); /// We keep track of which bit (BitProvenance) inside which value (BitValues) /// defines each bit in the result. SmallVector BitValues(BW, nullptr); SmallVector BitProvenance(BW, -1); // Try to find all the pieces corresponding to the bswap. APInt BitMask = APInt::getAllOnesValue(BitValues.size()); if (CollectBitParts(&I, 0, BitMask, BitValues, BitProvenance)) return nullptr; // Check to see if all of the bits come from the same value. Value *V = BitValues[0]; if (!V) return nullptr; // Didn't find a bit? Must be zero. if (!std::all_of(BitValues.begin(), BitValues.end(), [&](const Value *X) { return X == V; })) return nullptr; // Now, is the bit permutation correct for a bswap or a bitreverse? We can // only byteswap values with an even number of bytes. bool OKForBSwap = BW % 16 == 0, OKForBitReverse = true;; for (unsigned i = 0, e = BitValues.size(); i != e; ++i) { OKForBSwap &= bitTransformIsCorrectForBSwap(BitProvenance[i], i, BW); OKForBitReverse &= bitTransformIsCorrectForBitReverse(BitProvenance[i], i, BW); } Intrinsic::ID Intrin; if (OKForBSwap) Intrin = Intrinsic::bswap; else if (OKForBitReverse) Intrin = Intrinsic::bitreverse; else return nullptr; Function *F = Intrinsic::getDeclaration(I.getModule(), Intrin, ITy); return CallInst::Create(F, V); } /// We have an expression of the form (A&C)|(B&D). Check if A is (cond?-1:0) /// and either B or D is ~(cond?-1,0) or (cond?0,-1), then we can simplify this /// expression to "cond ? C : D or B". static Instruction *MatchSelectFromAndOr(Value *A, Value *B, Value *C, Value *D) { // If A is not a select of -1/0, this cannot match. Value *Cond = nullptr; if (!match(A, m_SExt(m_Value(Cond))) || !Cond->getType()->isIntegerTy(1)) return nullptr; // ((cond?-1:0)&C) | (B&(cond?0:-1)) -> cond ? C : B. if (match(D, m_Not(m_SExt(m_Specific(Cond))))) return SelectInst::Create(Cond, C, B); if (match(D, m_SExt(m_Not(m_Specific(Cond))))) return SelectInst::Create(Cond, C, B); // ((cond?-1:0)&C) | ((cond?0:-1)&D) -> cond ? C : D. if (match(B, m_Not(m_SExt(m_Specific(Cond))))) return SelectInst::Create(Cond, C, D); if (match(B, m_SExt(m_Not(m_Specific(Cond))))) return SelectInst::Create(Cond, C, D); return nullptr; } /// Fold (icmp)|(icmp) if possible. Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS, Instruction *CxtI) { ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate(); // Fold (iszero(A & K1) | iszero(A & K2)) -> (A & (K1 | K2)) != (K1 | K2) // if K1 and K2 are a one-bit mask. ConstantInt *LHSCst = dyn_cast(LHS->getOperand(1)); ConstantInt *RHSCst = dyn_cast(RHS->getOperand(1)); if (LHS->getPredicate() == ICmpInst::ICMP_EQ && LHSCst && LHSCst->isZero() && RHS->getPredicate() == ICmpInst::ICMP_EQ && RHSCst && RHSCst->isZero()) { BinaryOperator *LAnd = dyn_cast(LHS->getOperand(0)); BinaryOperator *RAnd = dyn_cast(RHS->getOperand(0)); if (LAnd && RAnd && LAnd->hasOneUse() && RHS->hasOneUse() && LAnd->getOpcode() == Instruction::And && RAnd->getOpcode() == Instruction::And) { Value *Mask = nullptr; Value *Masked = nullptr; if (LAnd->getOperand(0) == RAnd->getOperand(0) && isKnownToBeAPowerOfTwo(LAnd->getOperand(1), DL, false, 0, AC, CxtI, DT) && isKnownToBeAPowerOfTwo(RAnd->getOperand(1), DL, false, 0, AC, CxtI, DT)) { Mask = Builder->CreateOr(LAnd->getOperand(1), RAnd->getOperand(1)); Masked = Builder->CreateAnd(LAnd->getOperand(0), Mask); } else if (LAnd->getOperand(1) == RAnd->getOperand(1) && isKnownToBeAPowerOfTwo(LAnd->getOperand(0), DL, false, 0, AC, CxtI, DT) && isKnownToBeAPowerOfTwo(RAnd->getOperand(0), DL, false, 0, AC, CxtI, DT)) { Mask = Builder->CreateOr(LAnd->getOperand(0), RAnd->getOperand(0)); Masked = Builder->CreateAnd(LAnd->getOperand(1), Mask); } if (Masked) return Builder->CreateICmp(ICmpInst::ICMP_NE, Masked, Mask); } } // Fold (icmp ult/ule (A + C1), C3) | (icmp ult/ule (A + C2), C3) // --> (icmp ult/ule ((A & ~(C1 ^ C2)) + max(C1, C2)), C3) // The original condition actually refers to the following two ranges: // [MAX_UINT-C1+1, MAX_UINT-C1+1+C3] and [MAX_UINT-C2+1, MAX_UINT-C2+1+C3] // We can fold these two ranges if: // 1) C1 and C2 is unsigned greater than C3. // 2) The two ranges are separated. // 3) C1 ^ C2 is one-bit mask. // 4) LowRange1 ^ LowRange2 and HighRange1 ^ HighRange2 are one-bit mask. // This implies all values in the two ranges differ by exactly one bit. if ((LHSCC == ICmpInst::ICMP_ULT || LHSCC == ICmpInst::ICMP_ULE) && LHSCC == RHSCC && LHSCst && RHSCst && LHS->hasOneUse() && RHS->hasOneUse() && LHSCst->getType() == RHSCst->getType() && LHSCst->getValue() == (RHSCst->getValue())) { Value *LAdd = LHS->getOperand(0); Value *RAdd = RHS->getOperand(0); Value *LAddOpnd, *RAddOpnd; ConstantInt *LAddCst, *RAddCst; if (match(LAdd, m_Add(m_Value(LAddOpnd), m_ConstantInt(LAddCst))) && match(RAdd, m_Add(m_Value(RAddOpnd), m_ConstantInt(RAddCst))) && LAddCst->getValue().ugt(LHSCst->getValue()) && RAddCst->getValue().ugt(LHSCst->getValue())) { APInt DiffCst = LAddCst->getValue() ^ RAddCst->getValue(); if (LAddOpnd == RAddOpnd && DiffCst.isPowerOf2()) { ConstantInt *MaxAddCst = nullptr; if (LAddCst->getValue().ult(RAddCst->getValue())) MaxAddCst = RAddCst; else MaxAddCst = LAddCst; APInt RRangeLow = -RAddCst->getValue(); APInt RRangeHigh = RRangeLow + LHSCst->getValue(); APInt LRangeLow = -LAddCst->getValue(); APInt LRangeHigh = LRangeLow + LHSCst->getValue(); APInt LowRangeDiff = RRangeLow ^ LRangeLow; APInt HighRangeDiff = RRangeHigh ^ LRangeHigh; APInt RangeDiff = LRangeLow.sgt(RRangeLow) ? LRangeLow - RRangeLow : RRangeLow - LRangeLow; if (LowRangeDiff.isPowerOf2() && LowRangeDiff == HighRangeDiff && RangeDiff.ugt(LHSCst->getValue())) { Value *MaskCst = ConstantInt::get(LAddCst->getType(), ~DiffCst); Value *NewAnd = Builder->CreateAnd(LAddOpnd, MaskCst); Value *NewAdd = Builder->CreateAdd(NewAnd, MaxAddCst); return (Builder->CreateICmp(LHS->getPredicate(), NewAdd, LHSCst)); } } } } // (icmp1 A, B) | (icmp2 A, B) --> (icmp3 A, B) if (PredicatesFoldable(LHSCC, RHSCC)) { if (LHS->getOperand(0) == RHS->getOperand(1) && LHS->getOperand(1) == RHS->getOperand(0)) LHS->swapOperands(); if (LHS->getOperand(0) == RHS->getOperand(0) && LHS->getOperand(1) == RHS->getOperand(1)) { Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1); unsigned Code = getICmpCode(LHS) | getICmpCode(RHS); bool isSigned = LHS->isSigned() || RHS->isSigned(); return getNewICmpValue(isSigned, Code, Op0, Op1, Builder); } } // handle (roughly): // (icmp ne (A & B), C) | (icmp ne (A & D), E) if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, false, Builder)) return V; Value *Val = LHS->getOperand(0), *Val2 = RHS->getOperand(0); if (LHS->hasOneUse() || RHS->hasOneUse()) { // (icmp eq B, 0) | (icmp ult A, B) -> (icmp ule A, B-1) // (icmp eq B, 0) | (icmp ugt B, A) -> (icmp ule A, B-1) Value *A = nullptr, *B = nullptr; if (LHSCC == ICmpInst::ICMP_EQ && LHSCst && LHSCst->isZero()) { B = Val; if (RHSCC == ICmpInst::ICMP_ULT && Val == RHS->getOperand(1)) A = Val2; else if (RHSCC == ICmpInst::ICMP_UGT && Val == Val2) A = RHS->getOperand(1); } // (icmp ult A, B) | (icmp eq B, 0) -> (icmp ule A, B-1) // (icmp ugt B, A) | (icmp eq B, 0) -> (icmp ule A, B-1) else if (RHSCC == ICmpInst::ICMP_EQ && RHSCst && RHSCst->isZero()) { B = Val2; if (LHSCC == ICmpInst::ICMP_ULT && Val2 == LHS->getOperand(1)) A = Val; else if (LHSCC == ICmpInst::ICMP_UGT && Val2 == Val) A = LHS->getOperand(1); } if (A && B) return Builder->CreateICmp( ICmpInst::ICMP_UGE, Builder->CreateAdd(B, ConstantInt::getSigned(B->getType(), -1)), A); } // E.g. (icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n if (Value *V = simplifyRangeCheck(LHS, RHS, /*Inverted=*/true)) return V; // E.g. (icmp sgt x, n) | (icmp slt x, 0) --> icmp ugt x, n if (Value *V = simplifyRangeCheck(RHS, LHS, /*Inverted=*/true)) return V; // This only handles icmp of constants: (icmp1 A, C1) | (icmp2 B, C2). if (!LHSCst || !RHSCst) return nullptr; if (LHSCst == RHSCst && LHSCC == RHSCC) { // (icmp ne A, 0) | (icmp ne B, 0) --> (icmp ne (A|B), 0) if (LHSCC == ICmpInst::ICMP_NE && LHSCst->isZero()) { Value *NewOr = Builder->CreateOr(Val, Val2); return Builder->CreateICmp(LHSCC, NewOr, LHSCst); } } // (icmp ult (X + CA), C1) | (icmp eq X, C2) -> (icmp ule (X + CA), C1) // iff C2 + CA == C1. if (LHSCC == ICmpInst::ICMP_ULT && RHSCC == ICmpInst::ICMP_EQ) { ConstantInt *AddCst; if (match(Val, m_Add(m_Specific(Val2), m_ConstantInt(AddCst)))) if (RHSCst->getValue() + AddCst->getValue() == LHSCst->getValue()) return Builder->CreateICmpULE(Val, LHSCst); } // From here on, we only handle: // (icmp1 A, C1) | (icmp2 A, C2) --> something simpler. if (Val != Val2) return nullptr; // ICMP_[US][GL]E X, CST is folded to ICMP_[US][GL]T elsewhere. if (LHSCC == ICmpInst::ICMP_UGE || LHSCC == ICmpInst::ICMP_ULE || RHSCC == ICmpInst::ICMP_UGE || RHSCC == ICmpInst::ICMP_ULE || LHSCC == ICmpInst::ICMP_SGE || LHSCC == ICmpInst::ICMP_SLE || RHSCC == ICmpInst::ICMP_SGE || RHSCC == ICmpInst::ICMP_SLE) return nullptr; // We can't fold (ugt x, C) | (sgt x, C2). if (!PredicatesFoldable(LHSCC, RHSCC)) return nullptr; // Ensure that the larger constant is on the RHS. bool ShouldSwap; if (CmpInst::isSigned(LHSCC) || (ICmpInst::isEquality(LHSCC) && CmpInst::isSigned(RHSCC))) ShouldSwap = LHSCst->getValue().sgt(RHSCst->getValue()); else ShouldSwap = LHSCst->getValue().ugt(RHSCst->getValue()); if (ShouldSwap) { std::swap(LHS, RHS); std::swap(LHSCst, RHSCst); std::swap(LHSCC, RHSCC); } // At this point, we know we have two icmp instructions // comparing a value against two constants and or'ing the result // together. Because of the above check, we know that we only have // ICMP_EQ, ICMP_NE, ICMP_LT, and ICMP_GT here. We also know (from the // icmp folding check above), that the two constants are not // equal. assert(LHSCst != RHSCst && "Compares not folded above?"); switch (LHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_EQ: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_EQ: if (LHS->getOperand(0) == RHS->getOperand(0)) { // if LHSCst and RHSCst differ only by one bit: // (A == C1 || A == C2) -> (A | (C1 ^ C2)) == C2 assert(LHSCst->getValue().ule(LHSCst->getValue())); APInt Xor = LHSCst->getValue() ^ RHSCst->getValue(); if (Xor.isPowerOf2()) { Value *Cst = Builder->getInt(Xor); Value *Or = Builder->CreateOr(LHS->getOperand(0), Cst); return Builder->CreateICmp(ICmpInst::ICMP_EQ, Or, RHSCst); } } if (LHSCst == SubOne(RHSCst)) { // (X == 13 | X == 14) -> X-13 CreateAdd(Val, AddCST, Val->getName()+".off"); AddCST = ConstantExpr::getSub(AddOne(RHSCst), LHSCst); return Builder->CreateICmpULT(Add, AddCST); } break; // (X == 13 | X == 15) -> no change case ICmpInst::ICMP_UGT: // (X == 13 | X u> 14) -> no change case ICmpInst::ICMP_SGT: // (X == 13 | X s> 14) -> no change break; case ICmpInst::ICMP_NE: // (X == 13 | X != 15) -> X != 15 case ICmpInst::ICMP_ULT: // (X == 13 | X u< 15) -> X u< 15 case ICmpInst::ICMP_SLT: // (X == 13 | X s< 15) -> X s< 15 return RHS; } break; case ICmpInst::ICMP_NE: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_EQ: // (X != 13 | X == 15) -> X != 13 case ICmpInst::ICMP_UGT: // (X != 13 | X u> 15) -> X != 13 case ICmpInst::ICMP_SGT: // (X != 13 | X s> 15) -> X != 13 return LHS; case ICmpInst::ICMP_NE: // (X != 13 | X != 15) -> true case ICmpInst::ICMP_ULT: // (X != 13 | X u< 15) -> true case ICmpInst::ICMP_SLT: // (X != 13 | X s< 15) -> true return Builder->getTrue(); } case ICmpInst::ICMP_ULT: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_EQ: // (X u< 13 | X == 14) -> no change break; case ICmpInst::ICMP_UGT: // (X u< 13 | X u> 15) -> (X-13) u> 2 // If RHSCst is [us]MAXINT, it is always false. Not handling // this can cause overflow. if (RHSCst->isMaxValue(false)) return LHS; return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), false, false); case ICmpInst::ICMP_SGT: // (X u< 13 | X s> 15) -> no change break; case ICmpInst::ICMP_NE: // (X u< 13 | X != 15) -> X != 15 case ICmpInst::ICMP_ULT: // (X u< 13 | X u< 15) -> X u< 15 return RHS; case ICmpInst::ICMP_SLT: // (X u< 13 | X s< 15) -> no change break; } break; case ICmpInst::ICMP_SLT: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_EQ: // (X s< 13 | X == 14) -> no change break; case ICmpInst::ICMP_SGT: // (X s< 13 | X s> 15) -> (X-13) s> 2 // If RHSCst is [us]MAXINT, it is always false. Not handling // this can cause overflow. if (RHSCst->isMaxValue(true)) return LHS; return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), true, false); case ICmpInst::ICMP_UGT: // (X s< 13 | X u> 15) -> no change break; case ICmpInst::ICMP_NE: // (X s< 13 | X != 15) -> X != 15 case ICmpInst::ICMP_SLT: // (X s< 13 | X s< 15) -> X s< 15 return RHS; case ICmpInst::ICMP_ULT: // (X s< 13 | X u< 15) -> no change break; } break; case ICmpInst::ICMP_UGT: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_EQ: // (X u> 13 | X == 15) -> X u> 13 case ICmpInst::ICMP_UGT: // (X u> 13 | X u> 15) -> X u> 13 return LHS; case ICmpInst::ICMP_SGT: // (X u> 13 | X s> 15) -> no change break; case ICmpInst::ICMP_NE: // (X u> 13 | X != 15) -> true case ICmpInst::ICMP_ULT: // (X u> 13 | X u< 15) -> true return Builder->getTrue(); case ICmpInst::ICMP_SLT: // (X u> 13 | X s< 15) -> no change break; } break; case ICmpInst::ICMP_SGT: switch (RHSCC) { default: llvm_unreachable("Unknown integer condition code!"); case ICmpInst::ICMP_EQ: // (X s> 13 | X == 15) -> X > 13 case ICmpInst::ICMP_SGT: // (X s> 13 | X s> 15) -> X > 13 return LHS; case ICmpInst::ICMP_UGT: // (X s> 13 | X u> 15) -> no change break; case ICmpInst::ICMP_NE: // (X s> 13 | X != 15) -> true case ICmpInst::ICMP_SLT: // (X s> 13 | X s< 15) -> true return Builder->getTrue(); case ICmpInst::ICMP_ULT: // (X s> 13 | X u< 15) -> no change break; } break; } return nullptr; } /// Optimize (fcmp)|(fcmp). NOTE: Unlike the rest of instcombine, this returns /// a Value which should already be inserted into the function. Value *InstCombiner::FoldOrOfFCmps(FCmpInst *LHS, FCmpInst *RHS) { if (LHS->getPredicate() == FCmpInst::FCMP_UNO && RHS->getPredicate() == FCmpInst::FCMP_UNO && LHS->getOperand(0)->getType() == RHS->getOperand(0)->getType()) { if (ConstantFP *LHSC = dyn_cast(LHS->getOperand(1))) if (ConstantFP *RHSC = dyn_cast(RHS->getOperand(1))) { // If either of the constants are nans, then the whole thing returns // true. if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN()) return Builder->getTrue(); // Otherwise, no need to compare the two constants, compare the // rest. return Builder->CreateFCmpUNO(LHS->getOperand(0), RHS->getOperand(0)); } // Handle vector zeros. This occurs because the canonical form of // "fcmp uno x,x" is "fcmp uno x, 0". if (isa(LHS->getOperand(1)) && isa(RHS->getOperand(1))) return Builder->CreateFCmpUNO(LHS->getOperand(0), RHS->getOperand(0)); return nullptr; } Value *Op0LHS = LHS->getOperand(0), *Op0RHS = LHS->getOperand(1); Value *Op1LHS = RHS->getOperand(0), *Op1RHS = RHS->getOperand(1); FCmpInst::Predicate Op0CC = LHS->getPredicate(), Op1CC = RHS->getPredicate(); if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) { // Swap RHS operands to match LHS. Op1CC = FCmpInst::getSwappedPredicate(Op1CC); std::swap(Op1LHS, Op1RHS); } if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) { // Simplify (fcmp cc0 x, y) | (fcmp cc1 x, y). if (Op0CC == Op1CC) return Builder->CreateFCmp((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS); if (Op0CC == FCmpInst::FCMP_TRUE || Op1CC == FCmpInst::FCMP_TRUE) return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1); if (Op0CC == FCmpInst::FCMP_FALSE) return RHS; if (Op1CC == FCmpInst::FCMP_FALSE) return LHS; bool Op0Ordered; bool Op1Ordered; unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered); unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered); if (Op0Ordered == Op1Ordered) { // If both are ordered or unordered, return a new fcmp with // or'ed predicates. return getFCmpValue(Op0Ordered, Op0Pred|Op1Pred, Op0LHS, Op0RHS, Builder); } } return nullptr; } /// This helper function folds: /// /// ((A | B) & C1) | (B & C2) /// /// into: /// /// (A & C1) | B /// /// when the XOR of the two constants is "all ones" (-1). Instruction *InstCombiner::FoldOrWithConstants(BinaryOperator &I, Value *Op, Value *A, Value *B, Value *C) { ConstantInt *CI1 = dyn_cast(C); if (!CI1) return nullptr; Value *V1 = nullptr; ConstantInt *CI2 = nullptr; if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2)))) return nullptr; APInt Xor = CI1->getValue() ^ CI2->getValue(); if (!Xor.isAllOnesValue()) return nullptr; if (V1 == A || V1 == B) { Value *NewOp = Builder->CreateAnd((V1 == A) ? B : A, CI1); return BinaryOperator::CreateOr(NewOp, V1); } return nullptr; } /// \brief This helper function folds: /// /// ((A | B) & C1) ^ (B & C2) /// /// into: /// /// (A & C1) ^ B /// /// when the XOR of the two constants is "all ones" (-1). Instruction *InstCombiner::FoldXorWithConstants(BinaryOperator &I, Value *Op, Value *A, Value *B, Value *C) { ConstantInt *CI1 = dyn_cast(C); if (!CI1) return nullptr; Value *V1 = nullptr; ConstantInt *CI2 = nullptr; if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2)))) return nullptr; APInt Xor = CI1->getValue() ^ CI2->getValue(); if (!Xor.isAllOnesValue()) return nullptr; if (V1 == A || V1 == B) { Value *NewOp = Builder->CreateAnd(V1 == A ? B : A, CI1); return BinaryOperator::CreateXor(NewOp, V1); } return nullptr; } Instruction *InstCombiner::visitOr(BinaryOperator &I) { bool Changed = SimplifyAssociativeOrCommutative(I); Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); if (Value *V = SimplifyVectorOp(I)) return ReplaceInstUsesWith(I, V); if (Value *V = SimplifyOrInst(Op0, Op1, DL, TLI, DT, AC)) return ReplaceInstUsesWith(I, V); // (A&B)|(A&C) -> A&(B|C) etc if (Value *V = SimplifyUsingDistributiveLaws(I)) return ReplaceInstUsesWith(I, V); // See if we can simplify any instructions used by the instruction whose sole // purpose is to compute bits we don't care about. if (SimplifyDemandedInstructionBits(I)) return &I; if (Value *V = SimplifyBSwap(I)) return ReplaceInstUsesWith(I, V); if (ConstantInt *RHS = dyn_cast(Op1)) { ConstantInt *C1 = nullptr; Value *X = nullptr; // (X & C1) | C2 --> (X | C2) & (C1|C2) // iff (C1 & C2) == 0. if (match(Op0, m_And(m_Value(X), m_ConstantInt(C1))) && (RHS->getValue() & C1->getValue()) != 0 && Op0->hasOneUse()) { Value *Or = Builder->CreateOr(X, RHS); Or->takeName(Op0); return BinaryOperator::CreateAnd(Or, Builder->getInt(RHS->getValue() | C1->getValue())); } // (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2) if (match(Op0, m_Xor(m_Value(X), m_ConstantInt(C1))) && Op0->hasOneUse()) { Value *Or = Builder->CreateOr(X, RHS); Or->takeName(Op0); return BinaryOperator::CreateXor(Or, Builder->getInt(C1->getValue() & ~RHS->getValue())); } // Try to fold constant and into select arguments. if (SelectInst *SI = dyn_cast(Op0)) if (Instruction *R = FoldOpIntoSelect(I, SI)) return R; if (isa(Op0)) if (Instruction *NV = FoldOpIntoPhi(I)) return NV; } Value *A = nullptr, *B = nullptr; ConstantInt *C1 = nullptr, *C2 = nullptr; // (A | B) | C and A | (B | C) -> bswap if possible. bool OrOfOrs = match(Op0, m_Or(m_Value(), m_Value())) || match(Op1, m_Or(m_Value(), m_Value())); // (A >> B) | (C << D) and (A << B) | (B >> C) -> bswap if possible. bool OrOfShifts = match(Op0, m_LogicalShift(m_Value(), m_Value())) && match(Op1, m_LogicalShift(m_Value(), m_Value())); // (A & B) | (C & D) -> bswap if possible. bool OrOfAnds = match(Op0, m_And(m_Value(), m_Value())) && match(Op1, m_And(m_Value(), m_Value())); if (OrOfOrs || OrOfShifts || OrOfAnds) if (Instruction *BSwap = MatchBSwapOrBitReverse(I)) return BSwap; // (X^C)|Y -> (X|Y)^C iff Y&C == 0 if (Op0->hasOneUse() && match(Op0, m_Xor(m_Value(A), m_ConstantInt(C1))) && MaskedValueIsZero(Op1, C1->getValue(), 0, &I)) { Value *NOr = Builder->CreateOr(A, Op1); NOr->takeName(Op0); return BinaryOperator::CreateXor(NOr, C1); } // Y|(X^C) -> (X|Y)^C iff Y&C == 0 if (Op1->hasOneUse() && match(Op1, m_Xor(m_Value(A), m_ConstantInt(C1))) && MaskedValueIsZero(Op0, C1->getValue(), 0, &I)) { Value *NOr = Builder->CreateOr(A, Op0); NOr->takeName(Op0); return BinaryOperator::CreateXor(NOr, C1); } // ((~A & B) | A) -> (A | B) if (match(Op0, m_And(m_Not(m_Value(A)), m_Value(B))) && match(Op1, m_Specific(A))) return BinaryOperator::CreateOr(A, B); // ((A & B) | ~A) -> (~A | B) if (match(Op0, m_And(m_Value(A), m_Value(B))) && match(Op1, m_Not(m_Specific(A)))) return BinaryOperator::CreateOr(Builder->CreateNot(A), B); // (A & (~B)) | (A ^ B) -> (A ^ B) if (match(Op0, m_And(m_Value(A), m_Not(m_Value(B)))) && match(Op1, m_Xor(m_Specific(A), m_Specific(B)))) return BinaryOperator::CreateXor(A, B); // (A ^ B) | ( A & (~B)) -> (A ^ B) if (match(Op0, m_Xor(m_Value(A), m_Value(B))) && match(Op1, m_And(m_Specific(A), m_Not(m_Specific(B))))) return BinaryOperator::CreateXor(A, B); // (A & C)|(B & D) Value *C = nullptr, *D = nullptr; if (match(Op0, m_And(m_Value(A), m_Value(C))) && match(Op1, m_And(m_Value(B), m_Value(D)))) { Value *V1 = nullptr, *V2 = nullptr; C1 = dyn_cast(C); C2 = dyn_cast(D); if (C1 && C2) { // (A & C1)|(B & C2) if ((C1->getValue() & C2->getValue()) == 0) { // ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2) // iff (C1&C2) == 0 and (N&~C1) == 0 if (match(A, m_Or(m_Value(V1), m_Value(V2))) && ((V1 == B && MaskedValueIsZero(V2, ~C1->getValue(), 0, &I)) || // (V|N) (V2 == B && MaskedValueIsZero(V1, ~C1->getValue(), 0, &I)))) // (N|V) return BinaryOperator::CreateAnd(A, Builder->getInt(C1->getValue()|C2->getValue())); // Or commutes, try both ways. if (match(B, m_Or(m_Value(V1), m_Value(V2))) && ((V1 == A && MaskedValueIsZero(V2, ~C2->getValue(), 0, &I)) || // (V|N) (V2 == A && MaskedValueIsZero(V1, ~C2->getValue(), 0, &I)))) // (N|V) return BinaryOperator::CreateAnd(B, Builder->getInt(C1->getValue()|C2->getValue())); // ((V|C3)&C1) | ((V|C4)&C2) --> (V|C3|C4)&(C1|C2) // iff (C1&C2) == 0 and (C3&~C1) == 0 and (C4&~C2) == 0. ConstantInt *C3 = nullptr, *C4 = nullptr; if (match(A, m_Or(m_Value(V1), m_ConstantInt(C3))) && (C3->getValue() & ~C1->getValue()) == 0 && match(B, m_Or(m_Specific(V1), m_ConstantInt(C4))) && (C4->getValue() & ~C2->getValue()) == 0) { V2 = Builder->CreateOr(V1, ConstantExpr::getOr(C3, C4), "bitfield"); return BinaryOperator::CreateAnd(V2, Builder->getInt(C1->getValue()|C2->getValue())); } } } // (A & (C0?-1:0)) | (B & ~(C0?-1:0)) -> C0 ? A : B, and commuted variants. // Don't do this for vector select idioms, the code generator doesn't handle // them well yet. if (!I.getType()->isVectorTy()) { if (Instruction *Match = MatchSelectFromAndOr(A, B, C, D)) return Match; if (Instruction *Match = MatchSelectFromAndOr(B, A, D, C)) return Match; if (Instruction *Match = MatchSelectFromAndOr(C, B, A, D)) return Match; if (Instruction *Match = MatchSelectFromAndOr(D, A, B, C)) return Match; } // ((A&~B)|(~A&B)) -> A^B if ((match(C, m_Not(m_Specific(D))) && match(B, m_Not(m_Specific(A))))) return BinaryOperator::CreateXor(A, D); // ((~B&A)|(~A&B)) -> A^B if ((match(A, m_Not(m_Specific(D))) && match(B, m_Not(m_Specific(C))))) return BinaryOperator::CreateXor(C, D); // ((A&~B)|(B&~A)) -> A^B if ((match(C, m_Not(m_Specific(B))) && match(D, m_Not(m_Specific(A))))) return BinaryOperator::CreateXor(A, B); // ((~B&A)|(B&~A)) -> A^B if ((match(A, m_Not(m_Specific(B))) && match(D, m_Not(m_Specific(C))))) return BinaryOperator::CreateXor(C, B); // ((A|B)&1)|(B&-2) -> (A&1) | B if (match(A, m_Or(m_Value(V1), m_Specific(B))) || match(A, m_Or(m_Specific(B), m_Value(V1)))) { Instruction *Ret = FoldOrWithConstants(I, Op1, V1, B, C); if (Ret) return Ret; } // (B&-2)|((A|B)&1) -> (A&1) | B if (match(B, m_Or(m_Specific(A), m_Value(V1))) || match(B, m_Or(m_Value(V1), m_Specific(A)))) { Instruction *Ret = FoldOrWithConstants(I, Op0, A, V1, D); if (Ret) return Ret; } // ((A^B)&1)|(B&-2) -> (A&1) ^ B if (match(A, m_Xor(m_Value(V1), m_Specific(B))) || match(A, m_Xor(m_Specific(B), m_Value(V1)))) { Instruction *Ret = FoldXorWithConstants(I, Op1, V1, B, C); if (Ret) return Ret; } // (B&-2)|((A^B)&1) -> (A&1) ^ B if (match(B, m_Xor(m_Specific(A), m_Value(V1))) || match(B, m_Xor(m_Value(V1), m_Specific(A)))) { Instruction *Ret = FoldXorWithConstants(I, Op0, A, V1, D); if (Ret) return Ret; } } // (A ^ B) | ((B ^ C) ^ A) -> (A ^ B) | C if (match(Op0, m_Xor(m_Value(A), m_Value(B)))) if (match(Op1, m_Xor(m_Xor(m_Specific(B), m_Value(C)), m_Specific(A)))) if (Op1->hasOneUse() || cast(Op1)->hasOneUse()) return BinaryOperator::CreateOr(Op0, C); // ((A ^ C) ^ B) | (B ^ A) -> (B ^ A) | C if (match(Op0, m_Xor(m_Xor(m_Value(A), m_Value(C)), m_Value(B)))) if (match(Op1, m_Xor(m_Specific(B), m_Specific(A)))) if (Op0->hasOneUse() || cast(Op0)->hasOneUse()) return BinaryOperator::CreateOr(Op1, C); // ((B | C) & A) | B -> B | (A & C) if (match(Op0, m_And(m_Or(m_Specific(Op1), m_Value(C)), m_Value(A)))) return BinaryOperator::CreateOr(Op1, Builder->CreateAnd(A, C)); if (Instruction *DeMorgan = matchDeMorgansLaws(I, Builder)) return DeMorgan; // Canonicalize xor to the RHS. bool SwappedForXor = false; if (match(Op0, m_Xor(m_Value(), m_Value()))) { std::swap(Op0, Op1); SwappedForXor = true; } // A | ( A ^ B) -> A | B // A | (~A ^ B) -> A | ~B // (A & B) | (A ^ B) if (match(Op1, m_Xor(m_Value(A), m_Value(B)))) { if (Op0 == A || Op0 == B) return BinaryOperator::CreateOr(A, B); if (match(Op0, m_And(m_Specific(A), m_Specific(B))) || match(Op0, m_And(m_Specific(B), m_Specific(A)))) return BinaryOperator::CreateOr(A, B); if (Op1->hasOneUse() && match(A, m_Not(m_Specific(Op0)))) { Value *Not = Builder->CreateNot(B, B->getName()+".not"); return BinaryOperator::CreateOr(Not, Op0); } if (Op1->hasOneUse() && match(B, m_Not(m_Specific(Op0)))) { Value *Not = Builder->CreateNot(A, A->getName()+".not"); return BinaryOperator::CreateOr(Not, Op0); } } // A | ~(A | B) -> A | ~B // A | ~(A ^ B) -> A | ~B if (match(Op1, m_Not(m_Value(A)))) if (BinaryOperator *B = dyn_cast(A)) if ((Op0 == B->getOperand(0) || Op0 == B->getOperand(1)) && Op1->hasOneUse() && (B->getOpcode() == Instruction::Or || B->getOpcode() == Instruction::Xor)) { Value *NotOp = Op0 == B->getOperand(0) ? B->getOperand(1) : B->getOperand(0); Value *Not = Builder->CreateNot(NotOp, NotOp->getName()+".not"); return BinaryOperator::CreateOr(Not, Op0); } // (A & B) | ((~A) ^ B) -> (~A ^ B) if (match(Op0, m_And(m_Value(A), m_Value(B))) && match(Op1, m_Xor(m_Not(m_Specific(A)), m_Specific(B)))) return BinaryOperator::CreateXor(Builder->CreateNot(A), B); // ((~A) ^ B) | (A & B) -> (~A ^ B) if (match(Op0, m_Xor(m_Not(m_Value(A)), m_Value(B))) && match(Op1, m_And(m_Specific(A), m_Specific(B)))) return BinaryOperator::CreateXor(Builder->CreateNot(A), B); if (SwappedForXor) std::swap(Op0, Op1); { ICmpInst *LHS = dyn_cast(Op0); ICmpInst *RHS = dyn_cast(Op1); if (LHS && RHS) if (Value *Res = FoldOrOfICmps(LHS, RHS, &I)) return ReplaceInstUsesWith(I, Res); // TODO: Make this recursive; it's a little tricky because an arbitrary // number of 'or' instructions might have to be created. Value *X, *Y; if (LHS && match(Op1, m_OneUse(m_Or(m_Value(X), m_Value(Y))))) { if (auto *Cmp = dyn_cast(X)) if (Value *Res = FoldOrOfICmps(LHS, Cmp, &I)) return ReplaceInstUsesWith(I, Builder->CreateOr(Res, Y)); if (auto *Cmp = dyn_cast(Y)) if (Value *Res = FoldOrOfICmps(LHS, Cmp, &I)) return ReplaceInstUsesWith(I, Builder->CreateOr(Res, X)); } if (RHS && match(Op0, m_OneUse(m_Or(m_Value(X), m_Value(Y))))) { if (auto *Cmp = dyn_cast(X)) if (Value *Res = FoldOrOfICmps(Cmp, RHS, &I)) return ReplaceInstUsesWith(I, Builder->CreateOr(Res, Y)); if (auto *Cmp = dyn_cast(Y)) if (Value *Res = FoldOrOfICmps(Cmp, RHS, &I)) return ReplaceInstUsesWith(I, Builder->CreateOr(Res, X)); } } // (fcmp uno x, c) | (fcmp uno y, c) -> (fcmp uno x, y) if (FCmpInst *LHS = dyn_cast(I.getOperand(0))) if (FCmpInst *RHS = dyn_cast(I.getOperand(1))) if (Value *Res = FoldOrOfFCmps(LHS, RHS)) return ReplaceInstUsesWith(I, Res); // fold (or (cast A), (cast B)) -> (cast (or A, B)) if (CastInst *Op0C = dyn_cast(Op0)) { CastInst *Op1C = dyn_cast(Op1); if (Op1C && Op0C->getOpcode() == Op1C->getOpcode()) {// same cast kind ? Type *SrcTy = Op0C->getOperand(0)->getType(); if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntOrIntVectorTy()) { Value *Op0COp = Op0C->getOperand(0), *Op1COp = Op1C->getOperand(0); if ((!isa(Op0COp) || !isa(Op1COp)) && // Only do this if the casts both really cause code to be // generated. ShouldOptimizeCast(Op0C->getOpcode(), Op0COp, I.getType()) && ShouldOptimizeCast(Op1C->getOpcode(), Op1COp, I.getType())) { Value *NewOp = Builder->CreateOr(Op0COp, Op1COp, I.getName()); return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType()); } // If this is or(cast(icmp), cast(icmp)), try to fold this even if the // cast is otherwise not optimizable. This happens for vector sexts. if (ICmpInst *RHS = dyn_cast(Op1COp)) if (ICmpInst *LHS = dyn_cast(Op0COp)) if (Value *Res = FoldOrOfICmps(LHS, RHS, &I)) return CastInst::Create(Op0C->getOpcode(), Res, I.getType()); // If this is or(cast(fcmp), cast(fcmp)), try to fold this even if the // cast is otherwise not optimizable. This happens for vector sexts. if (FCmpInst *RHS = dyn_cast(Op1COp)) if (FCmpInst *LHS = dyn_cast(Op0COp)) if (Value *Res = FoldOrOfFCmps(LHS, RHS)) return CastInst::Create(Op0C->getOpcode(), Res, I.getType()); } } } // or(sext(A), B) -> A ? -1 : B where A is an i1 // or(A, sext(B)) -> B ? -1 : A where B is an i1 if (match(Op0, m_SExt(m_Value(A))) && A->getType()->isIntegerTy(1)) return SelectInst::Create(A, ConstantInt::getSigned(I.getType(), -1), Op1); if (match(Op1, m_SExt(m_Value(A))) && A->getType()->isIntegerTy(1)) return SelectInst::Create(A, ConstantInt::getSigned(I.getType(), -1), Op0); // Note: If we've gotten to the point of visiting the outer OR, then the // inner one couldn't be simplified. If it was a constant, then it won't // be simplified by a later pass either, so we try swapping the inner/outer // ORs in the hopes that we'll be able to simplify it this way. // (X|C) | V --> (X|V) | C if (Op0->hasOneUse() && !isa(Op1) && match(Op0, m_Or(m_Value(A), m_ConstantInt(C1)))) { Value *Inner = Builder->CreateOr(A, Op1); Inner->takeName(Op0); return BinaryOperator::CreateOr(Inner, C1); } // Change (or (bool?A:B),(bool?C:D)) --> (bool?(or A,C):(or B,D)) // Since this OR statement hasn't been optimized further yet, we hope // that this transformation will allow the new ORs to be optimized. { Value *X = nullptr, *Y = nullptr; if (Op0->hasOneUse() && Op1->hasOneUse() && match(Op0, m_Select(m_Value(X), m_Value(A), m_Value(B))) && match(Op1, m_Select(m_Value(Y), m_Value(C), m_Value(D))) && X == Y) { Value *orTrue = Builder->CreateOr(A, C); Value *orFalse = Builder->CreateOr(B, D); return SelectInst::Create(X, orTrue, orFalse); } } return Changed ? &I : nullptr; } Instruction *InstCombiner::visitXor(BinaryOperator &I) { bool Changed = SimplifyAssociativeOrCommutative(I); Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); if (Value *V = SimplifyVectorOp(I)) return ReplaceInstUsesWith(I, V); if (Value *V = SimplifyXorInst(Op0, Op1, DL, TLI, DT, AC)) return ReplaceInstUsesWith(I, V); // (A&B)^(A&C) -> A&(B^C) etc if (Value *V = SimplifyUsingDistributiveLaws(I)) return ReplaceInstUsesWith(I, V); // See if we can simplify any instructions used by the instruction whose sole // purpose is to compute bits we don't care about. if (SimplifyDemandedInstructionBits(I)) return &I; if (Value *V = SimplifyBSwap(I)) return ReplaceInstUsesWith(I, V); // Is this a ~ operation? if (Value *NotOp = dyn_castNotVal(&I)) { if (BinaryOperator *Op0I = dyn_cast(NotOp)) { if (Op0I->getOpcode() == Instruction::And || Op0I->getOpcode() == Instruction::Or) { // ~(~X & Y) --> (X | ~Y) - De Morgan's Law // ~(~X | Y) === (X & ~Y) - De Morgan's Law if (dyn_castNotVal(Op0I->getOperand(1))) Op0I->swapOperands(); if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0))) { Value *NotY = Builder->CreateNot(Op0I->getOperand(1), Op0I->getOperand(1)->getName()+".not"); if (Op0I->getOpcode() == Instruction::And) return BinaryOperator::CreateOr(Op0NotVal, NotY); return BinaryOperator::CreateAnd(Op0NotVal, NotY); } // ~(X & Y) --> (~X | ~Y) - De Morgan's Law // ~(X | Y) === (~X & ~Y) - De Morgan's Law if (IsFreeToInvert(Op0I->getOperand(0), Op0I->getOperand(0)->hasOneUse()) && IsFreeToInvert(Op0I->getOperand(1), Op0I->getOperand(1)->hasOneUse())) { Value *NotX = Builder->CreateNot(Op0I->getOperand(0), "notlhs"); Value *NotY = Builder->CreateNot(Op0I->getOperand(1), "notrhs"); if (Op0I->getOpcode() == Instruction::And) return BinaryOperator::CreateOr(NotX, NotY); return BinaryOperator::CreateAnd(NotX, NotY); } } else if (Op0I->getOpcode() == Instruction::AShr) { // ~(~X >>s Y) --> (X >>s Y) if (Value *Op0NotVal = dyn_castNotVal(Op0I->getOperand(0))) return BinaryOperator::CreateAShr(Op0NotVal, Op0I->getOperand(1)); } } } if (Constant *RHS = dyn_cast(Op1)) { if (RHS->isAllOnesValue() && Op0->hasOneUse()) // xor (cmp A, B), true = not (cmp A, B) = !cmp A, B if (CmpInst *CI = dyn_cast(Op0)) return CmpInst::Create(CI->getOpcode(), CI->getInversePredicate(), CI->getOperand(0), CI->getOperand(1)); } if (ConstantInt *RHS = dyn_cast(Op1)) { // fold (xor(zext(cmp)), 1) and (xor(sext(cmp)), -1) to ext(!cmp). if (CastInst *Op0C = dyn_cast(Op0)) { if (CmpInst *CI = dyn_cast(Op0C->getOperand(0))) { if (CI->hasOneUse() && Op0C->hasOneUse()) { Instruction::CastOps Opcode = Op0C->getOpcode(); if ((Opcode == Instruction::ZExt || Opcode == Instruction::SExt) && (RHS == ConstantExpr::getCast(Opcode, Builder->getTrue(), Op0C->getDestTy()))) { CI->setPredicate(CI->getInversePredicate()); return CastInst::Create(Opcode, CI, Op0C->getType()); } } } } if (BinaryOperator *Op0I = dyn_cast(Op0)) { // ~(c-X) == X-c-1 == X+(-c-1) if (Op0I->getOpcode() == Instruction::Sub && RHS->isAllOnesValue()) if (Constant *Op0I0C = dyn_cast(Op0I->getOperand(0))) { Constant *NegOp0I0C = ConstantExpr::getNeg(Op0I0C); Constant *ConstantRHS = ConstantExpr::getSub(NegOp0I0C, ConstantInt::get(I.getType(), 1)); return BinaryOperator::CreateAdd(Op0I->getOperand(1), ConstantRHS); } if (ConstantInt *Op0CI = dyn_cast(Op0I->getOperand(1))) { if (Op0I->getOpcode() == Instruction::Add) { // ~(X-c) --> (-c-1)-X if (RHS->isAllOnesValue()) { Constant *NegOp0CI = ConstantExpr::getNeg(Op0CI); return BinaryOperator::CreateSub( ConstantExpr::getSub(NegOp0CI, ConstantInt::get(I.getType(), 1)), Op0I->getOperand(0)); } else if (RHS->getValue().isSignBit()) { // (X + C) ^ signbit -> (X + C + signbit) Constant *C = Builder->getInt(RHS->getValue() + Op0CI->getValue()); return BinaryOperator::CreateAdd(Op0I->getOperand(0), C); } } else if (Op0I->getOpcode() == Instruction::Or) { // (X|C1)^C2 -> X^(C1|C2) iff X&~C1 == 0 if (MaskedValueIsZero(Op0I->getOperand(0), Op0CI->getValue(), 0, &I)) { Constant *NewRHS = ConstantExpr::getOr(Op0CI, RHS); // Anything in both C1 and C2 is known to be zero, remove it from // NewRHS. Constant *CommonBits = ConstantExpr::getAnd(Op0CI, RHS); NewRHS = ConstantExpr::getAnd(NewRHS, ConstantExpr::getNot(CommonBits)); Worklist.Add(Op0I); I.setOperand(0, Op0I->getOperand(0)); I.setOperand(1, NewRHS); return &I; } } else if (Op0I->getOpcode() == Instruction::LShr) { // ((X^C1) >> C2) ^ C3 -> (X>>C2) ^ ((C1>>C2)^C3) // E1 = "X ^ C1" BinaryOperator *E1; ConstantInt *C1; if (Op0I->hasOneUse() && (E1 = dyn_cast(Op0I->getOperand(0))) && E1->getOpcode() == Instruction::Xor && (C1 = dyn_cast(E1->getOperand(1)))) { // fold (C1 >> C2) ^ C3 ConstantInt *C2 = Op0CI, *C3 = RHS; APInt FoldConst = C1->getValue().lshr(C2->getValue()); FoldConst ^= C3->getValue(); // Prepare the two operands. Value *Opnd0 = Builder->CreateLShr(E1->getOperand(0), C2); Opnd0->takeName(Op0I); cast(Opnd0)->setDebugLoc(I.getDebugLoc()); Value *FoldVal = ConstantInt::get(Opnd0->getType(), FoldConst); return BinaryOperator::CreateXor(Opnd0, FoldVal); } } } } // Try to fold constant and into select arguments. if (SelectInst *SI = dyn_cast(Op0)) if (Instruction *R = FoldOpIntoSelect(I, SI)) return R; if (isa(Op0)) if (Instruction *NV = FoldOpIntoPhi(I)) return NV; } BinaryOperator *Op1I = dyn_cast(Op1); if (Op1I) { Value *A, *B; if (match(Op1I, m_Or(m_Value(A), m_Value(B)))) { if (A == Op0) { // B^(B|A) == (A|B)^B Op1I->swapOperands(); I.swapOperands(); std::swap(Op0, Op1); } else if (B == Op0) { // B^(A|B) == (A|B)^B I.swapOperands(); // Simplified below. std::swap(Op0, Op1); } } else if (match(Op1I, m_And(m_Value(A), m_Value(B))) && Op1I->hasOneUse()){ if (A == Op0) { // A^(A&B) -> A^(B&A) Op1I->swapOperands(); std::swap(A, B); } if (B == Op0) { // A^(B&A) -> (B&A)^A I.swapOperands(); // Simplified below. std::swap(Op0, Op1); } } } BinaryOperator *Op0I = dyn_cast(Op0); if (Op0I) { Value *A, *B; if (match(Op0I, m_Or(m_Value(A), m_Value(B))) && Op0I->hasOneUse()) { if (A == Op1) // (B|A)^B == (A|B)^B std::swap(A, B); if (B == Op1) // (A|B)^B == A & ~B return BinaryOperator::CreateAnd(A, Builder->CreateNot(Op1)); } else if (match(Op0I, m_And(m_Value(A), m_Value(B))) && Op0I->hasOneUse()){ if (A == Op1) // (A&B)^A -> (B&A)^A std::swap(A, B); if (B == Op1 && // (B&A)^A == ~B & A !isa(Op1)) { // Canonical form is (B&C)^C return BinaryOperator::CreateAnd(Builder->CreateNot(A), Op1); } } } if (Op0I && Op1I) { Value *A, *B, *C, *D; // (A & B)^(A | B) -> A ^ B if (match(Op0I, m_And(m_Value(A), m_Value(B))) && match(Op1I, m_Or(m_Value(C), m_Value(D)))) { if ((A == C && B == D) || (A == D && B == C)) return BinaryOperator::CreateXor(A, B); } // (A | B)^(A & B) -> A ^ B if (match(Op0I, m_Or(m_Value(A), m_Value(B))) && match(Op1I, m_And(m_Value(C), m_Value(D)))) { if ((A == C && B == D) || (A == D && B == C)) return BinaryOperator::CreateXor(A, B); } // (A | ~B) ^ (~A | B) -> A ^ B if (match(Op0I, m_Or(m_Value(A), m_Not(m_Value(B)))) && match(Op1I, m_Or(m_Not(m_Specific(A)), m_Specific(B)))) { return BinaryOperator::CreateXor(A, B); } // (~A | B) ^ (A | ~B) -> A ^ B if (match(Op0I, m_Or(m_Not(m_Value(A)), m_Value(B))) && match(Op1I, m_Or(m_Specific(A), m_Not(m_Specific(B))))) { return BinaryOperator::CreateXor(A, B); } // (A & ~B) ^ (~A & B) -> A ^ B if (match(Op0I, m_And(m_Value(A), m_Not(m_Value(B)))) && match(Op1I, m_And(m_Not(m_Specific(A)), m_Specific(B)))) { return BinaryOperator::CreateXor(A, B); } // (~A & B) ^ (A & ~B) -> A ^ B if (match(Op0I, m_And(m_Not(m_Value(A)), m_Value(B))) && match(Op1I, m_And(m_Specific(A), m_Not(m_Specific(B))))) { return BinaryOperator::CreateXor(A, B); } // (A ^ C)^(A | B) -> ((~A) & B) ^ C if (match(Op0I, m_Xor(m_Value(D), m_Value(C))) && match(Op1I, m_Or(m_Value(A), m_Value(B)))) { if (D == A) return BinaryOperator::CreateXor( Builder->CreateAnd(Builder->CreateNot(A), B), C); if (D == B) return BinaryOperator::CreateXor( Builder->CreateAnd(Builder->CreateNot(B), A), C); } // (A | B)^(A ^ C) -> ((~A) & B) ^ C if (match(Op0I, m_Or(m_Value(A), m_Value(B))) && match(Op1I, m_Xor(m_Value(D), m_Value(C)))) { if (D == A) return BinaryOperator::CreateXor( Builder->CreateAnd(Builder->CreateNot(A), B), C); if (D == B) return BinaryOperator::CreateXor( Builder->CreateAnd(Builder->CreateNot(B), A), C); } // (A & B) ^ (A ^ B) -> (A | B) if (match(Op0I, m_And(m_Value(A), m_Value(B))) && match(Op1I, m_Xor(m_Specific(A), m_Specific(B)))) return BinaryOperator::CreateOr(A, B); // (A ^ B) ^ (A & B) -> (A | B) if (match(Op0I, m_Xor(m_Value(A), m_Value(B))) && match(Op1I, m_And(m_Specific(A), m_Specific(B)))) return BinaryOperator::CreateOr(A, B); } Value *A = nullptr, *B = nullptr; // (A & ~B) ^ (~A) -> ~(A & B) if (match(Op0, m_And(m_Value(A), m_Not(m_Value(B)))) && match(Op1, m_Not(m_Specific(A)))) return BinaryOperator::CreateNot(Builder->CreateAnd(A, B)); // (icmp1 A, B) ^ (icmp2 A, B) --> (icmp3 A, B) if (ICmpInst *RHS = dyn_cast(I.getOperand(1))) if (ICmpInst *LHS = dyn_cast(I.getOperand(0))) if (PredicatesFoldable(LHS->getPredicate(), RHS->getPredicate())) { if (LHS->getOperand(0) == RHS->getOperand(1) && LHS->getOperand(1) == RHS->getOperand(0)) LHS->swapOperands(); if (LHS->getOperand(0) == RHS->getOperand(0) && LHS->getOperand(1) == RHS->getOperand(1)) { Value *Op0 = LHS->getOperand(0), *Op1 = LHS->getOperand(1); unsigned Code = getICmpCode(LHS) ^ getICmpCode(RHS); bool isSigned = LHS->isSigned() || RHS->isSigned(); return ReplaceInstUsesWith(I, getNewICmpValue(isSigned, Code, Op0, Op1, Builder)); } } // fold (xor (cast A), (cast B)) -> (cast (xor A, B)) if (CastInst *Op0C = dyn_cast(Op0)) { if (CastInst *Op1C = dyn_cast(Op1)) if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind? Type *SrcTy = Op0C->getOperand(0)->getType(); if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isIntegerTy() && // Only do this if the casts both really cause code to be generated. ShouldOptimizeCast(Op0C->getOpcode(), Op0C->getOperand(0), I.getType()) && ShouldOptimizeCast(Op1C->getOpcode(), Op1C->getOperand(0), I.getType())) { Value *NewOp = Builder->CreateXor(Op0C->getOperand(0), Op1C->getOperand(0), I.getName()); return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType()); } } } return Changed ? &I : nullptr; }