| //===- 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 "InstCombine.h" |
| #include "llvm/Intrinsics.h" |
| #include "llvm/Analysis/InstructionSimplify.h" |
| #include "llvm/Support/ConstantRange.h" |
| #include "llvm/Support/PatternMatch.h" |
| using namespace llvm; |
| using namespace PatternMatch; |
| |
| |
| /// AddOne - Add one to a ConstantInt. |
| static Constant *AddOne(Constant *C) { |
| return ConstantExpr::getAdd(C, ConstantInt::get(C->getType(), 1)); |
| } |
| /// SubOne - Subtract one from a ConstantInt. |
| static Constant *SubOne(ConstantInt *C) { |
| return ConstantInt::get(C->getContext(), C->getValue()-1); |
| } |
| |
| /// isFreeToInvert - Return true if the specified value is free to invert (apply |
| /// ~ to). This happens in cases where the ~ can be eliminated. |
| static inline bool isFreeToInvert(Value *V) { |
| // ~(~(X)) -> X. |
| if (BinaryOperator::isNot(V)) |
| return true; |
| |
| // Constants can be considered to be not'ed values. |
| if (isa<ConstantInt>(V)) |
| return true; |
| |
| // Compares can be inverted if they have a single use. |
| if (CmpInst *CI = dyn_cast<CmpInst>(V)) |
| return CI->hasOneUse(); |
| |
| return false; |
| } |
| |
| 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)) |
| return Operand; |
| } |
| |
| // Constants can be considered to be not'ed values... |
| if (ConstantInt *C = dyn_cast<ConstantInt>(V)) |
| return ConstantInt::get(C->getType(), ~C->getValue()); |
| return 0; |
| } |
| |
| |
| /// getICmpCode - Encode a icmp predicate into a three bit mask. These bits |
| /// are carefully arranged to allow folding of expressions such as: |
| /// |
| /// (A < B) | (A > B) --> (A != B) |
| /// |
| /// Note that this is only valid if the first and second predicates have the |
| /// same sign. Is illegal to do: (A u< B) | (A s> B) |
| /// |
| /// Three bits are used to represent the condition, as follows: |
| /// 0 A > B |
| /// 1 A == B |
| /// 2 A < B |
| /// |
| /// <=> Value Definition |
| /// 000 0 Always false |
| /// 001 1 A > B |
| /// 010 2 A == B |
| /// 011 3 A >= B |
| /// 100 4 A < B |
| /// 101 5 A != B |
| /// 110 6 A <= B |
| /// 111 7 Always true |
| /// |
| static unsigned getICmpCode(const ICmpInst *ICI) { |
| switch (ICI->getPredicate()) { |
| // False -> 0 |
| case ICmpInst::ICMP_UGT: return 1; // 001 |
| case ICmpInst::ICMP_SGT: return 1; // 001 |
| case ICmpInst::ICMP_EQ: return 2; // 010 |
| case ICmpInst::ICMP_UGE: return 3; // 011 |
| case ICmpInst::ICMP_SGE: return 3; // 011 |
| case ICmpInst::ICMP_ULT: return 4; // 100 |
| case ICmpInst::ICMP_SLT: return 4; // 100 |
| case ICmpInst::ICMP_NE: return 5; // 101 |
| case ICmpInst::ICMP_ULE: return 6; // 110 |
| case ICmpInst::ICMP_SLE: return 6; // 110 |
| // True -> 7 |
| default: |
| llvm_unreachable("Invalid ICmp predicate!"); |
| return 0; |
| } |
| } |
| |
| /// getFCmpCode - 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!"); |
| return 0; |
| } |
| } |
| |
| /// getICmpValue - 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 *getICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS, |
| InstCombiner::BuilderTy *Builder) { |
| CmpInst::Predicate Pred; |
| switch (Code) { |
| default: assert(0 && "Illegal ICmp code!"); |
| case 0: // False. |
| return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0); |
| case 1: Pred = Sign ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT; break; |
| case 2: Pred = ICmpInst::ICMP_EQ; break; |
| case 3: Pred = Sign ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE; break; |
| case 4: Pred = Sign ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT; break; |
| case 5: Pred = ICmpInst::ICMP_NE; break; |
| case 6: Pred = Sign ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE; break; |
| case 7: // True. |
| return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1); |
| } |
| return Builder->CreateICmp(Pred, LHS, RHS); |
| } |
| |
| /// getFCmpValue - 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: assert(0 && "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::getTrue(LHS->getContext()); |
| Pred = FCmpInst::FCMP_ORD; break; |
| } |
| return Builder->CreateFCmp(Pred, LHS, RHS); |
| } |
| |
| /// PredicatesFoldable - Return true if both predicates match sign or if at |
| /// least one of them is an equality comparison (which is signless). |
| static bool PredicatesFoldable(ICmpInst::Predicate p1, ICmpInst::Predicate p2) { |
| return (CmpInst::isSigned(p1) == CmpInst::isSigned(p2)) || |
| (CmpInst::isSigned(p1) && ICmpInst::isEquality(p2)) || |
| (CmpInst::isSigned(p2) && ICmpInst::isEquality(p1)); |
| } |
| |
| // OptAndOp - 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 = 0; |
| 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<ConstantInt>(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 = cast<ConstantInt>(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 = cast<ConstantInt>(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 = ConstantInt::get(AndRHS->getContext(), |
| 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 = ConstantInt::get(Op->getContext(), |
| 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 = ConstantInt::get(Op->getContext(), |
| 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 0; |
| } |
| |
| |
| /// InsertRangeTest - 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) <u Hi-Lo. This method expects that Lo <= Hi. isSigned indicates |
| /// whether to treat the V, Lo and HI as signed or not. IB is the location to |
| /// insert new instructions. |
| Value *InstCombiner::InsertRangeTest(Value *V, Constant *Lo, Constant *Hi, |
| bool isSigned, bool Inside) { |
| assert(cast<ConstantInt>(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 ConstantInt::getFalse(V->getContext()); |
| |
| // V >= Min && V < Hi --> V < Hi |
| if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) { |
| ICmpInst::Predicate pred = (isSigned ? |
| ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT); |
| return Builder->CreateICmp(pred, V, Hi); |
| } |
| |
| // Emit V-Lo <u Hi-Lo |
| Constant *NegLo = ConstantExpr::getNeg(Lo); |
| Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off"); |
| Constant *UpperBound = ConstantExpr::getAdd(NegLo, Hi); |
| return Builder->CreateICmpULT(Add, UpperBound); |
| } |
| |
| if (Lo == Hi) // Trivially true. |
| return ConstantInt::getTrue(V->getContext()); |
| |
| // V < Min || V >= Hi -> V > Hi-1 |
| Hi = SubOne(cast<ConstantInt>(Hi)); |
| if (cast<ConstantInt>(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<ConstantInt>(ConstantExpr::getNeg(Lo)); |
| Value *Add = Builder->CreateAdd(V, NegLo, V->getName()+".off"); |
| Constant *LowerBound = ConstantExpr::getAdd(NegLo, Hi); |
| return Builder->CreateICmpUGT(Add, LowerBound); |
| } |
| |
| // isRunOfOnes - 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; |
| } |
| |
| /// FoldLogicalPlusAnd - 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<Instruction>(LHS); |
| if (!LHSI || LHSI->getNumOperands() != 2 || |
| !isa<ConstantInt>(LHSI->getOperand(1))) return 0; |
| |
| ConstantInt *N = cast<ConstantInt>(LHSI->getOperand(1)); |
| |
| switch (LHSI->getOpcode()) { |
| default: return 0; |
| 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<IntegerType>(RHS->getType())->getBitWidth(); |
| APInt Mask(APInt::getLowBitsSet(BitWidth, MB-1)); |
| if (MaskedValueIsZero(RHS, Mask)) |
| break; |
| } |
| } |
| return 0; |
| 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 0; |
| } |
| |
| 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<ConstantInt>(A); |
| ConstantInt *BCst = dyn_cast<ConstantInt>(B); |
| ConstantInt *CCst = dyn_cast<ConstantInt>(C); |
| bool icmp_eq = (SCC == ICmpInst::ICMP_EQ); |
| bool icmp_abit = (ACst != 0 && !ACst->isZero() && |
| ACst->getValue().isPowerOf2()); |
| bool icmp_bbit = (BCst != 0 && !BCst->isZero() && |
| BCst->getValue().isPowerOf2()); |
| unsigned result = 0; |
| if (CCst != 0 && 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 != 0 && CCst != 0 && |
| 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 != 0 && CCst != 0 && |
| ConstantExpr::getAnd(BCst, CCst) == CCst) { |
| result |= (icmp_eq ? FoldMskICmp_BMask_Mixed |
| : FoldMskICmp_BMask_NotMixed); |
| } |
| return result; |
| } |
| |
| /// foldLogOpOfMaskedICmpsHelper: |
| /// 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 = LHS->getPredicate(), RHSCC = RHS->getPredicate(); |
| if (LHSCC != ICmpInst::ICMP_EQ && LHSCC != ICmpInst::ICMP_NE) return 0; |
| if (RHSCC != ICmpInst::ICMP_EQ && RHSCC != ICmpInst::ICMP_NE) return 0; |
| 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; |
| if (match(L1, m_And(m_Value(L11), m_Value(L12)))) { |
| if (!match(L2, m_And(m_Value(L21), m_Value(L22)))) |
| L21 = L22 = 0; |
| } |
| else { |
| if (!match(L2, m_And(m_Value(L11), m_Value(L12)))) |
| return 0; |
| std::swap(L1, L2); |
| L21 = L22 = 0; |
| } |
| |
| Value *R1 = RHS->getOperand(0); |
| Value *R2 = RHS->getOperand(1); |
| Value *R11,*R12; |
| bool ok = false; |
| if (match(R1, m_And(m_Value(R11), m_Value(R12)))) { |
| if (R11 != 0 && (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22)) { |
| A = R11; D = R12; E = R2; ok = true; |
| } |
| else |
| if (R12 != 0 && (R12 == L11 || R12 == L12 || R12 == L21 || R12 == L22)) { |
| A = R12; D = R11; E = R2; ok = true; |
| } |
| } |
| if (!ok && match(R2, m_And(m_Value(R11), m_Value(R12)))) { |
| if (R11 != 0 && (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22)) { |
| A = R11; D = R12; E = R1; ok = true; |
| } |
| else |
| if (R12 != 0 && (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; |
| } |
| /// foldLogOpOfMaskedICmps: |
| /// 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, |
| ICmpInst::Predicate NEWCC, |
| llvm::InstCombiner::BuilderTy* Builder) { |
| Value *A = 0, *B = 0, *C = 0, *D = 0, *E = 0; |
| unsigned mask = foldLogOpOfMaskedICmpsHelper(A, B, C, D, E, LHS, RHS); |
| if (mask == 0) return 0; |
| |
| if (NEWCC == ICmpInst::ICMP_NE) |
| mask >>= 1; // treat "Not"-states as normal states |
| |
| 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); |
| } |
| else 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); |
| } |
| else 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); |
| } |
| else 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. |
| ConstantInt *BCst = dyn_cast<ConstantInt>(B); |
| if (BCst == 0) return 0; |
| ConstantInt *DCst = dyn_cast<ConstantInt>(D); |
| if (DCst == 0) return 0; |
| // 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<ConstantInt>(C); |
| if (CCst == 0) return 0; |
| if (LHS->getPredicate() != NEWCC) |
| CCst = dyn_cast<ConstantInt>( ConstantExpr::getXor(BCst, CCst) ); |
| ConstantInt *ECst = dyn_cast<ConstantInt>(E); |
| if (ECst == 0) return 0; |
| if (RHS->getPredicate() != NEWCC) |
| ECst = dyn_cast<ConstantInt>( ConstantExpr::getXor(DCst, ECst) ); |
| ConstantInt* MCst = dyn_cast<ConstantInt>( |
| ConstantExpr::getAnd(ConstantExpr::getAnd(BCst, DCst), |
| ConstantExpr::getXor(CCst, ECst)) ); |
| // if there is a conflict we should actually return a false for the |
| // whole construct |
| if (!MCst->isZero()) |
| return 0; |
| 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 0; |
| } |
| |
| /// FoldAndOfICmps - 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 getICmpValue(isSigned, Code, Op0, Op1, Builder); |
| } |
| } |
| |
| // handle (roughly): (icmp eq (A & B), C) & (icmp eq (A & D), E) |
| if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, ICmpInst::ICMP_EQ, Builder)) |
| 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<ConstantInt>(LHS->getOperand(1)); |
| ConstantInt *RHSCst = dyn_cast<ConstantInt>(RHS->getOperand(1)); |
| if (LHSCst == 0 || RHSCst == 0) return 0; |
| |
| 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); |
| } |
| |
| // (icmp slt A, 0) & (icmp slt B, 0) --> (icmp slt (A&B), 0) |
| if (LHSCC == ICmpInst::ICMP_SLT && LHSCst->isZero()) { |
| Value *NewAnd = Builder->CreateAnd(Val, Val2); |
| return Builder->CreateICmp(LHSCC, NewAnd, LHSCst); |
| } |
| |
| // (icmp sgt A, -1) & (icmp sgt B, -1) --> (icmp sgt (A|B), -1) |
| if (LHSCC == ICmpInst::ICMP_SGT && LHSCst->isAllOnesValue()) { |
| 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 == RHSCC && ICmpInst::isEquality(LHSCC) && |
| LHS->hasOneUse() && RHS->hasOneUse()) { |
| Value *V; |
| ConstantInt *AndCst, *SmallCst = 0, *BigCst = 0; |
| |
| // (trunc x) == C1 & (and x, CA) == C2 |
| if (match(Val2, m_Trunc(m_Value(V))) && |
| match(Val, m_And(m_Specific(V), m_ConstantInt(AndCst)))) { |
| SmallCst = RHSCst; |
| BigCst = LHSCst; |
| } |
| // (and x, CA) == C2 & (trunc x) == C1 |
| 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 0; |
| |
| // 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 0; |
| |
| // 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::makeICmpRegion(LHSCC, LHSCst->getValue()); |
| ConstantRange RHSRange = |
| ConstantRange::makeICmpRegion(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 0; |
| |
| // 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); |
| 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: |
| 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)); |
| } |
| 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) <u 1 |
| return InsertRangeTest(Val, AddOne(LHSCst), RHSCst, false, true); |
| 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 == 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 0; |
| } |
| |
| /// FoldAndOfFCmps - 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) { |
| // (fcmp ord x, c) & (fcmp ord y, c) -> (fcmp ord x, y) |
| if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1))) |
| if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) { |
| // If either of the constants are nans, then the whole thing returns |
| // false. |
| if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN()) |
| return ConstantInt::getFalse(LHS->getContext()); |
| 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<ConstantAggregateZero>(LHS->getOperand(1)) && |
| isa<ConstantAggregateZero>(RHS->getOperand(1))) |
| return Builder->CreateFCmpORD(LHS->getOperand(0), RHS->getOperand(0)); |
| return 0; |
| } |
| |
| 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); |
| if (Op1Pred == 0) { |
| std::swap(LHS, RHS); |
| std::swap(Op0Pred, Op1Pred); |
| std::swap(Op0Ordered, Op1Ordered); |
| } |
| if (Op0Pred == 0) { |
| // uno && ueq -> uno && (uno || eq) -> ueq |
| // ord && olt -> ord && (ord && lt) -> olt |
| if (Op0Ordered == Op1Ordered) |
| return RHS; |
| |
| // uno && oeq -> uno && (ord && eq) -> false |
| // uno && ord -> 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 0; |
| } |
| |
| |
| Instruction *InstCombiner::visitAnd(BinaryOperator &I) { |
| bool Changed = SimplifyAssociativeOrCommutative(I); |
| Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); |
| |
| if (Value *V = SimplifyAndInst(Op0, Op1, TD)) |
| 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 (ConstantInt *AndRHS = dyn_cast<ConstantInt>(Op1)) { |
| const APInt &AndRHSMask = AndRHS->getValue(); |
| |
| // Optimize a variety of ((val OP C1) & C2) combinations... |
| if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(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)) { |
| // 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<Constant>(Op0RHS) && |
| MaskedValueIsZero(Op0RHS, NotAndRHS)) { |
| // 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); |
| |
| // (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)) { |
| 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<ConstantInt>(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 = 0; ConstantInt *YC = 0; |
| 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<SelectInst>(Op0)) |
| if (Instruction *R = FoldOpIntoSelect(I, SI)) |
| return R; |
| if (isa<PHINode>(Op0)) |
| if (Instruction *NV = FoldOpIntoPhi(I)) |
| return NV; |
| } |
| |
| |
| // (~A & ~B) == (~(A | B)) - De Morgan's Law |
| if (Value *Op0NotVal = dyn_castNotVal(Op0)) |
| if (Value *Op1NotVal = dyn_castNotVal(Op1)) |
| if (Op0->hasOneUse() && Op1->hasOneUse()) { |
| Value *Or = Builder->CreateOr(Op0NotVal, Op1NotVal, |
| I.getName()+".demorgan"); |
| return BinaryOperator::CreateNot(Or); |
| } |
| |
| { |
| Value *A = 0, *B = 0, *C = 0, *D = 0; |
| // (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); |
| |
| if (Op0->hasOneUse() && |
| match(Op0, m_Xor(m_Value(A), m_Value(B)))) { |
| if (A == Op1) { // (A^B)&A -> A&(A^B) |
| I.swapOperands(); // Simplify below |
| std::swap(Op0, Op1); |
| } else if (B == Op1) { // (A^B)&B -> B&(B^A) |
| cast<BinaryOperator>(Op0)->swapOperands(); |
| I.swapOperands(); // Simplify below |
| std::swap(Op0, Op1); |
| } |
| } |
| |
| if (Op1->hasOneUse() && |
| match(Op1, m_Xor(m_Value(A), m_Value(B)))) { |
| if (B == Op0) { // B&(A^B) -> B&(B^A) |
| cast<BinaryOperator>(Op1)->swapOperands(); |
| 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 == Op0 && !isa<Constant>(A)) // A&(A^B) -> A & ~B |
| return BinaryOperator::CreateAnd(A, Builder->CreateNot(B, "tmp")); |
| } |
| |
| // (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); |
| } |
| |
| if (ICmpInst *RHS = dyn_cast<ICmpInst>(Op1)) |
| if (ICmpInst *LHS = dyn_cast<ICmpInst>(Op0)) |
| if (Value *Res = FoldAndOfICmps(LHS, RHS)) |
| return ReplaceInstUsesWith(I, Res); |
| |
| // If and'ing two fcmp, try combine them into one. |
| if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0))) |
| if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1))) |
| if (Value *Res = FoldAndOfFCmps(LHS, RHS)) |
| return ReplaceInstUsesWith(I, Res); |
| |
| |
| // fold (and (cast A), (cast B)) -> (cast (and A, B)) |
| if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) |
| if (CastInst *Op1C = dyn_cast<CastInst>(Op1)) { |
| const Type *SrcTy = Op0C->getOperand(0)->getType(); |
| if (Op0C->getOpcode() == Op1C->getOpcode() && // same cast kind ? |
| SrcTy == Op1C->getOperand(0)->getType() && |
| SrcTy->isIntOrIntVectorTy()) { |
| Value *Op0COp = Op0C->getOperand(0), *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<ICmpInst>(Op1COp)) |
| if (ICmpInst *LHS = dyn_cast<ICmpInst>(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<FCmpInst>(Op1COp)) |
| if (FCmpInst *LHS = dyn_cast<FCmpInst>(Op0COp)) |
| if (Value *Res = FoldAndOfFCmps(LHS, RHS)) |
| return CastInst::Create(Op0C->getOpcode(), Res, I.getType()); |
| } |
| } |
| |
| // (X >> Z) & (Y >> Z) -> (X&Y) >> Z for all shifts. |
| if (BinaryOperator *SI1 = dyn_cast<BinaryOperator>(Op1)) { |
| if (BinaryOperator *SI0 = dyn_cast<BinaryOperator>(Op0)) |
| if (SI0->isShift() && SI0->getOpcode() == SI1->getOpcode() && |
| SI0->getOperand(1) == SI1->getOperand(1) && |
| (SI0->hasOneUse() || SI1->hasOneUse())) { |
| Value *NewOp = |
| Builder->CreateAnd(SI0->getOperand(0), SI1->getOperand(0), |
| SI0->getName()); |
| return BinaryOperator::Create(SI1->getOpcode(), NewOp, |
| SI1->getOperand(1)); |
| } |
| } |
| |
| return Changed ? &I : 0; |
| } |
| |
| /// CollectBSwapParts - Analyze the specified subexpression and see if it is |
| /// capable of providing pieces of a bswap. The subexpression provides pieces |
| /// of a bswap if it is proven that each of the non-zero bytes in the output of |
| /// the expression came from the corresponding "byte swapped" byte in some other |
| /// value. For example, if the current subexpression is "(shl i32 %X, 24)" then |
| /// we know that the expression deposits the low byte of %X into the high byte |
| /// of the bswap result and that all other bytes are zero. This expression is |
| /// accepted, the high byte of ByteValues is set to X to indicate a correct |
| /// match. |
| /// |
| /// 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 bytes that the subexpression is later shifted. For |
| /// example, if the expression is later right shifted by 16 bits, the |
| /// OverallLeftShift value would be -2 on entry. This is used to specify which |
| /// byte of ByteValues is actually being set. |
| /// |
| /// Similarly, ByteMask is a bitmask where a bit is clear if its corresponding |
| /// byte is masked to zero by a user. For example, in (X & 255), X will be |
| /// processed with a bytemask of 1. Because bytemask is 32-bits, this limits |
| /// this function to working on up to 32-byte (256 bit) values. ByteMask is |
| /// always in the local (OverallLeftShift) coordinate space. |
| /// |
| static bool CollectBSwapParts(Value *V, int OverallLeftShift, uint32_t ByteMask, |
| SmallVector<Value*, 8> &ByteValues) { |
| if (Instruction *I = dyn_cast<Instruction>(V)) { |
| // If this is an or instruction, it may be an inner node of the bswap. |
| if (I->getOpcode() == Instruction::Or) { |
| return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask, |
| ByteValues) || |
| CollectBSwapParts(I->getOperand(1), OverallLeftShift, ByteMask, |
| ByteValues); |
| } |
| |
| // If this is a logical shift by a constant multiple of 8, recurse with |
| // OverallLeftShift and ByteMask adjusted. |
| if (I->isLogicalShift() && isa<ConstantInt>(I->getOperand(1))) { |
| unsigned ShAmt = |
| cast<ConstantInt>(I->getOperand(1))->getLimitedValue(~0U); |
| // Ensure the shift amount is defined and of a byte value. |
| if ((ShAmt & 7) || (ShAmt > 8*ByteValues.size())) |
| return true; |
| |
| unsigned ByteShift = ShAmt >> 3; |
| if (I->getOpcode() == Instruction::Shl) { |
| // X << 2 -> collect(X, +2) |
| OverallLeftShift += ByteShift; |
| ByteMask >>= ByteShift; |
| } else { |
| // X >>u 2 -> collect(X, -2) |
| OverallLeftShift -= ByteShift; |
| ByteMask <<= ByteShift; |
| ByteMask &= (~0U >> (32-ByteValues.size())); |
| } |
| |
| if (OverallLeftShift >= (int)ByteValues.size()) return true; |
| if (OverallLeftShift <= -(int)ByteValues.size()) return true; |
| |
| return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask, |
| ByteValues); |
| } |
| |
| // If this is a logical 'and' with a mask that clears bytes, clear the |
| // corresponding bytes in ByteMask. |
| if (I->getOpcode() == Instruction::And && |
| isa<ConstantInt>(I->getOperand(1))) { |
| // Scan every byte of the and mask, seeing if the byte is either 0 or 255. |
| unsigned NumBytes = ByteValues.size(); |
| APInt Byte(I->getType()->getPrimitiveSizeInBits(), 255); |
| const APInt &AndMask = cast<ConstantInt>(I->getOperand(1))->getValue(); |
| |
| for (unsigned i = 0; i != NumBytes; ++i, Byte <<= 8) { |
| // If this byte is masked out by a later operation, we don't care what |
| // the and mask is. |
| if ((ByteMask & (1 << i)) == 0) |
| continue; |
| |
| // If the AndMask is all zeros for this byte, clear the bit. |
| APInt MaskB = AndMask & Byte; |
| if (MaskB == 0) { |
| ByteMask &= ~(1U << i); |
| continue; |
| } |
| |
| // If the AndMask is not all ones for this byte, it's not a bytezap. |
| if (MaskB != Byte) |
| return true; |
| |
| // Otherwise, this byte is kept. |
| } |
| |
| return CollectBSwapParts(I->getOperand(0), OverallLeftShift, ByteMask, |
| ByteValues); |
| } |
| } |
| |
| // Okay, we got to something that isn't a shift, 'or' or 'and'. This must be |
| // the input value to the bswap. Some observations: 1) if more than one byte |
| // is demanded from this input, then it could not be successfully assembled |
| // into a byteswap. At least one of the two bytes would not be aligned with |
| // their ultimate destination. |
| if (!isPowerOf2_32(ByteMask)) return true; |
| unsigned InputByteNo = CountTrailingZeros_32(ByteMask); |
| |
| // 2) The input and ultimate destinations must line up: if byte 3 of an i32 |
| // is demanded, it needs to go into byte 0 of the result. This means that the |
| // byte needs to be shifted until it lands in the right byte bucket. The |
| // shift amount depends on the position: if the byte is coming from the high |
| // part of the value (e.g. byte 3) then it must be shifted right. If from the |
| // low part, it must be shifted left. |
| unsigned DestByteNo = InputByteNo + OverallLeftShift; |
| if (InputByteNo < ByteValues.size()/2) { |
| if (ByteValues.size()-1-DestByteNo != InputByteNo) |
| return true; |
| } else { |
| if (ByteValues.size()-1-DestByteNo != InputByteNo) |
| return true; |
| } |
| |
| // If the destination byte value is already defined, the values are or'd |
| // together, which isn't a bswap (unless it's an or of the same bits). |
| if (ByteValues[DestByteNo] && ByteValues[DestByteNo] != V) |
| return true; |
| ByteValues[DestByteNo] = V; |
| return false; |
| } |
| |
| /// MatchBSwap - Given an OR instruction, check to see if this is a bswap idiom. |
| /// If so, insert the new bswap intrinsic and return it. |
| Instruction *InstCombiner::MatchBSwap(BinaryOperator &I) { |
| const IntegerType *ITy = dyn_cast<IntegerType>(I.getType()); |
| if (!ITy || ITy->getBitWidth() % 16 || |
| // ByteMask only allows up to 32-byte values. |
| ITy->getBitWidth() > 32*8) |
| return 0; // Can only bswap pairs of bytes. Can't do vectors. |
| |
| /// ByteValues - For each byte of the result, we keep track of which value |
| /// defines each byte. |
| SmallVector<Value*, 8> ByteValues; |
| ByteValues.resize(ITy->getBitWidth()/8); |
| |
| // Try to find all the pieces corresponding to the bswap. |
| uint32_t ByteMask = ~0U >> (32-ByteValues.size()); |
| if (CollectBSwapParts(&I, 0, ByteMask, ByteValues)) |
| return 0; |
| |
| // Check to see if all of the bytes come from the same value. |
| Value *V = ByteValues[0]; |
| if (V == 0) return 0; // Didn't find a byte? Must be zero. |
| |
| // Check to make sure that all of the bytes come from the same value. |
| for (unsigned i = 1, e = ByteValues.size(); i != e; ++i) |
| if (ByteValues[i] != V) |
| return 0; |
| const Type *Tys[] = { ITy }; |
| Module *M = I.getParent()->getParent()->getParent(); |
| Function *F = Intrinsic::getDeclaration(M, Intrinsic::bswap, Tys, 1); |
| return CallInst::Create(F, V); |
| } |
| |
| /// MatchSelectFromAndOr - 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 = 0; |
| if (!match(A, m_SExt(m_Value(Cond))) || |
| !Cond->getType()->isIntegerTy(1)) |
| return 0; |
| |
| // ((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 0; |
| } |
| |
| /// FoldOrOfICmps - Fold (icmp)|(icmp) if possible. |
| Value *InstCombiner::FoldOrOfICmps(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 getICmpValue(isSigned, Code, Op0, Op1, Builder); |
| } |
| } |
| |
| // handle (roughly): |
| // (icmp ne (A & B), C) | (icmp ne (A & D), E) |
| if (Value *V = foldLogOpOfMaskedICmps(LHS, RHS, ICmpInst::ICMP_NE, Builder)) |
| 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<ConstantInt>(LHS->getOperand(1)); |
| ConstantInt *RHSCst = dyn_cast<ConstantInt>(RHS->getOperand(1)); |
| if (LHSCst == 0 || RHSCst == 0) return 0; |
| |
| 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 slt A, 0) | (icmp slt B, 0) --> (icmp slt (A|B), 0) |
| if (LHSCC == ICmpInst::ICMP_SLT && LHSCst->isZero()) { |
| Value *NewOr = Builder->CreateOr(Val, Val2); |
| return Builder->CreateICmp(LHSCC, NewOr, LHSCst); |
| } |
| |
| // (icmp sgt A, -1) | (icmp sgt B, -1) --> (icmp sgt (A&B), -1) |
| if (LHSCC == ICmpInst::ICMP_SGT && LHSCst->isAllOnesValue()) { |
| Value *NewAnd = Builder->CreateAnd(Val, Val2); |
| return Builder->CreateICmp(LHSCC, NewAnd, 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 0; |
| |
| // 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 0; |
| |
| // We can't fold (ugt x, C) | (sgt x, C2). |
| if (!PredicatesFoldable(LHSCC, RHSCC)) |
| return 0; |
| |
| // 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 (LHSCst == SubOne(RHSCst)) { |
| // (X == 13 | X == 14) -> X-13 <u 2 |
| Constant *AddCST = ConstantExpr::getNeg(LHSCst); |
| Value *Add = Builder->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 ConstantInt::getTrue(LHS->getContext()); |
| } |
| break; |
| 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 ConstantInt::getTrue(LHS->getContext()); |
| 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 ConstantInt::getTrue(LHS->getContext()); |
| case ICmpInst::ICMP_ULT: // (X s> 13 | X u< 15) -> no change |
| break; |
| } |
| break; |
| } |
| return 0; |
| } |
| |
| /// FoldOrOfFCmps - 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<ConstantFP>(LHS->getOperand(1))) |
| if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) { |
| // If either of the constants are nans, then the whole thing returns |
| // true. |
| if (LHSC->getValueAPF().isNaN() || RHSC->getValueAPF().isNaN()) |
| return ConstantInt::getTrue(LHS->getContext()); |
| |
| // 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<ConstantAggregateZero>(LHS->getOperand(1)) && |
| isa<ConstantAggregateZero>(RHS->getOperand(1))) |
| return Builder->CreateFCmpUNO(LHS->getOperand(0), RHS->getOperand(0)); |
| |
| return 0; |
| } |
| |
| 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 0; |
| } |
| |
| /// FoldOrWithConstants - 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<ConstantInt>(C); |
| if (!CI1) return 0; |
| |
| Value *V1 = 0; |
| ConstantInt *CI2 = 0; |
| if (!match(Op, m_And(m_Value(V1), m_ConstantInt(CI2)))) return 0; |
| |
| APInt Xor = CI1->getValue() ^ CI2->getValue(); |
| if (!Xor.isAllOnesValue()) return 0; |
| |
| if (V1 == A || V1 == B) { |
| Value *NewOp = Builder->CreateAnd((V1 == A) ? B : A, CI1); |
| return BinaryOperator::CreateOr(NewOp, V1); |
| } |
| |
| return 0; |
| } |
| |
| Instruction *InstCombiner::visitOr(BinaryOperator &I) { |
| bool Changed = SimplifyAssociativeOrCommutative(I); |
| Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); |
| |
| if (Value *V = SimplifyOrInst(Op0, Op1, TD)) |
| 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 (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) { |
| ConstantInt *C1 = 0; Value *X = 0; |
| // (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, |
| ConstantInt::get(I.getContext(), |
| 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, |
| ConstantInt::get(I.getContext(), |
| C1->getValue() & ~RHS->getValue())); |
| } |
| |
| // Try to fold constant and into select arguments. |
| if (SelectInst *SI = dyn_cast<SelectInst>(Op0)) |
| if (Instruction *R = FoldOpIntoSelect(I, SI)) |
| return R; |
| |
| if (isa<PHINode>(Op0)) |
| if (Instruction *NV = FoldOpIntoPhi(I)) |
| return NV; |
| } |
| |
| Value *A = 0, *B = 0; |
| ConstantInt *C1 = 0, *C2 = 0; |
| |
| // (A | B) | C and A | (B | C) -> bswap if possible. |
| // (A >> B) | (C << D) and (A << B) | (B >> C) -> bswap if possible. |
| if (match(Op0, m_Or(m_Value(), m_Value())) || |
| match(Op1, m_Or(m_Value(), m_Value())) || |
| (match(Op0, m_LogicalShift(m_Value(), m_Value())) && |
| match(Op1, m_LogicalShift(m_Value(), m_Value())))) { |
| if (Instruction *BSwap = MatchBSwap(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())) { |
| 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())) { |
| Value *NOr = Builder->CreateOr(A, Op0); |
| NOr->takeName(Op0); |
| return BinaryOperator::CreateXor(NOr, C1); |
| } |
| |
| // (A & C)|(B & D) |
| Value *C = 0, *D = 0; |
| if (match(Op0, m_And(m_Value(A), m_Value(C))) && |
| match(Op1, m_And(m_Value(B), m_Value(D)))) { |
| Value *V1 = 0, *V2 = 0; |
| C1 = dyn_cast<ConstantInt>(C); |
| C2 = dyn_cast<ConstantInt>(D); |
| if (C1 && C2) { // (A & C1)|(B & C2) |
| // If we have: ((V + N) & C1) | (V & C2) |
| // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0 |
| // replace with V+N. |
| if (C1->getValue() == ~C2->getValue()) { |
| if ((C2->getValue() & (C2->getValue()+1)) == 0 && // C2 == 0+1+ |
| match(A, m_Add(m_Value(V1), m_Value(V2)))) { |
| // Add commutes, try both ways. |
| if (V1 == B && MaskedValueIsZero(V2, C2->getValue())) |
| return ReplaceInstUsesWith(I, A); |
| if (V2 == B && MaskedValueIsZero(V1, C2->getValue())) |
| return ReplaceInstUsesWith(I, A); |
| } |
| // Or commutes, try both ways. |
| if ((C1->getValue() & (C1->getValue()+1)) == 0 && |
| match(B, m_Add(m_Value(V1), m_Value(V2)))) { |
| // Add commutes, try both ways. |
| if (V1 == A && MaskedValueIsZero(V2, C1->getValue())) |
| return ReplaceInstUsesWith(I, B); |
| if (V2 == A && MaskedValueIsZero(V1, C1->getValue())) |
| return ReplaceInstUsesWith(I, B); |
| } |
| } |
| |
| 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())) || // (V|N) |
| (V2 == B && MaskedValueIsZero(V1, ~C1->getValue())))) // (N|V) |
| return BinaryOperator::CreateAnd(A, |
| ConstantInt::get(A->getContext(), |
| 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())) || // (V|N) |
| (V2 == A && MaskedValueIsZero(V1, ~C2->getValue())))) // (N|V) |
| return BinaryOperator::CreateAnd(B, |
| ConstantInt::get(B->getContext(), |
| 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 = 0, *C4 = 0; |
| 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, |
| ConstantInt::get(B->getContext(), |
| 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; |
| } |
| } |
| |
| // (X >> Z) | (Y >> Z) -> (X|Y) >> Z for all shifts. |
| if (BinaryOperator *SI1 = dyn_cast<BinaryOperator>(Op1)) { |
| if (BinaryOperator *SI0 = dyn_cast<BinaryOperator>(Op0)) |
| if (SI0->isShift() && SI0->getOpcode() == SI1->getOpcode() && |
| SI0->getOperand(1) == SI1->getOperand(1) && |
| (SI0->hasOneUse() || SI1->hasOneUse())) { |
| Value *NewOp = Builder->CreateOr(SI0->getOperand(0), SI1->getOperand(0), |
| SI0->getName()); |
| return BinaryOperator::Create(SI1->getOpcode(), NewOp, |
| SI1->getOperand(1)); |
| } |
| } |
| |
| // (~A | ~B) == (~(A & B)) - De Morgan's Law |
| if (Value *Op0NotVal = dyn_castNotVal(Op0)) |
| if (Value *Op1NotVal = dyn_castNotVal(Op1)) |
| if (Op0->hasOneUse() && Op1->hasOneUse()) { |
| Value *And = Builder->CreateAnd(Op0NotVal, Op1NotVal, |
| I.getName()+".demorgan"); |
| return BinaryOperator::CreateNot(And); |
| } |
| |
| // Canonicalize xor to the RHS. |
| if (match(Op0, m_Xor(m_Value(), m_Value()))) |
| std::swap(Op0, Op1); |
| |
| // A | ( A ^ B) -> A | B |
| // A | (~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 (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<BinaryOperator>(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); |
| } |
| |
| if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1))) |
| if (ICmpInst *LHS = dyn_cast<ICmpInst>(I.getOperand(0))) |
| if (Value *Res = FoldOrOfICmps(LHS, RHS)) |
| return ReplaceInstUsesWith(I, Res); |
| |
| // (fcmp uno x, c) | (fcmp uno y, c) -> (fcmp uno x, y) |
| if (FCmpInst *LHS = dyn_cast<FCmpInst>(I.getOperand(0))) |
| if (FCmpInst *RHS = dyn_cast<FCmpInst>(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<CastInst>(Op0)) { |
| CastInst *Op1C = dyn_cast<CastInst>(Op1); |
| if (Op1C && Op0C->getOpcode() == Op1C->getOpcode()) {// same cast kind ? |
| const 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<ICmpInst>(Op0COp) || !isa<ICmpInst>(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<ICmpInst>(Op1COp)) |
| if (ICmpInst *LHS = dyn_cast<ICmpInst>(Op0COp)) |
| if (Value *Res = FoldOrOfICmps(LHS, RHS)) |
| 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<FCmpInst>(Op1COp)) |
| if (FCmpInst *LHS = dyn_cast<FCmpInst>(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<ConstantInt>(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); |
| } |
| |
| return Changed ? &I : 0; |
| } |
| |
| Instruction *InstCombiner::visitXor(BinaryOperator &I) { |
| bool Changed = SimplifyAssociativeOrCommutative(I); |
| Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); |
| |
| if (Value *V = SimplifyXorInst(Op0, Op1, TD)) |
| 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; |
| |
| // Is this a ~ operation? |
| if (Value *NotOp = dyn_castNotVal(&I)) { |
| if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(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)) && |
| isFreeToInvert(Op0I->getOperand(1))) { |
| 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 (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) { |
| if (RHS->isOne() && Op0->hasOneUse()) |
| // xor (cmp A, B), true = not (cmp A, B) = !cmp A, B |
| if (CmpInst *CI = dyn_cast<CmpInst>(Op0)) |
| return CmpInst::Create(CI->getOpcode(), |
| CI->getInversePredicate(), |
| CI->getOperand(0), CI->getOperand(1)); |
| |
| // fold (xor(zext(cmp)), 1) and (xor(sext(cmp)), -1) to ext(!cmp). |
| if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) { |
| if (CmpInst *CI = dyn_cast<CmpInst>(Op0C->getOperand(0))) { |
| if (CI->hasOneUse() && Op0C->hasOneUse()) { |
| Instruction::CastOps Opcode = Op0C->getOpcode(); |
| if ((Opcode == Instruction::ZExt || Opcode == Instruction::SExt) && |
| (RHS == ConstantExpr::getCast(Opcode, |
| ConstantInt::getTrue(I.getContext()), |
| Op0C->getDestTy()))) { |
| CI->setPredicate(CI->getInversePredicate()); |
| return CastInst::Create(Opcode, CI, Op0C->getType()); |
| } |
| } |
| } |
| } |
| |
| if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) { |
| // ~(c-X) == X-c-1 == X+(-c-1) |
| if (Op0I->getOpcode() == Instruction::Sub && RHS->isAllOnesValue()) |
| if (Constant *Op0I0C = dyn_cast<Constant>(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<ConstantInt>(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 = ConstantInt::get(I.getContext(), |
| 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())) { |
| 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; |
| } |
| } |
| } |
| } |
| |
| // Try to fold constant and into select arguments. |
| if (SelectInst *SI = dyn_cast<SelectInst>(Op0)) |
| if (Instruction *R = FoldOpIntoSelect(I, SI)) |
| return R; |
| if (isa<PHINode>(Op0)) |
| if (Instruction *NV = FoldOpIntoPhi(I)) |
| return NV; |
| } |
| |
| BinaryOperator *Op1I = dyn_cast<BinaryOperator>(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<BinaryOperator>(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, "tmp")); |
| } 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<ConstantInt>(Op1)) { // Canonical form is (B&C)^C |
| return BinaryOperator::CreateAnd(Builder->CreateNot(A, "tmp"), Op1); |
| } |
| } |
| } |
| |
| // (X >> Z) ^ (Y >> Z) -> (X^Y) >> Z for all shifts. |
| if (Op0I && Op1I && Op0I->isShift() && |
| Op0I->getOpcode() == Op1I->getOpcode() && |
| Op0I->getOperand(1) == Op1I->getOperand(1) && |
| (Op1I->hasOneUse() || Op1I->hasOneUse())) { |
| Value *NewOp = |
| Builder->CreateXor(Op0I->getOperand(0), Op1I->getOperand(0), |
| Op0I->getName()); |
| return BinaryOperator::Create(Op1I->getOpcode(), NewOp, |
| Op1I->getOperand(1)); |
| } |
| |
| 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); |
| } |
| } |
| |
| // (icmp1 A, B) ^ (icmp2 A, B) --> (icmp3 A, B) |
| if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1))) |
| if (ICmpInst *LHS = dyn_cast<ICmpInst>(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, |
| getICmpValue(isSigned, Code, Op0, Op1, Builder)); |
| } |
| } |
| |
| // fold (xor (cast A), (cast B)) -> (cast (xor A, B)) |
| if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) { |
| if (CastInst *Op1C = dyn_cast<CastInst>(Op1)) |
| if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind? |
| const 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 : 0; |
| } |