diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/CMakeLists.txt | 1 | ||||
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp | 1977 | ||||
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstructionCombining.cpp | 1963 |
3 files changed, 1978 insertions, 1963 deletions
diff --git a/llvm/lib/Transforms/InstCombine/CMakeLists.txt b/llvm/lib/Transforms/InstCombine/CMakeLists.txt index 29a53de3cad..5b1ff3e23bb 100644 --- a/llvm/lib/Transforms/InstCombine/CMakeLists.txt +++ b/llvm/lib/Transforms/InstCombine/CMakeLists.txt @@ -1,6 +1,7 @@ add_llvm_library(LLVMInstCombine InstructionCombining.cpp InstCombineAddSub.cpp + InstCombineAndOrXor.cpp InstCombineCalls.cpp InstCombineCasts.cpp InstCombineCompares.cpp diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp new file mode 100644 index 00000000000..a8dd1b88c97 --- /dev/null +++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -0,0 +1,1977 @@ +//===- 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/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) { + switch (Code) { + default: assert(0 && "Illegal ICmp code!"); + case 0: + return ConstantInt::getFalse(LHS->getContext()); + case 1: + if (Sign) + return new ICmpInst(ICmpInst::ICMP_SGT, LHS, RHS); + return new ICmpInst(ICmpInst::ICMP_UGT, LHS, RHS); + case 2: + return new ICmpInst(ICmpInst::ICMP_EQ, LHS, RHS); + case 3: + if (Sign) + return new ICmpInst(ICmpInst::ICMP_SGE, LHS, RHS); + return new ICmpInst(ICmpInst::ICMP_UGE, LHS, RHS); + case 4: + if (Sign) + return new ICmpInst(ICmpInst::ICMP_SLT, LHS, RHS); + return new ICmpInst(ICmpInst::ICMP_ULT, LHS, RHS); + case 5: + return new ICmpInst(ICmpInst::ICMP_NE, LHS, RHS); + case 6: + if (Sign) + return new ICmpInst(ICmpInst::ICMP_SLE, LHS, RHS); + return new ICmpInst(ICmpInst::ICMP_ULE, LHS, RHS); + case 7: + return ConstantInt::getTrue(LHS->getContext()); + } +} + +/// 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) { + switch (code) { + default: llvm_unreachable("Illegal FCmp code!"); + case 0: + if (isordered) + return new FCmpInst(FCmpInst::FCMP_ORD, LHS, RHS); + else + return new FCmpInst(FCmpInst::FCMP_UNO, LHS, RHS); + case 1: + if (isordered) + return new FCmpInst(FCmpInst::FCMP_OGT, LHS, RHS); + else + return new FCmpInst(FCmpInst::FCMP_UGT, LHS, RHS); + case 2: + if (isordered) + return new FCmpInst(FCmpInst::FCMP_OEQ, LHS, RHS); + else + return new FCmpInst(FCmpInst::FCMP_UEQ, LHS, RHS); + case 3: + if (isordered) + return new FCmpInst(FCmpInst::FCMP_OGE, LHS, RHS); + else + return new FCmpInst(FCmpInst::FCMP_UGE, LHS, RHS); + case 4: + if (isordered) + return new FCmpInst(FCmpInst::FCMP_OLT, LHS, RHS); + else + return new FCmpInst(FCmpInst::FCMP_ULT, LHS, RHS); + case 5: + if (isordered) + return new FCmpInst(FCmpInst::FCMP_ONE, LHS, RHS); + else + return new FCmpInst(FCmpInst::FCMP_UNE, LHS, RHS); + case 6: + if (isordered) + return new FCmpInst(FCmpInst::FCMP_OLE, LHS, RHS); + else + return new FCmpInst(FCmpInst::FCMP_ULE, LHS, RHS); + case 7: return ConstantInt::getTrue(LHS->getContext()); + } +} + +/// 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 (Together == AndRHS) // (X | C) & C --> C + return ReplaceInstUsesWith(TheAnd, AndRHS); + + if (Op->hasOneUse() && Together != OpRHS) { + // (X | C1) & C2 --> (X | (C1&C2)) & C2 + Value *Or = Builder->CreateOr(X, Together); + Or->takeName(Op); + return BinaryOperator::CreateAnd(Or, AndRHS); + } + 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. + } else 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); + } else 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 pratice, 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. +Instruction *InstCombiner::InsertRangeTest(Value *V, Constant *Lo, Constant *Hi, + bool isSigned, bool Inside, + Instruction &IB) { + 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 new ICmpInst(ICmpInst::ICMP_NE, V, V); + + // V >= Min && V < Hi --> V < Hi + if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) { + ICmpInst::Predicate pred = (isSigned ? + ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT); + return new ICmpInst(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 new ICmpInst(ICmpInst::ICMP_ULT, Add, UpperBound); + } + + if (Lo == Hi) // Trivially true. + return new ICmpInst(ICmpInst::ICMP_EQ, V, V); + + // 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 new ICmpInst(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 new ICmpInst(ICmpInst::ICMP_UGT, 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"); +} + +/// FoldAndOfICmps - Fold (icmp)&(icmp) if possible. +Instruction *InstCombiner::FoldAndOfICmps(Instruction &I, + 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(); + Value *RV = getICmpValue(isSigned, Code, Op0, Op1); + if (Instruction *I = dyn_cast<Instruction>(RV)) + return I; + // Otherwise, it's a constant boolean value. + return ReplaceInstUsesWith(I, RV); + } + } + + // 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 new ICmpInst(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 new ICmpInst(LHSCC, NewOr, 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 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_EQ: // (X == 13 & X == 15) -> false + case ICmpInst::ICMP_UGT: // (X == 13 & X > 15) -> false + case ICmpInst::ICMP_SGT: // (X == 13 & X > 15) -> false + return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + 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 ReplaceInstUsesWith(I, 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 new ICmpInst(ICmpInst::ICMP_ULT, 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 new ICmpInst(ICmpInst::ICMP_SLT, 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 ReplaceInstUsesWith(I, 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 new ICmpInst(ICmpInst::ICMP_UGT, 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 ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + 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 ReplaceInstUsesWith(I, 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_EQ: // (X s< 13 & X == 15) -> false + case ICmpInst::ICMP_SGT: // (X s< 13 & X s> 15) -> false + return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + 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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, 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 new ICmpInst(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, I); + 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 ReplaceInstUsesWith(I, 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 new ICmpInst(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, I); + case ICmpInst::ICMP_ULT: // (X s> 13 & X u< 15) -> no change + break; + } + break; + } + + return 0; +} + +Instruction *InstCombiner::FoldAndOfFCmps(Instruction &I, 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 ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + return new FCmpInst(FCmpInst::FCMP_ORD, + 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 new FCmpInst(FCmpInst::FCMP_ORD, + 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 new FCmpInst((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS); + + if (Op0CC == FCmpInst::FCMP_FALSE || Op1CC == FCmpInst::FCMP_FALSE) + return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + if (Op0CC == FCmpInst::FCMP_TRUE) + return ReplaceInstUsesWith(I, RHS); + if (Op1CC == FCmpInst::FCMP_TRUE) + return ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, RHS); + + // uno && oeq -> uno && (ord && eq) -> false + // uno && ord -> false + if (!Op0Ordered) + return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + // ord && ueq -> ord && (uno || eq) -> oeq + return cast<Instruction>(getFCmpValue(true, Op1Pred, Op0LHS, Op0RHS)); + } + } + + return 0; +} + + +Instruction *InstCombiner::visitAnd(BinaryOperator &I) { + bool Changed = SimplifyCommutative(I); + Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); + + if (Value *V = SimplifyAndInst(Op0, Op1, TD)) + 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(); + APInt NotAndRHS(~AndRHSMask); + + // 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; + + 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()) { + uint32_t BitWidth = AndRHSMask.getBitWidth(); + uint32_t Zeros = AndRHSMask.countLeadingZeros(); + APInt Mask = APInt::getLowBitsSet(BitWidth, BitWidth - Zeros); + + ConstantInt *A = dyn_cast<ConstantInt>(Op0LHS); + if (!(A && A->isZero()) && // avoid infinite recursion. + 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; + } else if (CastInst *CI = dyn_cast<CastInst>(Op0)) { + // If this is an integer truncation or change from signed-to-unsigned, and + // if the source is an and/or with immediate, transform it. This + // frequently occurs for bitfield accesses. + if (Instruction *CastOp = dyn_cast<Instruction>(CI->getOperand(0))) { + if ((isa<TruncInst>(CI) || isa<BitCastInst>(CI)) && + CastOp->getNumOperands() == 2) + if (ConstantInt *AndCI =dyn_cast<ConstantInt>(CastOp->getOperand(1))){ + if (CastOp->getOpcode() == Instruction::And) { + // Change: and (cast (and X, C1) to T), C2 + // into : and (cast X to T), trunc_or_bitcast(C1)&C2 + // This will fold the two constants together, which may allow + // other simplifications. + Value *NewCast = Builder->CreateTruncOrBitCast( + CastOp->getOperand(0), I.getType(), + CastOp->getName()+".shrunk"); + // trunc_or_bitcast(C1)&C2 + Constant *C3 = ConstantExpr::getTruncOrBitCast(AndCI,I.getType()); + C3 = ConstantExpr::getAnd(C3, AndRHS); + return BinaryOperator::CreateAnd(NewCast, C3); + } else if (CastOp->getOpcode() == Instruction::Or) { + // Change: and (cast (or X, C1) to T), C2 + // into : trunc(C1)&C2 iff trunc(C1)&C2 == C2 + Constant *C3 = ConstantExpr::getTruncOrBitCast(AndCI,I.getType()); + if (ConstantExpr::getAnd(C3, AndRHS) == AndRHS) + // trunc(C1)&C2 + return ReplaceInstUsesWith(I, AndRHS); + } + } + } + } + + // 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); + } + if (A == Op0) // 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 (Instruction *Res = FoldAndOfICmps(I, LHS, RHS)) + return 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)) + if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind ? + const Type *SrcTy = Op0C->getOperand(0)->getType(); + if (SrcTy == Op1C->getOperand(0)->getType() && + SrcTy->isIntOrIntVector() && + // Only do this if the casts both really cause code to be generated. + ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0), + I.getType()) && + ValueRequiresCast(Op1C->getOpcode(), Op1C->getOperand(0), + I.getType())) { + Value *NewOp = Builder->CreateAnd(Op0C->getOperand(0), + Op1C->getOperand(0), I.getName()); + return CastInst::Create(Op0C->getOpcode(), NewOp, 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)); + } + } + + // 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 (Instruction *Res = FoldAndOfFCmps(I, LHS, RHS)) + return Res; + } + + 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_SelectCst<-1, 0>(m_Value(Cond)))) + return 0; + + // ((cond?-1:0)&C) | (B&(cond?0:-1)) -> cond ? C : B. + if (match(D, m_SelectCst<0, -1>(m_Specific(Cond)))) + return SelectInst::Create(Cond, C, B); + if (match(D, m_Not(m_SelectCst<-1, 0>(m_Specific(Cond))))) + return SelectInst::Create(Cond, C, B); + // ((cond?-1:0)&C) | ((cond?0:-1)&D) -> cond ? C : D. + if (match(B, m_SelectCst<0, -1>(m_Specific(Cond)))) + return SelectInst::Create(Cond, C, D); + if (match(B, m_Not(m_SelectCst<-1, 0>(m_Specific(Cond))))) + return SelectInst::Create(Cond, C, D); + return 0; +} + +/// FoldOrOfICmps - Fold (icmp)|(icmp) if possible. +Instruction *InstCombiner::FoldOrOfICmps(Instruction &I, + 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(); + Value *RV = getICmpValue(isSigned, Code, Op0, Op1); + if (Instruction *I = dyn_cast<Instruction>(RV)) + return I; + // Otherwise, it's a constant boolean value. + return ReplaceInstUsesWith(I, RV); + } + } + + // 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; + + // (icmp ne A, 0) | (icmp ne B, 0) --> (icmp ne (A|B), 0) + if (LHSCst == RHSCst && LHSCC == RHSCC && + LHSCC == ICmpInst::ICMP_NE && LHSCst->isZero()) { + Value *NewOr = Builder->CreateOr(Val, Val2); + return new ICmpInst(LHSCC, NewOr, 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 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 new ICmpInst(ICmpInst::ICMP_ULT, 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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, ConstantInt::getTrue(I.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 ReplaceInstUsesWith(I, LHS); + return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), + false, false, I); + 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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, LHS); + return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), + true, false, I); + 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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, ConstantInt::getTrue(I.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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); + case ICmpInst::ICMP_ULT: // (X s> 13 | X u< 15) -> no change + break; + } + break; + } + return 0; +} + +Instruction *InstCombiner::FoldOrOfFCmps(Instruction &I, 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 ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); + + // Otherwise, no need to compare the two constants, compare the + // rest. + return new FCmpInst(FCmpInst::FCMP_UNO, + 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 new FCmpInst(FCmpInst::FCMP_UNO, + 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 new FCmpInst((FCmpInst::Predicate)Op0CC, + Op0LHS, Op0RHS); + if (Op0CC == FCmpInst::FCMP_TRUE || Op1CC == FCmpInst::FCMP_TRUE) + return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); + if (Op0CC == FCmpInst::FCMP_FALSE) + return ReplaceInstUsesWith(I, RHS); + if (Op1CC == FCmpInst::FCMP_FALSE) + return ReplaceInstUsesWith(I, 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. + Value *RV = getFCmpValue(Op0Ordered, Op0Pred|Op1Pred, Op0LHS, Op0RHS); + if (Instruction *I = dyn_cast<Instruction>(RV)) + return I; + // Otherwise, it's a constant boolean value... + return ReplaceInstUsesWith(I, RV); + } + } + 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 = SimplifyCommutative(I); + Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); + + if (Value *V = SimplifyOrInst(Op0, Op1, TD)) + 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) + if (match(Op0, m_And(m_Value(X), m_ConstantInt(C1))) && + 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_Shift(m_Value(), m_Value())) && + match(Op1, m_Shift(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, *V3 = 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); + } + } + + // ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2) + // iff (C1&C2) == 0 and (N&~C1) == 0 + if ((C1->getValue() & C2->getValue()) == 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())); + } + } + + // Check to see if we have any common things being and'ed. If so, find the + // terms for V1 & (V2|V3). + if (Op0->hasOneUse() || Op1->hasOneUse()) { + V1 = 0; + if (A == B) // (A & C)|(A & D) == A & (C|D) + V1 = A, V2 = C, V3 = D; + else if (A == D) // (A & C)|(B & A) == A & (B|C) + V1 = A, V2 = B, V3 = C; + else if (C == B) // (A & C)|(C & D) == C & (A|D) + V1 = C, V2 = A, V3 = D; + else if (C == D) // (A & C)|(B & C) == C & (A|B) + V1 = C, V2 = A, V3 = B; + + if (V1) { + Value *Or = Builder->CreateOr(V2, V3, "tmp"); + return BinaryOperator::CreateAnd(V1, Or); + } + } + + // (A & (C0?-1:0)) | (B & ~(C0?-1:0)) -> C0 ? A : B, and commuted variants + 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); + } + + // (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)&1)|(B&-2) -> (A&1) | B + if (match(Op0, m_And(m_Or(m_Value(A), m_Value(B)), m_Value(C))) || + match(Op0, m_And(m_Value(C), m_Or(m_Value(A), m_Value(B))))) { + Instruction *Ret = FoldOrWithConstants(I, Op1, A, B, C); + if (Ret) return Ret; + } + // (B&-2)|((A|B)&1) -> (A&1) | B + if (match(Op1, m_And(m_Or(m_Value(A), m_Value(B)), m_Value(C))) || + match(Op1, m_And(m_Value(C), m_Or(m_Value(A), m_Value(B))))) { + Instruction *Ret = FoldOrWithConstants(I, Op0, A, B, C); + if (Ret) return Ret; + } + + // (~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); + } + + if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1))) + if (ICmpInst *LHS = dyn_cast<ICmpInst>(I.getOperand(0))) + if (Instruction *Res = FoldOrOfICmps(I, LHS, RHS)) + return Res; + + // fold (or (cast A), (cast B)) -> (cast (or A, B)) + if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) { + if (CastInst *Op1C = dyn_cast<CastInst>(Op1)) + if (Op0C->getOpcode() == Op1C->getOpcode()) {// same cast kind ? + if (!isa<ICmpInst>(Op0C->getOperand(0)) || + !isa<ICmpInst>(Op1C->getOperand(0))) { + const Type *SrcTy = Op0C->getOperand(0)->getType(); + if (SrcTy == Op1C->getOperand(0)->getType() && + SrcTy->isIntOrIntVector() && + // Only do this if the casts both really cause code to be + // generated. + ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0), + I.getType()) && + ValueRequiresCast(Op1C->getOpcode(), Op1C->getOperand(0), + I.getType())) { + Value *NewOp = Builder->CreateOr(Op0C->getOperand(0), + Op1C->getOperand(0), I.getName()); + return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType()); + } + } + } + } + + + // (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 (Instruction *Res = FoldOrOfFCmps(I, LHS, RHS)) + return Res; + } + + return Changed ? &I : 0; +} + +Instruction *InstCombiner::visitXor(BinaryOperator &I) { + bool Changed = SimplifyCommutative(I); + Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); + + if (isa<UndefValue>(Op1)) { + if (isa<UndefValue>(Op0)) + // Handle undef ^ undef -> 0 special case. This is a common + // idiom (misuse). + return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); + return ReplaceInstUsesWith(I, Op1); // X ^ undef -> undef + } + + // xor X, X = 0 + if (Op0 == Op1) + return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); + + // 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 (isa<VectorType>(I.getType())) + if (isa<ConstantAggregateZero>(Op1)) + return ReplaceInstUsesWith(I, Op0); // X ^ <0,0> -> X + + // 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); + } + } + } + } + + + 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 (ICmpInst *ICI = dyn_cast<ICmpInst>(Op0)) + return new ICmpInst(ICI->getInversePredicate(), + ICI->getOperand(0), ICI->getOperand(1)); + + if (FCmpInst *FCI = dyn_cast<FCmpInst>(Op0)) + return new FCmpInst(FCI->getInversePredicate(), + FCI->getOperand(0), FCI->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; + } + + if (Value *X = dyn_castNotVal(Op0)) // ~A ^ A == -1 + if (X == Op1) + return ReplaceInstUsesWith(I, Constant::getAllOnesValue(I.getType())); + + if (Value *X = dyn_castNotVal(Op1)) // A ^ ~A == -1 + if (X == Op0) + return ReplaceInstUsesWith(I, Constant::getAllOnesValue(I.getType())); + + + 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_Xor(m_Specific(Op0), m_Value(B)))) { + return ReplaceInstUsesWith(I, B); // A^(A^B) == B + } else if (match(Op1I, m_Xor(m_Value(A), m_Specific(Op0)))) { + return ReplaceInstUsesWith(I, A); // A^(B^A) == B + } 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_Xor(m_Specific(Op1), m_Value(B)))) { + return ReplaceInstUsesWith(I, B); // (A^B)^A == B + } else if (match(Op0I, m_Xor(m_Value(A), m_Specific(Op1)))) { + return ReplaceInstUsesWith(I, A); // (B^A)^A == B + } 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); + } + + // (A & B)^(C & D) + if ((Op0I->hasOneUse() || Op1I->hasOneUse()) && + match(Op0I, m_And(m_Value(A), m_Value(B))) && + match(Op1I, m_And(m_Value(C), m_Value(D)))) { + // (X & Y)^(X & Y) -> (Y^Z) & X + Value *X = 0, *Y = 0, *Z = 0; + if (A == C) + X = A, Y = B, Z = D; + else if (A == D) + X = A, Y = B, Z = C; + else if (B == C) + X = B, Y = A, Z = D; + else if (B == D) + X = B, Y = A, Z = C; + + if (X) { + Value *NewOp = Builder->CreateXor(Y, Z, Op0->getName()); + return BinaryOperator::CreateAnd(NewOp, X); + } + } + } + + // (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(); + Value *RV = getICmpValue(isSigned, Code, Op0, Op1); + if (Instruction *I = dyn_cast<Instruction>(RV)) + return I; + // Otherwise, it's a constant boolean value. + return ReplaceInstUsesWith(I, RV); + } + } + + // 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->isInteger() && + // Only do this if the casts both really cause code to be generated. + ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0), + I.getType()) && + ValueRequiresCast(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; +} diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp index 769f2960569..7b8d6647b99 100644 --- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp +++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp @@ -190,51 +190,6 @@ Value *InstCombiner::dyn_castFNegVal(Value *V) const { return 0; } -/// 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; -} - - - -/// 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); -} - - static Value *FoldOperationIntoSelectOperand(Instruction &I, Value *SO, InstCombiner *IC) { if (CastInst *CI = dyn_cast<CastInst>(&I)) @@ -413,1924 +368,6 @@ Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I, return ReplaceInstUsesWith(I, NewPN); } - -/// 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) { - switch (Code) { - default: assert(0 && "Illegal ICmp code!"); - case 0: - return ConstantInt::getFalse(LHS->getContext()); - case 1: - if (Sign) - return new ICmpInst(ICmpInst::ICMP_SGT, LHS, RHS); - return new ICmpInst(ICmpInst::ICMP_UGT, LHS, RHS); - case 2: - return new ICmpInst(ICmpInst::ICMP_EQ, LHS, RHS); - case 3: - if (Sign) - return new ICmpInst(ICmpInst::ICMP_SGE, LHS, RHS); - return new ICmpInst(ICmpInst::ICMP_UGE, LHS, RHS); - case 4: - if (Sign) - return new ICmpInst(ICmpInst::ICMP_SLT, LHS, RHS); - return new ICmpInst(ICmpInst::ICMP_ULT, LHS, RHS); - case 5: - return new ICmpInst(ICmpInst::ICMP_NE, LHS, RHS); - case 6: - if (Sign) - return new ICmpInst(ICmpInst::ICMP_SLE, LHS, RHS); - return new ICmpInst(ICmpInst::ICMP_ULE, LHS, RHS); - case 7: - return ConstantInt::getTrue(LHS->getContext()); - } -} - -/// 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) { - switch (code) { - default: llvm_unreachable("Illegal FCmp code!"); - case 0: - if (isordered) - return new FCmpInst(FCmpInst::FCMP_ORD, LHS, RHS); - else - return new FCmpInst(FCmpInst::FCMP_UNO, LHS, RHS); - case 1: - if (isordered) - return new FCmpInst(FCmpInst::FCMP_OGT, LHS, RHS); - else - return new FCmpInst(FCmpInst::FCMP_UGT, LHS, RHS); - case 2: - if (isordered) - return new FCmpInst(FCmpInst::FCMP_OEQ, LHS, RHS); - else - return new FCmpInst(FCmpInst::FCMP_UEQ, LHS, RHS); - case 3: - if (isordered) - return new FCmpInst(FCmpInst::FCMP_OGE, LHS, RHS); - else - return new FCmpInst(FCmpInst::FCMP_UGE, LHS, RHS); - case 4: - if (isordered) - return new FCmpInst(FCmpInst::FCMP_OLT, LHS, RHS); - else - return new FCmpInst(FCmpInst::FCMP_ULT, LHS, RHS); - case 5: - if (isordered) - return new FCmpInst(FCmpInst::FCMP_ONE, LHS, RHS); - else - return new FCmpInst(FCmpInst::FCMP_UNE, LHS, RHS); - case 6: - if (isordered) - return new FCmpInst(FCmpInst::FCMP_OLE, LHS, RHS); - else - return new FCmpInst(FCmpInst::FCMP_ULE, LHS, RHS); - case 7: return ConstantInt::getTrue(LHS->getContext()); - } -} - -/// 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 (Together == AndRHS) // (X | C) & C --> C - return ReplaceInstUsesWith(TheAnd, AndRHS); - - if (Op->hasOneUse() && Together != OpRHS) { - // (X | C1) & C2 --> (X | (C1&C2)) & C2 - Value *Or = Builder->CreateOr(X, Together); - Or->takeName(Op); - return BinaryOperator::CreateAnd(Or, AndRHS); - } - 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. - } else 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); - } else 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 pratice, 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. -Instruction *InstCombiner::InsertRangeTest(Value *V, Constant *Lo, Constant *Hi, - bool isSigned, bool Inside, - Instruction &IB) { - 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 new ICmpInst(ICmpInst::ICMP_NE, V, V); - - // V >= Min && V < Hi --> V < Hi - if (cast<ConstantInt>(Lo)->isMinValue(isSigned)) { - ICmpInst::Predicate pred = (isSigned ? - ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT); - return new ICmpInst(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 new ICmpInst(ICmpInst::ICMP_ULT, Add, UpperBound); - } - - if (Lo == Hi) // Trivially true. - return new ICmpInst(ICmpInst::ICMP_EQ, V, V); - - // 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 new ICmpInst(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 new ICmpInst(ICmpInst::ICMP_UGT, 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"); -} - -/// FoldAndOfICmps - Fold (icmp)&(icmp) if possible. -Instruction *InstCombiner::FoldAndOfICmps(Instruction &I, - 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(); - Value *RV = getICmpValue(isSigned, Code, Op0, Op1); - if (Instruction *I = dyn_cast<Instruction>(RV)) - return I; - // Otherwise, it's a constant boolean value. - return ReplaceInstUsesWith(I, RV); - } - } - - // 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 new ICmpInst(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 new ICmpInst(LHSCC, NewOr, 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 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_EQ: // (X == 13 & X == 15) -> false - case ICmpInst::ICMP_UGT: // (X == 13 & X > 15) -> false - case ICmpInst::ICMP_SGT: // (X == 13 & X > 15) -> false - return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); - 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 ReplaceInstUsesWith(I, 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 new ICmpInst(ICmpInst::ICMP_ULT, 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 new ICmpInst(ICmpInst::ICMP_SLT, 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 ReplaceInstUsesWith(I, 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 new ICmpInst(ICmpInst::ICMP_UGT, 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 ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); - 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 ReplaceInstUsesWith(I, 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_EQ: // (X s< 13 & X == 15) -> false - case ICmpInst::ICMP_SGT: // (X s< 13 & X s> 15) -> false - return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); - 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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, 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 new ICmpInst(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, I); - 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 ReplaceInstUsesWith(I, 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 new ICmpInst(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, I); - case ICmpInst::ICMP_ULT: // (X s> 13 & X u< 15) -> no change - break; - } - break; - } - - return 0; -} - -Instruction *InstCombiner::FoldAndOfFCmps(Instruction &I, 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 ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); - return new FCmpInst(FCmpInst::FCMP_ORD, - 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 new FCmpInst(FCmpInst::FCMP_ORD, - 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 new FCmpInst((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS); - - if (Op0CC == FCmpInst::FCMP_FALSE || Op1CC == FCmpInst::FCMP_FALSE) - return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); - if (Op0CC == FCmpInst::FCMP_TRUE) - return ReplaceInstUsesWith(I, RHS); - if (Op1CC == FCmpInst::FCMP_TRUE) - return ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, RHS); - - // uno && oeq -> uno && (ord && eq) -> false - // uno && ord -> false - if (!Op0Ordered) - return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); - // ord && ueq -> ord && (uno || eq) -> oeq - return cast<Instruction>(getFCmpValue(true, Op1Pred, Op0LHS, Op0RHS)); - } - } - - return 0; -} - - -Instruction *InstCombiner::visitAnd(BinaryOperator &I) { - bool Changed = SimplifyCommutative(I); - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - - if (Value *V = SimplifyAndInst(Op0, Op1, TD)) - 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(); - APInt NotAndRHS(~AndRHSMask); - - // 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; - - 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()) { - uint32_t BitWidth = AndRHSMask.getBitWidth(); - uint32_t Zeros = AndRHSMask.countLeadingZeros(); - APInt Mask = APInt::getLowBitsSet(BitWidth, BitWidth - Zeros); - - ConstantInt *A = dyn_cast<ConstantInt>(Op0LHS); - if (!(A && A->isZero()) && // avoid infinite recursion. - 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; - } else if (CastInst *CI = dyn_cast<CastInst>(Op0)) { - // If this is an integer truncation or change from signed-to-unsigned, and - // if the source is an and/or with immediate, transform it. This - // frequently occurs for bitfield accesses. - if (Instruction *CastOp = dyn_cast<Instruction>(CI->getOperand(0))) { - if ((isa<TruncInst>(CI) || isa<BitCastInst>(CI)) && - CastOp->getNumOperands() == 2) - if (ConstantInt *AndCI =dyn_cast<ConstantInt>(CastOp->getOperand(1))){ - if (CastOp->getOpcode() == Instruction::And) { - // Change: and (cast (and X, C1) to T), C2 - // into : and (cast X to T), trunc_or_bitcast(C1)&C2 - // This will fold the two constants together, which may allow - // other simplifications. - Value *NewCast = Builder->CreateTruncOrBitCast( - CastOp->getOperand(0), I.getType(), - CastOp->getName()+".shrunk"); - // trunc_or_bitcast(C1)&C2 - Constant *C3 = ConstantExpr::getTruncOrBitCast(AndCI,I.getType()); - C3 = ConstantExpr::getAnd(C3, AndRHS); - return BinaryOperator::CreateAnd(NewCast, C3); - } else if (CastOp->getOpcode() == Instruction::Or) { - // Change: and (cast (or X, C1) to T), C2 - // into : trunc(C1)&C2 iff trunc(C1)&C2 == C2 - Constant *C3 = ConstantExpr::getTruncOrBitCast(AndCI,I.getType()); - if (ConstantExpr::getAnd(C3, AndRHS) == AndRHS) - // trunc(C1)&C2 - return ReplaceInstUsesWith(I, AndRHS); - } - } - } - } - - // 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); - } - if (A == Op0) // 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 (Instruction *Res = FoldAndOfICmps(I, LHS, RHS)) - return 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)) - if (Op0C->getOpcode() == Op1C->getOpcode()) { // same cast kind ? - const Type *SrcTy = Op0C->getOperand(0)->getType(); - if (SrcTy == Op1C->getOperand(0)->getType() && - SrcTy->isIntOrIntVector() && - // Only do this if the casts both really cause code to be generated. - ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0), - I.getType()) && - ValueRequiresCast(Op1C->getOpcode(), Op1C->getOperand(0), - I.getType())) { - Value *NewOp = Builder->CreateAnd(Op0C->getOperand(0), - Op1C->getOperand(0), I.getName()); - return CastInst::Create(Op0C->getOpcode(), NewOp, 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)); - } - } - - // 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 (Instruction *Res = FoldAndOfFCmps(I, LHS, RHS)) - return Res; - } - - 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_SelectCst<-1, 0>(m_Value(Cond)))) - return 0; - - // ((cond?-1:0)&C) | (B&(cond?0:-1)) -> cond ? C : B. - if (match(D, m_SelectCst<0, -1>(m_Specific(Cond)))) - return SelectInst::Create(Cond, C, B); - if (match(D, m_Not(m_SelectCst<-1, 0>(m_Specific(Cond))))) - return SelectInst::Create(Cond, C, B); - // ((cond?-1:0)&C) | ((cond?0:-1)&D) -> cond ? C : D. - if (match(B, m_SelectCst<0, -1>(m_Specific(Cond)))) - return SelectInst::Create(Cond, C, D); - if (match(B, m_Not(m_SelectCst<-1, 0>(m_Specific(Cond))))) - return SelectInst::Create(Cond, C, D); - return 0; -} - -/// FoldOrOfICmps - Fold (icmp)|(icmp) if possible. -Instruction *InstCombiner::FoldOrOfICmps(Instruction &I, - 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(); - Value *RV = getICmpValue(isSigned, Code, Op0, Op1); - if (Instruction *I = dyn_cast<Instruction>(RV)) - return I; - // Otherwise, it's a constant boolean value. - return ReplaceInstUsesWith(I, RV); - } - } - - // 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; - - // (icmp ne A, 0) | (icmp ne B, 0) --> (icmp ne (A|B), 0) - if (LHSCst == RHSCst && LHSCC == RHSCC && - LHSCC == ICmpInst::ICMP_NE && LHSCst->isZero()) { - Value *NewOr = Builder->CreateOr(Val, Val2); - return new ICmpInst(LHSCC, NewOr, 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 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 new ICmpInst(ICmpInst::ICMP_ULT, 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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, ConstantInt::getTrue(I.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 ReplaceInstUsesWith(I, LHS); - return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), - false, false, I); - 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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, LHS); - return InsertRangeTest(Val, LHSCst, AddOne(RHSCst), - true, false, I); - 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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, ConstantInt::getTrue(I.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 ReplaceInstUsesWith(I, 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 ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); - case ICmpInst::ICMP_ULT: // (X s> 13 | X u< 15) -> no change - break; - } - break; - } - return 0; -} - -Instruction *InstCombiner::FoldOrOfFCmps(Instruction &I, 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 ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); - - // Otherwise, no need to compare the two constants, compare the - // rest. - return new FCmpInst(FCmpInst::FCMP_UNO, - 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 new FCmpInst(FCmpInst::FCMP_UNO, - 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 new FCmpInst((FCmpInst::Predicate)Op0CC, - Op0LHS, Op0RHS); - if (Op0CC == FCmpInst::FCMP_TRUE || Op1CC == FCmpInst::FCMP_TRUE) - return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); - if (Op0CC == FCmpInst::FCMP_FALSE) - return ReplaceInstUsesWith(I, RHS); - if (Op1CC == FCmpInst::FCMP_FALSE) - return ReplaceInstUsesWith(I, 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. - Value *RV = getFCmpValue(Op0Ordered, Op0Pred|Op1Pred, Op0LHS, Op0RHS); - if (Instruction *I = dyn_cast<Instruction>(RV)) - return I; - // Otherwise, it's a constant boolean value... - return ReplaceInstUsesWith(I, RV); - } - } - 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 = SimplifyCommutative(I); - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - - if (Value *V = SimplifyOrInst(Op0, Op1, TD)) - 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) - if (match(Op0, m_And(m_Value(X), m_ConstantInt(C1))) && - 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_Shift(m_Value(), m_Value())) && - match(Op1, m_Shift(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, *V3 = 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); - } - } - - // ((V | N) & C1) | (V & C2) --> (V|N) & (C1|C2) - // iff (C1&C2) == 0 and (N&~C1) == 0 - if ((C1->getValue() & C2->getValue()) == 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())); - } - } - - // Check to see if we have any common things being and'ed. If so, find the - // terms for V1 & (V2|V3). - if (Op0->hasOneUse() || Op1->hasOneUse()) { - V1 = 0; - if (A == B) // (A & C)|(A & D) == A & (C|D) - V1 = A, V2 = C, V3 = D; - else if (A == D) // (A & C)|(B & A) == A & (B|C) - V1 = A, V2 = B, V3 = C; - else if (C == B) // (A & C)|(C & D) == C & (A|D) - V1 = C, V2 = A, V3 = D; - else if (C == D) // (A & C)|(B & C) == C & (A|B) - V1 = C, V2 = A, V3 = B; - - if (V1) { - Value *Or = Builder->CreateOr(V2, V3, "tmp"); - return BinaryOperator::CreateAnd(V1, Or); - } - } - - // (A & (C0?-1:0)) | (B & ~(C0?-1:0)) -> C0 ? A : B, and commuted variants - 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); - } - - // (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)&1)|(B&-2) -> (A&1) | B - if (match(Op0, m_And(m_Or(m_Value(A), m_Value(B)), m_Value(C))) || - match(Op0, m_And(m_Value(C), m_Or(m_Value(A), m_Value(B))))) { - Instruction *Ret = FoldOrWithConstants(I, Op1, A, B, C); - if (Ret) return Ret; - } - // (B&-2)|((A|B)&1) -> (A&1) | B - if (match(Op1, m_And(m_Or(m_Value(A), m_Value(B)), m_Value(C))) || - match(Op1, m_And(m_Value(C), m_Or(m_Value(A), m_Value(B))))) { - Instruction *Ret = FoldOrWithConstants(I, Op0, A, B, C); - if (Ret) return Ret; - } - - // (~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); - } - - if (ICmpInst *RHS = dyn_cast<ICmpInst>(I.getOperand(1))) - if (ICmpInst *LHS = dyn_cast<ICmpInst>(I.getOperand(0))) - if (Instruction *Res = FoldOrOfICmps(I, LHS, RHS)) - return Res; - - // fold (or (cast A), (cast B)) -> (cast (or A, B)) - if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) { - if (CastInst *Op1C = dyn_cast<CastInst>(Op1)) - if (Op0C->getOpcode() == Op1C->getOpcode()) {// same cast kind ? - if (!isa<ICmpInst>(Op0C->getOperand(0)) || - !isa<ICmpInst>(Op1C->getOperand(0))) { - const Type *SrcTy = Op0C->getOperand(0)->getType(); - if (SrcTy == Op1C->getOperand(0)->getType() && - SrcTy->isIntOrIntVector() && - // Only do this if the casts both really cause code to be - // generated. - ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0), - I.getType()) && - ValueRequiresCast(Op1C->getOpcode(), Op1C->getOperand(0), - I.getType())) { - Value *NewOp = Builder->CreateOr(Op0C->getOperand(0), - Op1C->getOperand(0), I.getName()); - return CastInst::Create(Op0C->getOpcode(), NewOp, I.getType()); - } - } - } - } - - - // (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 (Instruction *Res = FoldOrOfFCmps(I, LHS, RHS)) - return Res; - } - - return Changed ? &I : 0; -} - -Instruction *InstCombiner::visitXor(BinaryOperator &I) { - bool Changed = SimplifyCommutative(I); - Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); - - if (isa<UndefValue>(Op1)) { - if (isa<UndefValue>(Op0)) - // Handle undef ^ undef -> 0 special case. This is a common - // idiom (misuse). - return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); - return ReplaceInstUsesWith(I, Op1); // X ^ undef -> undef - } - - // xor X, X = 0 - if (Op0 == Op1) - return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); - - // 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 (isa<VectorType>(I.getType())) - if (isa<ConstantAggregateZero>(Op1)) - return ReplaceInstUsesWith(I, Op0); // X ^ <0,0> -> X - - // 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); - } - } - } - } - - - 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 (ICmpInst *ICI = dyn_cast<ICmpInst>(Op0)) - return new ICmpInst(ICI->getInversePredicate(), - ICI->getOperand(0), ICI->getOperand(1)); - - if (FCmpInst *FCI = dyn_cast<FCmpInst>(Op0)) - return new FCmpInst(FCI->getInversePredicate(), - FCI->getOperand(0), FCI->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; - } - - if (Value *X = dyn_castNotVal(Op0)) // ~A ^ A == -1 - if (X == Op1) - return ReplaceInstUsesWith(I, Constant::getAllOnesValue(I.getType())); - - if (Value *X = dyn_castNotVal(Op1)) // A ^ ~A == -1 - if (X == Op0) - return ReplaceInstUsesWith(I, Constant::getAllOnesValue(I.getType())); - - - 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_Xor(m_Specific(Op0), m_Value(B)))) { - return ReplaceInstUsesWith(I, B); // A^(A^B) == B - } else if (match(Op1I, m_Xor(m_Value(A), m_Specific(Op0)))) { - return ReplaceInstUsesWith(I, A); // A^(B^A) == B - } 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_Xor(m_Specific(Op1), m_Value(B)))) { - return ReplaceInstUsesWith(I, B); // (A^B)^A == B - } else if (match(Op0I, m_Xor(m_Value(A), m_Specific(Op1)))) { - return ReplaceInstUsesWith(I, A); // (B^A)^A == B - } 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); - } - - // (A & B)^(C & D) - if ((Op0I->hasOneUse() || Op1I->hasOneUse()) && - match(Op0I, m_And(m_Value(A), m_Value(B))) && - match(Op1I, m_And(m_Value(C), m_Value(D)))) { - // (X & Y)^(X & Y) -> (Y^Z) & X - Value *X = 0, *Y = 0, *Z = 0; - if (A == C) - X = A, Y = B, Z = D; - else if (A == D) - X = A, Y = B, Z = C; - else if (B == C) - X = B, Y = A, Z = D; - else if (B == D) - X = B, Y = A, Z = C; - - if (X) { - Value *NewOp = Builder->CreateXor(Y, Z, Op0->getName()); - return BinaryOperator::CreateAnd(NewOp, X); - } - } - } - - // (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(); - Value *RV = getICmpValue(isSigned, Code, Op0, Op1); - if (Instruction *I = dyn_cast<Instruction>(RV)) - return I; - // Otherwise, it's a constant boolean value. - return ReplaceInstUsesWith(I, RV); - } - } - - // 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->isInteger() && - // Only do this if the casts both really cause code to be generated. - ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0), - I.getType()) && - ValueRequiresCast(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; -} - - - - /// FindElementAtOffset - Given a type and a constant offset, determine whether /// or not there is a sequence of GEP indices into the type that will land us at /// the specified offset. If so, fill them into NewIndices and return the |
