diff options
Diffstat (limited to 'contrib/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp')
| -rw-r--r-- | contrib/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 392 |
1 files changed, 290 insertions, 102 deletions
diff --git a/contrib/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/contrib/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index 4c252c0..9bb65ef 100644 --- a/contrib/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/contrib/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -227,7 +227,8 @@ Instruction *InstCombiner:: FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP, GlobalVariable *GV, CmpInst &ICI, ConstantInt *AndCst) { // We need TD information to know the pointer size unless this is inbounds. - if (!GEP->isInBounds() && TD == 0) return 0; + if (!GEP->isInBounds() && TD == 0) + return 0; Constant *Init = GV->getInitializer(); if (!isa<ConstantArray>(Init) && !isa<ConstantDataArray>(Init)) @@ -393,16 +394,19 @@ FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP, GlobalVariable *GV, // If the index is larger than the pointer size of the target, truncate the // index down like the GEP would do implicitly. We don't have to do this for // an inbounds GEP because the index can't be out of range. - if (!GEP->isInBounds() && - Idx->getType()->getPrimitiveSizeInBits() > TD->getPointerSizeInBits()) - Idx = Builder->CreateTrunc(Idx, TD->getIntPtrType(Idx->getContext())); + if (!GEP->isInBounds()) { + Type *IntPtrTy = TD->getIntPtrType(GEP->getType()); + unsigned PtrSize = IntPtrTy->getIntegerBitWidth(); + if (Idx->getType()->getPrimitiveSizeInBits() > PtrSize) + Idx = Builder->CreateTrunc(Idx, IntPtrTy); + } // If the comparison is only true for one or two elements, emit direct // comparisons. if (SecondTrueElement != Overdefined) { // None true -> false. if (FirstTrueElement == Undefined) - return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(GEP->getContext())); + return ReplaceInstUsesWith(ICI, Builder->getFalse()); Value *FirstTrueIdx = ConstantInt::get(Idx->getType(), FirstTrueElement); @@ -422,7 +426,7 @@ FoldCmpLoadFromIndexedGlobal(GetElementPtrInst *GEP, GlobalVariable *GV, if (SecondFalseElement != Overdefined) { // None false -> true. if (FirstFalseElement == Undefined) - return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(GEP->getContext())); + return ReplaceInstUsesWith(ICI, Builder->getTrue()); Value *FirstFalseIdx = ConstantInt::get(Idx->getType(), FirstFalseElement); @@ -562,16 +566,18 @@ static Value *EvaluateGEPOffsetExpression(User *GEP, InstCombiner &IC) { } } + + // Okay, we know we have a single variable index, which must be a // pointer/array/vector index. If there is no offset, life is simple, return // the index. - unsigned IntPtrWidth = TD.getPointerSizeInBits(); + Type *IntPtrTy = TD.getIntPtrType(GEP->getOperand(0)->getType()); + unsigned IntPtrWidth = IntPtrTy->getIntegerBitWidth(); if (Offset == 0) { // Cast to intptrty in case a truncation occurs. If an extension is needed, // we don't need to bother extending: the extension won't affect where the // computation crosses zero. if (VariableIdx->getType()->getPrimitiveSizeInBits() > IntPtrWidth) { - Type *IntPtrTy = TD.getIntPtrType(VariableIdx->getContext()); VariableIdx = IC.Builder->CreateTrunc(VariableIdx, IntPtrTy); } return VariableIdx; @@ -593,7 +599,6 @@ static Value *EvaluateGEPOffsetExpression(User *GEP, InstCombiner &IC) { return 0; // Okay, we can do this evaluation. Start by converting the index to intptr. - Type *IntPtrTy = TD.getIntPtrType(VariableIdx->getContext()); if (VariableIdx->getType() != IntPtrTy) VariableIdx = IC.Builder->CreateIntCast(VariableIdx, IntPtrTy, true /*Signed*/); @@ -647,8 +652,7 @@ Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS, // If all indices are the same, just compare the base pointers. if (IndicesTheSame) - return new ICmpInst(ICmpInst::getSignedPredicate(Cond), - GEPLHS->getOperand(0), GEPRHS->getOperand(0)); + return new ICmpInst(Cond, GEPLHS->getOperand(0), GEPRHS->getOperand(0)); // If we're comparing GEPs with two base pointers that only differ in type // and both GEPs have only constant indices or just one use, then fold @@ -679,7 +683,7 @@ Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS, } if (AllZeros) return FoldGEPICmp(GEPRHS, GEPLHS->getOperand(0), - ICmpInst::getSwappedPredicate(Cond), I); + ICmpInst::getSwappedPredicate(Cond), I); // If the other GEP has all zero indices, recurse. AllZeros = true; @@ -712,8 +716,7 @@ Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS, if (NumDifferences == 0) // SAME GEP? return ReplaceInstUsesWith(I, // No comparison is needed here. - ConstantInt::get(Type::getInt1Ty(I.getContext()), - ICmpInst::isTrueWhenEqual(Cond))); + Builder->getInt1(ICmpInst::isTrueWhenEqual(Cond))); else if (NumDifferences == 1 && GEPsInBounds) { Value *LHSV = GEPLHS->getOperand(DiffOperand); @@ -739,10 +742,9 @@ Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS, } /// FoldICmpAddOpCst - Fold "icmp pred (X+CI), X". -Instruction *InstCombiner::FoldICmpAddOpCst(ICmpInst &ICI, +Instruction *InstCombiner::FoldICmpAddOpCst(Instruction &ICI, Value *X, ConstantInt *CI, - ICmpInst::Predicate Pred, - Value *TheAdd) { + ICmpInst::Predicate Pred) { // If we have X+0, exit early (simplifying logic below) and let it get folded // elsewhere. icmp X+0, X -> icmp X, X if (CI->isZero()) { @@ -752,11 +754,11 @@ Instruction *InstCombiner::FoldICmpAddOpCst(ICmpInst &ICI, // (X+4) == X -> false. if (Pred == ICmpInst::ICMP_EQ) - return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(X->getContext())); + return ReplaceInstUsesWith(ICI, Builder->getFalse()); // (X+4) != X -> true. if (Pred == ICmpInst::ICMP_NE) - return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(X->getContext())); + return ReplaceInstUsesWith(ICI, Builder->getTrue()); // From this point on, we know that (X+C <= X) --> (X+C < X) because C != 0, // so the values can never be equal. Similarly for all other "or equals" @@ -798,7 +800,7 @@ Instruction *InstCombiner::FoldICmpAddOpCst(ICmpInst &ICI, // (X+ -1) >s X --> X <s (MAXSINT-(-1-1)) --> X == -128 assert(Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE); - Constant *C = ConstantInt::get(X->getContext(), CI->getValue()-1); + Constant *C = Builder->getInt(CI->getValue()-1); return new ICmpInst(ICmpInst::ICMP_SLT, X, ConstantExpr::getSub(SMax, C)); } @@ -921,7 +923,7 @@ Instruction *InstCombiner::FoldICmpDivCst(ICmpInst &ICI, BinaryOperator *DivI, default: llvm_unreachable("Unhandled icmp opcode!"); case ICmpInst::ICMP_EQ: if (LoOverflow && HiOverflow) - return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(ICI.getContext())); + return ReplaceInstUsesWith(ICI, Builder->getFalse()); if (HiOverflow) return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE, X, LoBound); @@ -932,7 +934,7 @@ Instruction *InstCombiner::FoldICmpDivCst(ICmpInst &ICI, BinaryOperator *DivI, DivIsSigned, true)); case ICmpInst::ICMP_NE: if (LoOverflow && HiOverflow) - return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(ICI.getContext())); + return ReplaceInstUsesWith(ICI, Builder->getTrue()); if (HiOverflow) return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT, X, LoBound); @@ -944,16 +946,16 @@ Instruction *InstCombiner::FoldICmpDivCst(ICmpInst &ICI, BinaryOperator *DivI, case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_SLT: if (LoOverflow == +1) // Low bound is greater than input range. - return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(ICI.getContext())); + return ReplaceInstUsesWith(ICI, Builder->getTrue()); if (LoOverflow == -1) // Low bound is less than input range. - return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(ICI.getContext())); + return ReplaceInstUsesWith(ICI, Builder->getFalse()); return new ICmpInst(Pred, X, LoBound); case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_SGT: if (HiOverflow == +1) // High bound greater than input range. - return ReplaceInstUsesWith(ICI, ConstantInt::getFalse(ICI.getContext())); + return ReplaceInstUsesWith(ICI, Builder->getFalse()); if (HiOverflow == -1) // High bound less than input range. - return ReplaceInstUsesWith(ICI, ConstantInt::getTrue(ICI.getContext())); + return ReplaceInstUsesWith(ICI, Builder->getTrue()); if (Pred == ICmpInst::ICMP_UGT) return new ICmpInst(ICmpInst::ICMP_UGE, X, HiBound); return new ICmpInst(ICmpInst::ICMP_SGE, X, HiBound); @@ -1017,7 +1019,7 @@ Instruction *InstCombiner::FoldICmpShrCst(ICmpInst &ICI, BinaryOperator *Shr, // If we are comparing against bits always shifted out, the // comparison cannot succeed. APInt Comp = CmpRHSV << ShAmtVal; - ConstantInt *ShiftedCmpRHS = ConstantInt::get(ICI.getContext(), Comp); + ConstantInt *ShiftedCmpRHS = Builder->getInt(Comp); if (Shr->getOpcode() == Instruction::LShr) Comp = Comp.lshr(ShAmtVal); else @@ -1025,8 +1027,7 @@ Instruction *InstCombiner::FoldICmpShrCst(ICmpInst &ICI, BinaryOperator *Shr, if (Comp != CmpRHSV) { // Comparing against a bit that we know is zero. bool IsICMP_NE = ICI.getPredicate() == ICmpInst::ICMP_NE; - Constant *Cst = ConstantInt::get(Type::getInt1Ty(ICI.getContext()), - IsICMP_NE); + Constant *Cst = Builder->getInt1(IsICMP_NE); return ReplaceInstUsesWith(ICI, Cst); } @@ -1039,7 +1040,7 @@ Instruction *InstCombiner::FoldICmpShrCst(ICmpInst &ICI, BinaryOperator *Shr, if (Shr->hasOneUse()) { // Otherwise strength reduce the shift into an and. APInt Val(APInt::getHighBitsSet(TypeBits, TypeBits - ShAmtVal)); - Constant *Mask = ConstantInt::get(ICI.getContext(), Val); + Constant *Mask = Builder->getInt(Val); Value *And = Builder->CreateAnd(Shr->getOperand(0), Mask, Shr->getName()+".mask"); @@ -1072,7 +1073,7 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, APInt NewRHS = RHS->getValue().zext(SrcBits); NewRHS |= KnownOne & APInt::getHighBitsSet(SrcBits, SrcBits-DstBits); return new ICmpInst(ICI.getPredicate(), LHSI->getOperand(0), - ConstantInt::get(ICI.getContext(), NewRHS)); + Builder->getInt(NewRHS)); } } break; @@ -1115,8 +1116,7 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, ? ICI.getUnsignedPredicate() : ICI.getSignedPredicate(); return new ICmpInst(Pred, LHSI->getOperand(0), - ConstantInt::get(ICI.getContext(), - RHSV ^ SignBit)); + Builder->getInt(RHSV ^ SignBit)); } // (icmp u/s (xor A ~SignBit), C) -> (icmp s/u (xor C ~SignBit), A) @@ -1127,10 +1127,21 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, : ICI.getSignedPredicate(); Pred = ICI.getSwappedPredicate(Pred); return new ICmpInst(Pred, LHSI->getOperand(0), - ConstantInt::get(ICI.getContext(), - RHSV ^ NotSignBit)); + Builder->getInt(RHSV ^ NotSignBit)); } } + + // (icmp ugt (xor X, C), ~C) -> (icmp ult X, C) + // iff -C is a power of 2 + if (ICI.getPredicate() == ICmpInst::ICMP_UGT && + XorCST->getValue() == ~RHSV && (RHSV + 1).isPowerOf2()) + return new ICmpInst(ICmpInst::ICMP_ULT, LHSI->getOperand(0), XorCST); + + // (icmp ult (xor X, C), -C) -> (icmp uge X, C) + // iff -C is a power of 2 + if (ICI.getPredicate() == ICmpInst::ICMP_ULT && + XorCST->getValue() == -RHSV && RHSV.isPowerOf2()) + return new ICmpInst(ICmpInst::ICMP_UGE, LHSI->getOperand(0), XorCST); } break; case Instruction::And: // (icmp pred (and X, AndCST), RHS) @@ -1187,11 +1198,16 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, Type *AndTy = AndCST->getType(); // Type of the and. // We can fold this as long as we can't shift unknown bits - // into the mask. This can only happen with signed shift - // rights, as they sign-extend. + // into the mask. This can happen with signed shift + // rights, as they sign-extend. With logical shifts, + // we must still make sure the comparison is not signed + // because we are effectively changing the + // position of the sign bit (PR17827). + // TODO: We can relax these constraints a bit more. if (ShAmt) { - bool CanFold = Shift->isLogicalShift(); - if (!CanFold) { + bool CanFold = false; + unsigned ShiftOpcode = Shift->getOpcode(); + if (ShiftOpcode == Instruction::AShr) { // To test for the bad case of the signed shr, see if any // of the bits shifted in could be tested after the mask. uint32_t TyBits = Ty->getPrimitiveSizeInBits(); @@ -1201,6 +1217,9 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, if ((APInt::getHighBitsSet(BitWidth, BitWidth-ShAmtVal) & AndCST->getValue()) == 0) CanFold = true; + } else if (ShiftOpcode == Instruction::Shl || + ShiftOpcode == Instruction::LShr) { + CanFold = !ICI.isSigned(); } if (CanFold) { @@ -1218,11 +1237,9 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, // As a special case, check to see if this means that the // result is always true or false now. if (ICI.getPredicate() == ICmpInst::ICMP_EQ) - return ReplaceInstUsesWith(ICI, - ConstantInt::getFalse(ICI.getContext())); + return ReplaceInstUsesWith(ICI, Builder->getFalse()); if (ICI.getPredicate() == ICmpInst::ICMP_NE) - return ReplaceInstUsesWith(ICI, - ConstantInt::getTrue(ICI.getContext())); + return ReplaceInstUsesWith(ICI, Builder->getTrue()); } else { ICI.setOperand(1, NewCst); Constant *NewAndCST; @@ -1284,6 +1301,15 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, return Res; } } + + // X & -C == -C -> X > u ~C + // X & -C != -C -> X <= u ~C + // iff C is a power of 2 + if (ICI.isEquality() && RHS == LHSI->getOperand(1) && (-RHSV).isPowerOf2()) + return new ICmpInst( + ICI.getPredicate() == ICmpInst::ICMP_EQ ? ICmpInst::ICMP_UGT + : ICmpInst::ICMP_ULE, + LHSI->getOperand(0), SubOne(RHS)); break; case Instruction::Or: { @@ -1325,10 +1351,80 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, } case Instruction::Shl: { // (icmp pred (shl X, ShAmt), CI) + uint32_t TypeBits = RHSV.getBitWidth(); ConstantInt *ShAmt = dyn_cast<ConstantInt>(LHSI->getOperand(1)); - if (!ShAmt) break; + if (!ShAmt) { + Value *X; + // (1 << X) pred P2 -> X pred Log2(P2) + if (match(LHSI, m_Shl(m_One(), m_Value(X)))) { + bool RHSVIsPowerOf2 = RHSV.isPowerOf2(); + ICmpInst::Predicate Pred = ICI.getPredicate(); + if (ICI.isUnsigned()) { + if (!RHSVIsPowerOf2) { + // (1 << X) < 30 -> X <= 4 + // (1 << X) <= 30 -> X <= 4 + // (1 << X) >= 30 -> X > 4 + // (1 << X) > 30 -> X > 4 + if (Pred == ICmpInst::ICMP_ULT) + Pred = ICmpInst::ICMP_ULE; + else if (Pred == ICmpInst::ICMP_UGE) + Pred = ICmpInst::ICMP_UGT; + } + unsigned RHSLog2 = RHSV.logBase2(); + + // (1 << X) >= 2147483648 -> X >= 31 -> X == 31 + // (1 << X) > 2147483648 -> X > 31 -> false + // (1 << X) <= 2147483648 -> X <= 31 -> true + // (1 << X) < 2147483648 -> X < 31 -> X != 31 + if (RHSLog2 == TypeBits-1) { + if (Pred == ICmpInst::ICMP_UGE) + Pred = ICmpInst::ICMP_EQ; + else if (Pred == ICmpInst::ICMP_UGT) + return ReplaceInstUsesWith(ICI, Builder->getFalse()); + else if (Pred == ICmpInst::ICMP_ULE) + return ReplaceInstUsesWith(ICI, Builder->getTrue()); + else if (Pred == ICmpInst::ICMP_ULT) + Pred = ICmpInst::ICMP_NE; + } - uint32_t TypeBits = RHSV.getBitWidth(); + return new ICmpInst(Pred, X, + ConstantInt::get(RHS->getType(), RHSLog2)); + } else if (ICI.isSigned()) { + if (RHSV.isAllOnesValue()) { + // (1 << X) <= -1 -> X == 31 + if (Pred == ICmpInst::ICMP_SLE) + return new ICmpInst(ICmpInst::ICMP_EQ, X, + ConstantInt::get(RHS->getType(), TypeBits-1)); + + // (1 << X) > -1 -> X != 31 + if (Pred == ICmpInst::ICMP_SGT) + return new ICmpInst(ICmpInst::ICMP_NE, X, + ConstantInt::get(RHS->getType(), TypeBits-1)); + } else if (!RHSV) { + // (1 << X) < 0 -> X == 31 + // (1 << X) <= 0 -> X == 31 + if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SLE) + return new ICmpInst(ICmpInst::ICMP_EQ, X, + ConstantInt::get(RHS->getType(), TypeBits-1)); + + // (1 << X) >= 0 -> X != 31 + // (1 << X) > 0 -> X != 31 + if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE) + return new ICmpInst(ICmpInst::ICMP_NE, X, + ConstantInt::get(RHS->getType(), TypeBits-1)); + } + } else if (ICI.isEquality()) { + if (RHSVIsPowerOf2) + return new ICmpInst( + Pred, X, ConstantInt::get(RHS->getType(), RHSV.logBase2())); + + return ReplaceInstUsesWith( + ICI, Pred == ICmpInst::ICMP_EQ ? Builder->getFalse() + : Builder->getTrue()); + } + } + break; + } // Check that the shift amount is in range. If not, don't perform // undefined shifts. When the shift is visited it will be @@ -1344,8 +1440,7 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, ShAmt); if (Comp != RHS) {// Comparing against a bit that we know is zero. bool IsICMP_NE = ICI.getPredicate() == ICmpInst::ICMP_NE; - Constant *Cst = - ConstantInt::get(Type::getInt1Ty(ICI.getContext()), IsICMP_NE); + Constant *Cst = Builder->getInt1(IsICMP_NE); return ReplaceInstUsesWith(ICI, Cst); } @@ -1364,9 +1459,8 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, if (LHSI->hasOneUse()) { // Otherwise strength reduce the shift into an and. uint32_t ShAmtVal = (uint32_t)ShAmt->getLimitedValue(TypeBits); - Constant *Mask = - ConstantInt::get(ICI.getContext(), APInt::getLowBitsSet(TypeBits, - TypeBits-ShAmtVal)); + Constant *Mask = Builder->getInt(APInt::getLowBitsSet(TypeBits, + TypeBits - ShAmtVal)); Value *And = Builder->CreateAnd(LHSI->getOperand(0),Mask, LHSI->getName()+".mask"); @@ -1451,6 +1545,30 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, return R; break; + case Instruction::Sub: { + ConstantInt *LHSC = dyn_cast<ConstantInt>(LHSI->getOperand(0)); + if (!LHSC) break; + const APInt &LHSV = LHSC->getValue(); + + // C1-X <u C2 -> (X|(C2-1)) == C1 + // iff C1 & (C2-1) == C2-1 + // C2 is a power of 2 + if (ICI.getPredicate() == ICmpInst::ICMP_ULT && LHSI->hasOneUse() && + RHSV.isPowerOf2() && (LHSV & (RHSV - 1)) == (RHSV - 1)) + return new ICmpInst(ICmpInst::ICMP_EQ, + Builder->CreateOr(LHSI->getOperand(1), RHSV - 1), + LHSC); + + // C1-X >u C2 -> (X|C2) != C1 + // iff C1 & C2 == C2 + // C2+1 is a power of 2 + if (ICI.getPredicate() == ICmpInst::ICMP_UGT && LHSI->hasOneUse() && + (RHSV + 1).isPowerOf2() && (LHSV & RHSV) == RHSV) + return new ICmpInst(ICmpInst::ICMP_NE, + Builder->CreateOr(LHSI->getOperand(1), RHSV), LHSC); + break; + } + case Instruction::Add: // Fold: icmp pred (add X, C1), C2 if (!ICI.isEquality()) { @@ -1464,20 +1582,38 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, if (ICI.isSigned()) { if (CR.getLower().isSignBit()) { return new ICmpInst(ICmpInst::ICMP_SLT, LHSI->getOperand(0), - ConstantInt::get(ICI.getContext(),CR.getUpper())); + Builder->getInt(CR.getUpper())); } else if (CR.getUpper().isSignBit()) { return new ICmpInst(ICmpInst::ICMP_SGE, LHSI->getOperand(0), - ConstantInt::get(ICI.getContext(),CR.getLower())); + Builder->getInt(CR.getLower())); } } else { if (CR.getLower().isMinValue()) { return new ICmpInst(ICmpInst::ICMP_ULT, LHSI->getOperand(0), - ConstantInt::get(ICI.getContext(),CR.getUpper())); + Builder->getInt(CR.getUpper())); } else if (CR.getUpper().isMinValue()) { return new ICmpInst(ICmpInst::ICMP_UGE, LHSI->getOperand(0), - ConstantInt::get(ICI.getContext(),CR.getLower())); + Builder->getInt(CR.getLower())); } } + + // X-C1 <u C2 -> (X & -C2) == C1 + // iff C1 & (C2-1) == 0 + // C2 is a power of 2 + if (ICI.getPredicate() == ICmpInst::ICMP_ULT && LHSI->hasOneUse() && + RHSV.isPowerOf2() && (LHSV & (RHSV - 1)) == 0) + return new ICmpInst(ICmpInst::ICMP_EQ, + Builder->CreateAnd(LHSI->getOperand(0), -RHSV), + ConstantExpr::getNeg(LHSC)); + + // X-C1 >u C2 -> (X & ~C2) != C1 + // iff C1 & C2 == 0 + // C2+1 is a power of 2 + if (ICI.getPredicate() == ICmpInst::ICMP_UGT && LHSI->hasOneUse() && + (RHSV + 1).isPowerOf2() && (LHSV & RHSV) == 0) + return new ICmpInst(ICmpInst::ICMP_NE, + Builder->CreateAnd(LHSI->getOperand(0), ~RHSV), + ConstantExpr::getNeg(LHSC)); } break; } @@ -1555,9 +1691,7 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, if (ConstantInt *BOC = dyn_cast<ConstantInt>(BO->getOperand(1))) { Constant *NotCI = ConstantExpr::getNot(RHS); if (!ConstantExpr::getAnd(BOC, NotCI)->isNullValue()) - return ReplaceInstUsesWith(ICI, - ConstantInt::get(Type::getInt1Ty(ICI.getContext()), - isICMP_NE)); + return ReplaceInstUsesWith(ICI, Builder->getInt1(isICMP_NE)); } break; @@ -1566,9 +1700,7 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, // If bits are being compared against that are and'd out, then the // comparison can never succeed! if ((RHSV & ~BOC->getValue()) != 0) - return ReplaceInstUsesWith(ICI, - ConstantInt::get(Type::getInt1Ty(ICI.getContext()), - isICMP_NE)); + return ReplaceInstUsesWith(ICI, Builder->getInt1(isICMP_NE)); // If we have ((X & C) == C), turn it into ((X & C) != 0). if (RHS == BOC && RHSV.isPowerOf2()) @@ -1619,7 +1751,7 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI, case Intrinsic::bswap: Worklist.Add(II); ICI.setOperand(0, II->getArgOperand(0)); - ICI.setOperand(1, ConstantInt::get(II->getContext(), RHSV.byteSwap())); + ICI.setOperand(1, Builder->getInt(RHSV.byteSwap())); return &ICI; case Intrinsic::ctlz: case Intrinsic::cttz: @@ -1661,8 +1793,7 @@ Instruction *InstCombiner::visitICmpInstWithCastAndCast(ICmpInst &ICI) { // Turn icmp (ptrtoint x), (ptrtoint/c) into a compare of the input if the // integer type is the same size as the pointer type. if (TD && LHSCI->getOpcode() == Instruction::PtrToInt && - TD->getPointerSizeInBits() == - cast<IntegerType>(DestTy)->getBitWidth()) { + TD->getPointerTypeSizeInBits(SrcTy) == DestTy->getIntegerBitWidth()) { Value *RHSOp = 0; if (Constant *RHSC = dyn_cast<Constant>(ICI.getOperand(1))) { RHSOp = ConstantExpr::getIntToPtr(RHSC, SrcTy); @@ -1915,14 +2046,59 @@ static APInt DemandedBitsLHSMask(ICmpInst &I, } +/// \brief Check if the order of \p Op0 and \p Op1 as operand in an ICmpInst +/// should be swapped. +/// The descision is based on how many times these two operands are reused +/// as subtract operands and their positions in those instructions. +/// The rational is that several architectures use the same instruction for +/// both subtract and cmp, thus it is better if the order of those operands +/// match. +/// \return true if Op0 and Op1 should be swapped. +static bool swapMayExposeCSEOpportunities(const Value * Op0, + const Value * Op1) { + // Filter out pointer value as those cannot appears directly in subtract. + // FIXME: we may want to go through inttoptrs or bitcasts. + if (Op0->getType()->isPointerTy()) + return false; + // Count every uses of both Op0 and Op1 in a subtract. + // Each time Op0 is the first operand, count -1: swapping is bad, the + // subtract has already the same layout as the compare. + // Each time Op0 is the second operand, count +1: swapping is good, the + // subtract has a diffrent layout as the compare. + // At the end, if the benefit is greater than 0, Op0 should come second to + // expose more CSE opportunities. + int GlobalSwapBenefits = 0; + for (Value::const_use_iterator UI = Op0->use_begin(), UIEnd = Op0->use_end(); UI != UIEnd; ++UI) { + const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(*UI); + if (!BinOp || BinOp->getOpcode() != Instruction::Sub) + continue; + // If Op0 is the first argument, this is not beneficial to swap the + // arguments. + int LocalSwapBenefits = -1; + unsigned Op1Idx = 1; + if (BinOp->getOperand(Op1Idx) == Op0) { + Op1Idx = 0; + LocalSwapBenefits = 1; + } + if (BinOp->getOperand(Op1Idx) != Op1) + continue; + GlobalSwapBenefits += LocalSwapBenefits; + } + return GlobalSwapBenefits > 0; +} + Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { bool Changed = false; Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); + unsigned Op0Cplxity = getComplexity(Op0); + unsigned Op1Cplxity = getComplexity(Op1); /// Orders the operands of the compare so that they are listed from most /// complex to least complex. This puts constants before unary operators, /// before binary operators. - if (getComplexity(Op0) < getComplexity(Op1)) { + if (Op0Cplxity < Op1Cplxity || + (Op0Cplxity == Op1Cplxity && + swapMayExposeCSEOpportunities(Op0, Op1))) { I.swapOperands(); std::swap(Op0, Op1); Changed = true; @@ -2041,19 +2217,19 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { case ICmpInst::ICMP_ULE: assert(!CI->isMaxValue(false)); // A <=u MAX -> TRUE return new ICmpInst(ICmpInst::ICMP_ULT, Op0, - ConstantInt::get(CI->getContext(), CI->getValue()+1)); + Builder->getInt(CI->getValue()+1)); case ICmpInst::ICMP_SLE: assert(!CI->isMaxValue(true)); // A <=s MAX -> TRUE return new ICmpInst(ICmpInst::ICMP_SLT, Op0, - ConstantInt::get(CI->getContext(), CI->getValue()+1)); + Builder->getInt(CI->getValue()+1)); case ICmpInst::ICMP_UGE: assert(!CI->isMinValue(false)); // A >=u MIN -> TRUE return new ICmpInst(ICmpInst::ICMP_UGT, Op0, - ConstantInt::get(CI->getContext(), CI->getValue()-1)); + Builder->getInt(CI->getValue()-1)); case ICmpInst::ICMP_SGE: assert(!CI->isMinValue(true)); // A >=s MIN -> TRUE return new ICmpInst(ICmpInst::ICMP_SGT, Op0, - ConstantInt::get(CI->getContext(), CI->getValue()-1)); + Builder->getInt(CI->getValue()-1)); } // If this comparison is a normal comparison, it demands all @@ -2192,7 +2368,7 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { if (Op1Max == Op0Min+1) // A <u C -> A == C-1 if min(A)+1 == C return new ICmpInst(ICmpInst::ICMP_EQ, Op0, - ConstantInt::get(CI->getContext(), CI->getValue()-1)); + Builder->getInt(CI->getValue()-1)); // (x <u 2147483648) -> (x >s -1) -> true if sign bit clear if (CI->isMinValue(true)) @@ -2211,7 +2387,7 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { if (Op1Min == Op0Max-1) // A >u C -> A == C+1 if max(a)-1 == C return new ICmpInst(ICmpInst::ICMP_EQ, Op0, - ConstantInt::get(CI->getContext(), CI->getValue()+1)); + Builder->getInt(CI->getValue()+1)); // (x >u 2147483647) -> (x <s 0) -> true if sign bit set if (CI->isMaxValue(true)) @@ -2229,7 +2405,7 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { if (Op1Max == Op0Min+1) // A <s C -> A == C-1 if min(A)+1 == C return new ICmpInst(ICmpInst::ICMP_EQ, Op0, - ConstantInt::get(CI->getContext(), CI->getValue()-1)); + Builder->getInt(CI->getValue()-1)); } break; case ICmpInst::ICMP_SGT: @@ -2243,7 +2419,7 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { if (Op1Min == Op0Max-1) // A >s C -> A == C+1 if max(A)-1 == C return new ICmpInst(ICmpInst::ICMP_EQ, Op0, - ConstantInt::get(CI->getContext(), CI->getValue()+1)); + Builder->getInt(CI->getValue()+1)); } break; case ICmpInst::ICMP_SGE: @@ -2357,7 +2533,7 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { case Instruction::IntToPtr: // icmp pred inttoptr(X), null -> icmp pred X, 0 if (RHSC->isNullValue() && TD && - TD->getIntPtrType(RHSC->getContext()) == + TD->getIntPtrType(RHSC->getType()) == LHSI->getOperand(0)->getType()) return new ICmpInst(I.getPredicate(), LHSI->getOperand(0), Constant::getNullValue(LHSI->getOperand(0)->getType())); @@ -2719,8 +2895,7 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { ConstantInt *C1, *C2; if (match(B, m_ConstantInt(C1)) && match(D, m_ConstantInt(C2)) && Op1->hasOneUse()) { - Constant *NC = ConstantInt::get(I.getContext(), - C1->getValue() ^ C2->getValue()); + Constant *NC = Builder->getInt(C1->getValue() ^ C2->getValue()); Value *Xor = Builder->CreateXor(C, NC); return new ICmpInst(I.getPredicate(), A, Xor); } @@ -2781,6 +2956,24 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { Builder->CreateTrunc(B, A->getType())); } + // (A >> C) == (B >> C) --> (A^B) u< (1 << C) + // For lshr and ashr pairs. + if ((match(Op0, m_OneUse(m_LShr(m_Value(A), m_ConstantInt(Cst1)))) && + match(Op1, m_OneUse(m_LShr(m_Value(B), m_Specific(Cst1))))) || + (match(Op0, m_OneUse(m_AShr(m_Value(A), m_ConstantInt(Cst1)))) && + match(Op1, m_OneUse(m_AShr(m_Value(B), m_Specific(Cst1)))))) { + unsigned TypeBits = Cst1->getBitWidth(); + unsigned ShAmt = (unsigned)Cst1->getLimitedValue(TypeBits); + if (ShAmt < TypeBits && ShAmt != 0) { + ICmpInst::Predicate Pred = I.getPredicate() == ICmpInst::ICMP_NE + ? ICmpInst::ICMP_UGE + : ICmpInst::ICMP_ULT; + Value *Xor = Builder->CreateXor(A, B, I.getName() + ".unshifted"); + APInt CmpVal = APInt::getOneBitSet(TypeBits, ShAmt); + return new ICmpInst(Pred, Xor, Builder->getInt(CmpVal)); + } + } + // Transform "icmp eq (trunc (lshr(X, cst1)), cst" to // "icmp (and X, mask), cst" uint64_t ShAmt = 0; @@ -2811,20 +3004,15 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { Value *X; ConstantInt *Cst; // icmp X+Cst, X if (match(Op0, m_Add(m_Value(X), m_ConstantInt(Cst))) && Op1 == X) - return FoldICmpAddOpCst(I, X, Cst, I.getPredicate(), Op0); + return FoldICmpAddOpCst(I, X, Cst, I.getPredicate()); // icmp X, X+Cst if (match(Op1, m_Add(m_Value(X), m_ConstantInt(Cst))) && Op0 == X) - return FoldICmpAddOpCst(I, X, Cst, I.getSwappedPredicate(), Op1); + return FoldICmpAddOpCst(I, X, Cst, I.getSwappedPredicate()); } return Changed ? &I : 0; } - - - - - /// FoldFCmp_IntToFP_Cst - Fold fcmp ([us]itofp x, cst) if possible. /// Instruction *InstCombiner::FoldFCmp_IntToFP_Cst(FCmpInst &I, @@ -2885,9 +3073,9 @@ Instruction *InstCombiner::FoldFCmp_IntToFP_Cst(FCmpInst &I, Pred = ICmpInst::ICMP_NE; break; case FCmpInst::FCMP_ORD: - return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); + return ReplaceInstUsesWith(I, Builder->getTrue()); case FCmpInst::FCMP_UNO: - return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + return ReplaceInstUsesWith(I, Builder->getFalse()); } IntegerType *IntTy = cast<IntegerType>(LHSI->getOperand(0)->getType()); @@ -2901,50 +3089,50 @@ Instruction *InstCombiner::FoldFCmp_IntToFP_Cst(FCmpInst &I, if (!LHSUnsigned) { // If the RHS value is > SignedMax, fold the comparison. This handles +INF // and large values. - APFloat SMax(RHS.getSemantics(), APFloat::fcZero, false); + APFloat SMax(RHS.getSemantics()); SMax.convertFromAPInt(APInt::getSignedMaxValue(IntWidth), true, APFloat::rmNearestTiesToEven); if (SMax.compare(RHS) == APFloat::cmpLessThan) { // smax < 13123.0 if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SLE) - return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); - return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + return ReplaceInstUsesWith(I, Builder->getTrue()); + return ReplaceInstUsesWith(I, Builder->getFalse()); } } else { // If the RHS value is > UnsignedMax, fold the comparison. This handles // +INF and large values. - APFloat UMax(RHS.getSemantics(), APFloat::fcZero, false); + APFloat UMax(RHS.getSemantics()); UMax.convertFromAPInt(APInt::getMaxValue(IntWidth), false, APFloat::rmNearestTiesToEven); if (UMax.compare(RHS) == APFloat::cmpLessThan) { // umax < 13123.0 if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_ULE) - return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); - return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + return ReplaceInstUsesWith(I, Builder->getTrue()); + return ReplaceInstUsesWith(I, Builder->getFalse()); } } if (!LHSUnsigned) { // See if the RHS value is < SignedMin. - APFloat SMin(RHS.getSemantics(), APFloat::fcZero, false); + APFloat SMin(RHS.getSemantics()); SMin.convertFromAPInt(APInt::getSignedMinValue(IntWidth), true, APFloat::rmNearestTiesToEven); if (SMin.compare(RHS) == APFloat::cmpGreaterThan) { // smin > 12312.0 if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE) - return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); - return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + return ReplaceInstUsesWith(I, Builder->getTrue()); + return ReplaceInstUsesWith(I, Builder->getFalse()); } } else { // See if the RHS value is < UnsignedMin. - APFloat SMin(RHS.getSemantics(), APFloat::fcZero, false); + APFloat SMin(RHS.getSemantics()); SMin.convertFromAPInt(APInt::getMinValue(IntWidth), true, APFloat::rmNearestTiesToEven); if (SMin.compare(RHS) == APFloat::cmpGreaterThan) { // umin > 12312.0 if (Pred == ICmpInst::ICMP_NE || Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_UGE) - return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); - return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + return ReplaceInstUsesWith(I, Builder->getTrue()); + return ReplaceInstUsesWith(I, Builder->getFalse()); } } @@ -2966,14 +3154,14 @@ Instruction *InstCombiner::FoldFCmp_IntToFP_Cst(FCmpInst &I, switch (Pred) { default: llvm_unreachable("Unexpected integer comparison!"); case ICmpInst::ICMP_NE: // (float)int != 4.4 --> true - return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); + return ReplaceInstUsesWith(I, Builder->getTrue()); case ICmpInst::ICMP_EQ: // (float)int == 4.4 --> false - return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + return ReplaceInstUsesWith(I, Builder->getFalse()); case ICmpInst::ICMP_ULE: // (float)int <= 4.4 --> int <= 4 // (float)int <= -4.4 --> false if (RHS.isNegative()) - return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + return ReplaceInstUsesWith(I, Builder->getFalse()); break; case ICmpInst::ICMP_SLE: // (float)int <= 4.4 --> int <= 4 @@ -2985,7 +3173,7 @@ Instruction *InstCombiner::FoldFCmp_IntToFP_Cst(FCmpInst &I, // (float)int < -4.4 --> false // (float)int < 4.4 --> int <= 4 if (RHS.isNegative()) - return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + return ReplaceInstUsesWith(I, Builder->getFalse()); Pred = ICmpInst::ICMP_ULE; break; case ICmpInst::ICMP_SLT: @@ -2998,7 +3186,7 @@ Instruction *InstCombiner::FoldFCmp_IntToFP_Cst(FCmpInst &I, // (float)int > 4.4 --> int > 4 // (float)int > -4.4 --> true if (RHS.isNegative()) - return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); + return ReplaceInstUsesWith(I, Builder->getTrue()); break; case ICmpInst::ICMP_SGT: // (float)int > 4.4 --> int > 4 @@ -3010,7 +3198,7 @@ Instruction *InstCombiner::FoldFCmp_IntToFP_Cst(FCmpInst &I, // (float)int >= -4.4 --> true // (float)int >= 4.4 --> int > 4 if (RHS.isNegative()) - return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); + return ReplaceInstUsesWith(I, Builder->getTrue()); Pred = ICmpInst::ICMP_UGT; break; case ICmpInst::ICMP_SGE: |
