diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 43 |
1 files changed, 28 insertions, 15 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 09a94ebe19..5dbc5240e8 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -582,29 +582,30 @@ static ConstantInt *SubOne(ConstantInt *C) { /// this won't lose us code quality. static void ComputeMaskedBits(Value *V, APInt Mask, APInt& KnownZero, APInt& KnownOne, unsigned Depth = 0) { + assert(V && "No Value?"); + assert(Depth <= 6 && "Limit Search Depth"); uint32_t BitWidth = Mask.getBitWidth(); - assert(KnownZero.getBitWidth() == BitWidth && + const IntegerType *VTy = cast<IntegerType>(V->getType()); + assert(VTy->getBitWidth() == BitWidth && + KnownZero.getBitWidth() == BitWidth && KnownOne.getBitWidth() == BitWidth && - "Mask, KnownOne and KnownZero should have same BitWidth"); + "VTy, Mask, KnownOne and KnownZero should have same BitWidth"); if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) { // We know all of the bits for a constant! - APInt Tmp(CI->getValue()); - Tmp.zextOrTrunc(BitWidth); - KnownOne = Tmp & Mask; + KnownOne = CI->getValue() & Mask; KnownZero = ~KnownOne & Mask; return; } - KnownZero.clear(); KnownOne.clear(); // Don't know anything. if (Depth == 6 || Mask == 0) return; // Limit search depth. Instruction *I = dyn_cast<Instruction>(V); if (!I) return; + KnownZero.clear(); KnownOne.clear(); // Don't know anything. APInt KnownZero2(KnownZero), KnownOne2(KnownOne); - Mask &= APInt::getAllOnesValue( - cast<IntegerType>(V->getType())->getBitWidth()).zextOrTrunc(BitWidth); + Mask &= APInt::getAllOnesValue(BitWidth); switch (I->getOpcode()) { case Instruction::And: @@ -664,10 +665,16 @@ static void ComputeMaskedBits(Value *V, APInt Mask, APInt& KnownZero, case Instruction::UIToFP: case Instruction::IntToPtr: return; // Can't work with floating point or pointers - case Instruction::Trunc: + case Instruction::Trunc: { // All these have integer operands - ComputeMaskedBits(I->getOperand(0), Mask, KnownZero, KnownOne, Depth+1); + uint32_t SrcBitWidth = + cast<IntegerType>(I->getOperand(0)->getType())->getBitWidth(); + ComputeMaskedBits(I->getOperand(0), Mask.zext(SrcBitWidth), + KnownZero.zext(SrcBitWidth), KnownOne.zext(SrcBitWidth), Depth+1); + KnownZero.trunc(BitWidth); + KnownOne.trunc(BitWidth); return; + } case Instruction::BitCast: { const Type *SrcTy = I->getOperand(0)->getType(); if (SrcTy->isInteger()) { @@ -681,10 +688,13 @@ static void ComputeMaskedBits(Value *V, APInt Mask, APInt& KnownZero, const IntegerType *SrcTy = cast<IntegerType>(I->getOperand(0)->getType()); APInt NewBits(APInt::getAllOnesValue(BitWidth).shl(SrcTy->getBitWidth())); - Mask &= SrcTy->getMask().zextOrTrunc(BitWidth); - ComputeMaskedBits(I->getOperand(0), Mask, KnownZero, KnownOne, Depth+1); + uint32_t SrcBitWidth = SrcTy->getBitWidth(); + ComputeMaskedBits(I->getOperand(0), Mask.trunc(SrcBitWidth), + KnownZero.trunc(SrcBitWidth), KnownOne.trunc(SrcBitWidth), Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); // The top bits are known to be zero. + KnownZero.zext(BitWidth); + KnownOne.zext(BitWidth); KnownZero |= NewBits; return; } @@ -693,14 +703,17 @@ static void ComputeMaskedBits(Value *V, APInt Mask, APInt& KnownZero, const IntegerType *SrcTy = cast<IntegerType>(I->getOperand(0)->getType()); APInt NewBits(APInt::getAllOnesValue(BitWidth).shl(SrcTy->getBitWidth())); - Mask &= SrcTy->getMask().zextOrTrunc(BitWidth); - ComputeMaskedBits(I->getOperand(0), Mask, KnownZero, KnownOne, Depth+1); + uint32_t SrcBitWidth = SrcTy->getBitWidth(); + ComputeMaskedBits(I->getOperand(0), Mask.trunc(SrcBitWidth), + KnownZero.trunc(SrcBitWidth), KnownOne.trunc(SrcBitWidth), Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); + KnownZero.zext(BitWidth); + KnownOne.zext(BitWidth); // If the sign bit of the input is known set or clear, then we know the // top bits of the result. APInt InSignBit(APInt::getSignBit(SrcTy->getBitWidth())); - InSignBit.zextOrTrunc(BitWidth); + InSignBit.zext(BitWidth); if ((KnownZero & InSignBit) != 0) { // Input sign bit known zero KnownZero |= NewBits; KnownOne &= ~NewBits; |