diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 9d327c7883..02336e59c4 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -675,11 +675,9 @@ static void ComputeMaskedBits(Value *V, APInt Mask, APInt& KnownZero, case Instruction::ZExt: { // Compute the bits in the result that are not present in the input. const IntegerType *SrcTy = cast<IntegerType>(I->getOperand(0)->getType()); - APInt NotIn(~SrcTy->getMask()); - APInt NewBits = APInt::getAllOnesValue(BitWidth) & - NotIn.zext(BitWidth); + APInt NewBits(APInt::getAllOnesValue(BitWidth).shl(SrcTy->getBitWidth())); - Mask &= ~NotIn; + Mask &= SrcTy->getMask().zext(BitWidth); ComputeMaskedBits(I->getOperand(0), Mask, KnownZero, KnownOne, Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); // The top bits are known to be zero. @@ -689,11 +687,9 @@ static void ComputeMaskedBits(Value *V, APInt Mask, APInt& KnownZero, case Instruction::SExt: { // Compute the bits in the result that are not present in the input. const IntegerType *SrcTy = cast<IntegerType>(I->getOperand(0)->getType()); - APInt NotIn(~SrcTy->getMask()); - APInt NewBits = APInt::getAllOnesValue(BitWidth) & - NotIn.zext(BitWidth); + APInt NewBits(APInt::getAllOnesValue(BitWidth).shl(SrcTy->getBitWidth())); - Mask &= ~NotIn; + Mask &= SrcTy->getMask().zext(BitWidth); ComputeMaskedBits(I->getOperand(0), Mask, KnownZero, KnownOne, Depth+1); assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?"); |