[InstCombine] Use APInt::setSignBit and APInt::isNegative(). NFC

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@300305 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Craig Topper 2017-04-14 05:09:04 +00:00
parent de136fdf4c
commit d62c8b3151

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@ -571,7 +571,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
// If any of the "high bits" are demanded, we should set the sign bit as
// demanded.
if (DemandedMask.countLeadingZeros() <= ShiftAmt)
DemandedMaskIn.setBit(BitWidth-1);
DemandedMaskIn.setSignBit();
// If the shift is exact, then it does demand the low bits (and knows that
// they are zero).
@ -629,12 +629,12 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
// If LHS is non-negative or has all low bits zero, then the upper bits
// are all zero.
if (LHSKnownZero[BitWidth-1] || ((LHSKnownZero & LowBits) == LowBits))
if (LHSKnownZero.isNegative() || ((LHSKnownZero & LowBits) == LowBits))
KnownZero |= ~LowBits;
// If LHS is negative and not all low bits are zero, then the upper bits
// are all one.
if (LHSKnownOne[BitWidth-1] && ((LHSKnownOne & LowBits) != 0))
if (LHSKnownOne.isNegative() && ((LHSKnownOne & LowBits) != 0))
KnownOne |= ~LowBits;
assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?");