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[SelectionDAG] Use getActiveBits() and countTrailingZeros() to avoid creating temporary APInts with lshr and trunc. NFCI 

llvm-svn: 300819
This commit is contained in:
Craig Topper 2017-04-20 04:23:43 +00:00
parent ff04109ca2
commit d3884b8402
1 changed files with 3 additions and 4 deletions
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7
llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
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@ -839,7 +839,7 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op,
SDValue InnerOp = InOp.getNode()->getOperand(0);
EVT InnerVT = InnerOp.getValueType();
unsigned InnerBits = InnerVT.getSizeInBits();
if (ShAmt < InnerBits && NewMask.lshr(InnerBits) == 0 &&
if (ShAmt < InnerBits && NewMask.getActiveBits() <= InnerBits &&
isTypeDesirableForOp(ISD::SHL, InnerVT)) {
EVT ShTy = getShiftAmountTy(InnerVT, DL);
if (!APInt(BitWidth, ShAmt).isIntN(ShTy.getSizeInBits()))
@ -865,9 +865,8 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op,
->getZExtValue();
if (InnerShAmt < ShAmt &&
InnerShAmt < InnerBits &&
NewMask.lshr(std::min(InnerBits - InnerShAmt + ShAmt,
BitWidth)) == 0 &&
NewMask.trunc(ShAmt) == 0) {
NewMask.getActiveBits() <= (InnerBits - InnerShAmt + ShAmt) &&
NewMask.countTrailingZeros() >= ShAmt) {
SDValue NewSA =
TLO.DAG.getConstant(ShAmt - InnerShAmt, dl,
Op.getOperand(1).getValueType());