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[DAGCombiner] Refactor code in visitShiftByConstant slightly to make it more readable. NFC 

This changes the isShift variable to include the constant operand
check that was previously in the if statement.

While there fix an 80 column violation and an unnecessary use of
getNode. Also fix variable name capitalization.

llvm-svn: 361168
This commit is contained in:
Craig Topper 2019-05-20 16:26:55 +00:00
parent 5239298b0d
commit 203bfdd0f0
1 changed files with 11 additions and 10 deletions
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21
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -6618,19 +6618,20 @@ SDValue DAGCombiner::visitShiftByConstant(SDNode *N, ConstantSDNode *Amt) {
return SDValue();
// FIXME: disable this unless the input to the binop is a shift by a constant
// or is copy/select.Enable this in other cases when figure out it's exactly profitable.
SDNode *BinOpLHSVal = LHS->getOperand(0).getNode();
bool isShift = BinOpLHSVal->getOpcode() == ISD::SHL ||
BinOpLHSVal->getOpcode() == ISD::SRA ||
BinOpLHSVal->getOpcode() == ISD::SRL;
bool isCopyOrSelect = BinOpLHSVal->getOpcode() == ISD::CopyFromReg ||
BinOpLHSVal->getOpcode() == ISD::SELECT;
// or is copy/select. Enable this in other cases when figure out it's exactly
// profitable.
SDValue BinOpLHSVal = LHS->getOperand(0);
bool IsShiftByConstant = (BinOpLHSVal.getOpcode() == ISD::SHL ||
BinOpLHSVal.getOpcode() == ISD::SRA ||
BinOpLHSVal.getOpcode() == ISD::SRL) &&
isa<ConstantSDNode>(BinOpLHSVal.getOperand(1));
bool IsCopyOrSelect = BinOpLHSVal.getOpcode() == ISD::CopyFromReg ||
BinOpLHSVal.getOpcode() == ISD::SELECT;
if ((!isShift || !isa<ConstantSDNode>(BinOpLHSVal->getOperand(1))) &&
!isCopyOrSelect)
if (!IsShiftByConstant && !IsCopyOrSelect)
return SDValue();
if (isCopyOrSelect && N->hasOneUse())
if (IsCopyOrSelect && N->hasOneUse())
return SDValue();
EVT VT = N->getValueType(0);