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[DAG] expandAddSubSat - break if-else chain. NFCI. 

Fix styleguide issue - each if() block always returns so we don't need to make them a if-else chain.
This commit is contained in:
Simon Pilgrim 2021-02-26 10:59:54 +00:00
parent a754dc2358
commit 73adc26ac0
1 changed files with 14 additions and 13 deletions
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27
llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
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@ -7892,8 +7892,7 @@ SDValue TargetLowering::expandAddSubSat(SDNode *Node, SelectionDAG &DAG) const {
unsigned BitWidth = LHS.getScalarValueSizeInBits(); unsigned BitWidth = LHS.getScalarValueSizeInBits();
EVT BoolVT = getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT); EVT BoolVT = getSetCCResultType(DAG.getDataLayout(), *DAG.getContext(), VT);
SDValue Result = DAG.getNode(OverflowOp, dl, DAG.getVTList(VT, BoolVT), SDValue Result = DAG.getNode(OverflowOp, dl, DAG.getVTList(VT, BoolVT), LHS, RHS);
LHS, RHS);
SDValue SumDiff = Result.getValue(0); SDValue SumDiff = Result.getValue(0);
SDValue Overflow = Result.getValue(1); SDValue Overflow = Result.getValue(1);
SDValue Zero = DAG.getConstant(0, dl, VT); SDValue Zero = DAG.getConstant(0, dl, VT);
@ -7907,7 +7906,9 @@ SDValue TargetLowering::expandAddSubSat(SDNode *Node, SelectionDAG &DAG) const {
} }
// Overflow ? 0xffff.... : (LHS + RHS) // Overflow ? 0xffff.... : (LHS + RHS)
return DAG.getSelect(dl, VT, Overflow, AllOnes, SumDiff); return DAG.getSelect(dl, VT, Overflow, AllOnes, SumDiff);
} else if (Opcode == ISD::USUBSAT) { }
if (Opcode == ISD::USUBSAT) {
if (getBooleanContents(VT) == ZeroOrNegativeOneBooleanContent) { if (getBooleanContents(VT) == ZeroOrNegativeOneBooleanContent) {
// (LHS - RHS) & ~OverflowMask // (LHS - RHS) & ~OverflowMask
SDValue OverflowMask = DAG.getSExtOrTrunc(Overflow, dl, VT); SDValue OverflowMask = DAG.getSExtOrTrunc(Overflow, dl, VT);
@ -7916,17 +7917,17 @@ SDValue TargetLowering::expandAddSubSat(SDNode *Node, SelectionDAG &DAG) const {
} }
// Overflow ? 0 : (LHS - RHS) // Overflow ? 0 : (LHS - RHS)
return DAG.getSelect(dl, VT, Overflow, Zero, SumDiff); return DAG.getSelect(dl, VT, Overflow, Zero, SumDiff);
} else {
// SatMax -> Overflow && SumDiff < 0
// SatMin -> Overflow && SumDiff >= 0
APInt MinVal = APInt::getSignedMinValue(BitWidth);
APInt MaxVal = APInt::getSignedMaxValue(BitWidth);
SDValue SatMin = DAG.getConstant(MinVal, dl, VT);
SDValue SatMax = DAG.getConstant(MaxVal, dl, VT);
SDValue SumNeg = DAG.getSetCC(dl, BoolVT, SumDiff, Zero, ISD::SETLT);
Result = DAG.getSelect(dl, VT, SumNeg, SatMax, SatMin);
return DAG.getSelect(dl, VT, Overflow, Result, SumDiff);
} }
// SatMax -> Overflow && SumDiff < 0
// SatMin -> Overflow && SumDiff >= 0
APInt MinVal = APInt::getSignedMinValue(BitWidth);
APInt MaxVal = APInt::getSignedMaxValue(BitWidth);
SDValue SatMin = DAG.getConstant(MinVal, dl, VT);
SDValue SatMax = DAG.getConstant(MaxVal, dl, VT);
SDValue SumNeg = DAG.getSetCC(dl, BoolVT, SumDiff, Zero, ISD::SETLT);
Result = DAG.getSelect(dl, VT, SumNeg, SatMax, SatMin);
return DAG.getSelect(dl, VT, Overflow, Result, SumDiff);
} }
SDValue TargetLowering::expandShlSat(SDNode *Node, SelectionDAG &DAG) const { SDValue TargetLowering::expandShlSat(SDNode *Node, SelectionDAG &DAG) const {