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[SelectionDAG] Early-out in TargetLowering::expandMUL (NFC)

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Summary: Reduce indentation level; preparation for D24956.

Reviewers: efriedma

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D27063

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287831 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nicolai Haehnle 2016-11-23 22:14:20 +00:00
parent cfae859e0c
commit da8f0a5694
1 changed files with 79 additions and 76 deletions
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155
lib/CodeGen/SelectionDAG/TargetLowering.cpp
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@ -3089,97 +3089,100 @@ bool TargetLowering::expandMUL(SDNode *N, SDValue &Lo, SDValue &Hi, EVT HiLoVT,
bool HasMULHU = isOperationLegalOrCustom(ISD::MULHU, HiLoVT);
bool HasSMUL_LOHI = isOperationLegalOrCustom(ISD::SMUL_LOHI, HiLoVT);
bool HasUMUL_LOHI = isOperationLegalOrCustom(ISD::UMUL_LOHI, HiLoVT);
if (HasMULHU || HasMULHS || HasUMUL_LOHI || HasSMUL_LOHI) {
unsigned OuterBitSize = VT.getSizeInBits();
unsigned InnerBitSize = HiLoVT.getSizeInBits();
unsigned LHSSB = DAG.ComputeNumSignBits(N->getOperand(0));
unsigned RHSSB = DAG.ComputeNumSignBits(N->getOperand(1));
// LL, LH, RL, and RH must be either all NULL or all set to a value.
assert((LL.getNode() && LH.getNode() && RL.getNode() && RH.getNode()) ||
(!LL.getNode() && !LH.getNode() && !RL.getNode() && !RH.getNode()));
if (!HasMULHU && !HasMULHS && !HasUMUL_LOHI && !HasSMUL_LOHI)
return false;
if (!LL.getNode() && !RL.getNode() &&
isOperationLegalOrCustom(ISD::TRUNCATE, HiLoVT)) {
LL = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, N->getOperand(0));
RL = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, N->getOperand(1));
}
unsigned OuterBitSize = VT.getSizeInBits();
unsigned InnerBitSize = HiLoVT.getSizeInBits();
unsigned LHSSB = DAG.ComputeNumSignBits(N->getOperand(0));
unsigned RHSSB = DAG.ComputeNumSignBits(N->getOperand(1));
if (!LL.getNode())
return false;
// LL, LH, RL, and RH must be either all NULL or all set to a value.
assert((LL.getNode() && LH.getNode() && RL.getNode() && RH.getNode()) ||
(!LL.getNode() && !LH.getNode() && !RL.getNode() && !RH.getNode()));
APInt HighMask = APInt::getHighBitsSet(OuterBitSize, InnerBitSize);
if (DAG.MaskedValueIsZero(N->getOperand(0), HighMask) &&
DAG.MaskedValueIsZero(N->getOperand(1), HighMask)) {
// The inputs are both zero-extended.
if (HasUMUL_LOHI) {
// We can emit a umul_lohi.
Lo = DAG.getNode(ISD::UMUL_LOHI, dl, DAG.getVTList(HiLoVT, HiLoVT), LL,
RL);
Hi = SDValue(Lo.getNode(), 1);
return true;
}
if (HasMULHU) {
// We can emit a mulhu+mul.
Lo = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RL);
Hi = DAG.getNode(ISD::MULHU, dl, HiLoVT, LL, RL);
return true;
}
}
if (LHSSB > InnerBitSize && RHSSB > InnerBitSize) {
// The input values are both sign-extended.
if (HasSMUL_LOHI) {
// We can emit a smul_lohi.
Lo = DAG.getNode(ISD::SMUL_LOHI, dl, DAG.getVTList(HiLoVT, HiLoVT), LL,
RL);
Hi = SDValue(Lo.getNode(), 1);
return true;
}
if (HasMULHS) {
// We can emit a mulhs+mul.
Lo = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RL);
Hi = DAG.getNode(ISD::MULHS, dl, HiLoVT, LL, RL);
return true;
}
}
if (!LL.getNode() && !RL.getNode() &&
isOperationLegalOrCustom(ISD::TRUNCATE, HiLoVT)) {
LL = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, N->getOperand(0));
RL = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, N->getOperand(1));
}
if (!LH.getNode() && !RH.getNode() &&
isOperationLegalOrCustom(ISD::SRL, VT) &&
isOperationLegalOrCustom(ISD::TRUNCATE, HiLoVT)) {
auto &DL = DAG.getDataLayout();
unsigned ShiftAmt = VT.getSizeInBits() - HiLoVT.getSizeInBits();
SDValue Shift = DAG.getConstant(ShiftAmt, dl, getShiftAmountTy(VT, DL));
LH = DAG.getNode(ISD::SRL, dl, VT, N->getOperand(0), Shift);
LH = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, LH);
RH = DAG.getNode(ISD::SRL, dl, VT, N->getOperand(1), Shift);
RH = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, RH);
}
if (!LH.getNode())
return false;
if (!LL.getNode())
return false;
APInt HighMask = APInt::getHighBitsSet(OuterBitSize, InnerBitSize);
if (DAG.MaskedValueIsZero(N->getOperand(0), HighMask) &&
DAG.MaskedValueIsZero(N->getOperand(1), HighMask)) {
// The inputs are both zero-extended.
if (HasUMUL_LOHI) {
// Lo,Hi = umul LHS, RHS.
SDValue UMulLOHI = DAG.getNode(ISD::UMUL_LOHI, dl,
DAG.getVTList(HiLoVT, HiLoVT), LL, RL);
Lo = UMulLOHI;
Hi = UMulLOHI.getValue(1);
RH = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RH);
LH = DAG.getNode(ISD::MUL, dl, HiLoVT, LH, RL);
Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, RH);
Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, LH);
// We can emit a umul_lohi.
Lo = DAG.getNode(ISD::UMUL_LOHI, dl, DAG.getVTList(HiLoVT, HiLoVT), LL,
RL);
Hi = SDValue(Lo.getNode(), 1);
return true;
}
if (HasMULHU) {
// We can emit a mulhu+mul.
Lo = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RL);
Hi = DAG.getNode(ISD::MULHU, dl, HiLoVT, LL, RL);
RH = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RH);
LH = DAG.getNode(ISD::MUL, dl, HiLoVT, LH, RL);
Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, RH);
Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, LH);
return true;
}
}
if (LHSSB > InnerBitSize && RHSSB > InnerBitSize) {
// The input values are both sign-extended.
if (HasSMUL_LOHI) {
// We can emit a smul_lohi.
Lo = DAG.getNode(ISD::SMUL_LOHI, dl, DAG.getVTList(HiLoVT, HiLoVT), LL,
RL);
Hi = SDValue(Lo.getNode(), 1);
return true;
}
if (HasMULHS) {
// We can emit a mulhs+mul.
Lo = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RL);
Hi = DAG.getNode(ISD::MULHS, dl, HiLoVT, LL, RL);
return true;
}
}
if (!LH.getNode() && !RH.getNode() &&
isOperationLegalOrCustom(ISD::SRL, VT) &&
isOperationLegalOrCustom(ISD::TRUNCATE, HiLoVT)) {
auto &DL = DAG.getDataLayout();
unsigned ShiftAmt = VT.getSizeInBits() - HiLoVT.getSizeInBits();
SDValue Shift = DAG.getConstant(ShiftAmt, dl, getShiftAmountTy(VT, DL));
LH = DAG.getNode(ISD::SRL, dl, VT, N->getOperand(0), Shift);
LH = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, LH);
RH = DAG.getNode(ISD::SRL, dl, VT, N->getOperand(1), Shift);
RH = DAG.getNode(ISD::TRUNCATE, dl, HiLoVT, RH);
}
if (!LH.getNode())
return false;
if (HasUMUL_LOHI) {
// Lo,Hi = umul LHS, RHS.
SDValue UMulLOHI = DAG.getNode(ISD::UMUL_LOHI, dl,
DAG.getVTList(HiLoVT, HiLoVT), LL, RL);
Lo = UMulLOHI;
Hi = UMulLOHI.getValue(1);
RH = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RH);
LH = DAG.getNode(ISD::MUL, dl, HiLoVT, LH, RL);
Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, RH);
Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, LH);
return true;
}
if (HasMULHU) {
Lo = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RL);
Hi = DAG.getNode(ISD::MULHU, dl, HiLoVT, LL, RL);
RH = DAG.getNode(ISD::MUL, dl, HiLoVT, LL, RH);
LH = DAG.getNode(ISD::MUL, dl, HiLoVT, LH, RL);
Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, RH);
Hi = DAG.getNode(ISD::ADD, dl, HiLoVT, Hi, LH);
return true;
}
return false;
}