[TargetLowering] Begin generalizing TargetLowering::expandFP_TO_SINT support. NFCI.

Prior to initial work to add vector expansion support, remove assumptions that we're working on scalar types.

llvm-svn: 346139
This commit is contained in:
Simon Pilgrim 2018-11-05 15:49:09 +00:00
parent 3f04db3eb2
commit be432898f5

View File

@ -4077,64 +4077,64 @@ bool TargetLowering::expandMUL(SDNode *N, SDValue &Lo, SDValue &Hi, EVT HiLoVT,
bool TargetLowering::expandFP_TO_SINT(SDNode *Node, SDValue &Result,
SelectionDAG &DAG) const {
EVT VT = Node->getOperand(0).getValueType();
EVT NVT = Node->getValueType(0);
SDValue Src = Node->getOperand(0);
EVT SrcVT = Src.getValueType();
EVT DstVT = Node->getValueType(0);
SDLoc dl(SDValue(Node, 0));
// FIXME: Only f32 to i64 conversions are supported.
if (VT != MVT::f32 || NVT != MVT::i64)
if (SrcVT != MVT::f32 || DstVT != MVT::i64)
return false;
// Expand f32 -> i64 conversion
// This algorithm comes from compiler-rt's implementation of fixsfdi:
// https://github.com/llvm-mirror/compiler-rt/blob/master/lib/builtins/fixsfdi.c
EVT IntVT = EVT::getIntegerVT(*DAG.getContext(),
VT.getSizeInBits());
unsigned SrcEltBits = SrcVT.getScalarSizeInBits();
EVT IntVT = SrcVT.changeTypeToInteger();
EVT IntShVT = getShiftAmountTy(IntVT, DAG.getDataLayout());
SDValue ExponentMask = DAG.getConstant(0x7F800000, dl, IntVT);
SDValue ExponentLoBit = DAG.getConstant(23, dl, IntVT);
SDValue Bias = DAG.getConstant(127, dl, IntVT);
SDValue SignMask = DAG.getConstant(APInt::getSignMask(VT.getSizeInBits()), dl,
IntVT);
SDValue SignLowBit = DAG.getConstant(VT.getSizeInBits() - 1, dl, IntVT);
SDValue SignMask = DAG.getConstant(APInt::getSignMask(SrcEltBits), dl, IntVT);
SDValue SignLowBit = DAG.getConstant(SrcEltBits - 1, dl, IntVT);
SDValue MantissaMask = DAG.getConstant(0x007FFFFF, dl, IntVT);
SDValue Bits = DAG.getNode(ISD::BITCAST, dl, IntVT, Node->getOperand(0));
SDValue Bits = DAG.getNode(ISD::BITCAST, dl, IntVT, Src);
auto &DL = DAG.getDataLayout();
SDValue ExponentBits = DAG.getNode(
ISD::SRL, dl, IntVT, DAG.getNode(ISD::AND, dl, IntVT, Bits, ExponentMask),
DAG.getZExtOrTrunc(ExponentLoBit, dl, getShiftAmountTy(IntVT, DL)));
DAG.getZExtOrTrunc(ExponentLoBit, dl, IntShVT));
SDValue Exponent = DAG.getNode(ISD::SUB, dl, IntVT, ExponentBits, Bias);
SDValue Sign = DAG.getNode(
ISD::SRA, dl, IntVT, DAG.getNode(ISD::AND, dl, IntVT, Bits, SignMask),
DAG.getZExtOrTrunc(SignLowBit, dl, getShiftAmountTy(IntVT, DL)));
Sign = DAG.getSExtOrTrunc(Sign, dl, NVT);
SDValue Sign = DAG.getNode(ISD::SRA, dl, IntVT,
DAG.getNode(ISD::AND, dl, IntVT, Bits, SignMask),
DAG.getZExtOrTrunc(SignLowBit, dl, IntShVT));
Sign = DAG.getSExtOrTrunc(Sign, dl, DstVT);
SDValue R = DAG.getNode(ISD::OR, dl, IntVT,
DAG.getNode(ISD::AND, dl, IntVT, Bits, MantissaMask),
DAG.getConstant(0x00800000, dl, IntVT));
DAG.getNode(ISD::AND, dl, IntVT, Bits, MantissaMask),
DAG.getConstant(0x00800000, dl, IntVT));
R = DAG.getZExtOrTrunc(R, dl, NVT);
R = DAG.getZExtOrTrunc(R, dl, DstVT);
R = DAG.getSelectCC(
dl, Exponent, ExponentLoBit,
DAG.getNode(ISD::SHL, dl, NVT, R,
DAG.getNode(ISD::SHL, dl, DstVT, R,
DAG.getZExtOrTrunc(
DAG.getNode(ISD::SUB, dl, IntVT, Exponent, ExponentLoBit),
dl, getShiftAmountTy(IntVT, DL))),
DAG.getNode(ISD::SRL, dl, NVT, R,
dl, IntShVT)),
DAG.getNode(ISD::SRL, dl, DstVT, R,
DAG.getZExtOrTrunc(
DAG.getNode(ISD::SUB, dl, IntVT, ExponentLoBit, Exponent),
dl, getShiftAmountTy(IntVT, DL))),
dl, IntShVT)),
ISD::SETGT);
SDValue Ret = DAG.getNode(ISD::SUB, dl, NVT,
DAG.getNode(ISD::XOR, dl, NVT, R, Sign),
Sign);
SDValue Ret = DAG.getNode(ISD::SUB, dl, DstVT,
DAG.getNode(ISD::XOR, dl, DstVT, R, Sign), Sign);
Result = DAG.getSelectCC(dl, Exponent, DAG.getConstant(0, dl, IntVT),
DAG.getConstant(0, dl, NVT), Ret, ISD::SETLT);
DAG.getConstant(0, dl, DstVT), Ret, ISD::SETLT);
return true;
}