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R600: Simplify LowerUDIVREM 

optimizations can handle removing the Hi part operations.
The generated code is identical for R600, ~10% icount reduction for SI

v2: rebase

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
Reviewed-by: Matt Arsenault <Matthew.Arsenault@amd.com>
llvm-svn: 226879
This commit is contained in:
Jan Vesely 2015-01-22 23:42:39 +00:00
parent 405de4ae10
commit f7987ca5a7
1 changed files with 11 additions and 19 deletions
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30
llvm/lib/Target/R600/AMDGPUISelLowering.cpp
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@ -1665,8 +1665,8 @@ void AMDGPUTargetLowering::LowerUDIVREM64(SDValue Op,
SDValue DIV_Part = DAG.getNode(ISD::UDIV, DL, HalfVT, LHS_Hi, RHS_Lo);
SDValue REM_Part = DAG.getNode(ISD::UREM, DL, HalfVT, LHS_Hi, RHS_Lo);
SDValue REM_Hi = zero;
SDValue REM_Lo = DAG.getSelectCC(DL, RHS_Hi, zero, REM_Part, LHS_Hi, ISD::SETEQ);
SDValue REM = DAG.getNode(ISD::BUILD_PAIR, DL, VT, REM_Lo, zero);
SDValue DIV_Hi = DAG.getSelectCC(DL, RHS_Hi, zero, DIV_Part, zero, ISD::SETEQ);
SDValue DIV_Lo = zero;
@ -1674,8 +1674,10 @@ void AMDGPUTargetLowering::LowerUDIVREM64(SDValue Op,
const unsigned halfBitWidth = HalfVT.getSizeInBits();
for (unsigned i = 0; i < halfBitWidth; ++i) {
SDValue POS = DAG.getConstant(halfBitWidth - i - 1, HalfVT);
// Get Value of high bit
const unsigned bitPos = halfBitWidth - i - 1;
SDValue POS = DAG.getConstant(bitPos, HalfVT);
// Get value of high bit
// TODO: Remove the BFE part when the optimization is fixed
SDValue HBit;
if (halfBitWidth == 32 && Subtarget->hasBFE()) {
HBit = DAG.getNode(AMDGPUISD::BFE_U32, DL, HalfVT, LHS_Lo, POS, one);
@ -1683,33 +1685,23 @@ void AMDGPUTargetLowering::LowerUDIVREM64(SDValue Op,
HBit = DAG.getNode(ISD::SRL, DL, HalfVT, LHS_Lo, POS);
HBit = DAG.getNode(ISD::AND, DL, HalfVT, HBit, one);
}
HBit = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, HBit);
SDValue Carry = DAG.getNode(ISD::SRL, DL, HalfVT, REM_Lo,
DAG.getConstant(halfBitWidth - 1, HalfVT));
REM_Hi = DAG.getNode(ISD::SHL, DL, HalfVT, REM_Hi, one);
REM_Hi = DAG.getNode(ISD::OR, DL, HalfVT, REM_Hi, Carry);
// Shift
REM = DAG.getNode(ISD::SHL, DL, VT, REM, DAG.getConstant(1, VT));
// Add LHS high bit
REM = DAG.getNode(ISD::OR, DL, VT, REM, HBit);
REM_Lo = DAG.getNode(ISD::SHL, DL, HalfVT, REM_Lo, one);
REM_Lo = DAG.getNode(ISD::OR, DL, HalfVT, REM_Lo, HBit);
SDValue REM = DAG.getNode(ISD::BUILD_PAIR, DL, VT, REM_Lo, REM_Hi);
SDValue BIT = DAG.getConstant(1 << (halfBitWidth - i - 1), HalfVT);
SDValue BIT = DAG.getConstant(1 << bitPos, HalfVT);
SDValue realBIT = DAG.getSelectCC(DL, REM, RHS, BIT, zero, ISD::SETUGE);
DIV_Lo = DAG.getNode(ISD::OR, DL, HalfVT, DIV_Lo, realBIT);
// Update REM
SDValue REM_sub = DAG.getNode(ISD::SUB, DL, VT, REM, RHS);
REM = DAG.getSelectCC(DL, REM, RHS, REM_sub, REM, ISD::SETUGE);
REM_Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, HalfVT, REM, zero);
REM_Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, HalfVT, REM, one);
}
SDValue REM = DAG.getNode(ISD::BUILD_PAIR, DL, VT, REM_Lo, REM_Hi);
SDValue DIV = DAG.getNode(ISD::BUILD_PAIR, DL, VT, DIV_Lo, DIV_Hi);
Results.push_back(DIV);
Results.push_back(REM);