diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index fd218939727..51ff5219228 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -30921,6 +30921,59 @@ static SDValue foldVectorXorShiftIntoCmp(SDNode *N, SelectionDAG &DAG, return DAG.getNode(X86ISD::PCMPGT, SDLoc(N), VT, Shift.getOperand(0), Ones); } +/// Check if truncation with saturation form type \p SrcVT to \p DstVT +/// is valid for the given \p Subtarget. +static bool +isSATValidOnSubtarget(EVT SrcVT, EVT DstVT, const X86Subtarget &Subtarget) { + if (!Subtarget.hasAVX512()) + return false; + EVT SrcElVT = SrcVT.getScalarType(); + EVT DstElVT = DstVT.getScalarType(); + if (SrcElVT.getSizeInBits() < 16 || SrcElVT.getSizeInBits() > 64) + return false; + if (DstElVT.getSizeInBits() < 8 || DstElVT.getSizeInBits() > 32) + return false; + if (SrcVT.is512BitVector() || Subtarget.hasVLX()) + return SrcElVT.getSizeInBits() >= 32 || Subtarget.hasBWI(); + return false; +} + +/// Detect a pattern of truncation with saturation: +/// (truncate (umin (x, unsigned_max_of_dest_type)) to dest_type). +/// Return the source value to be truncated or SDValue() if the pattern was not +/// matched or the unsupported on the current target. +static SDValue +detectUSatPattern(SDValue In, EVT VT, const X86Subtarget &Subtarget) { + if (In.getOpcode() != ISD::UMIN) + return SDValue(); + + EVT InVT = In.getValueType(); + // FIXME: Scalar type may be supported if we move it to vector register. + if (!InVT.isVector() || !InVT.isSimple()) + return SDValue(); + + if (!isSATValidOnSubtarget(InVT, VT, Subtarget)) + return SDValue(); + + //Saturation with truncation. We truncate from InVT to VT. + assert(InVT.getScalarSizeInBits() > VT.getScalarSizeInBits() && + "Unexpected types for truncate operation"); + + SDValue SrcVal; + APInt C; + if (ISD::isConstantSplatVector(In.getOperand(0).getNode(), C)) + SrcVal = In.getOperand(1); + else if (ISD::isConstantSplatVector(In.getOperand(1).getNode(), C)) + SrcVal = In.getOperand(0); + else + return SDValue(); + + // C should be equal to UINT32_MAX / UINT16_MAX / UINT8_MAX according + // the element size of the destination type. + return (C == ((uint64_t)1 << VT.getScalarSizeInBits()) - 1) ? + SrcVal : SDValue(); +} + /// This function detects the AVG pattern between vectors of unsigned i8/i16, /// which is c = (a + b + 1) / 2, and replace this operation with the efficient /// X86ISD::AVG instruction. @@ -31487,6 +31540,12 @@ static SDValue combineStore(SDNode *N, SelectionDAG &DAG, St->getPointerInfo(), St->getAlignment(), St->getMemOperand()->getFlags()); + if (SDValue Val = + detectUSatPattern(St->getValue(), St->getMemoryVT(), Subtarget)) + return EmitTruncSStore(false /* Unsigned saturation */, St->getChain(), + dl, Val, St->getBasePtr(), + St->getMemoryVT(), St->getMemOperand(), DAG); + const TargetLowering &TLI = DAG.getTargetLoweringInfo(); unsigned NumElems = VT.getVectorNumElements(); assert(StVT != VT && "Cannot truncate to the same type"); @@ -32104,6 +32163,10 @@ static SDValue combineTruncate(SDNode *N, SelectionDAG &DAG, if (SDValue Avg = detectAVGPattern(Src, VT, DAG, Subtarget, DL)) return Avg; + // Try the truncation with unsigned saturation. + if (SDValue Val = detectUSatPattern(Src, VT, Subtarget)) + return DAG.getNode(X86ISD::VTRUNCUS, DL, VT, Val); + // The bitcast source is a direct mmx result. // Detect bitcasts between i32 to x86mmx if (Src.getOpcode() == ISD::BITCAST && VT == MVT::i32) { |
