[llvm-commits] [llvm] r148537 - /llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
Bruno Cardoso Lopes
bruno.cardoso at gmail.com
Fri Jan 20 09:22:34 PST 2012
Hi Craig,
On Fri, Jan 20, 2012 at 7:29 AM, Craig Topper <craig.topper at gmail.com> wrote:
> Author: ctopper
> Date: Fri Jan 20 03:29:03 2012
> New Revision: 148537
>
> URL: http://llvm.org/viewvc/llvm-project?rev=148537&view=rev
> Log:
> Improve 256-bit shuffle splitting to allow 2 sources in each 128-bit lane. As long as only a single lane of the source is used in the lane in the destination. This makes the splitting match much closer to what happens with 256-bit shuffles when AVX is disabled and only 128-bit XMM is allowed.
>
> Modified:
> llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
>
> Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=148537&r1=148536&r2=148537&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Fri Jan 20 03:29:03 2012
> @@ -3162,17 +3162,6 @@
> return (Val < 0) || (Val >= Low && Val < Hi);
> }
>
> -/// isUndefOrInRange - Return true if every element in Mask, begining
> -/// from position Pos and ending in Pos+Size, falls within the specified
> -/// range (L, L+Pos]. or is undef.
> -static bool isUndefOrInRange(ArrayRef<int> Mask,
> - int Pos, int Size, int Low, int Hi) {
> - for (int i = Pos, e = Pos+Size; i != e; ++i)
> - if (!isUndefOrInRange(Mask[i], Low, Hi))
> - return false;
> - return true;
> -}
> -
> /// isUndefOrEqual - Val is either less than zero (undef) or equal to the
> /// specified value.
> static bool isUndefOrEqual(int Val, int CmpVal) {
> @@ -5948,95 +5937,106 @@
> OpVT, SrcOp)));
> }
>
> -/// areShuffleHalvesWithinDisjointLanes - Check whether each half of a vector
> -/// shuffle node referes to only one lane in the sources.
> -static bool areShuffleHalvesWithinDisjointLanes(ShuffleVectorSDNode *SVOp) {
> - EVT VT = SVOp->getValueType(0);
> - int NumElems = VT.getVectorNumElements();
> - int HalfSize = NumElems/2;
> - ArrayRef<int> M = SVOp->getMask();
> - bool MatchA = false, MatchB = false;
> -
> - for (int l = 0; l < NumElems*2; l += HalfSize) {
> - if (isUndefOrInRange(M, 0, HalfSize, l, l+HalfSize)) {
> - MatchA = true;
> - break;
> - }
> - }
> -
> - for (int l = 0; l < NumElems*2; l += HalfSize) {
> - if (isUndefOrInRange(M, HalfSize, HalfSize, l, l+HalfSize)) {
> - MatchB = true;
> - break;
> - }
> - }
> -
> - return MatchA && MatchB;
> -}
> -
> /// LowerVECTOR_SHUFFLE_256 - Handle all 256-bit wide vectors shuffles
> /// which could not be matched by any known target speficic shuffle
> static SDValue
> LowerVECTOR_SHUFFLE_256(ShuffleVectorSDNode *SVOp, SelectionDAG &DAG) {
> - if (areShuffleHalvesWithinDisjointLanes(SVOp)) {
> - // If each half of a vector shuffle node referes to only one lane in the
> - // source vectors, extract each used 128-bit lane and shuffle them using
> - // 128-bit shuffles. Then, concatenate the results. Otherwise leave
> - // the work to the legalizer.
> - DebugLoc dl = SVOp->getDebugLoc();
> - EVT VT = SVOp->getValueType(0);
> - int NumElems = VT.getVectorNumElements();
> - int HalfSize = NumElems/2;
> + EVT VT = SVOp->getValueType(0);
> +
> + unsigned NumElems = VT.getVectorNumElements();
> + unsigned NumLaneElems = NumElems / 2;
>
> - // Extract the reference for each half
> - int FstVecExtractIdx = 0, SndVecExtractIdx = 0;
> - int FstVecOpNum = 0, SndVecOpNum = 0;
> - for (int i = 0; i < HalfSize; ++i) {
> - int Elt = SVOp->getMaskElt(i);
> - if (SVOp->getMaskElt(i) < 0)
> + int MinRange[2][2] = { { static_cast<int>(NumElems),
> + static_cast<int>(NumElems) },
> + { static_cast<int>(NumElems),
> + static_cast<int>(NumElems) } };
> + int MaxRange[2][2] = { { -1, -1 }, { -1, -1 } };
The initial ideia of having all those different function was to make
the code more readable, could you please add a bunch of comments
making all this new code more understandable?
> + // Collect used ranges for each source in each lane
> + for (unsigned l = 0; l < 2; ++l) {
> + unsigned LaneStart = l*NumLaneElems;
> + for (unsigned i = 0; i != NumLaneElems; ++i) {
> + int Idx = SVOp->getMaskElt(i+LaneStart);
> + if (Idx < 0)
> continue;
> - FstVecOpNum = Elt/NumElems;
> - FstVecExtractIdx = Elt % NumElems < HalfSize ? 0 : HalfSize;
> - break;
> +
> + int Input = 0;
> + if (Idx >= (int)NumElems) {
> + Idx -= NumElems;
> + Input = 1;
> + }
> +
> + if (Idx > MaxRange[l][Input])
> + MaxRange[l][Input] = Idx;
> + if (Idx < MinRange[l][Input])
> + MinRange[l][Input] = Idx;
> }
> - for (int i = HalfSize; i < NumElems; ++i) {
> - int Elt = SVOp->getMaskElt(i);
> - if (SVOp->getMaskElt(i) < 0)
> + }
> +
> + // Make sure each range is 128-bits
> + int ExtractIdx[2][2] = { { -1, -1 }, { -1, -1 } };
> + for (unsigned l = 0; l < 2; ++l) {
> + for (unsigned Input = 0; Input < 2; ++Input) {
> + if (MinRange[l][Input] == (int)NumElems && MaxRange[l][Input] < 0)
> continue;
> - SndVecOpNum = Elt/NumElems;
> - SndVecExtractIdx = Elt % NumElems < HalfSize ? 0 : HalfSize;
> - break;
> +
> + if (MinRange[l][Input] >= 0 && MinRange[l][Input] < (int)NumLaneElems)
> + ExtractIdx[l][Input] = 0;
> + else if (MinRange[l][Input] >= (int)NumLaneElems &&
> + MinRange[l][Input] < (int)NumElems)
> + ExtractIdx[l][Input] = NumLaneElems;
> + else
> + return SDValue();
> }
> + }
>
> - // Extract the subvectors
> - SDValue V1 = Extract128BitVector(SVOp->getOperand(FstVecOpNum),
> - DAG.getConstant(FstVecExtractIdx, MVT::i32), DAG, dl);
> - SDValue V2 = Extract128BitVector(SVOp->getOperand(SndVecOpNum),
> - DAG.getConstant(SndVecExtractIdx, MVT::i32), DAG, dl);
> + DebugLoc dl = SVOp->getDebugLoc();
> + MVT EltVT = VT.getVectorElementType().getSimpleVT();
> + EVT NVT = MVT::getVectorVT(EltVT, NumElems/2);
>
> - // Generate 128-bit shuffles
> - SmallVector<int, 16> MaskV1, MaskV2;
> - for (int i = 0; i < HalfSize; ++i) {
> - int Elt = SVOp->getMaskElt(i);
> - MaskV1.push_back(Elt < 0 ? Elt : Elt % HalfSize);
> - }
> - for (int i = HalfSize; i < NumElems; ++i) {
> - int Elt = SVOp->getMaskElt(i);
> - MaskV2.push_back(Elt < 0 ? Elt : Elt % HalfSize);
> + SDValue Ops[2][2];
> + for (unsigned l = 0; l < 2; ++l) {
> + for (unsigned Input = 0; Input < 2; ++Input) {
> + if (ExtractIdx[l][Input] >= 0)
> + Ops[l][Input] = Extract128BitVector(SVOp->getOperand(Input),
> + DAG.getConstant(ExtractIdx[l][Input], MVT::i32),
> + DAG, dl);
> + else
> + Ops[l][Input] = DAG.getUNDEF(NVT);
> }
> + }
>
> - EVT NVT = V1.getValueType();
> - V1 = DAG.getVectorShuffle(NVT, dl, V1, DAG.getUNDEF(NVT), &MaskV1[0]);
> - V2 = DAG.getVectorShuffle(NVT, dl, V2, DAG.getUNDEF(NVT), &MaskV2[0]);
> -
> - // Concatenate the result back
> - SDValue V = Insert128BitVector(DAG.getNode(ISD::UNDEF, dl, VT), V1,
> - DAG.getConstant(0, MVT::i32), DAG, dl);
> - return Insert128BitVector(V, V2, DAG.getConstant(NumElems/2, MVT::i32),
> - DAG, dl);
> + // Generate 128-bit shuffles
> + SmallVector<int, 16> Mask1, Mask2;
> + for (unsigned i = 0; i != NumLaneElems; ++i) {
> + int Elt = SVOp->getMaskElt(i);
> + if (Elt >= (int)NumElems) {
> + Elt %= NumLaneElems;
> + Elt += NumLaneElems;
> + } else if (Elt >= 0) {
> + Elt %= NumLaneElems;
> + }
> + Mask1.push_back(Elt);
> + }
> + for (unsigned i = NumLaneElems; i != NumElems; ++i) {
> + int Elt = SVOp->getMaskElt(i);
> + if (Elt >= (int)NumElems) {
> + Elt %= NumLaneElems;
> + Elt += NumLaneElems;
> + } else if (Elt >= 0) {
> + Elt %= NumLaneElems;
> + }
> + Mask2.push_back(Elt);
> }
>
> - return SDValue();
> + SDValue Shuf1 = DAG.getVectorShuffle(NVT, dl, Ops[0][0], Ops[0][1], &Mask1[0]);
> + SDValue Shuf2 = DAG.getVectorShuffle(NVT, dl, Ops[1][0], Ops[1][1], &Mask2[0]);
> +
> + // Concatenate the result back
> + SDValue V = Insert128BitVector(DAG.getNode(ISD::UNDEF, dl, VT), Shuf1,
> + DAG.getConstant(0, MVT::i32), DAG, dl);
> + return Insert128BitVector(V, Shuf2, DAG.getConstant(NumElems/2, MVT::i32),
> + DAG, dl);
> }
>
> /// LowerVECTOR_SHUFFLE_128v4 - Handle all 128-bit wide vectors with
>
>
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--
Bruno Cardoso Lopes
http://www.brunocardoso.cc
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