diff options
Diffstat (limited to 'llvm/lib/Target/ARM/ARMISelLowering.cpp')
| -rw-r--r-- | llvm/lib/Target/ARM/ARMISelLowering.cpp | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp index e00e338bd28..ac4233cf92e 100644 --- a/llvm/lib/Target/ARM/ARMISelLowering.cpp +++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp @@ -5715,6 +5715,44 @@ static SDValue LowerVECTOR_SHUFFLE(SDValue Op, SelectionDAG &DAG) { .getValue(WhichResult); } + // Also check for these shuffles through CONCAT_VECTORS: we canonicalize + // shuffles that produce a result larger than their operands with: + // shuffle(concat(v1, undef), concat(v2, undef)) + // -> + // shuffle(concat(v1, v2), undef) + // because we can access quad vectors (see PerformVECTOR_SHUFFLECombine). + // + // This is useful in the general case, but there are special cases where + // native shuffles produce larger results: the two-result ops. + // + // Look through the concat when lowering them: + // shuffle(concat(v1, v2), undef) + // -> + // concat(VZIP(v1, v2):0, :1) + // + if (V1->getOpcode() == ISD::CONCAT_VECTORS && + V2->getOpcode() == ISD::UNDEF) { + SDValue SubV1 = V1->getOperand(0); + SDValue SubV2 = V1->getOperand(1); + EVT SubVT = SubV1.getValueType(); + + // We expect these to have been canonicalized to -1. + assert(std::all_of(ShuffleMask.begin(), ShuffleMask.end(), [&](int i) { + return i < (int)VT.getVectorNumElements(); + }) && "Unexpected shuffle index into UNDEF operand!"); + + if (unsigned ShuffleOpc = isNEONTwoResultShuffleMask( + ShuffleMask, SubVT, WhichResult, isV_UNDEF)) { + if (isV_UNDEF) + SubV2 = SubV1; + assert((WhichResult == 0) && + "In-place shuffle of concat can only have one result!"); + SDValue Res = DAG.getNode(ShuffleOpc, dl, DAG.getVTList(SubVT, SubVT), + SubV1, SubV2); + return DAG.getNode(ISD::CONCAT_VECTORS, dl, VT, Res.getValue(0), + Res.getValue(1)); + } + } } // If the shuffle is not directly supported and it has 4 elements, use |
