diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/LegalizeDAG.cpp | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp index 7cf71418fa..30044471d4 100644 --- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp +++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp @@ -867,6 +867,34 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) { } // FALLTHROUGH case TargetLowering::Expand: { + // If the insert index is a constant, codegen this as a scalar_to_vector, + // then a shuffle that inserts it into the right position in the vector. + if (ConstantSDNode *InsertPos = dyn_cast<ConstantSDNode>(Tmp3)) { + SDOperand ScVec = DAG.getNode(ISD::SCALAR_TO_VECTOR, + Tmp1.getValueType(), Tmp2); + + unsigned NumElts = MVT::getVectorNumElements(Tmp1.getValueType()); + MVT::ValueType ShufMaskVT = MVT::getIntVectorWithNumElements(NumElts); + MVT::ValueType ShufMaskEltVT = MVT::getVectorBaseType(ShufMaskVT); + + // We generate a shuffle of InVec and ScVec, so the shuffle mask should + // be 0,1,2,3,4,5... with the appropriate element replaced with elt 0 of + // the RHS. + std::vector<SDOperand> ShufOps; + for (unsigned i = 0; i != NumElts; ++i) { + if (i != InsertPos->getValue()) + ShufOps.push_back(DAG.getConstant(i, ShufMaskEltVT)); + else + ShufOps.push_back(DAG.getConstant(NumElts, ShufMaskEltVT)); + } + SDOperand ShufMask = DAG.getNode(ISD::BUILD_VECTOR, ShufMaskVT,ShufOps); + + Result = DAG.getNode(ISD::VECTOR_SHUFFLE, Tmp1.getValueType(), + Tmp1, ScVec, ShufMask); + Result = LegalizeOp(Result); + break; + } + // If the target doesn't support this, we have to spill the input vector // to a temporary stack slot, update the element, then reload it. This is // badness. We could also load the value into a vector register (either |