diff options
Diffstat (limited to 'lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
-rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 7dd85a8be7..32c07ad4f5 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -274,6 +274,7 @@ namespace { SDValue visitCONCAT_VECTORS(SDNode *N); SDValue visitEXTRACT_SUBVECTOR(SDNode *N); SDValue visitVECTOR_SHUFFLE(SDNode *N); + SDValue visitINSERT_SUBVECTOR(SDNode *N); SDValue XformToShuffleWithZero(SDNode *N); SDValue ReassociateOps(unsigned Opc, SDLoc DL, SDValue LHS, SDValue RHS); @@ -1230,6 +1231,7 @@ SDValue DAGCombiner::visit(SDNode *N) { case ISD::CONCAT_VECTORS: return visitCONCAT_VECTORS(N); case ISD::EXTRACT_SUBVECTOR: return visitEXTRACT_SUBVECTOR(N); case ISD::VECTOR_SHUFFLE: return visitVECTOR_SHUFFLE(N); + case ISD::INSERT_SUBVECTOR: return visitINSERT_SUBVECTOR(N); } return SDValue(); } @@ -10433,6 +10435,33 @@ SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) { return SDValue(); } +SDValue DAGCombiner::visitINSERT_SUBVECTOR(SDNode *N) { + SDValue N0 = N->getOperand(0); + SDValue N2 = N->getOperand(2); + + // If the input vector is a concatenation, and the insert replaces + // one of the halves, we can optimize into a single concat_vectors. + if (N0.getOpcode() == ISD::CONCAT_VECTORS && + N0->getNumOperands() == 2 && N2.getOpcode() == ISD::Constant) { + APInt InsIdx = cast<ConstantSDNode>(N2)->getAPIntValue(); + EVT VT = N->getValueType(0); + + // Lower half: fold (insert_subvector (concat_vectors X, Y), Z) -> + // (concat_vectors Z, Y) + if (InsIdx == 0) + return DAG.getNode(ISD::CONCAT_VECTORS, SDLoc(N), VT, + N->getOperand(1), N0.getOperand(1)); + + // Upper half: fold (insert_subvector (concat_vectors X, Y), Z) -> + // (concat_vectors X, Z) + if (InsIdx == VT.getVectorNumElements()/2) + return DAG.getNode(ISD::CONCAT_VECTORS, SDLoc(N), VT, + N0.getOperand(0), N->getOperand(1)); + } + + return SDValue(); +} + /// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform /// an AND to a vector_shuffle with the destination vector and a zero vector. /// e.g. AND V, <0xffffffff, 0, 0xffffffff, 0>. ==> |