diff options
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 8ec0c45eaff..b9da13af752 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -9721,6 +9721,27 @@ SDValue DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) { return SDValue(); unsigned Elt = cast<ConstantSDNode>(EltNo)->getZExtValue(); + // Canonicalize insert_vector_elt dag nodes. + // Example: + // (insert_vector_elt (insert_vector_elt A, Idx0), Idx1) + // -> (insert_vector_elt (insert_vector_elt A, Idx1), Idx0) + // + // Do this only if the child insert_vector node has one use; also + // do this only if indices are both constants and Idx1 < Idx0. + if (InVec.getOpcode() == ISD::INSERT_VECTOR_ELT && InVec.hasOneUse() + && isa<ConstantSDNode>(InVec.getOperand(2))) { + unsigned OtherElt = + cast<ConstantSDNode>(InVec.getOperand(2))->getZExtValue(); + if (Elt < OtherElt) { + // Swap nodes. + SDValue NewOp = DAG.getNode(ISD::INSERT_VECTOR_ELT, SDLoc(N), VT, + InVec.getOperand(0), InVal, EltNo); + AddToWorkList(NewOp.getNode()); + return DAG.getNode(ISD::INSERT_VECTOR_ELT, SDLoc(InVec.getNode()), + VT, NewOp, InVec.getOperand(1), InVec.getOperand(2)); + } + } + // Check that the operand is a BUILD_VECTOR (or UNDEF, which can essentially // be converted to a BUILD_VECTOR). Fill in the Ops vector with the // vector elements. |
