diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 64014dcb054..f093bf46f68 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -1897,6 +1897,21 @@ SDOperand DAGCombiner::visitANY_EXTEND(SDNode *N) { return DAG.getNode(ISD::TRUNCATE, VT, TruncOp); return DAG.getNode(ISD::ANY_EXTEND, VT, TruncOp); } + + // fold (aext (and (trunc x), cst)) -> (and x, cst). + if (N0.getOpcode() == ISD::AND && + N0.getOperand(0).getOpcode() == ISD::TRUNCATE && + N0.getOperand(1).getOpcode() == ISD::Constant) { + SDOperand X = N0.getOperand(0).getOperand(0); + if (X.getValueType() < VT) { + X = DAG.getNode(ISD::ANY_EXTEND, VT, X); + } else if (X.getValueType() > VT) { + X = DAG.getNode(ISD::TRUNCATE, VT, X); + } + uint64_t Mask = cast(N0.getOperand(1))->getValue(); + return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT)); + } + // fold (aext (load x)) -> (aext (truncate (extload x))) if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() && (!AfterLegalize||TLI.isOperationLegal(ISD::EXTLOAD, N0.getValueType()))) {