diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index d4b6332..cfc52d9 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -801,6 +801,55 @@ SDOperand combineShlAddConstant(SDOperand N0, SDOperand N1, SelectionDAG &DAG) { return SDOperand(); } +static +SDOperand combineSelectAndUse(SDNode *N, SDOperand Slct, SDOperand OtherOp, + SelectionDAG &DAG) { + MVT::ValueType VT = N->getValueType(0); + unsigned Opc = N->getOpcode(); + bool isSlctCC = Slct.getOpcode() == ISD::SELECT_CC; + SDOperand LHS = isSlctCC ? Slct.getOperand(2) : Slct.getOperand(1); + SDOperand RHS = isSlctCC ? Slct.getOperand(3) : Slct.getOperand(2); + ISD::CondCode CC = ISD::SETCC_INVALID; + if (isSlctCC) + CC = cast<CondCodeSDNode>(Slct.getOperand(4))->get(); + else { + SDOperand CCOp = Slct.getOperand(0); + if (CCOp.getOpcode() == ISD::SETCC) + CC = cast<CondCodeSDNode>(CCOp.getOperand(2))->get(); + } + + bool DoXform = false; + bool InvCC = false; + assert ((Opc == ISD::ADD || (Opc == ISD::SUB && Slct == N->getOperand(1))) && + "Bad input!"); + if (LHS.getOpcode() == ISD::Constant && + cast<ConstantSDNode>(LHS)->isNullValue()) + DoXform = true; + else if (CC != ISD::SETCC_INVALID && + RHS.getOpcode() == ISD::Constant && + cast<ConstantSDNode>(RHS)->isNullValue()) { + std::swap(LHS, RHS); + bool isInt = MVT::isInteger(isSlctCC ? Slct.getOperand(0).getValueType() + : Slct.getOperand(0).getOperand(0).getValueType()); + CC = ISD::getSetCCInverse(CC, isInt); + DoXform = true; + InvCC = true; + } + + if (DoXform) { + SDOperand Result = DAG.getNode(Opc, VT, OtherOp, RHS); + if (isSlctCC) + return DAG.getSelectCC(OtherOp, Result, + Slct.getOperand(0), Slct.getOperand(1), CC); + SDOperand CCOp = Slct.getOperand(0); + if (InvCC) + CCOp = DAG.getSetCC(CCOp.getValueType(), CCOp.getOperand(0), + CCOp.getOperand(1), CC); + return DAG.getNode(ISD::SELECT, VT, CCOp, OtherOp, Result); + } + return SDOperand(); +} + SDOperand DAGCombiner::visitADD(SDNode *N) { SDOperand N0 = N->getOperand(0); SDOperand N1 = N->getOperand(1); @@ -869,6 +918,16 @@ SDOperand DAGCombiner::visitADD(SDNode *N) { if (Result.Val) return Result; } + // fold (add (select cc, 0, c), x) -> (select cc, x, (add, x, c)) + if (N0.getOpcode() == ISD::SELECT && N0.Val->hasOneUse()) { + SDOperand Result = combineSelectAndUse(N, N0, N1, DAG); + if (Result.Val) return Result; + } + if (N1.getOpcode() == ISD::SELECT && N1.Val->hasOneUse()) { + SDOperand Result = combineSelectAndUse(N, N1, N0, DAG); + if (Result.Val) return Result; + } + return SDOperand(); } @@ -960,6 +1019,11 @@ SDOperand DAGCombiner::visitSUB(SDNode *N) { // fold (A+B)-B -> A if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1) return N0.getOperand(0); + // fold (sub x, (select cc, 0, c)) -> (select cc, x, (sub, x, c)) + if (N1.getOpcode() == ISD::SELECT && N1.Val->hasOneUse()) { + SDOperand Result = combineSelectAndUse(N, N1, N0, DAG); + if (Result.Val) return Result; + } return SDOperand(); } |