diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 79e76125bb..4f0d2caca2 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -1001,7 +1001,7 @@ void DAGCombiner::Run(CombineLevel AtLevel) { dbgs() << "\nWith: "; RV.getNode()->dump(&DAG); dbgs() << '\n'); - + // Transfer debug value. DAG.TransferDbgValues(SDValue(N, 0), RV); WorkListRemover DeadNodes(*this); @@ -1566,6 +1566,8 @@ SDValue DAGCombiner::visitSUB(SDNode *N) { SDValue N1 = N->getOperand(1); ConstantSDNode *N0C = dyn_cast<ConstantSDNode>(N0.getNode()); ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode()); + ConstantSDNode *N1C1 = N1.getOpcode() != ISD::ADD ? 0 : + dyn_cast<ConstantSDNode>(N1.getOperand(1).getNode()); EVT VT = N0.getValueType(); // fold vector ops @@ -1597,6 +1599,12 @@ SDValue DAGCombiner::visitSUB(SDNode *N) { // fold (A+B)-B -> A if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1) return N0.getOperand(0); + // fold C2-(A+C1) -> (C2-C1)-A + if (N1.getOpcode() == ISD::ADD && N0C && N1C1) { + SDValue NewC = DAG.getConstant((N0C->getAPIntValue() - N1C1->getAPIntValue()), VT); + return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, NewC, + N1.getOperand(0)); + } // fold ((A+(B+or-C))-B) -> A+or-C if (N0.getOpcode() == ISD::ADD && (N0.getOperand(1).getOpcode() == ISD::SUB || @@ -2571,7 +2579,7 @@ SDValue DAGCombiner::MatchBSwapHWordLow(SDNode *N, SDValue N0, SDValue N1, (!LookPassAnd0 || !LookPassAnd1) && !DAG.MaskedValueIsZero(N10, APInt::getHighBitsSet(OpSizeInBits, 16))) return SDValue(); - + SDValue Res = DAG.getNode(ISD::BSWAP, N->getDebugLoc(), VT, N00); if (OpSizeInBits > 16) Res = DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, Res, |