diff options
Diffstat (limited to 'llvm/lib/CodeGen')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 49cd7596f5a..9a06077587d 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -2161,6 +2161,15 @@ SDValue DAGCombiner::visitADDLike(SDNode *N) { return N0; if (isConstantOrConstantVector(N1, /* NoOpaque */ true)) { + // fold ((A-c1)+c2) -> (A+(c2-c1)) + if (N0.getOpcode() == ISD::SUB && + isConstantOrConstantVector(N0.getOperand(1), /* NoOpaque */ true)) { + SDValue Sub = DAG.FoldConstantArithmetic(ISD::SUB, DL, VT, N1.getNode(), + N0.getOperand(1).getNode()); + assert(Sub && "Constant folding failed"); + return DAG.getNode(ISD::ADD, DL, VT, N0.getOperand(0), Sub); + } + // fold ((c1-A)+c2) -> (c1+c2)-A if (N0.getOpcode() == ISD::SUB && isConstantOrConstantVector(N0.getOperand(0), /* NoOpaque */ true)) { |
