diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 0d41e51f48d..16863e615a1 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -2115,6 +2115,18 @@ SDValue DAGCombiner::visitADD(SDNode *N) { if (N0.getOpcode() == ISD::SUB && N1 == N0.getOperand(1)) return N0.getOperand(0); + // fold ((A-B)+(C-A)) -> (C-B) + if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB && + N0.getOperand(0) == N1.getOperand(1)) + return DAG.getNode(ISD::SUB, DL, VT, N1.getOperand(0), + N0.getOperand(1)); + + // fold ((A-B)+(B-C)) -> (A-C) + if (N0.getOpcode() == ISD::SUB && N1.getOpcode() == ISD::SUB && + N0.getOperand(1) == N1.getOperand(0)) + return DAG.getNode(ISD::SUB, DL, VT, N0.getOperand(0), + N1.getOperand(1)); + // fold (A+(B-(A+C))) to (B-C) if (N1.getOpcode() == ISD::SUB && N1.getOperand(1).getOpcode() == ISD::ADD && N0 == N1.getOperand(1).getOperand(0)) |
