diff options
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 44a49e848aa..f460d529d05 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -4740,6 +4740,10 @@ SDValue DAGCombiner::visitSRA(SDNode *N) { EVT VT = N0.getValueType(); unsigned OpSizeInBits = VT.getScalarSizeInBits(); + // Arithmetic shifting an all-sign-bit value is a no-op. + if (DAG.ComputeNumSignBits(N0) == OpSizeInBits) + return N0; + // fold vector ops ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1); if (VT.isVector()) { |
