diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 35c981d..5b1d103 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -808,7 +808,7 @@
     if (ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {
       // If the RHS of the AND has zeros where the sign bits of the SRA will
       // land, turn the SRA into an SRL.
-      if (MaskedValueIsZero(N1, (~0ULL << N01C->getValue()) &
+      if (MaskedValueIsZero(N1, (~0ULL << (OpSizeInBits-N01C->getValue())) &
                             (~0ULL>>(64-OpSizeInBits)), TLI)) {
         WorkList.push_back(N);
         CombineTo(N0.Val, DAG.getNode(ISD::SRL, VT, N0.getOperand(0),