diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 0ce8b3faeb5ab5d43690688235f9df2cf2e98b50..30ada12bc73d2de40013f8603992b1ca40b08f1a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -587,7 +587,7 @@ bool TargetLowering::SimplifyDemandedBits(SDOperand Op, uint64_t DemandedMask,
           }          
           
           SDOperand NewSA = 
-            TLO.DAG.getConstant(ShAmt-C1, Op.getOperand(1).getValueType());
+            TLO.DAG.getConstant(Diff, Op.getOperand(1).getValueType());
           MVT::ValueType VT = Op.getValueType();
           return TLO.CombineTo(Op, TLO.DAG.getNode(Opc, VT,
                                                    InOp.getOperand(0), NewSA));