diff --git a/lib/ExecutionEngine/Interpreter/Execution.cpp b/lib/ExecutionEngine/Interpreter/Execution.cpp
index 732a485..abade5f 100644
--- a/lib/ExecutionEngine/Interpreter/Execution.cpp
+++ b/lib/ExecutionEngine/Interpreter/Execution.cpp
@@ -706,8 +706,7 @@
     if (const StructType *STy = dyn_cast<StructType>(*I)) {
       const StructLayout *SLO = TD.getStructLayout(STy);
       
-      // Indices must be ubyte constants...
-      const ConstantUInt *CPU = cast<ConstantUInt>(*I);
+      const ConstantUInt *CPU = cast<ConstantUInt>(I.getOperand());
       unsigned Index = CPU->getValue();
       
       Total += SLO->MemberOffsets[Index];