The index stored in the RegDefIter is one after the current index. When getting the index, decrement it so that it points to the current element. Fixes an off-by-one bug encountered when trying to make use of MVT::untyped.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133923 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.h

@@ -140,7 +140,7 @@ namespace llvm {
       }
 
       unsigned GetIdx() const {
-        return DefIdx;
+        return DefIdx-1;
       }
 
       void Advance();