diff --git a/lib/CodeGen/PrologEpilogInserter.cpp b/lib/CodeGen/PrologEpilogInserter.cpp
index a2a8af3..66ec0b3 100644
--- a/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/lib/CodeGen/PrologEpilogInserter.cpp
@@ -782,8 +782,8 @@
     unsigned CurrentScratchReg = 0;
     unsigned PrevScratchReg = 0;
     int PrevValue;
-    MachineInstr *PrevLastUseMI;
-    unsigned PrevLastUseOp;
+    MachineInstr *PrevLastUseMI = NULL;
+    unsigned PrevLastUseOp = 0;
 
     // The instruction stream may change in the loop, so check BB->end()
     // directly.
@@ -875,6 +875,7 @@
           if (MI->getOperand(i).isKill()) {
             PrevScratchReg = CurrentScratchReg;
             PrevLastUseMI = MI;
+            PrevLastUseOp = i;
             CurrentScratchReg = CurrentVirtReg = 0;
           }
         }