diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 37e3895..5bb3cfa 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -100,11 +100,14 @@
       i2miMap_.push_back(I);
       MIIndex += InstrSlots::NUM;
     }
-
+    
+    if (StartIdx == MIIndex) {
+      // Empty MBB
+      MIIndex += InstrSlots::NUM;
+      i2miMap_.push_back(0);
+    }
     // Set the MBB2IdxMap entry for this MBB.
-    MBB2IdxMap[MBB->getNumber()] = (StartIdx == MIIndex)
-      ? std::make_pair(StartIdx, StartIdx)  // Empty MBB
-      : std::make_pair(StartIdx, MIIndex - 1);
+    MBB2IdxMap[MBB->getNumber()] = std::make_pair(StartIdx, MIIndex - 1);
     Idx2MBBMap.push_back(std::make_pair(StartIdx, MBB));
   }
   std::sort(Idx2MBBMap.begin(), Idx2MBBMap.end(), Idx2MBBCompare());
@@ -661,6 +664,8 @@
       
       MIIndex += InstrSlots::NUM;
     }
+    
+    if (MBB->begin() == miEnd) MIIndex += InstrSlots::NUM; // Empty MBB
   }
 }