diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index f687675c722..9c108056445 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -356,7 +356,8 @@ void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock* mbb,
     }
 
     // a variable can only be killed by subsequent instructions
-    for (++mi; mi != e; ++mi) {
+    do {
+        ++mi;
         baseIndex += InstrSlots::NUM;
         for (KillIter ki = lv_->killed_begin(mi), ke = lv_->killed_end(mi);
              ki != ke; ++ki) {
@@ -366,13 +367,10 @@ void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock* mbb,
                 goto exit;
             }
         }
-    }
+    } while (mi != e);
 
-    // LiveVariables does not compute information for dead basic blocks.
-    DEBUG(std::cerr << "Didn't find the end of the interval.  Must be in a "
-          "dead block.");
-    end = getDefIndex(start)+1;
 exit:
+    assert(start < end && "did not find end of interval?");
     interval.addRange(start, end);
     DEBUG(std::cerr << '\n');
 }