diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1984,6 +1984,7 @@
                        CUID, getDwarfVersion(), getUnits());
     return PrologEndLoc;
   }
+  assert(false);
   return DebugLoc();
 }