Fixed msvc warnings

llvm-svn: 269242
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 6c934a8..bffa621 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -775,6 +775,7 @@
   case Triple::UnknownObjectFormat:
     return ".llvmbc";
   }
+  llvm_unreachable("Unimplemented ObjectFormatType");
 }
 
 static const char* getSectionNameForCommandline(const Triple &T) {
@@ -786,6 +787,7 @@
   case Triple::UnknownObjectFormat:
     return ".llvmcmd";
   }
+  llvm_unreachable("Unimplemented ObjectFormatType");
 }
 
 // With -fembed-bitcode, save a copy of the llvm IR as data in the