diff --git a/clang/lib/Driver/ToolChains/BareMetal.cpp b/clang/lib/Driver/ToolChains/BareMetal.cpp
index 60ecf6c09ba9..66246f6d71cd 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.cpp
+++ b/clang/lib/Driver/ToolChains/BareMetal.cpp
@@ -136,6 +136,7 @@ std::string BareMetal::findLibCxxIncludePath(CXXStdlibType LibType) const {
     return Dir.str();
   }
   }
+  llvm_unreachable("unhandled LibType");
 }
 
 void BareMetal::AddClangCXXStdlibIncludeArgs(