diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index a16fb7f9d004c763764e36dbbc8e4f62f255e811..c497865bef03c961992a33e154304fde57eed156 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -6449,6 +6449,7 @@ enum CX_StorageClass clang_Cursor_getStorageClass(CXCursor C) {
   case SC_Register:
     return CX_SC_Register;
   }
+  llvm_unreachable("Unhandled storage class!");
 }
 
 CXCursor clang_getCursorSemanticParent(CXCursor cursor) {