diff --git a/llvm/lib/IR/AsmWriter.cpp b/llvm/lib/IR/AsmWriter.cpp
index 777c240f01c8..477ed20d868a 100644
--- a/llvm/lib/IR/AsmWriter.cpp
+++ b/llvm/lib/IR/AsmWriter.cpp
@@ -3172,6 +3172,7 @@ static const char *getVisibilityName(GlobalValue::VisibilityTypes Vis) {
   case GlobalValue::ProtectedVisibility:
     return "protected";
   }
+  llvm_unreachable("invalid visibility");
 }
 
 void AssemblyWriter::printFunctionSummary(const FunctionSummary *FS) {