diff --git a/llvm/tools/llvm-ar/llvm-ar.cpp b/llvm/tools/llvm-ar/llvm-ar.cpp
index 515f8991e84c..a9297eb05755 100644
--- a/llvm/tools/llvm-ar/llvm-ar.cpp
+++ b/llvm/tools/llvm-ar/llvm-ar.cpp
@@ -655,6 +655,8 @@ bool shouldCreateArchive(ArchiveOperation Op) {
   case ReplaceOrInsert:
     return true;
   }
+
+  llvm_unreachable("Missing entry in covered switch.");
 }
 
 // main - main program for llvm-ar .. see comments in the code