diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index f64efd0..a84f2fe 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -4463,6 +4463,7 @@
   case OMPC_device_type:
   case OMPC_match:
   case OMPC_nontemporal:
+  case OMPC_order:
     llvm_unreachable("Clause is not allowed in 'omp atomic'.");
   }
 }