diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 8d4ea8d61042..434855ffa93f 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -23,7 +23,8 @@ def ext_expr_not_ice : Extension<
 
 // Semantic analysis of constant literals.
 def ext_predef_outside_function : Warning<
-  "predefined identifier is only valid inside function">;
+  "predefined identifier is only valid inside function">,
+  InGroup<DiagGroup<"predefined-identifier-outside-function">>;
 def warn_float_overflow : Warning<
   "magnitude of floating-point constant too large for type %0; maximum is %1">,
    InGroup<LiteralRange>;
diff --git a/clang/test/Misc/warning-flags.c b/clang/test/Misc/warning-flags.c
index 6ee27f84fa29..1099effba8b6 100644
--- a/clang/test/Misc/warning-flags.c
+++ b/clang/test/Misc/warning-flags.c
@@ -17,7 +17,7 @@ This test serves two purposes:
 
 The list of warnings below should NEVER grow.  It should gradually shrink to 0.
 
-CHECK: Warnings without flags (304):
+CHECK: Warnings without flags (303):
 CHECK-NEXT:   backslash_newline_space
 CHECK-NEXT:   charize_microsoft_ext
 CHECK-NEXT:   ext_anon_param_requires_type_specifier
@@ -81,7 +81,6 @@ CHECK-NEXT:   ext_pp_include_next_directive
 CHECK-NEXT:   ext_pp_line_too_big
 CHECK-NEXT:   ext_pp_macro_redef
 CHECK-NEXT:   ext_pp_warning_directive
-CHECK-NEXT:   ext_predef_outside_function
 CHECK-NEXT:   ext_return_has_void_expr
 CHECK-NEXT:   ext_subscript_non_lvalue
 CHECK-NEXT:   ext_template_arg_extra_parens