diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index be6ef60..b9d0c98 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -340,7 +340,8 @@
   "<ucontext.h>">,
   InGroup<BuiltinRequiresHeader>;
 def warn_redecl_library_builtin : Warning<
-  "incompatible redeclaration of library function %0">;
+  "incompatible redeclaration of library function %0">,
+  InGroup<DiagGroup<"incompatible-library-redeclaration">>;
 def err_builtin_definition : Error<"definition of builtin function %0">;
 def err_types_compatible_p_in_cplusplus : Error<
   "__builtin_types_compatible_p is not valid in C++">;
diff --git a/test/Misc/warning-flags.c b/test/Misc/warning-flags.c
index 3a8c61b..3131826 100644
--- a/test/Misc/warning-flags.c
+++ b/test/Misc/warning-flags.c
@@ -18,7 +18,7 @@
 
 The list of warnings below should NEVER grow.  It should gradually shrink to 0.
 
-CHECK: Warnings without flags (147):
+CHECK: Warnings without flags (146):
 CHECK-NEXT:   ext_delete_void_ptr_operand
 CHECK-NEXT:   ext_enum_friend
 CHECK-NEXT:   ext_expected_semi_decl_list
@@ -143,7 +143,6 @@
 CHECK-NEXT:   warn_property_getter_owning_mismatch
 CHECK-NEXT:   warn_property_types_are_incompatible
 CHECK-NEXT:   warn_readonly_property
-CHECK-NEXT:   warn_redecl_library_builtin
 CHECK-NEXT:   warn_redeclaration_without_attribute_prev_attribute_ignored
 CHECK-NEXT:   warn_register_objc_catch_parm
 CHECK-NEXT:   warn_related_result_type_compatibility_class