diff --git a/include/clang/Basic/DiagnosticGroups.td b/include/clang/Basic/DiagnosticGroups.td
index bc87e11..cce2720 100644
--- a/include/clang/Basic/DiagnosticGroups.td
+++ b/include/clang/Basic/DiagnosticGroups.td
@@ -285,6 +285,7 @@
 def VLA : DiagGroup<"vla">;
 def VolatileRegisterVar : DiagGroup<"volatile-register-var">;
 def Visibility : DiagGroup<"visibility">;
+def ZeroLengthArray : DiagGroup<"zero-length-array">;
 
 // GCC calls -Wdeprecated-writable-strings -Wwrite-strings.
 def GCCWriteStrings : DiagGroup<"write-strings" , [DeprecatedWritableStr]>;
@@ -432,7 +433,7 @@
 def C99 : DiagGroup<"c99-extensions">;
 
 // A warning group for warnings about GCC extensions.
-def GNU : DiagGroup<"gnu", [GNUDesignator, VLA]>;
+def GNU : DiagGroup<"gnu", [GNUDesignator, VLA, ZeroLengthArray]>;
 // A warning group for warnings about code that clang accepts but gcc doesn't.
 def GccCompat : DiagGroup<"gcc-compat">;
 
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index b026127..07a278e 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3286,7 +3286,7 @@
 def err_typecheck_invalid_restrict_invalid_pointee : Error<
   "pointer to function type %0 may not be 'restrict' qualified">;
 def ext_typecheck_zero_array_size : Extension<
-  "zero size arrays are an extension">;
+  "zero size arrays are an extension">, InGroup<ZeroLengthArray>;
 def err_typecheck_zero_array_size : Error<
   "zero-length arrays are not permitted in C++">;
 def warn_typecheck_zero_static_array_size : Warning<
diff --git a/test/Misc/warning-flags.c b/test/Misc/warning-flags.c
index a1a0d7e..fb5cd5c 100644
--- a/test/Misc/warning-flags.c
+++ b/test/Misc/warning-flags.c
@@ -180,4 +180,4 @@
 
 The list of warnings in -Wpedantic should NEVER grow.
 
-CHECK: Number in -Wpedantic (not covered by other -W flags): 38
+CHECK: Number in -Wpedantic (not covered by other -W flags): 37
diff --git a/test/Sema/array-init.c b/test/Sema/array-init.c
index ad0fc70..b3cae60 100644
--- a/test/Sema/array-init.c
+++ b/test/Sema/array-init.c
@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -fsyntax-only -pedantic -verify %s
+// RUN: %clang_cc1 -fsyntax-only -Wgnu -Wc11-extensions -verify %s
 // REQUIRES: LP64
 
 extern int foof() = 1; // expected-error{{illegal initializer (only variables can be initialized)}}