diff --git a/docs/LanguageExtensions.rst b/docs/LanguageExtensions.rst
index 65f4e7c63b6727d04c02db3657e06ee51129e401..917be931090afafaaeb8e5b2ffffae42d92e873e 100644
--- a/docs/LanguageExtensions.rst
+++ b/docs/LanguageExtensions.rst
@@ -921,8 +921,8 @@ enabled.
 C11 ``_Thread_local``
 ^^^^^^^^^^^^^^^^^^^^^
 
-Use ``__has_feature(c_thread_local)`` to determine if support for
-``_Thread_local`` variables is enabled.
+Use ``__has_feature(c_thread_local)`` or ``__has_extension(c_thread_local)``
+to determine if support for ``_Thread_local`` variables is enabled.
 
 Checks for Type Traits
 ======================
diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp
index 0eb1169c5ac5cee6285b85881f942382e2a7a276..0a4610d06c8b658a3f4c96bfda9486a785796ef9 100644
--- a/lib/Lex/PPMacroExpansion.cpp
+++ b/lib/Lex/PPMacroExpansion.cpp
@@ -1045,6 +1045,7 @@ static bool HasExtension(const Preprocessor &PP, const IdentifierInfo *II) {
            .Case("c_atomic", true)
            .Case("c_generic_selections", true)
            .Case("c_static_assert", true)
+           .Case("c_thread_local", PP.getTargetInfo().isTLSSupported())
            // C++11 features supported by other languages as extensions.
            .Case("cxx_atomic", LangOpts.CPlusPlus)
            .Case("cxx_deleted_functions", LangOpts.CPlusPlus)