diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 8d36a12c724..0a31f6bdb76 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,9 @@
+2019-07-02  Jonathan Wakely  <jwakely@redhat.com>
+
+	* include/bits/c++config (_GLIBCXX_HAVE_BUILTIN_LAUNDER)
+	(_GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED): Use __has_builtin
+	instead of __is_identifier to detect Clang support.
+
 2019-07-02  Jim Wilson  <jimw@sifive.com>
 
 	* configure.ac (BUILD_PDF): Also test for doxygen, dot, xsltproc,
diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
index 746e35efbfc..c8e099aaadd 100644
--- a/libstdc++-v3/include/bits/c++config
+++ b/libstdc++-v3/include/bits/c++config
@@ -636,7 +636,7 @@ namespace std
 # if __GNUC__ >= 9
 #  define _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED 1
 # endif
-#elif defined(__is_identifier)
+#elif defined(__is_identifier) && defined(__has_builtin)
 // For non-GNU compilers:
 # if ! __is_identifier(__has_unique_object_representations)
 #  define _GLIBCXX_HAVE_BUILTIN_HAS_UNIQ_OBJ_REP 1
@@ -644,10 +644,10 @@ namespace std
 # if ! __is_identifier(__is_aggregate)
 #  define _GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE 1
 # endif
-# if ! __is_identifier(__builtin_launder)
+# if __has_builtin(__builtin_launder)
 #  define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1
 # endif
-# if ! __is_identifier(__builtin_is_constant_evaluated)
+# if __has_builtin(__builtin_is_constant_evaluated)
 #  define _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED 1
 # endif
 #endif // GCC