@@ -3675,11 +3675,16 @@ template<typename _Ret, typename _Fn, typename... _Args>
/// True for a type that is an array of unknown bound.
/// @ingroup variable_templates
/// @since C++20
+# if _GLIBCXX_USE_BUILTIN_TRAIT(__is_unbounded_array)
+ template<typename _Tp>
+ inline constexpr bool is_unbounded_array_v = __is_unbounded_array(_Tp);
+# else
template<typename _Tp>
inline constexpr bool is_unbounded_array_v = false;
template<typename _Tp>
inline constexpr bool is_unbounded_array_v<_Tp[]> = true;
+# endif
/// True for a type that is an array of known bound.
/// @since C++20
This patch optimizes the compilation performance of std::is_unbounded_array by dispatching to the new __is_unbounded_array built-in trait. libstdc++-v3/ChangeLog: * include/std/type_traits (is_unbounded_array_v): Use __is_unbounded_array built-in trait. Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org> --- libstdc++-v3/include/std/type_traits | 5 +++++ 1 file changed, 5 insertions(+)