https://gcc.gnu.org/g:3f3eb16743a126ebe6d200ad0091495b6f11962a
commit r15-1291-g3f3eb16743a126ebe6d200ad0091495b6f11962a Author: Ken Matsui <kmat...@gcc.gnu.org> Date: Thu Feb 15 00:49:55 2024 -0800 libstdc++: Optimize std::add_rvalue_reference compilation performance This patch optimizes the compilation performance of std::add_rvalue_reference by dispatching to the new __add_rvalue_reference built-in trait. libstdc++-v3/ChangeLog: * include/std/type_traits (__add_rval_ref_t): Use __add_rvalue_reference built-in trait. Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org> Reviewed-by: Patrick Palka <ppa...@redhat.com> Reviewed-by: Jonathan Wakely <jwak...@redhat.com> Diff: --- libstdc++-v3/include/std/type_traits | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits index 79983ea980a1..a31de2ee4abb 100644 --- a/libstdc++-v3/include/std/type_traits +++ b/libstdc++-v3/include/std/type_traits @@ -1184,6 +1184,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION }; /// @cond undocumented +#if _GLIBCXX_USE_BUILTIN_TRAIT(__add_rvalue_reference) + template<typename _Tp> + using __add_rval_ref_t = __add_rvalue_reference(_Tp); +#else template<typename _Tp, typename = void> struct __add_rvalue_reference_helper { using type = _Tp; }; @@ -1194,6 +1198,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template<typename _Tp> using __add_rval_ref_t = typename __add_rvalue_reference_helper<_Tp>::type; +#endif /// @endcond /// is_move_constructible