https://gcc.gnu.org/g:6f0dfa6f1acdf78d764d6f5d6f53c2f2a768c047
commit r15-1252-g6f0dfa6f1acdf78d764d6f5d6f53c2f2a768c047 Author: Ken Matsui <kmat...@gcc.gnu.org> Date: Thu Feb 15 07:19:02 2024 -0800 libstdc++: Optimize std::rank compilation performance This patch optimizes the compilation performance of std::rank by dispatching to the new __array_rank built-in trait. libstdc++-v3/ChangeLog: * include/std/type_traits (rank): Use __array_rank built-in trait. (rank_v): Likewise. 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 | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits index 3d158f993a8b..5402574efe99 100644 --- a/libstdc++-v3/include/std/type_traits +++ b/libstdc++-v3/include/std/type_traits @@ -1447,6 +1447,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION }; /// rank +#if _GLIBCXX_USE_BUILTIN_TRAIT(__array_rank) + template<typename _Tp> + struct rank + : public integral_constant<std::size_t, __array_rank(_Tp)> { }; +#else template<typename> struct rank : public integral_constant<std::size_t, 0> { }; @@ -1458,6 +1463,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template<typename _Tp> struct rank<_Tp[]> : public integral_constant<std::size_t, 1 + rank<_Tp>::value> { }; +#endif /// extent template<typename, unsigned _Uint = 0> @@ -3531,12 +3537,17 @@ template <typename _Tp> template <typename _Tp> inline constexpr size_t alignment_of_v = alignment_of<_Tp>::value; +#if _GLIBCXX_USE_BUILTIN_TRAIT(__array_rank) +template <typename _Tp> + inline constexpr size_t rank_v = __array_rank(_Tp); +#else template <typename _Tp> inline constexpr size_t rank_v = 0; template <typename _Tp, size_t _Size> inline constexpr size_t rank_v<_Tp[_Size]> = 1 + rank_v<_Tp>; template <typename _Tp> inline constexpr size_t rank_v<_Tp[]> = 1 + rank_v<_Tp>; +#endif template <typename _Tp, unsigned _Idx = 0> inline constexpr size_t extent_v = 0;