https://gcc.gnu.org/g:b38aefbbc90a3334c6c5ba6569816d348a1a0c91
commit r15-1247-gb38aefbbc90a3334c6c5ba6569816d348a1a0c91
Author: Ken Matsui <kmat...@gcc.gnu.org>
Date: Mon Sep 11 13:58:35 2023 -0700
libstdc++: Optimize std::is_unbounded_array compilation performance
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 <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 748fa186881d..efbe273d38a9 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -3682,11 +3682,16 @@ 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
