diff mbox series

[v18,02/26] libstdc++: Optimize std::is_const compilation performance

Message ID 20240502201549.459244-3-kmatsui@gcc.gnu.org
State New
Headers
Series Optimize more type traits |

Commit Message

Ken Matsui May 2, 2024, 8:12 p.m. UTC 
  This patch optimizes the compilation performance of std::is_const
by dispatching to the new __is_const built-in trait.

libstdc++-v3/ChangeLog:

	* include/std/type_traits (is_const): Use __is_const built-in
	trait.
	(is_const_v): Likewise.

Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
---
 libstdc++-v3/include/std/type_traits | 12 ++++++++++++
 1 file changed, 12 insertions(+)

Comments

Ken Matsui May 7, 2024, 1:55 p.m. UTC | #1 
Hi Jonathan,

Since __is_const, __is_volatile, and __is_pointer were approved, could
you please review these patches for libstdc++?  I guess that you
already reviewed almost equivalent patches, but I wanted to make sure.

Sincerely,
Ken Matsui


On Thu, May 2, 2024 at 1:16 PM Ken Matsui <kmatsui@gcc.gnu.org> wrote:
>
> This patch optimizes the compilation performance of std::is_const
> by dispatching to the new __is_const built-in trait.
>
> libstdc++-v3/ChangeLog:
>
>         * include/std/type_traits (is_const): Use __is_const built-in
>         trait.
>         (is_const_v): Likewise.
>
> Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> ---
>  libstdc++-v3/include/std/type_traits | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
> index b441bf9908f..8df0cf3ac3b 100644
> --- a/libstdc++-v3/include/std/type_traits
> +++ b/libstdc++-v3/include/std/type_traits
> @@ -835,6 +835,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>    // Type properties.
>
>    /// is_const
> +#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_const)
> +  template<typename _Tp>
> +    struct is_const
> +    : public __bool_constant<__is_const(_Tp)>
> +    { };
> +#else
>    template<typename>
>      struct is_const
>      : public false_type { };
> @@ -842,6 +848,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>    template<typename _Tp>
>      struct is_const<_Tp const>
>      : public true_type { };
> +#endif
>
>    /// is_volatile
>    template<typename>
> @@ -3331,10 +3338,15 @@ template <typename _Tp>
>    inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
>  #endif
>
> +#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_const)
> +template <typename _Tp>
> +  inline constexpr bool is_const_v = __is_const(_Tp);
> +#else
>  template <typename _Tp>
>    inline constexpr bool is_const_v = false;
>  template <typename _Tp>
>    inline constexpr bool is_const_v<const _Tp> = true;
> +#endif
>
>  #if _GLIBCXX_USE_BUILTIN_TRAIT(__is_function)
>  template <typename _Tp>
> --
> 2.44.0
>
diff mbox series

Patch

diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index b441bf9908f..8df0cf3ac3b 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -835,6 +835,12 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
   // Type properties.
 
   /// is_const
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_const)
+  template<typename _Tp>
+    struct is_const
+    : public __bool_constant<__is_const(_Tp)>
+    { };
+#else
   template<typename>
     struct is_const
     : public false_type { };
@@ -842,6 +848,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<typename _Tp>
     struct is_const<_Tp const>
     : public true_type { };
+#endif
 
   /// is_volatile
   template<typename>
@@ -3331,10 +3338,15 @@  template <typename _Tp>
   inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
 #endif
 
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_const)
+template <typename _Tp>
+  inline constexpr bool is_const_v = __is_const(_Tp);
+#else
 template <typename _Tp>
   inline constexpr bool is_const_v = false;
 template <typename _Tp>
   inline constexpr bool is_const_v<const _Tp> = true;
+#endif
 
 #if _GLIBCXX_USE_BUILTIN_TRAIT(__is_function)
 template <typename _Tp>