diff mbox series

[v20,30/40] libstdc++: Optimize is_pointer trait performance

Message ID 20231016001227.2717180-31-kmatsui@gcc.gnu.org
State Unresolved
Headers
Series Optimize type traits performance |

Checks

Context Check Description
snail/gcc-patch-check warning Git am fail log

Commit Message

Ken Matsui Oct. 16, 2023, 12:10 a.m. UTC 
  This patch optimizes the performance of the is_pointer trait by dispatching to
the new __is_pointer built-in trait.

libstdc++-v3/ChangeLog:

	* include/bits/cpp_type_traits.h (__is_pointer): Use __is_pointer
	built-in trait.
	* include/std/type_traits (is_pointer): Likewise. Optimize its
	implementation.
	(is_pointer_v): Likewise.

Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
---
 libstdc++-v3/include/bits/cpp_type_traits.h |  8 ++++
 libstdc++-v3/include/std/type_traits        | 44 +++++++++++++++++----
 2 files changed, 44 insertions(+), 8 deletions(-)

Comments

Patrick Palka Oct. 16, 2023, 4:36 p.m. UTC | #1 
On Sun, 15 Oct 2023, Ken Matsui wrote:

> This patch optimizes the performance of the is_pointer trait by dispatching to
> the new __is_pointer built-in trait.
> 
> libstdc++-v3/ChangeLog:
> 
> 	* include/bits/cpp_type_traits.h (__is_pointer): Use __is_pointer
> 	built-in trait.
> 	* include/std/type_traits (is_pointer): Likewise. Optimize its
> 	implementation.
> 	(is_pointer_v): Likewise.
> 
> Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
> Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> ---
>  libstdc++-v3/include/bits/cpp_type_traits.h |  8 ++++
>  libstdc++-v3/include/std/type_traits        | 44 +++++++++++++++++----
>  2 files changed, 44 insertions(+), 8 deletions(-)
> 
> diff --git a/libstdc++-v3/include/bits/cpp_type_traits.h b/libstdc++-v3/include/bits/cpp_type_traits.h
> index 4312f32a4e0..cd5ce45951f 100644
> --- a/libstdc++-v3/include/bits/cpp_type_traits.h
> +++ b/libstdc++-v3/include/bits/cpp_type_traits.h
> @@ -363,6 +363,13 @@ __INT_N(__GLIBCXX_TYPE_INT_N_3)
>    //
>    // Pointer types
>    //
> +#if __has_builtin(__is_pointer)

Why not _GLIBCXX_USE_BUILTIN_TRAIT?  LGTM besides this.

> +  template<typename _Tp>
> +    struct __is_pointer : __truth_type<__is_pointer(_Tp)>
> +    {
> +      enum { __value = __is_pointer(_Tp) };
> +    };

Nice :D

> +#else
>    template<typename _Tp>
>      struct __is_pointer
>      {
> @@ -376,6 +383,7 @@ __INT_N(__GLIBCXX_TYPE_INT_N_3)
>        enum { __value = 1 };
>        typedef __true_type __type;
>      };
> +#endif
>  
>    //
>    // An arithmetic type is an integer type or a floating point type
> diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
> index 9c56d15c0b7..3acd843f2f2 100644
> --- a/libstdc++-v3/include/std/type_traits
> +++ b/libstdc++-v3/include/std/type_traits
> @@ -542,19 +542,33 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>      : public true_type { };
>  #endif
>  
> -  template<typename>
> -    struct __is_pointer_helper
> +  /// is_pointer
> +#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
> +  template<typename _Tp>
> +    struct is_pointer
> +    : public __bool_constant<__is_pointer(_Tp)>
> +    { };
> +#else
> +  template<typename _Tp>
> +    struct is_pointer
>      : public false_type { };
>  
>    template<typename _Tp>
> -    struct __is_pointer_helper<_Tp*>
> +    struct is_pointer<_Tp*>
>      : public true_type { };
>  
> -  /// is_pointer
>    template<typename _Tp>
> -    struct is_pointer
> -    : public __is_pointer_helper<__remove_cv_t<_Tp>>::type
> -    { };
> +    struct is_pointer<_Tp* const>
> +    : public true_type { };
> +
> +  template<typename _Tp>
> +    struct is_pointer<_Tp* volatile>
> +    : public true_type { };
> +
> +  template<typename _Tp>
> +    struct is_pointer<_Tp* const volatile>
> +    : public true_type { };
> +#endif
>  
>    /// is_lvalue_reference
>    template<typename>
> @@ -3254,8 +3268,22 @@ template <typename _Tp, size_t _Num>
>    inline constexpr bool is_array_v<_Tp[_Num]> = true;
>  #endif
>  
> +#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
> +template <typename _Tp>
> +  inline constexpr bool is_pointer_v = __is_pointer(_Tp);
> +#else
>  template <typename _Tp>
> -  inline constexpr bool is_pointer_v = is_pointer<_Tp>::value;
> +  inline constexpr bool is_pointer_v = false;
> +template <typename _Tp>
> +  inline constexpr bool is_pointer_v<_Tp*> = true;
> +template <typename _Tp>
> +  inline constexpr bool is_pointer_v<_Tp* const> = true;
> +template <typename _Tp>
> +  inline constexpr bool is_pointer_v<_Tp* volatile> = true;
> +template <typename _Tp>
> +  inline constexpr bool is_pointer_v<_Tp* const volatile> = true;
> +#endif
> +
>  template <typename _Tp>
>    inline constexpr bool is_lvalue_reference_v = false;
>  template <typename _Tp>
> -- 
> 2.42.0
> 
>
Ken Matsui Oct. 16, 2023, 8:22 p.m. UTC | #2 
On Mon, Oct 16, 2023 at 9:36 AM Patrick Palka <ppalka@redhat.com> wrote:
>
> On Sun, 15 Oct 2023, Ken Matsui wrote:
>
> > This patch optimizes the performance of the is_pointer trait by dispatching to
> > the new __is_pointer built-in trait.
> >
> > libstdc++-v3/ChangeLog:
> >
> >       * include/bits/cpp_type_traits.h (__is_pointer): Use __is_pointer
> >       built-in trait.
> >       * include/std/type_traits (is_pointer): Likewise. Optimize its
> >       implementation.
> >       (is_pointer_v): Likewise.
> >
> > Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
> > Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> > ---
> >  libstdc++-v3/include/bits/cpp_type_traits.h |  8 ++++
> >  libstdc++-v3/include/std/type_traits        | 44 +++++++++++++++++----
> >  2 files changed, 44 insertions(+), 8 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/bits/cpp_type_traits.h b/libstdc++-v3/include/bits/cpp_type_traits.h
> > index 4312f32a4e0..cd5ce45951f 100644
> > --- a/libstdc++-v3/include/bits/cpp_type_traits.h
> > +++ b/libstdc++-v3/include/bits/cpp_type_traits.h
> > @@ -363,6 +363,13 @@ __INT_N(__GLIBCXX_TYPE_INT_N_3)
> >    //
> >    // Pointer types
> >    //
> > +#if __has_builtin(__is_pointer)
>
> Why not _GLIBCXX_USE_BUILTIN_TRAIT?  LGTM besides this.
>

Oops, thank you for pointing this out :)

> > +  template<typename _Tp>
> > +    struct __is_pointer : __truth_type<__is_pointer(_Tp)>
> > +    {
> > +      enum { __value = __is_pointer(_Tp) };
> > +    };
>
> Nice :D
>

Yeees! But I thought this might be very confusing for someone who does
not know the new built-in behavior.

> > +#else
> >    template<typename _Tp>
> >      struct __is_pointer
> >      {
> > @@ -376,6 +383,7 @@ __INT_N(__GLIBCXX_TYPE_INT_N_3)
> >        enum { __value = 1 };
> >        typedef __true_type __type;
> >      };
> > +#endif
> >
> >    //
> >    // An arithmetic type is an integer type or a floating point type
> > diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
> > index 9c56d15c0b7..3acd843f2f2 100644
> > --- a/libstdc++-v3/include/std/type_traits
> > +++ b/libstdc++-v3/include/std/type_traits
> > @@ -542,19 +542,33 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >      : public true_type { };
> >  #endif
> >
> > -  template<typename>
> > -    struct __is_pointer_helper
> > +  /// is_pointer
> > +#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
> > +  template<typename _Tp>
> > +    struct is_pointer
> > +    : public __bool_constant<__is_pointer(_Tp)>
> > +    { };
> > +#else
> > +  template<typename _Tp>
> > +    struct is_pointer
> >      : public false_type { };
> >
> >    template<typename _Tp>
> > -    struct __is_pointer_helper<_Tp*>
> > +    struct is_pointer<_Tp*>
> >      : public true_type { };
> >
> > -  /// is_pointer
> >    template<typename _Tp>
> > -    struct is_pointer
> > -    : public __is_pointer_helper<__remove_cv_t<_Tp>>::type
> > -    { };
> > +    struct is_pointer<_Tp* const>
> > +    : public true_type { };
> > +
> > +  template<typename _Tp>
> > +    struct is_pointer<_Tp* volatile>
> > +    : public true_type { };
> > +
> > +  template<typename _Tp>
> > +    struct is_pointer<_Tp* const volatile>
> > +    : public true_type { };
> > +#endif
> >
> >    /// is_lvalue_reference
> >    template<typename>
> > @@ -3254,8 +3268,22 @@ template <typename _Tp, size_t _Num>
> >    inline constexpr bool is_array_v<_Tp[_Num]> = true;
> >  #endif
> >
> > +#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
> > +template <typename _Tp>
> > +  inline constexpr bool is_pointer_v = __is_pointer(_Tp);
> > +#else
> >  template <typename _Tp>
> > -  inline constexpr bool is_pointer_v = is_pointer<_Tp>::value;
> > +  inline constexpr bool is_pointer_v = false;
> > +template <typename _Tp>
> > +  inline constexpr bool is_pointer_v<_Tp*> = true;
> > +template <typename _Tp>
> > +  inline constexpr bool is_pointer_v<_Tp* const> = true;
> > +template <typename _Tp>
> > +  inline constexpr bool is_pointer_v<_Tp* volatile> = true;
> > +template <typename _Tp>
> > +  inline constexpr bool is_pointer_v<_Tp* const volatile> = true;
> > +#endif
> > +
> >  template <typename _Tp>
> >    inline constexpr bool is_lvalue_reference_v = false;
> >  template <typename _Tp>
> > --
> > 2.42.0
> >
> >
>
diff mbox series

Patch

diff --git a/libstdc++-v3/include/bits/cpp_type_traits.h b/libstdc++-v3/include/bits/cpp_type_traits.h
index 4312f32a4e0..cd5ce45951f 100644
--- a/libstdc++-v3/include/bits/cpp_type_traits.h
+++ b/libstdc++-v3/include/bits/cpp_type_traits.h
@@ -363,6 +363,13 @@  __INT_N(__GLIBCXX_TYPE_INT_N_3)
   //
   // Pointer types
   //
+#if __has_builtin(__is_pointer)
+  template<typename _Tp>
+    struct __is_pointer : __truth_type<__is_pointer(_Tp)>
+    {
+      enum { __value = __is_pointer(_Tp) };
+    };
+#else
   template<typename _Tp>
     struct __is_pointer
     {
@@ -376,6 +383,7 @@  __INT_N(__GLIBCXX_TYPE_INT_N_3)
       enum { __value = 1 };
       typedef __true_type __type;
     };
+#endif
 
   //
   // An arithmetic type is an integer type or a floating point type
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index 9c56d15c0b7..3acd843f2f2 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -542,19 +542,33 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     : public true_type { };
 #endif
 
-  template<typename>
-    struct __is_pointer_helper
+  /// is_pointer
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
+  template<typename _Tp>
+    struct is_pointer
+    : public __bool_constant<__is_pointer(_Tp)>
+    { };
+#else
+  template<typename _Tp>
+    struct is_pointer
     : public false_type { };
 
   template<typename _Tp>
-    struct __is_pointer_helper<_Tp*>
+    struct is_pointer<_Tp*>
     : public true_type { };
 
-  /// is_pointer
   template<typename _Tp>
-    struct is_pointer
-    : public __is_pointer_helper<__remove_cv_t<_Tp>>::type
-    { };
+    struct is_pointer<_Tp* const>
+    : public true_type { };
+
+  template<typename _Tp>
+    struct is_pointer<_Tp* volatile>
+    : public true_type { };
+
+  template<typename _Tp>
+    struct is_pointer<_Tp* const volatile>
+    : public true_type { };
+#endif
 
   /// is_lvalue_reference
   template<typename>
@@ -3254,8 +3268,22 @@  template <typename _Tp, size_t _Num>
   inline constexpr bool is_array_v<_Tp[_Num]> = true;
 #endif
 
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
+template <typename _Tp>
+  inline constexpr bool is_pointer_v = __is_pointer(_Tp);
+#else
 template <typename _Tp>
-  inline constexpr bool is_pointer_v = is_pointer<_Tp>::value;
+  inline constexpr bool is_pointer_v = false;
+template <typename _Tp>
+  inline constexpr bool is_pointer_v<_Tp*> = true;
+template <typename _Tp>
+  inline constexpr bool is_pointer_v<_Tp* const> = true;
+template <typename _Tp>
+  inline constexpr bool is_pointer_v<_Tp* volatile> = true;
+template <typename _Tp>
+  inline constexpr bool is_pointer_v<_Tp* const volatile> = true;
+#endif
+
 template <typename _Tp>
   inline constexpr bool is_lvalue_reference_v = false;
 template <typename _Tp>