Hi Patrick, There is an issue with the code in libstdc++-v3/include/bits/cpp_type_traits.h. Specifically, Clang 16 does not accept the code, while Clang 17 does. Given that we aim to support the last two versions of Clang, we need to ensure that Clang 16 accepts this code. Can you please advise on the best course of action regarding this matter?
https://godbolt.org/z/PbxhYcb7q Sincerely, Ken Matsui On Fri, Oct 20, 2023 at 7:12 AM Ken Matsui <kmat...@gcc.gnu.org> wrote: > > This patch optimizes the compilation performance of std::is_pointer > 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 <jwak...@redhat.com> > Signed-off-by: Ken Matsui <kmat...@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..246f2cc0b17 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 _GLIBCXX_USE_BUILTIN_TRAIT(__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 0641ecfdf2b..75a94cb8d7e 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> > @@ -3252,8 +3266,22 @@ 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 >
