Re: [PATCH v2] libstdc++: Use _GLIBCXX_USE_BUILTIN_TRAIT

[Ken Matsui <kmatsui@cs.washington.edu>]

On Thu, Jan 4, 2024 at 2:11 PM Jonathan Wakely <jwakely@redhat.com> wrote:
>
> On Sat, 23 Dec 2023 at 23:06, Ken Matsui <kmatsui@gcc.gnu.org> wrote:
> >
> > This patch uses _GLIBCXX_USE_BUILTIN_TRAIT macro instead of __has_builtin
> > in the type_traits header for traits that have a corresponding fallback
> > non-built-in implementation.  This macro supports to toggle the use of
> > built-in traits in the type_traits header through
> > _GLIBCXX_DO_NOT_USE_BUILTIN_TRAITS macro, without needing to modify the
> > source code.
>
> OK for trunk, thanks.
>
> +Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
>

Thank you for your reviews!
>
>
> >
> > libstdc++-v3/ChangeLog:
> >
> >         * include/std/type_traits: Use _GLIBCXX_USE_BUILTIN_TRAIT.
> >
> > Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> > Reviewed-by: Patrick Palka <ppalka@redhat.com>
> > ---
> >  libstdc++-v3/include/std/type_traits | 10 +++++-----
> >  1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
> > index f00c07f94f9..ba35ffb27fa 100644
> > --- a/libstdc++-v3/include/std/type_traits
> > +++ b/libstdc++-v3/include/std/type_traits
> > @@ -1481,7 +1481,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >      : public __bool_constant<__is_base_of(_Base, _Derived)>
> >      { };
> >
> > -#if __has_builtin(__is_convertible)
> > +#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_convertible)
> >    template<typename _From, typename _To>
> >      struct is_convertible
> >      : public __bool_constant<__is_convertible(_From, _To)>
> > @@ -1531,7 +1531,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >
> >  #ifdef __cpp_lib_is_nothrow_convertible // C++ >= 20
> >
> > -#if __has_builtin(__is_nothrow_convertible)
> > +#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_nothrow_convertible)
> >    /// is_nothrow_convertible_v
> >    template<typename _From, typename _To>
> >      inline constexpr bool is_nothrow_convertible_v
> > @@ -1606,7 +1606,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >      { using type = _Tp; };
> >
> >    /// remove_cv
> > -#if __has_builtin(__remove_cv)
> > +#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_cv)
> >    template<typename _Tp>
> >      struct remove_cv
> >      { using type = __remove_cv(_Tp); };
> > @@ -1672,7 +1672,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >    // Reference transformations.
> >
> >    /// remove_reference
> > -#if __has_builtin(__remove_reference)
> > +#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_reference)
> >    template<typename _Tp>
> >      struct remove_reference
> >      { using type = __remove_reference(_Tp); };
> > @@ -3537,7 +3537,7 @@ template<typename _Ret, typename _Fn, typename... _Args>
> >     * @{
> >     */
> >  #ifdef __cpp_lib_remove_cvref // C++ >= 20
> > -# if __has_builtin(__remove_cvref)
> > +# if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_cvref)
> >    template<typename _Tp>
> >      struct remove_cvref
> >      { using type = __remove_cvref(_Tp); };
> > --
> > 2.43.0
> >
>