On Tue, Jul 19, 2022 at 02:11:02PM +0100, Jonathan Wakely wrote: > Tested x86_64-linux, OK for trunk? > > -- >8 -- > > The new built-ins need to be detectable using __has_builtin, and the > library should use that to check for them. > > This fixes an error with Clang when C++23 is enabled.
LGTM but can't approve. Thanks and sorry for missing this! > gcc/cp/ChangeLog: > > * cp-objcp-common.cc (names_builtin_p): Return true for > RID_REF_CONSTRUCTS_FROM_TEMPORARY and > RID_REF_CONVERTS_FROM_TEMPORARY. > > libstdc++-v3/ChangeLog: > > * include/std/type_traits (__cpp_lib_reference_from_temporary) > (reference_constructs_from_temporary) > (reference_converts_from_temporary): Only define when the > built-ins are available. > --- > gcc/cp/cp-objcp-common.cc | 2 ++ > libstdc++-v3/include/std/type_traits | 4 ++++ > 2 files changed, 6 insertions(+) > > diff --git a/gcc/cp/cp-objcp-common.cc b/gcc/cp/cp-objcp-common.cc > index 0b70d5567e4..4079a4b4aec 100644 > --- a/gcc/cp/cp-objcp-common.cc > +++ b/gcc/cp/cp-objcp-common.cc > @@ -461,6 +461,8 @@ names_builtin_p (const char *name) > case RID_IS_ASSIGNABLE: > case RID_IS_CONSTRUCTIBLE: > case RID_UNDERLYING_TYPE: > + case RID_REF_CONSTRUCTS_FROM_TEMPORARY: > + case RID_REF_CONVERTS_FROM_TEMPORARY: > return true; > default: > break; > diff --git a/libstdc++-v3/include/std/type_traits > b/libstdc++-v3/include/std/type_traits > index b1a1deecf66..14b029cec64 100644 > --- a/libstdc++-v3/include/std/type_traits > +++ b/libstdc++-v3/include/std/type_traits > @@ -3505,6 +3505,9 @@ template<typename _Ret, typename _Fn, typename... _Args> > template<typename _Tp> > inline constexpr bool is_scoped_enum_v = is_scoped_enum<_Tp>::value; > > +#if __has_builtin(__reference_constructs_from_temporary) \ > + && __has_builtin(__reference_converts_from_temporary) > + > #define __cpp_lib_reference_from_temporary 202202L > > /// True if _Tp is a reference type, a _Up value can be bound to _Tp in > @@ -3544,6 +3547,7 @@ template<typename _Ret, typename _Fn, typename... _Args> > template<typename _Tp, typename _Up> > inline constexpr bool reference_converts_from_temporary_v > = reference_converts_from_temporary<_Tp, _Up>::value; > +#endif // __has_builtin for reference_from_temporary > #endif // C++23 > > #if _GLIBCXX_HAVE_IS_CONSTANT_EVALUATED > -- > 2.34.3 > Marek
