On Mon, 23 Oct 2023, Ken Matsui wrote:
> On Mon, Oct 23, 2023 at 10:05 AM Patrick Palka <ppa...@redhat.com> wrote:
> On Fri, Oct 20, 2023 at 12:22 PM Ken Matsui <kmat...@gcc.gnu.org> wrote:
> >
> > This patch optimizes the compilation performance of std::is_invocable
> > by dispatching to the new __is_invocable built-in trait.
> >
> > libstdc++-v3/ChangeLog:
> >
> > * include/std/type_traits (is_invocable): Use __is_invocable
> > built-in trait.
>
> Nice! We should use the trait directly in is_invocable_v too.
>
>
> Thank you! But we want to take account of static_assert’s in is_invocable, so
> I think we cannot use the built-in directly?
Good point, I guess that's a great reason to improvement the diagnostic
that check_trait_type emits: it'd speed up the class template version
because we could get rid of the static_asserts (without regressing
diagnostic quality), and it'd speed up the variable template version
because we could use the built-in directly there.
Your patch LGTM as is though, that could be a follow-up if anything.
>
>
> > * testsuite/20_util/is_invocable/incomplete_args_neg.cc:
> Handle
> > the new error from __is_invocable.
> > * testsuite/20_util/is_invocable/incomplete_neg.cc: Likewise.
> >
> > Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
> > ---
> > libstdc++-v3/include/std/type_traits | 6
> ++++++
> > .../testsuite/20_util/is_invocable/incomplete_args_neg.cc | 1 +
> > .../testsuite/20_util/is_invocable/incomplete_neg.cc | 1 +
> > 3 files changed, 8 insertions(+)
> >
> > diff --git a/libstdc++-v3/include/std/type_traits
> b/libstdc++-v3/include/std/type_traits
> > index 75a94cb8d7e..91851b78c7e 100644
> > --- a/libstdc++-v3/include/std/type_traits
> > +++ b/libstdc++-v3/include/std/type_traits
> > @@ -3167,9 +3167,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> > using invoke_result_t = typename invoke_result<_Fn,
> _Args...>::type;
> >
> > /// std::is_invocable
> > +#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_invocable)
> > + template<typename _Fn, typename... _ArgTypes>
> > + struct is_invocable
> > + : public __bool_constant<__is_invocable(_Fn, _ArgTypes...)>
> > +#else
> > template<typename _Fn, typename... _ArgTypes>
> > struct is_invocable
> > : __is_invocable_impl<__invoke_result<_Fn, _ArgTypes...>,
> void>::type
> > +#endif
> > {
> >
> static_assert(std::__is_complete_or_unbounded(__type_identity<_Fn>{}),
> > "_Fn must be a complete class or an unbounded array");
> > diff --git
> a/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_args_neg.cc
> b/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_args_neg.cc
> > index 34d1d9431d1..3f9e5274f3c 100644
> > ---
> a/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_args_neg.cc
> > +++
> b/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_args_neg.cc
> > @@ -18,6 +18,7 @@
> > // <http://www.gnu.org/licenses/>.
> >
> > // { dg-error "must be a complete class" "" { target *-*-* } 0 }
> > +// { dg-prune-output "invalid use of incomplete type" }
> >
> > #include <type_traits>
> >
> > diff --git
> a/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_neg.cc
> b/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_neg.cc
> > index e1e54d25ee5..92af48c48b6 100644
> > --- a/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_neg.cc
> > +++ b/libstdc++-v3/testsuite/20_util/is_invocable/incomplete_neg.cc
> > @@ -18,6 +18,7 @@
> > // <http://www.gnu.org/licenses/>.
> >
> > // { dg-error "must be a complete class" "" { target *-*-* } 0 }
> > +// { dg-prune-output "invalid use of incomplete type" }
> >
> > #include <type_traits>
> >
> > --
> > 2.42.0
> >
>
>
>
