From: Jonathan Wakely <jwakely.gcc@gmail.com>
To: Ken Matsui <kmatsui@cs.washington.edu>
Cc: gcc-patches <gcc-patches@gcc.gnu.org>,
Patrick Palka <ppalka@redhat.com>,
"libstdc++" <libstdc++@gcc.gnu.org>
Subject: Re: [PATCH] libstdc++: use new built-in trait __remove_pointer
Date: Mon, 20 Mar 2023 09:11:55 +0000 [thread overview]
Message-ID: <CAH6eHdSyy_DG7Hew4P8p0LPCLLtnaTV23MpDdxRbBvhf5xv+bw@mail.gmail.com> (raw)
In-Reply-To: <CAML+3pUXydMXzgmo8AvrBf6G9Ah=O_B8pq8kmo1hvA_rCt+DTw@mail.gmail.com>
On Mon, 20 Mar 2023 at 08:08, Ken Matsui <kmatsui@cs.washington.edu> wrote:
>
> Ooh... Thank you for pointing that out!
>
> > The helper doesn't need to be defined for the case where we don't use it.
>
> I thought that macroing them out leads to compiler errors since users
> are possibly using those helpers. But do we not have to care about
> that?
No, absolutely not.
>
> ---
> libstdc++-v3/ChangeLog:
>
> * include/std/type_traits (remove_pointer): Use __remove_pointer built-in trait.
>
> ---
> diff --git a/libstdc++-v3/include/std/type_traits
> b/libstdc++-v3/include/std/type_traits
> index 2bd607a8b8f..cba98091aad 100644
> --- a/libstdc++-v3/include/std/type_traits
> +++ b/libstdc++-v3/include/std/type_traits
> @@ -2025,17 +2025,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
> template<typename _Tp, typename>
> struct __remove_pointer_helper
> - { typedef _Tp type; };
> + { using type = _Tp; };
>
> template<typename _Tp, typename _Up>
> struct __remove_pointer_helper<_Tp, _Up*>
> - { typedef _Up type; };
> + { using type = _Up; };
>
> /// remove_pointer
> +#if __has_builtin(__remove_pointer)
> + template<typename _Tp>
> + struct remove_pointer
> + { using type = __remove_pointer(_Tp); };
> +#else
> template<typename _Tp>
> struct remove_pointer
> : public __remove_pointer_helper<_Tp, __remove_cv_t<_Tp>>
> { };
> +#endif
>
> template<typename _Tp, typename = void>
> struct __add_pointer_helper
>
> On Mon, Mar 20, 2023 at 12:57 AM Jonathan Wakely <jwakely.gcc@gmail.com> wrote:
> >
> >
> >
> > On Mon, 20 Mar 2023, 07:32 Ken Matsui via Libstdc++, <libstdc++@gcc.gnu.org> wrote:
> >>
> >> CCing libstdc++@gcc.gnu.org.
> >>
> >> On Sun, Mar 19, 2023 at 7:53 PM Ken Matsui <kmatsui@cs.washington.edu> wrote:
> >> >
> >> > libstdc++-v3/ChangeLog:
> >> >
> >> > * include/std/type_traits (is_reference): Use __remove_pointer built-in trait.
> >
> >
> > The changelog entry says is_reference but the patch is for remove_pointer.
> >
> >
> >> >
> >> > ---
> >> > diff --git a/libstdc++-v3/include/std/type_traits
> >> > b/libstdc++-v3/include/std/type_traits
> >> > index 2bd607a8b8f..cba98091aad 100644
> >> > --- a/libstdc++-v3/include/std/type_traits
> >> > +++ b/libstdc++-v3/include/std/type_traits
> >> > @@ -2025,17 +2025,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> >> >
> >> > template<typename _Tp, typename>
> >> > struct __remove_pointer_helper
> >> > - { typedef _Tp type; };
> >> > + { using type = _Tp; };
> >> >
> >> > template<typename _Tp, typename _Up>
> >> > struct __remove_pointer_helper<_Tp, _Up*>
> >> > - { typedef _Up type; };
> >> > + { using type = _Up; };
> >
> >
> > The helper doesn't need to be defined for the case where we don't use it.
> >
> >
> >> >
> >> > /// remove_pointer
> >> > +#if __has_builtin(__remove_pointer)
> >> > + template<typename _Tp>
> >> > + struct remove_pointer
> >> > + { using type = __remove_pointer(_Tp); };
> >> > +#else
> >> > template<typename _Tp>
> >> > struct remove_pointer
> >> > : public __remove_pointer_helper<_Tp, __remove_cv_t<_Tp>>
> >> > { };
> >> > +#endif
> >> >
> >> > template<typename _Tp, typename = void>
> >> > struct __add_pointer_helper
next prev parent reply other threads:[~2023-03-20 9:12 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-20 2:53 Ken Matsui
2023-03-20 7:31 ` Ken Matsui
2023-03-20 7:57 ` Jonathan Wakely
2023-03-20 8:07 ` Ken Matsui
2023-03-20 9:11 ` Jonathan Wakely [this message]
2023-03-20 13:26 ` Ken Matsui
2023-03-20 22:24 ` Ken Matsui
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAH6eHdSyy_DG7Hew4P8p0LPCLLtnaTV23MpDdxRbBvhf5xv+bw@mail.gmail.com \
--to=jwakely.gcc@gmail.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=kmatsui@cs.washington.edu \
--cc=libstdc++@gcc.gnu.org \
--cc=ppalka@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).