Re: [PATCH] libstdc++: use new built-in trait __is_reference

[Jonathan Wakely <jwakely.gcc@gmail.com>]

On Mon, 20 Mar 2023 at 08:08, Xi Ruoyao via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> On Mon, 2023-03-20 at 01:03 -0700, Ken Matsui wrote:
> > Oops, I assumed those were my email... Thank you for your heads up and
> > your comments!
> >
> > > Bad ChangeLog format.  You should have a tab (not 4 or 8 spaces, nor
> > > nothing) to indent the ChangeLog content.
> >
> > Do you mean like the following?
> >
> > ```
> > libstdc++-v3/ChangeLog:
> >
> > [TAB]* include/std/type_traits (is_reference): Use __is_reference
> > built-in
> > trait.
> > ```
>
> Yep.
>
> > > Is there any benefit to use a builtin, instead of the existing
> > > implementation?  I can see no but maybe I'm stupid.
> >
> > My patches are based on the GSoC project "C++: Implement compiler
> > built-in traits for the standard library traits". These built-in
> > traits basically make the compilation faster.
> >
> > https://gcc.gnu.org/wiki/SummerOfCode
>
> Ok, to me making compilation faster is a valid reason.

Does it actually make compilation faster though?

Has it been measured?

> > > The patch fails to apply.  It seems because your mail client inserted an
> > > additional newline before "b/".  Try to use git-send-email or configure
> > > the mail client properly.
> >
> > Let me try to use git-send-email instead. I stupidly don't understand
> > how to use them, so I was making my patches manually...
>
> Or adjust the mail client correctly.  You can send the patch to yourself
> first and see if it's not "mangled" by the mail client when you debug
> such an issue...
>
> But when you finally end up sending 10 patches in a series you'll find
> git send-email much easier :).

Figuring out how to generate proper patches is an important part of
contributing to GCC, so part of any GSoC project.