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From: Arnd Bergmann <arnd@arndb.de>
Date: Fri, 18 Oct 2019 09:56:01 +0200
Message-ID: <CAK8P3a0YLeqm71TNzTwJ0FwQKW4Ji0etA+6U=08Exk7fibyBQw@mail.gmail.com>
Subject: Re: [PATCH] [RFC, EXPERIMENTAL] allow building with --std=gnu99
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Sender: linux-kbuild-owner@vger.kernel.org
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To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Linus Torvalds <torvalds@linux-foundation.org>, Andrew Morton <akpm@linux-foundation.org>, Andrew Pinski <apinski@cavium.com>, Masahiro Yamada <yamada.masahiro@socionext.com>, Michal Marek <michal.lkml@markovi.net>, mm-commits@vger.kernel.org, Alexander Potapenko <glider@google.com>, Dmitry Vyukov <dvyukov@google.com>, Eric Dumazet <edumazet@google.com>, Kostya Serebryany <kcc@google.com>, Ingo Molnar <mingo@elte.hu>, linux-arch <linux-arch@vger.kernel.org>, Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>

On Thu, Oct 17, 2019 at 6:16 PM Kirill A. Shutemov <kirill@shutemov.name> wrote:
> On Thu, Oct 17, 2019 at 08:56:50AM -0700, Linus Torvalds wrote:
> > Yeah, that's certainly less than wonderful.
> >
> > That said, there's no way in hell we'll support gcc-4 for another 7
> > years (eg Suse 12-sp4), so at _some_ point the EOL dates aren't even
> > relevant any more.
> >
> > But it does look like we can't just say "gcc-5.1 is ok". Darn.
>
> I don't read the picture the same way. All distributions have at least one
> major release with GCC >= 5.
>
> The first release with gcc >= 5:
>
> - Debian 9 stretch has 6.3.0, released 2017-06-18;
>
> - Ubuntu 15.10 wily has 5.2.1, released 2015-10-22;
>
> - Fedora 24 has 6.1.1, released 2016-06-21;
>
> - OpenSUSE 15 has 7.4.1, released 2018-05-25;
>
> - RHEL 8.0 has 8.2.1, released 2019-05-06;
>
> - SUSE 15 has 7.3.1, released 2018-06-25;
>
> - Oracle 7.6.4 has 7.6.4, release 2019-07-18;
               ^^^ Oracle 8
>
> - Slackware 14.2 has 5.3.0, released 2016-07-01;

For /most/ of these I see no problem, but RHEL 7 / Centos 7 /
Oracle 7 and (to a lesser degree) SUSE 12 must have users
that want to build new kernels for some reason without a trivial
way to install new compilers.

OTOH, I agree that requiring a much more recent compiler has
some advantages that may outweigh these troubles. glibc has
moved to requiring a 3 (!) year old compiler or newer, which gives
them a reasonable time frame to make changes to gcc and then
build on requiring these changes.

      Arnd