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Subject: Re: [PATCH] compiler.h: Raise minimum version of GCC to 5.1 for
 arm64
From:   Joe Perches <joe@perches.com>
To:     Linus Torvalds <torvalds@linux-foundation.org>,
        Ard Biesheuvel <ardb@kernel.org>
Cc:     Russell King - ARM Linux admin <linux@armlinux.org.uk>,
        Florian Weimer <fweimer@redhat.com>,
        Arnd Bergmann <arnd@kernel.org>,
        "Cc: Android Kernel" <kernel-team@android.com>,
        Theodore Ts'o <tytso@mit.edu>,
        Peter Zijlstra <peterz@infradead.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Will Deacon <will@kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Date:   Thu, 14 Jan 2021 11:51:53 -0800
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On Thu, 2021-01-14 at 10:43 -0800, Linus Torvalds wrote:
> On Thu, Jan 14, 2021 at 12:18 AM Ard Biesheuvel <ardb@kernel.org> wrote:
> > 
> > So if the arguments are piling up, what is holding us back, other than
> > inertia?
> 
> I think we can most certainly just try increasing the minimum version
> to 5.1 in the next merge window and see.
> 
> > Note that banning 4.9 for arm64 and banning it in general should be
> > two different changes in any case, as the former will need to be
> > backported to -stable kernels as well.
> 
> Yes. The arm64 issue is a clear and known bug, plus I suspect gcc-4.9
> is ridiculously old in the arm64 ecosystem anyway.
> 
> So the arm64 issue is a bug-fix, the follow-up of just upgrading gcc
> requirements in general would be a "keep up with the times, and allow
> those variable declarations in loops".

Given the upgrade requirement, and how clang version requirements
constantly change, how much more difficult would it be for others
to use gcc 7.1 or higher now instead of later?