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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Mon, 11 Mar 2019 22:36:45 +0100
Message-ID: <CAK8P3a3NjTCgFd2dQ9KbHP8DpXf6s-ULfeU6acAYC4SDi+2qvw@mail.gmail.com>
Subject: Re: [PATCH] ARM: Ensure that NEON code always compiles with Clang
To:     Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc:     Nathan Chancellor <natechancellor@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        Nicolas Pitre <nicolas.pitre@linaro.org>,
        Tri Vo <trong@android.com>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
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On Mon, Mar 11, 2019 at 5:49 PM Ard Biesheuvel
<ard.biesheuvel@linaro.org> wrote:
>
> On Mon, 11 Mar 2019 at 17:22, Arnd Bergmann <arnd@arndb.de> wrote:
> >
> > On Sat, Dec 15, 2018 at 10:24 PM Nathan Chancellor
> > <natechancellor@gmail.com> wrote:
> > >  endif
> > > diff --git a/arch/arm/lib/xor-neon.c b/arch/arm/lib/xor-neon.c
> > > index a6741a895189..4600b62d845f 100644
> > > --- a/arch/arm/lib/xor-neon.c
> > > +++ b/arch/arm/lib/xor-neon.c
> > > @@ -14,7 +14,7 @@
> > >  MODULE_LICENSE("GPL");
> > >
> > >  #ifndef __ARM_NEON__
> > > -#error You should compile this file with '-mfloat-abi=softfp -mfpu=neon'
> > > +#error You should compile this file with '-march=armv7-a -mfloat-abi=softfp -mfpu=neon'
> > >  #endif
> > >
> >
> > I see this patch has made it in now, but I also see two other problems with the
> > same file that prevent it from working right with clang:
> >
> > - it triggers #warning This code requires at least version 4.6 of GCC
>
> What is currently the oldest GCC we support for ARM?

Linux overall requires gcc-4.6, so we could just as well drop this
check, good point.

       Arnd