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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Tue, 28 Aug 2018 16:00:55 -0700
Message-ID: <CAKwvOdkD0cmF5373LRS92U--ptRvikSrG_oKyE-AiaybCQYMBg@mail.gmail.com>
Subject: Re: [PATCH v2] compiler.h: give up __compiletime_assert_fallback()
To:     daniel.santos@pobox.com
Cc:     Masahiro Yamada <yamada.masahiro@socionext.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>, sparse@chrisli.org,
        linux-sparse@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
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On Mon, Aug 27, 2018 at 1:42 PM Daniel Santos <daniel.santos@pobox.com> wrote:
>
> Hello Nick,
>
> On 08/27/2018 03:09 PM, Nick Desaulniers wrote:
> >>> Let's give up __compiletime_assert_fallback().  This commit does not
> >>> change the current behavior since it just rips off the useless code.
> >> Clang is not the only target audience of
> >> __compiletime_assert_fallback().  Instead of ripping out something that
> >> may benefit builds with gcc 4.2 and earlier, why not override its
> > Note that with commit cafa0010cd51 ("Raise the minimum required gcc
> > version to 4.6") that gcc < 4.6 is irrelevant.
>
> Ah, I guess I'm not keeping up, that's wonderful news!  Considering that
> I guess I would be OK with its removal, but I still think it would be
> better if a similar mechanism to break the Clang build could be found.

I'm consulting with our best language lawyers to see what combinations
of _Static_assert and __builtin_constant_p would do the trick.