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Date:   Thu, 29 Aug 2019 03:32:59 -0500
From:   Segher Boessenkool <segher@kernel.crashing.org>
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Nathan Chancellor <natechancellor@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        "# 3.4.x" <stable@vger.kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>,
        Paul Mackerras <paulus@samba.org>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] powerpc: Avoid clang warnings around setjmp and longjmp
Message-ID: <20190829083259.GI31406@gate.crashing.org>
References: <20190812023214.107817-1-natechancellor@gmail.com> <878srdv206.fsf@mpe.ellerman.id.au> <20190828175322.GA121833@archlinux-threadripper> <CAKwvOdmXbYrR6n-cxKt3XxkE4Lmj0sSoZBUtHVb0V2LTUFHmug@mail.gmail.com> <20190828184529.GC127646@archlinux-threadripper> <CAKwvOd=wdscd7smcKZk40zD_n1OUVkhYYd7ZnoK8r1Y+pkvYVg@mail.gmail.com>
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On Wed, Aug 28, 2019 at 03:16:19PM -0700, Nick Desaulniers wrote:
> That's a good reason IMO.  IIRC, the -fno-builtin-* flags don't warn
> if * is some unrecognized value, so -fno-builtin-setjmp may not
> actually do anything, and you may need to scan the source (of clang or
> llvm).

-fno-builtin-foo makes the compiler not handle "foo" the same as it
handles "__builtin_foo".  If the compiler has no idea about "foo", well,
that is exactly what it does then anyhow, so why would it warn :-)


Segher