[FFmpeg-devel] [PATCH 2/2] Use gcc/clang builtins for av_sat_(add|sub)_64_c if available.

[Dale Curtis]

On Mon, May 4, 2020 at 11:19 AM James Almer <jamrial at gmail.com> wrote:

> On 5/4/2020 3:09 PM, Dale Curtis wrote:
> > Bump. I have 5 integer overflow fuzzing issues awaiting our resolution of
> > this discussion. Thanks.
> >
> > - dale
>
> What's the first version of clang with support for __builtin_*_overflow?
> Because with your patch as is (Checking only __clang__), it's very
> likely old clang builds could be broken. We have things like Clang 3 on
> FATE right now.
>

Clang 10.0 apparently:
https://clang.llvm.org/docs/LanguageExtensions.html#feature-checking-macros -
I'm fine with limiting support to where it works though. Attached patch
does that.


>
> Also, does clang-cl define __clang__ and these builtins? Because maybe
> we could remove that check and just keep the GCC + Intel one. The former
> should in theory cover Clang builds that are reportedly compatible with
> GCC >= 5.1
>

Yes, clang-cl defines __clang__ and these builtins.

- dale
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