Re: [PATCH 3.15 33/37] Fix gcc-4.9.0 miscompilation of load_balance() in scheduler

Linus Torvalds
2014-08-05T23:59:28Z

On Tue, Aug 5, 2014 at 4:30 PM, Frank Ch. Eigler <fche@redhat.com> wrote:
>
> Would you consider a patch that does a gcc COMPARE_DEBUG-based test?

Yes. But as mentioned, we don't have a really good way to do that. I
guess we can do something similar to what "cc-option" does, but that
will end up doing it for every single kernel build. I'd love to have
something like this be done at kconfig time (along with all the
*other* crazy conditional compiler options we do), but I guess that's
a largely independent issue.

And afaik, it will basically disallow every gcc version since 4.5 up
until 4.9.2 gets released. And afaik, even current gcc actually fails
the compare-debug test for at least some inputs, so ...

Linus