Re: [PATCH 20/22] x86,word-at-a-time: Remove .fixup usage

Nick Desaulniers
2021-11-09T21:26:04Z

On Tue, Nov 9, 2021 at 1:21 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Tue, Nov 09, 2021 at 12:59:12PM -0800, Bill Wendling wrote:
> >
> > Adding attributes to labels shouldn't be difficult, as you mention. In
> > the case of cold/hot, it's adjusting some of the metadata that already
> > exists on some basic blocks. It might be enough to allow the normal
> > block placement algorithms to move the hot and cold blocks around for
> > us. The question becomes how many attributes does GCC allow on labels?
>
> I'm aware of 3: unused, hot, cold. Also:
>
> https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html

Re: unused:
Being able to selectively disable -Wunused-label via
__attribute__((unused)); seems useful, too.
--
Thanks,
~Nick Desaulniers