Re: [RFC PATCH] tools/memory-model: Remove (dep ; rfi) from ppo

From: Paul E. McKenney
Date: Mon Mar 04 2019 - 11:09:54 EST


On Sun, Mar 03, 2019 at 12:27:12AM +0900, Akira Yokosawa wrote:
> Hello Peter,
>
> On Tue, 26 Feb 2019 14:49:06 +0100, Peter Zijlstra wrote:
> > On Tue, Feb 26, 2019 at 12:38:13PM +0100, Borislav Petkov wrote:
> >> On Tue, Feb 26, 2019 at 12:30:08PM +0100, Peter Zijlstra wrote:
> >>> When I used the argc variant, gcc-8 'works', but with s/argc/1/ it is
> >>> still broken.
> >>
> >> As requested on IRC:
> >
> > What I asked was if you could get your GCC developer friends to have a
> > look at this :-)
>
> JFYI, there is a bugzilla ticket regarding this behavior of GCC
> at https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61502,
> which started on 13 June 2014 and the latest entry was on
> 02 Feb 2019.

And that bug was submitted by none other than Peter Sewell, thank you!

This bug references https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88775,
where someone appears to -want- this sort of optimization. :-/

Thanx, Paul