GCC 5 Status Report (2015-01-19), Trunk in Stage 4

[Richard Biener]

On Tue, 27 Jan 2015, Jakub Jelinek wrote:

> On Tue, Jan 27, 2015 at 10:04:38AM +0100, Richard Biener wrote:
> > On Tue, 27 Jan 2015, Andreas Krebbel wrote:
> > > I would like to apply the following patch:
> > > 
> > > [PATCH] S/390: -mhotpatch v2
> > > https://gcc.gnu.org/ml/gcc-patches/2015-01/msg02370.html
> > > 
> > > It is a backend only change to our existing -mhotpatch feature
> > > requested by the Linux kernel guys for the ftrace implementation:
> > > https://lkml.org/lkml/2015/1/26/320
> > > 
> > > They need it in an upstream GCC asap. If we don't get it into 5.0 we
> > > probably would need to commit it onto 5.1 branch right after the
> > > release. I would rather try to avoid this since it would make the
> > > hotpatch feature incompatible between 5.0 and 5.1.
> > > 
> > > Ok to do it now?
> > 
> > Ok.  It needs an entry in changes.html.
> > 
> > Do you plan to backport this change?
> > 
> > Did you consider using an alternate option name instead of changing
> > it in an incompatible way?  I realize SUSE will need to backport this
> 
> Yeah, the option incompatibility worries me.  Can't -mhotpatch without =
> stand for the old behavior?  Does it map to some -mhotpatch=X,Y value,
> or is it not worth to support both?

It maps to -mhotpatch=12.  The old one had one argument while the new
one has two...  so eventually you can distinguish them this way,
though for the inlining I'd have added -minline-hotpatched and
if you switch the arguments of the new hotpatch then -mhotpatch=12
would trivially become supported again...

Richard.