[PATCH] Add flag to control straight-line strength reduction

[William J. Schmidt]

On Wed, 2012-07-18 at 08:24 -0500, William J. Schmidt wrote:
> On Wed, 2012-07-18 at 11:01 +0200, Richard Guenther wrote:
> > On Wed, 18 Jul 2012, Steven Bosscher wrote:
> > 
> > > On Wed, Jul 18, 2012 at 9:59 AM, Richard Guenther <rguenther@suse.de> wrote:
> > > > On Tue, 17 Jul 2012, William J. Schmidt wrote:
> > > >
> > > >> I overlooked adding a pass-control flag for strength reduction, added
> > > >> here.  I named it -ftree-slsr for consistency with other -ftree- flags,
> > > >> but could change it to -fgimple-slsr if you prefer that for a pass named
> > > >> gimple-ssa-...
> > > >>
> > > >> Bootstrapped and tested on powerpc-unknown-linux-gnu with no new
> > > >> regressions.  Ok for trunk?
> > > >
> > > > The switch needs documentation in doc/invoke.texi.  Other than that
> > > > it's fine to stick with -ftree-..., even that exposes details to our
> > > > users that are not necessary (RTL passes didn't have -frtl-... either).
> > > > So in the end, why not re-use -fstrength-reduce that is already available
> > > > (but stubbed out)?
> > > 
> > > In the past, -fstrength-reduce applied to loop strength reduction in
> > > loop.c. I don't think it should be re-used for a completely different
> > > code transformation.
> > 
> > Ok.  I suppose -ftree-slsr is ok then.
> 
> It turns out I was looking at a very old copy of the manual, and the
> -ftree... stuff is not as prevalent now as it once was.  I'll just go
> with -fslsr to be consistent with -fgcse, -fipa-sra, etc.

Well, posted too fast.  Paging down I see that isn't true, sorry.  I'll
use the tree- for consistency even though it is useless information.

Thanks,
Bill

> 
> Thanks for the pointer to doc/invoke.texi -- it appears I also failed to
> document -fhoist-adjacent-loads, so I will go ahead and do that as well.
> 
> Thanks!
> Bill
> 
> > 
> > Thanks,
> > Richard.
> > 
>