Re: ira-loop-pressure not marked as optimization?

["Paulo J. Matos" <paulo at matos-sorge dot com>]

On 06/03/14 15:15, Vladimir Makarov wrote:
> On 03/06/2014 08:55 AM, Paulo Matos wrote:
> > Hi,
> >
> > Upon noticing ira-hoist-pressure in `gcc --help=optimizers` and not ira-loop-pressure,
> > I am wondering why the latter is not marked as an Optimization in common.opt:
> >
> > fira-loop-pressure
> > Common Report Var(flag_ira_loop_pressure)
> > Use IRA based register pressure calculation
> > in RTL loop optimizations.
> >
> > Should we mark it as such?
> It is not an optimization strictly speaking.  It is a better register
> pressure calculation used for invariant loop motion decisions.
>
> On the other hand, using this option can improve generated code
> performance (e.g. as I remember it improved SPECFP2000 by 1% for
> ppc64).  So I guess, it should mark as such in order to see this
> possibility to improve the code by a programmer.

I have just run a few long benchmarks and even though I had high 
expectations for improving performance the flag in our port causes a ~3% 
degradation in performance. Haven't had time to investigate why.

Still, would you accept a patch to mark this flag as an optimization?

--
PMatos