ira-loop-pressure not marked as optimization?

Vladimir Makarov vmakarov@redhat.com
Thu Mar 6 15:16:00 GMT 2014


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.



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