This is the mail archive of the
mailing list for the GCC project.
Re: ira-loop-pressure not marked as optimization?
- From: Vladimir Makarov <vmakarov at redhat dot com>
- To: Paulo Matos <pmatos at broadcom dot com>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
- Date: Thu, 06 Mar 2014 10:15:59 -0500
- Subject: Re: ira-loop-pressure not marked as optimization?
- Authentication-results: sourceware.org; auth=none
- References: <19EB96622A777C4AB91610E763265F4642C773 at SJEXCHMB14 dot corp dot ad dot broadcom dot com>
On 03/06/2014 08:55 AM, Paulo Matos wrote:
> 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:
> 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.