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Re: Scheduler questions (related to PR17808)

From: James E Wilson <wilson at specifixinc dot com>
To: Steven Bosscher <stevenb at suse dot de>
Cc: Vladimir Makarov <vmakarov at redhat dot com>, rearnsha at gcc dot gnu dot org,gcc at gcc dot gnu dot org
Date: Thu, 30 Jun 2005 15:10:02 -0700
Subject: Re: Scheduler questions (related to PR17808)
References: <200506300046.22545.stevenb@suse.de> <42C3F88E.6070407@redhat.com> <42C3FF51.9040607@ispras.ru> <200506302245.12219.stevenb@suse.de>

Steven Bosscher wrote:

Are predicate checks free, or should there be some post-pass to
clean up this kind of useless predication?

On IA-64, predicate checks are free in terms of run-time. There is the problem that unnecessary predicate checks might increase register lifetimes, causing extra register pressure. However, this would matter only if you are going to do some register allocation after eliminating the now unnecessary predicate checks, and that doesn't seem to be an issue here. -- Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com

References:
- Scheduler questions (related to PR17808)
  - From: Steven Bosscher
- Re: Scheduler questions (related to PR17808)
  - From: Vladimir Makarov
- Re: Scheduler questions (related to PR17808)
  - From: Andrey Belevantsev
- Re: Scheduler questions (related to PR17808)
  - From: Steven Bosscher

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