Scheduler questions (related to PR17808)

[James E Wilson]

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