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Re: RFC: cache uses_template_parms in tree node?


> Richard Guenther wrote:
> 
> >Hi!
> >
> >To address the for_each_template_parm() performance problem, would it be
> >possible to cache the outcome of uses_template_parms() in the tree
> >node? Or would this caching somehow be invalidated later?
> 
> The right approach, as I've said before, is simply not to *use* 
> for_each_template_parm.
> 
> It should be unncessary; the right approach should be to use 
> type_dependent_p and its friends.
> 
> That's not a trivial change, but it's the right change.

Mark,
do you think such a change is possible for 3.4 GCC?  If not what would
you recommend to do for the release branch?  The for_each_template_parm
seems to be really one of the major CPU cycle consumers when it come to
C++ compilation and it would be shame to leave it that way for the
release.

Honza
> 
> There might be a very few places where for_each_template_parm would 
> still be necessary -- but they will not be anything that should up on 
> the profile.
> 
> -- 
> Mark Mitchell
> CodeSourcery, LLC
> mark@codesourcery.com


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