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Re: alias slowdown?


On Sun, 2006-11-19 at 20:16 -0500, Daniel Berlin wrote:
> >
> > In the meantime, is there a simple way to disable this "more correct"
> > mechanism so I can get my timings?
> 
> You'll get testsuite failures if you disable it because it fixes a
> bunch of bugs.
> 
> You can always disable all of PTA, but i would not recommend it.
> 

I don't care about testsuite failures, Im trying to time the new
out-of-ssa relative to the old one in compile time. I've already done
all the testsuite work. I just want to compare before and after times
and releative to total compile time. Disabling it works for me if it can
get me moving. Is there a simple way to do this? Weren't there any
performance checks done before checking the code in? These are pretty
severe regressions.


> With the attached patch, it should take less than 60 seconds per PTA
> run for all.i (i have no copy of cplusplus_grammar.i, and it's not
> clear where to get it).

Its originally from 15855. (compiled with -O2 -fpermissive)

60 seconds on what kind of machine?  I'm trying all.i with this patch
now, but it hasn't finished compiling after 13 minutes... (it use to
take 5). This is with a cross compiler on x86. Even an extra 60 seconds
per alias pass would double that overall time.

cplusplus_grammer.ii runs in 44 seconds on the branch I cut in the
summer. this patch doesn't make it very fast either.  My machine is a
3.0 Ghz P4 with 1GB of ram, and it appears to be just swapping its guts
out.   I killed it after 20 minutes, even with this patch applied.

Andrew


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