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Re: [tree-ssa] New regressions as of 2003-11-04
> On Wed, 2003-11-05 at 10:35, Jan Hubicka wrote:
>
> >
> > Webizer makes about 0.5% difference on mainline, over 1.5% difference on
> > tree-SSA, so we obviously made this worse by unnecesary re-use.
>
> My analysis of crafty indicated that the use of all these temporaries
> causes a lot of uneccesary spilling by the register allocator, and we
> were losing a lot of runtime because of that.
Yes, this is because our register allocator is broken enought to not
being able to reorganize registers to avoid reg-reg copies needed on
2-address machines.
My webizer pass is a loss for crafty too, but it pays back elsewhere.
> >
> > You do expect sane compiler, not GCC :)
>
> unfortunately, thats true :-) We're trying to make it more sane :-)
Unfourtnately making it sane requires expecting it to be insane at start
:)
>
> yep. I use the to find the spots where we have a significant difference
> between us and mainline in order to identify what we are doing wrong and
> fix it.
>
> Stability has bene a big problem later. Once we get some of these large
> pervasive things out of the way it ought to settle down.
Yes, thinks in general are shaping up nicely :)
Honza
>
> Andrew
>