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Re: [tree-ssa] New regressions as of 2003-11-04
On Wed, 2003-11-05 at 11:07, Jan Hubicka wrote:
> > 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.
It'll be interesting to see what the webizer does after my changes. with
the nature of tree-ssa its important to seperate those disjoint changes
since we generate a lot of them, and I suspect we will continue to in
some cases. At the very least with user vars its going to happen.
I dont suppose its in the code base now? I would say this is something
we are going to need for the SSA path always. Or at least have it
available via an option.
Right now the webizer *just* breaks up this disjoint ranges? or does it
do something else too?
Andrew