Re: [ast-optimizer-branch]: SSA-CCP on tree-ssa

[Jan Hubicka <jh at suse dot cz>]

> 
> 
> On Thu, 6 Dec 2001, Diego Novillo wrote:
> 
> > On Thu, 06 Dec 2001, Daniel Berlin wrote:
> >
> > > > Even if it means duplicating some code, I'm trying to
> > > > figure out which option is easier to maintain in the future.
> > > To be honest, I think it's easier to maintain ssa-ccp with function
> > > pointers.
> > > Besides the only real difference being in the evaluation function, and
> > > walking the SSA, it would also enable us to vary the optimization
> > > performed based on -O level or something, or combine it with other
> > > optimizations just by plugging in a seperate function.
> > >
> > OK then.  Thanks for the clarification.  If it will make our life
> > easier, I'm all for it.
> 
> >
> > > > You don't mention bootstrap/regression test results. Particulary,
> > > > using -ftree-ssa.  On the branch we should make -O2 trigger the
> > > > tree SSA transformations.
> > > Bootstraps okay on powerpc-linux-gnu.
> > >
> > With -ftree-ssa in BOOT_CFLAGS?
> Yes.
> 
> >
> > > Never got to checking test results.
> > >
> > We need to make sure it doesn't introduce regressions.  Since
> > it's going into the ast-branch that's not such a high priority
> > right now.
> >
> > Are you willing to keep maintaing it regularly?
> Sure, i already planned on it[1].
> 
>  >  I'd like to
> > merge the branch into the trunk for the 3.2 release.  If not, I
> > can take over as I'll be doing lots of maintenance on the branch
> > over the next few weeks.
> 
> Good to hear!
> 
> >
> > Thanks.  Diego.
> >
> [1] I've been writing (whenever i sit around tired of coding or waiting
> for compiles, so it's somewhat slow going) a guide to writing optimization
> passes for gcc for those who understand compiler optimization, but have
> never dealt with implementing them in gcc before.  Right now, we only have
> a guide to RTL, and a guide to trees, but no guide on things like our
> basic blocks, flow graph, dataflow framework, etc. I figured if there was
> a guide pointing out how these things work in gcc, and where they are,
> we'd get more people willing to implement optimizations or use gcc as a
> platform for research.
> 
> Pieces of the code to the tree SSA-CCP are  in the tree
> based  optimization chapter.
Hi,
I also wrote short introduction to using CFG and such pieces.  Can you please
send me your bits so we can put them together somewhat? I will try to find my
version too - I didn't worked on it in last two weeks.

Honza
>