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Re: [tree-ssa] Re: PATCH: [gcc3.5 improvement branch] Very Simple constant propagation
- From: Jan Hubicka <jh at suse dot cz>
- To: law at redhat dot com
- Cc: Jan Hubicka <jh at suse dot cz>, Dale Johannesen <dalej at apple dot com>,Jan Hubicka <hubicka at ucw dot cz>, Caroline Tice <ctice at apple dot com>,gcc-patches at gcc dot gnu dot org
- Date: Fri, 16 Jan 2004 13:20:22 +0100
- Subject: Re: [tree-ssa] Re: PATCH: [gcc3.5 improvement branch] Very Simple constant propagation
- References: <20040116001814.GA13682@kam.mff.cuni.cz> <200401160343.i0G3hjk0017212@speedy.slc.redhat.com>
> In message <20040116001814.GA13682@kam.mff.cuni.cz>, Jan Hubicka writes:
> >Yes, I invented that code some time ago. I really think that in
> >post-SSA world we should not do the trick on RTL.
> > Perhaps the patch
> >would need to wait for SSA equivalent of this transform that I can do
> >soon if this is considered important feature.
> >Dom doesn't have def-use chains readilly available, right?
> Nope, but it wouldn't be that hard to make then available (keeping them
> up-to-date might be more difficult).
Afaik Zdenek has proposed patch for this.
> My question is does this belong in dom at all. While we might want to
> do it as part of a dominator walk or other transforming pass, I don't
> see that it needs to live in the current dominator optimizer. Unless
> it's like to expose lots of additional optimization opportunities.
I wonder where to place it right now. Do we have some other pass that
walks the whole chain where this can be placed?
Or shall I invent new one. I think this can be run just after profile
is constructed and it can be place where our current profile value
transformation pass should be placed, so perhaps I can simply start
this. If this sounds sane, I can implement the new pass this week.