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Re: Bugs in SSA-CCP and SSA-PRE optimizers
- From: Diego Novillo <dnovillo at redhat dot com>
- To: Daniel Berlin <dberlin at dberlin dot org>
- Cc: Steven Bosscher <s dot bosscher at student dot tudelft dot nl>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
- Date: 17 Sep 2002 16:41:15 -0400
- Subject: Re: Bugs in SSA-CCP and SSA-PRE optimizers
- References: <5A104176-CA7C-11D6-9548-000393575BCC@dberlin.org>
On Tue, 2002-09-17 at 16:30, Daniel Berlin wrote:
> >
> > Stop.
> > already, you are screwed.
> > CCP doesn't update the SSA representation, thus, PRE won't have
> > correct data.
> >
> I said that backwards, since PRE is run before CCP, but PRE doesn't
> update the representaiton right now either.
>
Yup, and since we still haven't gotten a single pass to bootstrap
cleanly, we cannot test them together. To enable these passes, we have
to:
1. Fix enough bugs in each pass so that we can enable them by
default at -O2.
2. Make sure that each one either rebuilds SSA from scratch or
keeps it up-to-date.
Diego.