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Re: [tree-ssa] reaching def. question
- From: Diego Novillo <dnovillo at redhat dot com>
- To: Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>
- Cc: Jeff Law <law at redhat dot com>, Devang Patel <dpatel at apple dot com>, "gcc at gcc dot gnu dot org list" <gcc at gcc dot gnu dot org>
- Date: Wed, 17 Mar 2004 10:11:49 -0500
- Subject: Re: [tree-ssa] reaching def. question
- Organization: Red Hat Canada
- References: <200403170027.i2H0RtZU001850@speedy.slc.redhat.com> <20040317072115.GA12475@atrey.karlin.mff.cuni.cz>
On Wed, 2004-03-17 at 02:21, Zdenek Dvorak wrote:
> I have thought about this issue for some time -- would not it be better
> to do ssa rewriting over ssa names, thus not requiring the rewrite out
> of ssa?
>
That was the original design, yes. See my other reply to this thread
earlier today.
> I.e. to allow the ssa name temporarily have several definitions,
> and do rewriting just over them? It might be faster. It also would not
> need to do rewriting out of ssa, which may require you to insert new
> assignments that must be later optimized out. It would also allow you
> not to lose ssa name tags in the process.
>
It would also reduce the "missing variable" problem, like in the example
I quoted before. We'll see.
Diego.