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Re: Bug in reload_cse_move2add()
- To: Joern Rennecke <amylaar at redhat dot com>
- Subject: Re: Bug in reload_cse_move2add()
- From: Alexandre Oliva <aoliva at redhat dot com>
- Date: 04 Jan 2001 18:08:33 -0200
- Cc: gcc-patches at gcc dot gnu dot org, amylaar at cambridge dot redhat dot com, law at redhat dot com
- Organization: GCC Team, Red Hat
- References: <200101042002.f04K2bS03811@phal.cambridge.redhat.com>
On Jan 4, 2001, Joern Rennecke <amylaar@redhat.com> wrote:
>> Good idea! But what if the earliest register itself is incremented?
>> (I haven't studied your patch yet)
> In that case, the optimization would be disabled - because the luid is
> incremented. But I think that should hardly ever happen, so little
> potential performance should be lost.
How about not modifying the luid of the earliest register, but instead
just modifying its offset? The assumption is that the earliest
register will always have an initial offset of zero, so we can tell by
how much it has changed since the initial copy. There already seem to
be some assumptions about offsets being zero scattered along the code,
that I believe may have to do with this.
--
Alexandre Oliva Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer aoliva@{cygnus.com, redhat.com}
CS PhD student at IC-Unicamp oliva@{lsd.ic.unicamp.br, gnu.org}
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