This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: [ tree-ssa] PRE problem
- From: law at redhat dot com
- To: Diego Novillo <dnovillo at redhat dot com>
- Cc: Daniel Berlin <dberlin at dberlin dot org>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
- Date: Fri, 20 Feb 2004 13:28:20 -0700
- Subject: Re: [ tree-ssa] PRE problem
- Reply-to: law at redhat dot com
In message <1077307394.3169.188.camel@localhost.localdomain>, Diego Novillo wri
tes:
>On Fri, 2004-02-20 at 14:56, law@redhat.com wrote:
>
>> p = x;
>> y = p;
>> *y;
>>
>> "y" will have a tag, but by no means does that mean p or x will have a
>> tag.
>>
>We are talking past each other again.
It wouldn't be the first time.
> When I say it's impossible for
>them to have different tags, I am talking about *non-NULL* tags. It's
>perfectly OK for a pointer to *not* have a tag. Only dereferenced
>pointers need tags.
Now this statement I would believe! And it's fundamental to the problem
at hand. So just to be sure, we agree that we can have a copy between
pointers, one of which has a tag and one of which does not?
jeff