------- Additional Comments From law at redhat dot com 2005-03-21 17:22 -------
Subject: Re: [4.0/4.1 regression] extra
assignment inserted on the tree level
On Mon, 2005-03-21 at 16:51 +0000, stevenb at suse dot de wrote:
> ------- Additional Comments From stevenb at suse dot de 2005-03-21 16:51
> -------
> Subject: Re: [4.0/4.1 regression] extra assignment inserted on the tree level
>
> On Mar 21, 2005 04:53 PM, amacleod at redhat dot com > Perhaps the best thing
> would be a pass before out of ssa which does the opposite
> > of that DOM optimization.
>
> Wouldn't it be much easier to just disallow GIMPLE invariants
> as PHI arguments?
It would be easier, but it would be a step backwards in terms of
optimizations and our ability to subsume the bulk of CSE.
We could disallow this kind of propagation if the equivalency came
from following a conditional. That would be a smaller step backards,
but I believe if you look at the anti-dom/unpropagation approach that
Andrew and I mentioned you'll get the best of both worlds.
jeff
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14627
