This is the mail archive of the
mailing list for the GCC project.
Re: Why can't CSE recognize const_int's in HIGH LO_SUM pair?
- To: law at redhat dot com
- Subject: Re: Why can't CSE recognize const_int's in HIGH LO_SUM pair?
- From: "John David Anglin" <dave at hiauly1 dot hia dot nrc dot ca>
- Date: Mon, 10 Sep 2001 23:11:52 -0400 (EDT)
- Cc: rth at redhat dot com, bernds at redhat dot com, gcc at gcc dot gnu dot org
> > (set (reg T) (const_int 0x10000))
> > (set (reg A) (plus (reg T) (const_int 1)))
> > (set (reg B) (plus (reg T) (const_int 2)))
> > Now consider A and B loaded on two different paths. Code motion can
> > then pull T up into the dominator.
> But recall that we don't do this right now on the PA due to implementation
I was planning on trying to implement this later this week. At the moment,
I am pounding nails helping with a new house for my sister.
It is clear that either the above, or just
(set (reg A) (const_int))
is better than the current high/lo_sum. However, I don't see a consensis
from the discussion as to which approach is better.
J. David Anglin email@example.com
National Research Council of Canada (613) 990-0752 (FAX: 952-6605)