From mboxrd@z Thu Jan 1 00:00:00 1970 From: "John David Anglin" To: law@redhat.com Cc: rth@redhat.com, bernds@redhat.com, gcc@gcc.gnu.org Subject: Re: Why can't CSE recognize const_int's in HIGH LO_SUM pair? Date: Mon, 10 Sep 2001 20:12:00 -0000 Message-id: <200109110311.f8B3BrYm014073@hiauly1.hia.nrc.ca> References: <25993.1000147906@localhost.localdomain> X-SW-Source: 2001-09/msg00399.html > > (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 > issues. 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. Dave -- J. David Anglin dave.anglin@nrc.ca National Research Council of Canada (613) 990-0752 (FAX: 952-6605)