-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 11/04/11 14:23, Peter Bergner wrote: > On Fri, 2011-11-04 at 12:25 -0600, Jeff Law wrote: >> The only way I can think of to have two pseudos assigned the same >> hard reg at the same point in the insn stream is if the two >> pseudos are known to have the same value. > > Having the same value is the more common way two overlapping > pseudos don't conflict, but if one or both of the pseudos are > undefined (ie, no definition point), then they won't conflict > either. However, I'm pretty sure we do not take advantage of the fact that two pseudos with the same value with overlapping lifetimes do not conflict and thus can live in the same hard reg. In fact, if you try to implement that optimization, you'll find that reload chokes in fun and unpleasant ways. I actually tried this myself a while back ;-)
Jeff -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJOt2NYAAoJEBRtltQi2kC764cIAKvRkCrVtEjUfhZSg63dzkDp jbp9HObcAxT8I/vlDcgkftzx5xpQN4QpRRIN/cFcPdVcgsJHk97W/ZPo7Tnmwqkm DJRwNxCxrrSJ3xNiOdRZCJTomb/28K1nthJVpRin0i4QdHjvUP6Cs5NYQ4/Nuj+Z ponJRdldJYaAx7QFcb+4Z6R0e7mjaeQ8NUvs3SUkrmTeIn0JArZ9gkR1061Dv2KI Th3FPY9jnOHZw75Tmszt3DEKzXpwjA3NzFM919u3chrfDx21F2HqrycyLqECxylg fIyAFCPlMyj4Vhf07Nr59NId2j84bZy5KC2Zakvl0xYAIwyHZqqrpY0U7qQgr7Y= =59oA -----END PGP SIGNATURE-----
