byte-optimize for double negative

In XEmacs 21.2 (beta19) "Shinjuku" [Lucid] (i586-pc-linux, Mule) of Sat Jul 31 1999 on libretto configured using `configure --extra-verbose --with-x11=yes --dynamic --with-png=yes --with-xpm --with-xface --with-database=berkdb --with-sound=native --with-mule --with-xim=no --with-xfs --site-libraries=/usr/local/lib' Current version of byte-optimize.el optimizes double negative using byte-optimize-if. Such optimization is as follows; (if (not xxxx) (if xxxx nil ---> (progn yyyy) ) yyyy ) But if we uses `not' or `null' not in condition clause of `if', byte-optimize.el does not optimize them even if there is a double negative. I will send a diff to xemacs-patches (with ChangeLog) which will optimize all double negatives. Thanks. -- Mikio Nakajima <minakaji(a)osaka.email.ne.jp&gt; <minakaji(a)pdx.ne.jp&gt; (in case of emergency) http://www.asahi-net.or.jp/~gy2m-nkjm/