Untag more efficiently if USE_LSB_TAG.

This is based on a proposal by YAMAMOTO Mitsuharu in
<http://lists.gnu.org/archive/html/emacs-devel/2008-01/msg01876.html>.
For an admittedly artificial (nth 8000 longlist) benchmark on
Fedora 15 x86-64, this yields a 25% CPU speedup.  Also, it shrinks
Emacs's overall text size by 1%.
* lisp.h (XUNTAG): New macro.
(XCONS, XVECTOR, XSTRING, XSYMBOL, XFLOAT, XMISC, XPROCESS, XWINDOW)
(XTERMINAL, XSUBR, XBUFFER, XCHAR_TABLE, XSUB_CHAR_TABLE, XBOOL_VECTOR)
(XSETTYPED_PSEUDOVECTOR, XHASH_TABLE, TYPED_PSEUDOVECTORP): Use it.
* eval.c (Fautoload):
* font.h (XFONT_SPEC, XFONT_ENTITY, XFONT_OBJECT):
* frame.h (XFRAME): Use XUNTAG.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/eval.c b/src/eval.c
index cb0518f34ec..3d0e82c2d9f 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -2048,7 +2048,7 @@ this does nothing and returns nil.  */)
        We used to use 0 here, but that leads to accidental sharing in
        purecopy's hash-consing, so we use a (hopefully) unique integer
        instead.  */
-    docstring = make_number (XPNTR (function));
+    docstring = make_number (XUNTAG (function, Lisp_Symbol));
   return Ffset (function,
                 Fpurecopy (list5 (Qautoload, file, docstring,
                                   interactive, type)));