Compiling the attached short program reports "deleting unreachable
code" for the dpb 7 form, when compiled by SBCL 1.0 on my Athlon
running SUSE 10.3, and by SBCL 1.0.23 on my Mac G5 (PPC) running
MacOSX 10.4, but does not complain and apparently runs correctly when
compiled by SBCL 1.0.23 on my MacBook Pro (Intel) running MacOSX 10.5.
The program of which this function is a part seems to work better on
the MacBook, but I haven't yet determined whether this is the cause.
In any case, if I replace the form (floor (integer-length most-
positive-fixnum) 3) with 9 (the calculated value on the MacBook), it
seems happy. If I replace it with 20 (the value on the Athlon), the
Athlon complains, the MacBook is content.