Richard Stallman wrote:

> Now that we have your papers, what changes should we install now?

Probably the thing described at http://lists.gnu.org/archive/html/emacs-devel/2007-07/msg00094.html.
Attached is the latest stuff on this.

Note the same optimization may be performed on sweeping floats.  But, since an amount of allocated
floats is too small in comparison with conses, an effect is expected to be very negligible.

Dmitry