> Do you have some performance numbers?

Let arithcompare-benchmark.el contain:

  (defun arithcompare-many (lhs rhs)
    (dotimes (_ (floor 1e6))
      (< lhs rhs)))
  (message "%s" (benchmark-run 1 (arithcompare-many 100 101)))

Run by:

  emacs -Q --batch -f batch-byte-compile arithcompare-benchmark.el && emacs -Q --batch --load arithcompare-benchmark.elc

The results averaged over ten trials each:

  Before patch: (0.061 0 0.0)
  After patch: (0.084 0 0.0)

In GNU Emacs 24.3.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.10.4)
Windowing system distributor `The X.Org Foundation', version 11.0.70101000
System Description:    Red Hat Enterprise Linux Client release 5.4 (Tikanga)