weird when testing if 2 single floats are equal or not.

[Chisheng Huang]

It doesn't look like I can test if 2 single floats are equal (=)
or not reliably.  I'm using cmucl-19b-test-x86-linux.  To reproduce
this problem, enter the following forms into the REPL (do not compile them):

(declaim (inline sf=))

(defun sf= (x y)
  (< (abs (- (the Single-Float x) 
             (the Single-Float y)))
     single-float-epsilon))

(defun test (wh w)
  (declare (type fixnum w))
  (print (list (car wh)
               (/ w 3.8208954)
               (= (the Single-Float (car wh))
                  (/ w 3.8208954))
               (sf= (the Single-Float (car wh))
                    (/ w 3.8208954))
               (< (abs (- (car wh) 
                          (/ w 3.8208954)))
                  single-float-epsilon))))

Evaluating (test '(217.48828 . 0.0) 831) will give you:
(217.48828 217.48828 T T T), which is good.

After you do (compile 'sf=) and (compile 'test), evaluating
(test '(217.48828 . 0.0) 831) will give you (217.48828 217.48828 NIL NIL T),
which is weird.

The same code, interpreted or compiled, in Allegro CL 6.2 trial edition
gives (217.48828 217.48828 T T T).

If I strip all the type declarations in SF= and TEST, CMUCL always give
(217.48828 217.48828 T T T), regarless if COMPILE is applied to SF= or TEST.
But I do like to keep the type declarations in my real code.

Any ideas?

Thanks a lot.

-cph