-(macrolet ((def (name result minus-result)
- `(deftransform ,name ((x y) (t (constant-arg real)) *)
- "fold identity operations"
- (let ((val (lvar-value y)))
- (unless (and (= (abs val) 1)
- (not-more-contagious y x))
- (give-up-ir1-transform))
- (if (minusp val) ',minus-result ',result)))))
+;;;
+;;; %NEGATE might not always signal correctly.
+(macrolet
+ ((def (name result minus-result)
+ `(deftransform ,name ((x y)
+ (exact-number (constant-arg (member 1 -1))))
+ "fold identity operations"
+ (if (minusp (lvar-value y)) ',minus-result ',result))))