+(define-vop (fixnump/unsigned-byte-32 simple-type-predicate)
+ (:args (value :scs (unsigned-reg)))
+ (:arg-types unsigned-num)
+ (:translate fixnump)
+ (:generator 5
+ (inst cmp value #.sb!xc:most-positive-fixnum)
+ (inst jmp (if not-p :a :be) target)))
+