Index: /trunk/ccl/compiler/nx1.lisp
===================================================================
--- /trunk/ccl/compiler/nx1.lisp	(revision 355)
+++ /trunk/ccl/compiler/nx1.lisp	(revision 356)
@@ -1935,6 +1935,6 @@
 		     (nx1-form amt)))
         ((and (fixnump amt)
-              (<= 0 amt 27)
-              (or (nx-form-typep num `(signed-byte ,(- 28 amt)) env)
+              (<= 0 amt (integer-length most-positive-fixnum))
+              (or (nx-form-typep num `(signed-byte ,(- (1+ (integer-length most-positive-fixnum))  amt)) env)
                   (and (nx-form-typep num 'fixnum env)
                        (nx-trust-declarations env)