(compile nil '(lambda (x) (declare (bit x)) (+ x #xf0000000)))
1)
#xf0000001))
+
+;;; LOGBITP on bignums:
+(dolist (x '(((1+ most-positive-fixnum) 1 nil)
+ ((1+ most-positive-fixnum) -1 t)
+ ((1+ most-positive-fixnum) (1+ most-positive-fixnum) nil)
+ ((1+ most-positive-fixnum) (1- most-negative-fixnum) t)
+ (1 (ash most-negative-fixnum 1) nil)
+ (29 most-negative-fixnum t)
+ (30 (ash most-negative-fixnum 1) t)
+ (31 (ash most-negative-fixnum 1) t)
+ (64 (ash most-negative-fixnum 36) nil)
+ (65 (ash most-negative-fixnum 36) t)))
+ (destructuring-bind (index int result) x
+ (assert (eq (eval `(logbitp ,index ,int)) result))))
+
+;;; off-by-1 type inference error for %DPB and %DEPOSIT-FIELD:
+(let ((f (compile nil '(lambda (b)
+ (integer-length (dpb b (byte 4 28) -1005))))))
+ (assert (= (funcall f 1230070) 32)))
+(let ((f (compile nil '(lambda (b)
+ (integer-length (deposit-field b (byte 4 28) -1005))))))
+ (assert (= (funcall f 1230070) 32)))
+
+;;; type inference leading to an internal compiler error:
+(let ((f (compile nil '(lambda (x)
+ (declare (type fixnum x))
+ (ldb (byte 0 0) x)))))
+ (assert (= (funcall f 1) 0))
+ (assert (= (funcall f most-positive-fixnum) 0))
+ (assert (= (funcall f -1) 0)))