Fix bug in unsigned modular arithmetic using a signed implementation

[sbcl.git] / tests / compiler.pure.lisp

diff --git a/tests/compiler.pure.lisp b/tests/compiler.pure.lisp
index bcdfe32..fe4bd64 100644 (file)
--- a/tests/compiler.pure.lisp
+++ b/tests/compiler.pure.lisp
@@ -4209,3 +4209,30 @@
                                             :c))))
                 (style-warning ()
                   :style-warning)))))
+
+(with-test (:name :bug-974406)
+  (let ((fun32 (compile nil `(lambda (x)
+                               (declare (optimize speed (safety 0)))
+                               (declare (type (integer 53 86) x))
+                               (logand (+ x 1032791128) 11007078467))))
+        (fun64 (compile nil `(lambda (x)
+                               (declare (optimize speed (safety 0)))
+                               (declare (type (integer 53 86) x))
+                               (logand (+ x 1152921504606846975)
+                                       38046409652025950207)))))
+    (assert (= (funcall fun32 61) 268574721))
+    (assert (= (funcall fun64 61) 60)))
+  (let (result)
+    (do ((width 5 (1+ width)))
+        ((= width 130))
+      (dotimes (extra 4)
+        (let ((fun (compile nil `(lambda (x)
+                                   (declare (optimize speed (safety 0)))
+                                   (declare (type (integer 1 16) x))
+                                   (logand
+                                    (+ x ,(1- (ash 1 width)))
+                                    ,(logior (ash 1 (+ width 1 extra))
+                                             (1- (ash 1 width))))))))
+          (unless (= (funcall fun 16) (logand 15 (1- (ash 1 width))))
+            (push (cons width extra) result)))))
+    (assert (null result))))