diff --git a/src/compiler/x86-64/arith.lisp b/src/compiler/x86-64/arith.lisp
index 5512a4784..db9c20793 100644
--- a/src/compiler/x86-64/arith.lisp
+++ b/src/compiler/x86-64/arith.lisp
@@ -4561,7 +4561,7 @@
                :unused-if (csubtypep (tn-ref-type x-ref)
                                      (specifier-type 'integer)))
               temp)
-  (:generator 10
+  (:generator 9
     (let ((fixnum-mask-p (and (= n-fixnum-tag-bits 1)
                               (= mask (ash most-positive-word -1)))))
       (assemble ()