Index: /trunk/source/compiler/ARM/arm-vinsns.lisp
===================================================================
--- /trunk/source/compiler/ARM/arm-vinsns.lisp	(revision 15491)
+++ /trunk/source/compiler/ARM/arm-vinsns.lisp	(revision 15492)
@@ -1137,5 +1137,5 @@
   (cmp temp (:$ arm::tag-misc))
   (ldreq header (:@ src (:$ arm::misc-header-offset)))
-  (andeq temp src (:$ arm::subtag-mask))
+  (andeq temp header (:$ arm::subtag-mask))
   (moveq header (:lsr header (:$ arm::num-subtag-bits)))
   (cmpeq temp (:$ arm::subtag-bignum))