+#!+compare-and-swap-vops
+(defoptimizer ir2-convert-casser
+ ((object old new) node block name offset lowtag)
+ (let* ((lvar (node-lvar node))
+ (locs (lvar-result-tns lvar (list *backend-t-primitive-type*)))
+ (res (first locs)))
+ (vop compare-and-swap-slot node block
+ (lvar-tn node block object)
+ (lvar-tn node block old)
+ (lvar-tn node block new)
+ name offset lowtag
+ res)
+ (move-lvar-result node block locs lvar)))
+
+(defun emit-inits (node block name result lowtag inits args)
+ (let ((unbound-marker-tn nil)
+ (funcallable-instance-tramp-tn nil))