Doing so is both pointless (it extends the live range of an operation without eliminating redundancy) and incorrect (it scrazzles the ref counts). Patch forthcoming. <rdar://problem/12296311>
Created attachment 164002 [details] the patch Still polishing it but this should do the trick.
Created attachment 164003 [details] the patch
Landed in http://trac.webkit.org/changeset/128541