i#337: only some cmpxchg and cmpxchg8b operands are compares
i#337: only some cmpxchg and cmpxchg8b operands are compares

git-svn-id: fe3cd4388a6e5a968b09397a3d721fe124e8117a@228 5b54908e-ead4-fc18-b48a-0285e6dbc711

rnk/drmemory,rnk/drmemory,rnk/drmemory,rnk/drmemory