I'm not very familiar with the Fedora release schedule and how closely related it is with gcc, but in the odb package that I'm the maintainer for there appears to be a bug with the devirtualization that is claimed to be on the roadmap for a fix in 4.9.1 ( http://www.codesynthesis.com/pipermail/odb-users/2014-May/001851.html ). I currently have a workaround in odb that just disables the devirtualization ( http://pkgs.fedoraproject.org/cgit/odb.git/commit/?id=5549f93543ed60a7d2027d0eb932c8cf6737edb5 ), so should I just leave it that way and then remove that when 4.9.1 is finally released for F21 or what's the right way to handle that?

Sounds reasonable to me.