At the GNU Tools Cauldron we held a panel discussion on how GCC and LLVM can work together. The video of that discussion can be seen at https://www.youtube.com/watch?v=PnbJOSZXynA. We proposed a similar discussion to be held at the LLVM Developers Meeting, but the reviewers suggested that such a discussion would be better held as part of the FOSDEM LLVM Devroom, since that was more likely to attract GNU developers as well. We wish to explore how Clang/LLVM and the GCC can work together effectively. The participants will explore opportunities for co-operation between the projects. Areas to be covered include: collaboration on issues related to language standards, changes to existing standards or implementing new ones; maintaining ABI compatibility between the compilers; interoperability between tools and libraries e.g. building with clang and libstdc++ or building with gcc and linking with lld; and communication channels for developers via bugzilla or mailing lists. The compilers are part of wider projects providing all the components of the tool chain, and we anticipate the discussion will roam to low level utilities, source code debuggers and libraries as well. We hope the output of the discussion will inform future work between the two communities. The panelists are Arnaud de Grandmaison is a Director of the Linux Foundation, currently working at Arm. He has been developing with LLVM for his last 10+ years, to support custom architecture or enable architecture exploration. Pedro Alves is a global mainainer and major contributor to the GNU Debugger (GDB) Tom Tromey is a long-time GNU maintainer. He wrote Automake, worked on gcj and Classpath, and now is a GDB maintainer.