Well FreeBSD just bit the bullet and moved from GCC to Clang. Now I know there are licensing reasons for this. And I also know that this really isn’t a factor for Haiku until we start talking R2, but is there any limitation within Clang (likely related to c++ support) that needs to be addressed for Haiku to even consider switching?
IIRC Haiku makes use of some compiler extensions which aren’t supported under Clang/LLVM, I don’t know how hard it would be to remove them and replace them with something working with Clang but I think that for now there are much better things to put developer effort on than supporting another compiler toolchain.
It took FreeBSD something like 3 years to be able to switch fully to Clang, likely Clang is much more mature now than it was when they started that transition but it will obviously take time and energy and it’s not as if the Haiku devs doesn’t have their hands full as it is in order to reach in the foreseeable future r1.
Paul Davey has been working on this. This is the last message he sent to the Haiku development mailing list: http://www.freelists.org/post/haiku-development/haikucommits-haiku-hrev43838-buildjam-clang-llvm,15