That is nothing about "bloat" as gcc and llvm / clang are used for different reasons. The kernel for HyperbolaBSD is especially ported towards a newer GCC-version in usage with Hyperbola GNU/Linux-libre and therefore much more oriented on modern implementations. OpenBSD is using an older GCC-version because of their own strict way towards GPL. But in general BOTH compilers are there also. When it comes to ports you will need them! And as we have also ports in other ways later (extra-repository) there is no "bloat".

That is odd, I thought they just did clang directly.

Hmm... well if false, ignore my comment. I had thought it was done otherwise.

Ironically the whole llvm source is far larger and take much longer to compile than OpenBSD itself.

Aka, they don't use gcc in clang I believe.

If its possible, wouldn't it be good to do the same?

Less bloat would be possible this way anyhow.

Just an opinion