I am still eagerly waiting for Zen + Vega APU.
Other stuff, that's just using MSVC/gcc/clang/llvm code targeted to Skylake/Haswell etc will run just fine, as Zen's microarch is similar enough.
AMD's own compiler is like a 3% performance difference for us, compared to regular clang. No big influence, basically.
I am still eagerly waiting for Zen + Vega APU.