It's not truly a different architecture, but a reorganization of the standard architecture. Unfortunately, ghc doesn't currently make good use of the key Xeon Phi components even in the standard architecture; packages that want to make use of them generally use -fllvm because LLVM is better at using them, even given that LLVM isn't very good at understanding what ghc feeds it. This suggests that -fflvm might be useful in taking advantage of Xeon Phi architecture with ghc.