LLVM IR isn't architecture-neutral. It encodes type layout / alignment, as well as ABI details. You can construct an LLVM target that is itself compilable on mu

LLVM IR isn't architecture-neutral. It encodes type layout / alignment, as well as ABI details. You can construct an LLVM target that is itself compilable on multiple architectures (see Portable Native Client), but it requires a nonstandard ABI.