While thats nice and all, Apple has made no binding or even public statement to that fact. They also have at least one patent which mention LLVM by name (Converting javascript into a device-independent representation), even if that "just" is a frontend.

There is simply nothing that prevents apple from using patents against LLVM users. We can only hope that none of their numerous vaguely written patents cover any technology used by LLVM or any of their frontends like Clang.