https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94420
--- Comment #5 from Segher Boessenkool <segher at gcc dot gnu.org> --- It is undefined behaviour to access such a register in any way -- sure, you *can* inspect it, there just is no guarantee at all what value you will get. It still is a useful thing to do in debug code and the like, of course.
