[Bug fortran/90903] Implement runtime checks for bit manipulation intrinsics

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90903

--- Comment #1 from anlauf at gcc dot gnu.org ---
Patch addressing the bit manipulation functions so far:

https://gcc.gnu.org/ml/fortran/2019-06/msg00138.html