https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67314
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- This warning is only useful for c++. C defines the full range of the underlying type of the enum for the enum while c++ has different rules. Also I think this warning would be too noisy for c code and clang is wrong to implement it for c.
