[Bug target/106827] operator++ doesn't work for enum -O2 -mcpu=cortex-m0plus

[rearnsha at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106827

--- Comment #8 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
That's C++ for you, it permits you to overload operators in completely
meaningless ways.