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

[bugzilla--- via Gcc-bugs]

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

--- Comment #4 from Kio <bugzi...@little-bat.de> ---
(In reply to Richard Earnshaw from comment #2)
> Please put testcases in the bug report, godbolt links are not stable.

test case was also attached as a file with the bug report.