https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107931
--- Comment #5 from Tomasz Konojacki <me at xenu dot pl> --- To sum this thread up, there are undocumented rules that can cause a semantically identical program to be rejected by the compiler under certain optimisation levels (with an uninformative error message) and users are expected to know them. Thank you.
