[Bug c/66618] Failure to diagnose non-constant initializer for static object with -O1

[Keith.S.Thompson at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66618

--- Comment #3 from Keith Thompson <Keith.S.Thompson at gmail dot com> ---
It would be easier to argue that gcc accepts "other forms of constant 
expressions" if (a) those other forms were documented and (b) they were
accepted at all optimization levels.

Admittedly the standard doesn't seem to require such documentation (which I
find a little surprising), and you could argue that "gcc -O0" and "gcc -O1" are
two different implementations.