[Bug c/66963] __builtin_constant_p and __builtin_choose_expr do not agree on what is a constexpr with -O2

[nicstange at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66963

--- Comment #4 from Nicolai Stange <nicstange at gmail dot com> ---
Sorry, misunderstanding at my side. You probably did not mean constexprs in the
sense of C99, 6.6, but constexprs in the sense of constant folded expressions.