[Bug c++/110476] constexpr floating point regression with -std=c++XX

[pdimov at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110476

--- Comment #1 from Peter Dimov <pdimov at gmail dot com> ---
As discussed in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108742, this is a
consequence of applying the FLT_EVAL_METHOD=2 rules, and can be fixed by
casting 3.14f to (float).

That's... incredibly surprising, though. 3.14f is already a float.

For context, I encountered this regression in the Boost.Variant2 test suite
when I added GCC 13 to CI.