[Bug c++/88173] `std::numeric_limits::quiet_NaN()` is not constexpr

[g...@christoph-conrads.name]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88173

--- Comment #7 from Christoph Conrads <g...@christoph-conrads.name> ---
Created attachment 45081
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45081&action=edit
nan-lhs.ii created by GCC 6.3.0 on Raspbian 9.4