https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102916
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #4) > (In reply to Darrell Wright from comment #3) > > Also http://eel.is/c++draft/library#constexpr.functions-1 > > > > An issue is that it's high level observable and not just an optimization > > http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2013 So it looks GCC decided at the time when the defect report was filed to the C++ language working group, GCC changed to allow the constexpr and then the library working group changed how to explicitly reject these instead.
