https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88078
--- Comment #3 from Jeffrey Walton <noloader at gmail dot com> --- (In reply to Jonathan Wakely from comment #2) > For GCC 8.2 using -std=c++14 instead of -std=gnu++14 will disable the > __float128 specializations, avoiding the problem of long double and > __float128 being the same type. Thanks Jonathan.