https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113770
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Masahide Kashiwagi from comment #5) > I understand that g++ 13 no longer supports _Float64x in a very limited way. No, that's incorrect. In GCC 12, there was no C++ support for that type, it was just a typedef for long double. In GCC 13 there is limited support for a distinct _Float64x type in the compiler, but you can't use it with the standard library (iostreams, numeric_limits, etc.) > Does this mean that if I want to use 80-bit extended floating point numbers > in g++ 13 or later, is it best to use long double? If you use long double then you get exactly the same code as you would get using _Float64x with GCC 12. > Since long double may not be 80-bit on non-x86 architectures, I wanted to > use _Float64x or __float80, which are clearly 80-bit, if possible. You can use them, but you can't use _Float64x with the standard library. You need to convert to/from another type like long double to use standard APIs.
