On Fri, 12 Mar 2021, Jonathan Wakely wrote: > On Fri, 12 Mar 2021 at 12:26, Sjoerd Meijer via Gcc <gcc@gcc.gnu.org> wrote: > > So here's finally my concrete question: what do we think about making > > _Float16 available in C++ mode? > > I think GCC should do it.
What about types with the same format as an existing type (but which are nevertheless distinct types in C), such as _Float64 (typically same format as double) or _Float32 (typically same format as float, but not promoted when passed in variable arguments)? When those types escape into C++ code, they cause an ICE in name mangling; see bug 85518. (Incidental note on _Float16: various architectures have some hardware support for that format that don't have support for the type in GCC, although they may well have GCC built-in functions corresponding to the hardware support; also library support in glibc hasn't yet been implemented. In the case of x86_64 (F16C hardware conversion instructions from Ivy Bridge onwards), the psABI document defines an ABI for _Float16 and the corresponding complex type; in general such an ABI should be agreed with interested parties when adding _Float16 support for an architecture.) -- Joseph S. Myers jos...@codesourcery.com
