https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115054
--- Comment #7 from Trevor Gross <tmgross at umich dot edu> --- (In reply to connor horman from comment #6) > According to: https://cs61.seas.harvard.edu/site/pdf/x86-64-abi-20210928.pdf > > > Arguments of types _Float16, float, double, _Decimal32, _Decimal64 and > > __m64 are > in class SSE. > > So `_Float16` is SSE as well. I must have been looking at an ancient version of the psABI, it looks like _Float16 was added five years ago [1]. Thanks for the update. I think all of this is substantial enough reasoning for GCC to be the one to change its behavior. If Microsoft winds up adding these types then it seems rather likely for them to follow the precedent of SysV and their own float/double ABI, especially if the MinGW ecosystem does the same. Doesn't help anything here but I found some discussion on MSVC _Float16/_Float128 at [2]. [1]: https://gitlab.com/x86-psABIs/x86-64-ABI/-/commit/71d1183e7bb95e9f8ad732e0f2b5a4f127796e2a [2]: https://developercommunity.visualstudio.com/t/Implement-the-C23-Extended-Precision-P/10374212?viewtype=all
