https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114417
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Summary|std::experimental::simd |std::experimental::simd is |parameters are passed by |not a POD (by ABI |memory on x64 , not using |definitions) and is always |the available sse registers |passed by reference instead | |of by value Component|target |libstdc++ --- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Most likely because stdx::fixed_size_simd is not a POD type.