https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89485
Agner Fog <agner at agner dot org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |agner at agner dot org --- Comment #1 from Agner Fog <agner at agner dot org> --- I can confirm that both Clang, MS, and Intel compilers transfer vectors in registers for function parameters and function return in 64 bit Windows when __vectorcall is specified. There is still 32 or 40 bytes of superfluous shadow space allocated on the stack. Clang adds @@<size> to the mangled function name. Please support __vectorcall in Gcc as well.