https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54895
--- Comment #12 from Kai Tietz <ktietz at gcc dot gnu.org> --- This bug got partially fixed for x86 (32-bit) by PR/44282. For x64 we have the issue that there is made no difference between different calling-conventions, as all variants are treated as standard fastcall-convention under the hood.
