https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97822
--- Comment #32 from LIU Hao <lh_mouse at 126 dot com> --- I think the conclusion is probably that for 64-bit Windows targets `-mpreferred-stack-boundary` can't be anything other than 4. Increasing the alignment is not supported by SEH, and decreasing it violates the ABI. So the code in comment #13 is not supported, but it should have failed with a more friendly message.
