[Bug lto/70955] [6/7 Regression] Wrong code generation for __builtin_ms_va_list with -flto

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70955

--- Comment #17 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Steven Shi from comment #16)
> How to checkout the 6.3 code from GCC trunk? I hope to verify this fix on
> Uefi firmware GCC LTO build.

The patch is not checked in as I believe the fundamental issue is not solved
in a sensible way.