[Bug target/119628] Need better mechanisms to manage register saves in callee for tail calls (inc. preserve_none for x86_64?)

[hjl.tools at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119628

--- Comment #20 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Florian Weimer from comment #19)
> Note that this implementation of the preserve_none attribute is incompatible
> with Clang.

This isn't a critical issue since the same compiler should be used
to compile all sources with preserve_none attribute.