[Bug 38780] AArch64 platforms: register X18 must remain reserved for Wine to run 64-bit ARM Windows applications (Distro aarch64 toolchains need '-ffixed-x18' default, loader/libc/userland)

https://bugs.winehq.org/show_bug.cgi?id=38780

--- Comment #3 from André H.  ---
(In reply to Anastasius Focht from comment #5 from bug 38719)
> No special treatment, it's really used as general purpose register.
>
> The _dl_tlsdesc* X18 references result from NSAVEXREGPAIRS macro usage:
>
> https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/aarch64/dl-tlsdesc.
> S;h=be9b9b394c1aea8f3dfc1f0a9c4c32e002004822;hb=HEAD

First we should note that x18 is either the "platform register" or a temporary
register.
I think the macros in the linked code are fine, they just save and restore x18
and others (push/pop). The problem really is the compiler here as already
mentioned by you.