https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108968
--- Comment #2 from Andrew Cooper <andrew.cooper3 at citrix dot com> --- __builtin_frame_address() does appear to resolve the warning, but the knock-on effect for code generation is even worse than the asm() block. It forces a frame-pointer setup in all functions that use it (which is most functions in Xen), even leaf functions, and despite -fomit-frame-pointer, which in turn causes spilling of other registers now that %rbp isn't usable.
