[Bug c/104805] [12.0] x86_64 Extended asm may use rbp register to input/output even thougth "rbp" is in the clobber list when "rsp" and "rbp" are both in the in the clobber list

[jakub at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104805

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
rbp is hard frame pointer, so depending on whether the function needs a frame
pointer (at -O0 I think all functions do), the register isn't available for use
(and therefore for clobbering) in inline asm.
Only in functions where it isn't needed, it is not fixed then and can be used
for other purposes.