[Bug target/86673] [8/9 regression] inline asm sometimes ignores 'register asm("reg")' declarations

[arnd at linaro dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86673

--- Comment #5 from Arnd Bergmann <arnd at linaro dot org> ---
(In reply to Andreas Schwab from comment #4)
> Why are you using empty constraints when a register is required?

creduce did that, it had no effect on the result. The original source looks
like:

#define __get_user_x_64t(__r2, __p, __e, __l, __s)                      \
           __asm__ __volatile__ (                                       \
                __asmeq("%0", "r0") __asmeq("%1", "r2")                 \
                __asmeq("%3", "r1")                                     \
                "bl     __get_user_64t_" #__s                           \
                : "=&r" (__e), "=r" (__r2)                              \
                : "0" (__p), "r" (__l)                                  \
                : __GUP_CLOBBER_##__s)