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

[thopre01 at gcc dot gnu.org]

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

--- Comment #7 from Thomas Preud'homme <thopre01 at gcc dot gnu.org> ---
(In reply to Thomas Preud'homme from comment #6)
> The following simpler testcase also shows the problem:
> 
> void fn1() {
>   register const int h asm("r2") = 1;
>   __asm__(".ifnc %0,r2; .err; .endif\n\t"
>           "bl   __put_user_4" :: "r"(h));
> }

The register label gets optimized during gimple stages.