[Bug inline-asm/89334] unsupported size for integer register

[stsp at users dot sourceforge.net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89334

--- Comment #2 from Stas Sergeev <stsp at users dot sourceforge.net> ---
(In reply to Jakub Jelinek from comment #1)
> the same for -m64, but only al/bl/cl/dl for -m32, because there is no
> sil/dil/bpl for -m32.

But why does this matter?
I am perfectly fine with al/bl/cl/dl, never asked
to use sil/dil/bpl. What is the rationale? If "r"
is plain invalid for 8bit values, then shouldn't
the error be different and not to depend on an opt
level? Could you please explain a bit more what
exactly the error is and why it works with -O1?
Why invalid registers (sil/dil/bpl) even matter
at all?