[Bug inline-asm/90181] Feature request: provide a way to explicitly select specific named registers in constraints

[schwab@linux-m68k.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90181

--- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> ---
x86 doesn't support this either.  It just happens to have a few register
classes that consist of a single register, but only because of ISA constraints.