frame pointer must be single register?

[Paul Koning]

On Jul 8, 2011, at 1:07 PM, DJ Delorie wrote:

> 
> Is there an unwritten rule that the frame pointer must be a single
> hard register?  I'm working on a port where $fp is a register pair,
> and I've seen gcc allocate the second register to other things
> (causing all sorts of problems).

Would it suffice simply to mark the second register as a reserved register?  That should take it away from the allocator, right?

	paul