sparcv9 bootstrap failure; gengenrtl dumps core

[Jeff Sturm]

On Thu, 24 Jan 2002, Richard Henderson wrote:
> Actually, I'm not really sure what to do with the offset
> stack pointer on sparcv9 -- it's arguably incorrect to say
> that the stack pointer is aligned, since combine can jump
> to the wrong conclusion.

Well, we also claim VIRTUAL_STACK_VARS_REGNUM is aligned in init_emit ().
One or the other is a lie for any port where STARTING_FRAME_OFFSET isn't
a multiple of the alignment, as on both ppc and sparcv9.

I don't care for much for the STARTING_FRAME_PHASE macro, but I don't have
any better ideas.

Jeff