Help with constraint for single register

[Robert Baruch]

On Sat, 25 Dec 2004 17:13:20 -0800, Richard Henderson <rth@redhat.com> wrote:
> > QUESTION #2: Uh oh, somehow the compiler got a hold of W anyway, and
> > generated RTL for const -1 -> W, and passed that move to my expander.
> > How did the compiler grab W?
> 
> If you exposed W through an expander, that'll be the cause.
> You've let the rtl optimzers see the register.

I thought that expanders were only used during the initial RTL
generation phase? Except for that expander, I don't expose W anywhere
except in the structures I've shown before...

Thanks,

--Rob