pr11135: make PIC register a pseudo

[Rask Ingemann Lambertsen]

On Fri, Jan 06, 2006 at 02:48:30PM -0800, Richard Henderson wrote:
> 
> What they're looking for is, for functions that don't use
> the pic register, to not reserve the pic register so that
> it's available for computation.  This is harder.  In theory,
> ppc has some scheme for this, where they eliminate the pic
> register to itself.  I've never really understood how that's
> supposed to work.

   Suppose you tell reload that %rpic can be eliminated as %rpic + 0. Reload
will start out by assuming that the elimination is possible and %rpic will
be available for reloads. If no insns mention %rpic at all, it should just
work, and you will have recovered a register.

-- 
Rask Ingemann Lambertsen