mpn_rshift / mpn_lshift bug on m68000

[Kevin Ryde]

Patrick Pelissier <Patrick.Pelissier at loria.fr> writes:
>
> For mc68000, in most case, int = 16 bits, and long = 32 bits.
> So the assembly function read a random value.

I tried deliberately sticking a random value in the upper part, and
mpn_lshift still worked fine.

I suspect the only ill effect is to miss out on the shift-by-1 special
case (which could be addressed without too much trouble).

We ask that bug reports include a sample program exhibiting the
claimed bad behaviour in order to ensure that a reported problem
really is a problem.