Re: wide-int more performance fixes for wide multiplication.

[Kenneth Zadeck <zadeck at naturalbridge dot com>]

> > +      vallen = canonize (val, (uvlen + 1) >> 1, prec);
> > +
> > +      /* Shift is not always safe to write over one of the
> > +	 operands, so we must copy.  */
> > +      HOST_WIDE_INT tval[2 * WIDE_INT_MAX_ELTS];
> > +      memcpy (tval, val, vallen * CHAR_BIT / HOST_BITS_PER_WIDE_INT);


> vallen * sizeof (HOST_WIDE_INT) would be more typical.
> But why not unpack into tval directly and avoid the copy?
I could special case this, but the old code was not correct for odd 
precisions.