wide-int: Fix up set_bit_large

wide-int: Fix up set_bit_large

> >> wide_int new_lb = wi::set_bit (r.lower_bound (0), 127)
> >>
> >> and creates the value:
> >>
> >> p new_lb
> >> {<wide_int_storage> = {val = {-65535, -1, 0}, len = 2, precision = 128},
> >> static is_sign_extended = true}
> >
> > This is non-canonical and so invalid, if the low HWI has the MSB set
> > and the high HWI is -1, it should have been just
> > val = {-65535}, len = 1, precision = 128}
> >
> > I guess the bug is that wi::set_bit_large doesn't call canonize.
>
> Yeah, looks like a micro-optimisation gone wrong.

2020-10-28  Jakub Jelinek  <jakub@redhat.com>

	* wide-int.cc (wi::set_bit_large): Call canonize unless setting
	msb bit and clearing bits above it.