Re: [patch] canonicalize unsigned [1,MAX] ranges into ~[0,0]

[Jakub Jelinek <jakub at redhat dot com>]

On Tue, Oct 15, 2019 at 08:35:07AM -0400, Aldy Hernandez wrote:
> > I'm seeing this on 32-bit i386-pc-solaris2.11 and sparc-sun-solaris2.11,
> > with more reports for armv8l, pru, and s390x.
> > 
> > Comparing the dumps between 64 and 32-bit, I see
> > 
> > -_1: int * [1B, -1B]
> > +_1: int * [1B, 4294967295B]
> 
> I wonder why 32-bit targets at displaying 4294967295 instead of -1.  Or are
> pointers 64-bits here?

Because the dump method does:
      if (INTEGRAL_TYPE_P (ttype)
          && vrp_val_is_max (max ())
          && TYPE_PRECISION (ttype) != 1)
        fprintf (file, "+INF");
      else
        print_generic_expr (file, max ());
so for integral types and maximum value, it prints +INF, but not for
pointers.
Perhaps we want to print +INF also for pointers,
      if ((INTEGRAL_TYPE_P (ttype) || POINTER_TYPE_P (ttype))
	  && vrp_val_is_max (max (), true)
          && TYPE_PRECISION (ttype) != 1)
        fprintf (file, "+INF");
      else
        print_generic_expr (file, max ());
but maybe vrp_val_is_{min,max} should be rewritten for pointer types to be
more efficient, don't create trees, for min just use integer_zerop and for
max just compare wide_int?

	Jakub