Re: useless_type_conversion_p vs pointer sizes

[DJ Delorie <dj at redhat dot com>]

> That should not be necessary as there is a mode check below.  Do you
> hit the issue only when the VOID_TYPE_P check is true?  In that case
> simply delete it - it has become obsolete.

That seems to be happening, yes, but there are other checks
that might let differing modes through...

  /* Changes in machine mode are never useless conversions unless we
     deal with aggregate types in which case we defer to later checks.  */
  if (TYPE_MODE (inner_type) != TYPE_MODE (outer_type)
      && !AGGREGATE_TYPE_P (inner_type))
    return false;

Later,

  else if (POINTER_TYPE_P (inner_type)
	   && POINTER_TYPE_P (outer_type))
    {
      /* Do not lose casts to function pointer types.  */
      if ((TREE_CODE (TREE_TYPE (outer_type)) == FUNCTION_TYPE
	   || TREE_CODE (TREE_TYPE (outer_type)) == METHOD_TYPE)
	  && !(TREE_CODE (TREE_TYPE (inner_type)) == FUNCTION_TYPE
	       || TREE_CODE (TREE_TYPE (inner_type)) == METHOD_TYPE))
	return false;

      /* We do not care for const qualification of the pointed-to types
	 as const qualification has no semantic value to the middle-end.  */

      /* Otherwise pointers/references are equivalent.  */
      return true;
    }

So two different sized pointers to aggregate types will also have a problem?

I'm a little paranoid here because TPF uses different sized pointers a
*lot* so if we can't guarantee that the rest of the logic keeps the
conversion, I'd rather keep the explicit check.