On Thu, 14 Jul 2011, Eric Botcazou wrote:
> > I'm wondering why for Ada boolean_true_node has a value that is
> > not in the range of the Ada type but is, for the specific case,
> > 255 instead of 1. Is there a specific reason for that?
>
> None, boolean_true_node must be 1, that's why we (re)set it in gnat_init.
>
> > Does the following patch make sense (untested)?
>
> It's a no-op. TYPE_MAX_VALUE == TYPE_RM_MAX_VALUE if the latter exists.
Oh, ok. So TYPE_MAX_VALUE gets re-set by
SET_TYPE_RM_MAX_VALUE (boolean_type_node,
build_int_cst (boolean_type_node, 1));
I would have thought that it sets something different from its comment:
/* For numerical types, this is the RM upper bound of the type. There is
again a discrepancy between this upper bound and the GCC upper bound,
again because of the need to support invalid values.
These values can be outside the range of values allowed by the RM upper
bound but they must nevertheless be valid in the GCC type system,
otherwise
the optimizer can pretend that they simply don't exist. Therefore they
must be within the range of values allowed by the upper bound in the
GCC
sense, hence the GCC upper bound be set to that of the base type. */
#define TYPE_RM_MAX_VALUE(NODE) TYPE_RM_VALUE ((NODE), 2)
#define SET_TYPE_RM_MAX_VALUE(NODE, X) SET_TYPE_RM_VALUE ((NODE), 2, (X))
and from looking at SET_TYPE_RM_VALUEs definition it doesn't
touch TYPE_MAX_VALUE. So TYPE_MAX_VALUE is as set from
make_unsigned_type (8) which should set it to 255, not 1.
So ... how can it be a no-op?
> > Btw, I wonder if Ada cannot simply use its own boolean_type_node
> > global tree and leave the middle-ends boolean_type_node alone,
> > which is supposed to match the C ABI of the target.
>
> Only after Fortran does the same. :-)
Heh ;) At least Fortran doesn't play games with TYPE_PRECISION ;)
Richard.
