[Bug middle-end/17793] [4.0 Regression] Ada bootstrap failure

["ebotcazou at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From ebotcazou at gcc dot gnu dot org  2004-10-16 17:26 -------
[Thanks for elaborating on your position.]

> check_pointer_types_r is wrong but so is Ada assuming that integer types are
> not compatible (read the full bug report which I reported in the first place):
> "The integer_type's are not compatible by defined by the front-end, why?"

My understanding is that type compatibility is purely a front-end business, so
there is not really a notion of being right or wrong here.  The middle-end
should be able to cope with either situation.

> See this is where Ada becomes wrong with respect to generic and gimple where
> it needs integer types which have the same PRECISION, UNSIGNEDness, and SIZE
> are consided compatible types (so are their POINTERs).

Could you point me at where this requirement is documented?

The Ada front-end contains this comment (misc.c:560):

   ??? We may also want to generalize to considering lots of integer types
   compatible, but we need to understand the effects of alias sets first.

> For Kenner here, Generic and Gimple have the same type system which is partly
> described above. Yes this is not documented but should be.  This again is an
> Ada bug not doing what the middle-end generic and gimple expects to happen.

I think the issue is orthogonal to the discussion on the type systems of GENERIC
and GIMPLE.  The front-end generates a correct GENERIC tree AFAICS so the
gimplifier should be able to deal with it.

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17793