[patch] Fix aliasing problem with fortran

[Zdenek Dvorak]

Hello,

> On Tuesday 17 May 2005 01:22, Zdenek Dvorak wrote:
> > > It might not occur now, but I guess it could if we start passing
> > > alias information down from trees to rtl.
> >
> > This might be the case; if so, the types would have to be shared
> > completely to avoid this problem.
> 
> I'm not sure this is even possible.  Can't we tweak the alias analysis to say 
> that these types can alias? I'm fairly sure the C frontends do this for 
> structs with the same initial members.

IIRC, different types with the same structure cannot alias in C (I may
be wrong, but c_common_get_alias_set suggests so).
c_common_get_alias_set only uses a hash table to assign the same alias
set to the same types defined in different input files with IMA.

Hashing can be used to ensure sharing of the nodes produced by
gfc_get_array_type_bounds for arrays of the same type.

Zdenek