Enable pointer TBAA for LTO

[Jan Hubicka]

> On 11/11/2015 10:21 AM, Richard Biener wrote:
> >On Tue, 10 Nov 2015, Jan Hubicka wrote:
> >>The reason is that TYPE_CANONICAL is initialized in get_alias_set that may be
> >>called before we finish all merging and then it is more fine grained than what
> >>we need here (i.e. TYPE_CANONICAL of pointers to two differnt types will be
> >>different, but here we want them to be equal so we can match:
> >>
> >>struct aa { void *ptr;};
> >>struct bb { int * ptr;};
> >>
> >>Which is actually required for Fortran interoperability.
> 
> Just curious, is this sort of thing documented anywhere?

See http://www.j3-fortran.org/doc/year/10/10-007.pdf, section 15 (interoperability with C).
It defines that C_PTR is compatible with any C non-function pointer.

Honza
> 
> 
> Bernd