FDO usability: pid handling

[Jan Hubicka]

> On Tue, Apr 19, 2011 at 3:57 PM, Jan Hubicka <hubicka@ucw.cz> wrote:
> >> So between hashtab and VEC, which one do you prefer? Either one is fine with me.
> >
> > I would go with VEC. Â While the array will have holes, there are not many since
> > the ids are originally assigned sequentially.
> >
> > Actually given that we do IPA pass now, I think you can just remove cgraph->pid
> > field and replace it by cgraph->uid. Â The original issue was that profiling
> > made cgraph->uid diverge in between compilation and profling time becuase it
> > affected things like early inlining. Â This is not true anymore, so cgraph->uid
> > should work well now.
> 
> Why not using struct function's funcdef_no?

Well, we have DECL_UID, cgraph_node->uid and struct function funcdef_no.  I
think funcdef_no is least used and probably could be dropped in favour of the
other two. It seems to be used only in order to generate unique labels for functions,
that should be easilly replaceable by DECL_UID.

DECL_UID and cgraph_node->uid will probably have to stay since they drive quite
few datastructures. 

Honza