Hi Jeff,
On 28 October 2017 at 18:28, Jeff Law <l...@redhat.com> wrote:
>
> Jan,
>
> What's the purpose behind calling vrp_meet and
> extract_range_from_unary_expr from within the IPA passes?
This is used such that when we have an argument to a function and this
for which we know the VR and this intern is passed as a parameter to
another. For example:
void foo (int i)
{
...
bar (unary_op (i))
...
}
This is mainly to share what is done in tree-vrp.
>
> AFAICT that is not safe to do. Various paths through those routines
> will access static objects within tree-vrp.c which may not be
> initialized when IPA runs (vrp_equiv_obstack, vr_value).
IPA-VRP does not track equivalence and vr_value is not used.
Thanks,
Kugan
>
> While this seems to be working today, it's a failure waiting to happen.
>
> Is there any way you can avoid using those routines? I can't believe
> you really need all the complexity of those routines, particularly
> extract_range_from_unary_expr. Plus it's just downright fugly from a
> modularity standpoint.
>
>
> ?
>
> Jeff
