> On 11/18/21 5:41 AM, Jan Hubicka via Gcc-patches wrote:
> > > modref_tree<tree_node*>::merge(modref_tree<tree_node*>*,
> > > vec<modref_parm_map, va_heap, vl_ptr>*, modref_parm_map*, bool)
> > >
> > > is called with modref_parm_map chain_map;
> > >
> > > The variable has uninitialized m.parm_offset_known and it is accessed
> > > here:
> > >
> > > gcc/ipa-modref-tree.h:572 a.parm_offset_known &= m.parm_offset_known;
> > >
> > > Ready to be installed after testing?
> > > Thanks,
> > > Martin
> > >
> > > PR ipa/103230
> > >
> > > gcc/ChangeLog:
> > >
> > > * ipa-modref-tree.h (struct modref_parm_map): Add default
> > > constructor.
> > > * ipa-modref.c (ipa_merge_modref_summary_after_inlining): Use it.
> > > ---
> > > gcc/ipa-modref-tree.h | 5 +++++
> > > gcc/ipa-modref.c | 3 +--
> > > 2 files changed, 6 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/gcc/ipa-modref-tree.h b/gcc/ipa-modref-tree.h
> > > index 0a097349ebd..6796e6ecc34 100644
> > > --- a/gcc/ipa-modref-tree.h
> > > +++ b/gcc/ipa-modref-tree.h
> > > @@ -287,6 +287,11 @@ struct GTY((user)) modref_base_node
> > > struct modref_parm_map
> > > {
> > > + /* Default constructor. */
> > > + modref_parm_map ()
> > > + : parm_index (MODREF_UNKNOWN_PARM), parm_offset_known (false),
> > > parm_offset ()
> > > + {}
> > > +
> > I think we are generally not supposed to put non-pods to vec<..>
>
> I don't know what the guidance is on using vec in IPA passes
> but with respect to existing practice elsewhere, there are
> existing uses of vec and auto_vec with non-POD types and vec
> does work with them (see the vec_default_construct and
> vec_copy_construct templates, for example, whose goal is
> to support nontrivial classes).
I see, since 2017 :). The patch is OK then.
Nontrivial destructors also behave in a sane way these days?
Honza
>
> Martin
>
> > The diagnostics should be from
> > a.parm_offset_known &= m.parm_offset_known;
> > Becasue both in the parm_map (which is variable m) and access_node
> > (which is variable a) the parm_offset_known has no meaning when
> > parm_index == MODREF_UNKNOWN_PARM.
> >
> > If we want to avoid computing on these, perhaps this will work?
> >
> > diff --git a/gcc/ipa-modref-tree.h b/gcc/ipa-modref-tree.h
> > index 0a097349ebd..97736d0d8a4 100644
> > --- a/gcc/ipa-modref-tree.h
> > +++ b/gcc/ipa-modref-tree.h
> > @@ -568,9 +568,13 @@ struct GTY((user)) modref_tree
> > : (*parm_map) [a.parm_index];
> > if (m.parm_index == MODREF_LOCAL_MEMORY_PARM)
> > continue;
> > - a.parm_offset += m.parm_offset;
> > - a.parm_offset_known &= m.parm_offset_known;
> > a.parm_index = m.parm_index;
> > + if (a.parm_index != MODREF_UNKNOWN_PARM)
> > + {
> > + a.parm_offset_known &= m.parm_offset_known;
> > + if (a.parm_offset_known)
> > + a.parm_offset += m.parm_offset;
> > + }
> > }
> > }
> > changed |= insert (base_node->base, ref_node->ref, a,
> > > /* Index of parameter we translate to.
> > > Values from special_params enum are permitted too. */
> > > int parm_index;
> > > diff --git a/gcc/ipa-modref.c b/gcc/ipa-modref.c
> > > index c94f0589d44..630d202d5cf 100644
> > > --- a/gcc/ipa-modref.c
> > > +++ b/gcc/ipa-modref.c
> > > @@ -5020,8 +5020,7 @@ ipa_merge_modref_summary_after_inlining
> > > (cgraph_edge *edge)
> > > auto_vec <modref_parm_map, 32> parm_map;
> > > modref_parm_map chain_map;
> > > /* TODO: Once we get jump functions for static chains we could
> > > - compute this. */
> > > - chain_map.parm_index = MODREF_UNKNOWN_PARM;
> > > + compute parm_index. */
> > > compute_parm_map (edge, &parm_map);
> > > --
> > > 2.33.1
> > >
>
