> Hi,
>
> this bug is an interesting one. The immediate cause of the ICE is that
> IPA-SRA modification phase baked into clone materialization was
> expecting to see a body already changed by IPA-CP while it was actually
> looking at the original function.
>
> That was because we were materializing the (offline) clone in an ltrans
> from which it was called but where it did not belonged at all.
> remove_unreachable_nodes realized this and wanted to keep just the
> declaration and remove the body - and therefor also all traces of the
> IPA-CP clone which was necessary just for materialization. But
> materialization code still attempted to resurrect the clone.
>
> Honza proposed immediately removing any node which only needs to have a
> declaration from the tree of clones to prevent materialization code from
> even considering them which is what the following patch does.
>
> Unfortunately, I was not able to come up with a small testcase, the bug
> is triggered by fragile partitioning decisions. I have bootstrapped,
> LTO-bootstrapped and tested the patch on an x86_64-linux, OK for trunk?
>
> Thanks,
>
> Martin
>
>
>
> 2019-11-21 Martin Jambor <mjam...@suse.cz>
>
> PR ipa/92109
> * cgraph.h (cgraph_node::remove_from_clone_tree): Declare.
> * cgraphclones.c (cgraph_node::remove_from_clone_tree): New method.
> (cgraph_materialize_clone): Move removel from clone tree to the
> the new method and use it instead.
> * ipa.c (symbol_table::remove_unreachable_nodes): When removing
> bodies of clones, also remove it from the clone tree.
OK,
thanks!
Honza
> ---
> gcc/cgraph.h | 4 ++++
> gcc/cgraphclones.c | 35 ++++++++++++++++++++++-------------
> gcc/ipa.c | 11 ++++++++---
> 3 files changed, 34 insertions(+), 16 deletions(-)
>
> diff --git a/gcc/cgraph.h b/gcc/cgraph.h
> index a4f14743f00..0d2442c997c 100644
> --- a/gcc/cgraph.h
> +++ b/gcc/cgraph.h
> @@ -967,6 +967,10 @@ struct GTY((tag ("SYMTAB_FUNCTION"))) cgraph_node :
> public symtab_node
> ipa_param_adjustments *param_adjustments,
> const char * suffix, unsigned num_suffix);
>
> + /* Remove the node from the tree of virtual and inline clones and make it a
> + standalone node - not a clone any more. */
> + void remove_from_clone_tree ();
> +
> /* cgraph node being removed from symbol table; see if its entry can be
> replaced by other inline clone. */
> cgraph_node *find_replacement (void);
> diff --git a/gcc/cgraphclones.c b/gcc/cgraphclones.c
> index bfcebb20495..ac5c57a47aa 100644
> --- a/gcc/cgraphclones.c
> +++ b/gcc/cgraphclones.c
> @@ -1013,6 +1013,22 @@ cgraph_node::create_version_clone_with_body
> return new_version_node;
> }
>
> +/* Remove the node from the tree of virtual and inline clones and make it a
> + standalone node - not a clone any more. */
> +
> +void cgraph_node::remove_from_clone_tree ()
> +{
> + if (next_sibling_clone)
> + next_sibling_clone->prev_sibling_clone = prev_sibling_clone;
> + if (prev_sibling_clone)
> + prev_sibling_clone->next_sibling_clone = next_sibling_clone;
> + else
> + clone_of->clones = next_sibling_clone;
> + next_sibling_clone = NULL;
> + prev_sibling_clone = NULL;
> + clone_of = NULL;
> +}
> +
> /* Given virtual clone, turn it into actual clone. */
>
> static void
> @@ -1033,22 +1049,15 @@ cgraph_materialize_clone (cgraph_node *node)
> dump_function_to_file (node->decl, symtab->dump_file, dump_flags);
> }
>
> + cgraph_node *clone_of = node->clone_of;
> /* Function is no longer clone. */
> - if (node->next_sibling_clone)
> - node->next_sibling_clone->prev_sibling_clone = node->prev_sibling_clone;
> - if (node->prev_sibling_clone)
> - node->prev_sibling_clone->next_sibling_clone = node->next_sibling_clone;
> - else
> - node->clone_of->clones = node->next_sibling_clone;
> - node->next_sibling_clone = NULL;
> - node->prev_sibling_clone = NULL;
> - if (!node->clone_of->analyzed && !node->clone_of->clones)
> + node->remove_from_clone_tree ();
> + if (!clone_of->analyzed && !clone_of->clones)
> {
> - node->clone_of->release_body ();
> - node->clone_of->remove_callees ();
> - node->clone_of->remove_all_references ();
> + clone_of->release_body ();
> + clone_of->remove_callees ();
> + clone_of->remove_all_references ();
> }
> - node->clone_of = NULL;
> bitmap_obstack_release (NULL);
> }
>
> diff --git a/gcc/ipa.c b/gcc/ipa.c
> index 0c92980db46..2404024d722 100644
> --- a/gcc/ipa.c
> +++ b/gcc/ipa.c
> @@ -520,9 +520,14 @@ symbol_table::remove_unreachable_nodes (FILE *file)
> reliably. */
> if (node->alias || node->thunk.thunk_p)
> ;
> - else if (!body_needed_for_clonning.contains (node->decl)
> - && !node->alias && !node->thunk.thunk_p)
> - node->release_body ();
> + else if (!body_needed_for_clonning.contains (node->decl))
> + {
> + /* Make the node a non-clone so that we do not attempt to
> + materialize it later. */
> + if (node->clone_of)
> + node->remove_from_clone_tree ();
> + node->release_body ();
> + }
> else if (!node->clone_of)
> gcc_assert (in_lto_p || DECL_RESULT (node->decl));
> if (node->definition && !node->alias && !node->thunk.thunk_p)
> --
> 2.23.0
>
