> Hi,
>
> since r278669 (fix for PR ipa/91956), IPA-SRA makes sure that the clone
> it creates is put into the same same_comdat as the original cgraph_node,
> so that it can call private comdats (such as the ipa-split bits of a
> comdat that is private).
>
> However, that means that if there is non-comdat caller of a public
> comdat that is modified by IPA-SRA, it now finds itself calling a
> private comdat, which call graph verifier does not like (and for a
> reason, in theory it can disappear and since it is private it would not
> be available from other CUs).
>
> The patch fixes this by performing the fix for PR 91956 only when the
> node in question actually calls a local comdat and when it does, also
> making sure that no callers come from a different same_comdat (disabling
> IPA-SRA if both conditions are true), so that it plays by the rules in
> both modes, does not violate the private comdat calling rule and at the
> same time does not disable the transformation unnecessarily.
>
> The patch also fixes up the calls_comdat_local of callers of the
> modified node, despite that not triggering any known issues. It has
> passed LTO-bootstrap and testing. What do you think?
>
> Thanks,
>
> Martin
>
>
> 2019-12-16 Martin Jambor <mjam...@suse.cz>
>
> PR ipa/92676
> * ipa-sra.c (struct caller_issues): New fields candidate and
> call_from_outside_comdat.
> (check_for_caller_issues): Check for calls from outsied of
> candidate's same_comdat_group.
> (check_all_callers_for_issues): Set up issues.candidate, check result
> of the new check.
> (process_isra_node_results): Set calls_comdat_local of callers if
> appropriate.
OK except for ...
> @@ -3759,8 +3778,12 @@ process_isra_node_results (cgraph_node *node,
> = node->create_virtual_clone (callers, NULL, new_adjustments, "isra",
> suffix_counter);
> suffix_counter++;
> - if (node->same_comdat_group)
> - new_node->add_to_same_comdat_group (node);
> + if (node->calls_comdat_local && node->same_comdat_group)
> + {
> + new_node->add_to_same_comdat_group (node);
> + for (cgraph_edge *cs = new_node->callers; cs; cs = cs->next_caller)
> + cs->caller->calls_comdat_local = true;
You need to walk all aliases here.
> + }
> new_node->calls_comdat_local = node->calls_comdat_local;
>
> if (dump_file)
> --
> 2.24.0
>
