https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84658
--- Comment #23 from rguenther at suse dot de <rguenther at suse dot de> --- On Thu, 8 Mar 2018, marxin at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84658 > > --- Comment #22 from Martin Liška <marxin at gcc dot gnu.org> --- > (In reply to Martin Liška from comment #21) > > (In reply to Jakub Jelinek from comment #20) > > > How would IPA-PTA work then? > > > > Not having experience how that works, but I would expect a complete rebuild. > > Similar to what the tree PTA does? > > Note that the TREE PTA is just a TODO_rebuild_alias flag. Thus I would expect > IPA PTA is also a rebuild of PTA information. IPA PTA rebuilds everything (and with -fipa-pta we should be fine). The issue is the time between IPA ICF and the late pass_build_alias, we do the "invalid" folding in pass_ccp. And yes, we do want to do some scalar cleanup before running PTA. If we'd decide not to then the "proper" place would probably be pass_ipa_pta which then either would do local PTA or IPA PTA based on the flag. But that's too much for GCC 8 or 7.
