https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85598
--- Comment #15 from rguenther at suse dot de <rguenther at suse dot de> --- On Fri, 23 Nov 2018, jakub at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85598 > > --- Comment #14 from Jakub Jelinek <jakub at gcc dot gnu.org> --- > (In reply to rguent...@suse.de from comment #13) > > Note that dom after vrp1 should be able to adjust the value-ranges given > > it uses EVRP to track ranges... why doesn't that work? > > From what I see, dom never calls record_ranges_from_phis, but even if it > would, > it wouldn't handle the relevant case here, which is to interset the range of > the SSA_NAME phi arg with the edge condition (as if there was an assertion > registered). It records ranges from incoming edges though via evrp_range_analyzer.enter (dom_opt_dom_walker::before_dom_children). Yeah, it then just does /* Create equivalences from redundant PHIs. PHIs are only truly redundant when they exist in the same block, so push another marker and unwind right afterwards. */ m_avail_exprs_stack->push_marker (); for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) eliminate_redundant_computations (&gsi, m_const_and_copies, m_avail_exprs_stack); this is where it would need to call into evrp_range_analyzer. I guess simply doing evrp_range_analyzer.record_ranges_from_stmt (gsi_stmt (gsi), false); there would work? > I think I'm able to implement this in forwprop using with using the > get_range_info (const_tree, value_range_base &), > value_range::{deep_copy,intersect,union} APIs, or defer to somebody familiar > with dom and evrp range analyzer to do it in dom (Jeff, Aldy). > >
