On 6/21/19 6:28 AM, Richard Biener wrote: > On Fri, Jun 21, 2019 at 12:24 AM Jeff Law <l...@redhat.com> wrote: >> >> As outlined in the BZ, our alias analysis code is context insensitive. >> So when we copy-propagate pointers, we can can and do copy PTA >> information from members to the representative pointer in the copy-of >> chain (we do this when the representative pointer has no associated PTA >> information). >> >> However, [E]VRP can set the non-nullness of a pointer using context >> sensitive information. So we have to be more careful when copying PTA >> information. >> >> We already have similar issues with alignment information as well. This >> patch just extends the hack to avoid copying alignment information in >> some circumstances to also avoid copying the non-nullness property. >> >> Bootstrapped and regression tested on x86_64-linux-gnu. OK for the trunk? > > I think this should be done in reset_flow_sensitive_info () as well > and tree-ssa-copy.c should use that function instead of calling > mark_ptr_info_alignment_unknown. OK. Agreed that's better -- one centralized routine to reset this stuff if we find more over time.
> > I'd probably avoid the new clear_ptr_nonnull function since it might make > people miss the other half (alignment). OK. Presumably you just want to twiddle the field directly? THat's easy 'nuff. Jeff
