> > > I don't think 0001 is right either, although maybe for somewhat > different reasons. First, I think it only considers VAR OP CONST style > clauses, but that is leaving money on the table, because given a.x = > b.x AND mumble(a.x), we can decide to instead test mumble(b.x) if the > equality operator in question has is-binary-identical semantics. It > does not seem necessary for a first patch to deal with both that and > the somewhat more pleasing case where we're making deductions based on > operator families ... but we shouldn't commit to a design for the VAR > OP CONST case without understanding how it could be generalized. >
I can follow up with this and +1 with the statement. > Second, it looks to me like the patch takes the rather naive strategy > of enforcing the derived clauses everywhere that they can legally be > put, which seems certain not to be optimal. If we can have some agreement (after more discussion) the EC filter is acceptable on semantics level, I think we may have some chances to improve something at execution level. -- Best Regards Andy Fan
