On Tue, Aug 16, 2022 at 3:48 PM Andrew MacLeod <amacl...@redhat.com> wrote: > > > On 8/16/22 06:25, Aldy Hernandez wrote: > > On Mon, Aug 15, 2022 at 11:53 AM Richard Biener <rguent...@suse.de> wrote: > >> The remaining issue I have with the path_range_query is that > >> we re-use the same instance in the back threader but the > >> class doesn't provide any way to "restart", aka give m_path > >> a lifetime. The "start a new path" API seems to essentially > >> be compute_ranges (), but there's no convenient way to end. > >> It might be more appropriate to re-instantiate the path_range_query, > >> though that comes at a cost. Or abstract an actual query, like > >> adding a > > Yes, compute_ranges() is the way to start a new path. It resets exit > > dependencies, the path, relations, etc. I think it would be clearer > > to name it set_path (or reset_path if we want to share nomenclature > > with the path_oracle). > > > > Instantiating a new path_range_query per path is fine, as long as you > > allocate the ranger it uses yourself, instead of letting > > path_range_query allocate it. Instantiating a new ranger does have a > > cost, and it's best to let path_range_query re-use a ranger from path > > to path. This is why path_range_query is (class) global in the > > backwards threader. Andrew mentioned last year making the ranger > > start-up 0-cost, but it still leaves the internal caching the ranger > > will do from path to path (well, the stuff outside the current path, > > cause the stuff inside the path is irrelevant since it'll get > > recalculated). > > Yes, you will want to have one instance of ranger regardless... just > pass it to whatever/however many other instances you want to build paths > from. > > Ranger itself is primarily to provide range-on-entry to the path. > Trying to use it for values within the path would bring in values > outside the path as it doesnt understand you have selected on certain > edges along the way. > > The GORI engine within ranger can be utilized within the path because > GORI never looks outside the basic block being asked about, other than > thru the range-query that is provided to it. SO its perfectly safe to > use within the path. > > As both GORI and ranger cache things and share the def chains, its far > more efficient to have a global instance that is just utilized. Even a > zero-cost start up would incur costs as it recalculates the same things > over and over
I forgot about the def chains. That should be fine however, since we use the gori from within the ranger that got passed down. Aldy
