On Tue, 16 Aug 2022, 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). > > However, why can't you use compute_ranges (or whatever we rename it to ;-))??
I've added auto_bb_flag m_on_path; to the path query and at set_path time set m_on_path on each BB so the m_path->contains () linear walks go away. But I need to clear the flag for which I would need something like finish_path (), doing it just at the point we deallocate the path query object or when we set the next path via compute_ranges doesn't look right (and in fact it doesn't work out-of-the-box without adjusting the lifetime of the path query object). So a more incremental thing would be to add such finish_path () or to make the whole path query object single-shot, thus remove compute_ranges and instead use the CTOR for this. Probably not too important (for short paths). Richard. > Aldy > > > > > query start (const vec<basic_block> &); > > > > and make range_of_* and friends members of a new 'query' class > > instantiated by path_range_query. I ran into this when trying > > to axe the linear array walks for the .contains() query on the > > path where I need a convenient way to "clenanup" after a path > > query is done. > > > > Richard. > >
