https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117932
--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Richard Biener <rgue...@gcc.gnu.org>: https://gcc.gnu.org/g:6b390f8253b7f6575f18e356610aeb5d83e1140f commit r15-6031-g6b390f8253b7f6575f18e356610aeb5d83e1140f Author: Richard Biener <rguent...@suse.de> Date: Sat Dec 7 14:43:00 2024 +0100 middle-end/117932 - further speedup DF worklist solver The triple-indirect memory reference we perform for each incoming edge age <= last_change_age[bbindex_to_postorder[e->src->index]] is pretty bad and when there are a lot of small BBs like for the PR26854 testcase this shows in the profile. The following reduces this by one level by making last_change_age indexed by BB index rather than postorder number and realizing that for the first iteration the age check is always true. We pay for this by allocating last_change_age for all BBs in the function but we do it like for sparsesets and avoid initializing given we check the considerd bitmap anyway. We can also elide initializing last_visit_age in an obvious way given we separated the initial iteration in the previous change. Together this improves compile-time in the PR117932 setting by another 2%. PR middle-end/117932 * df-core.cc (df_worklist_propagate_forward): Elide age check for the first iteration, adjust for last_change_age change. (df_worklist_propagate_backward): Likewise. (df_worklist_dataflow_doublequeue): Make last_change_age indexed by BB index, avoid clearing both age arrays.
