On Thu, Sep 19, 2019 at 11:06 AM Martin Liška <mli...@suse.cz> wrote: > > Hi. > > As Alexander pointed out, the sort_congruence_class_groups_by_decl_uid is the > most > expensive qsort operator in tramp3d compilation. It does unfortunate 7 > pointer dereferences > via: DECL_UID (classes[i]->classes[0]->members[0]->decl). I'm suggesting to > cache that > in congruence_class_group. > > Patch can bootstrap on x86_64-linux-gnu and survives regression tests. > > Ready to be installed?
Since we're populating the classes vector right before you could elide the new field and do it in the same iteration by having auto_vec <std::pair<congruence_class_group *, unsigned> > classes and pushing *it, DECL_UID and then sorting by the readily available UID in the data? That makes the sort use a linear memory region w/o dereferences. Richard. > Thanks, > Martin > > gcc/ChangeLog: > > 2019-09-19 Martin Liska <mli...@suse.cz> > > * ipa-icf.c (sort_sem_items_by_decl_uid): Simplify comparator. > (sort_congruence_classes_by_decl_uid): Likewise. > (sort_congruence_class_groups_by_decl_uid): Use > congruence_class_group::uid. > (sem_item_optimizer::merge_classes): Cache > DECL_UID (classes[i]->classes[0]->members[0]->decl). > * ipa-icf.h (struct congruence_class_group): New field. > --- > gcc/ipa-icf.c | 29 +++++------------------------ > gcc/ipa-icf.h | 1 + > 2 files changed, 6 insertions(+), 24 deletions(-) > >
