------- Comment #24 from amylaar at gcc dot gnu dot org 2009-02-02 20:02 ------- (In reply to comment #22) > If you post a patch to add the option to enable/disable partial-PRE I will > happily review and approve it for 4.4.
I experimented using Seteven Bosscher's patch as a starting point and augmenting the test in do_regular_insertion with a speed based heuristic to throttle the calls to insert_into_preds_of_block. That was worse than turning off partial-PRE altogether. Then I added the heuristic also in do_partial_insertion, which worked better. Then I tried to remove the speed heuristoc from do_regular_insertion, and taht change only very tiny, although overall beneficial, effects. To get meaningful results we had to modify the linking a bit to reduce instruction cache effects: the most needed libgcc function were pulled out early and placed next to the core benchmark objects. applying heuristic only to partial-partial vs. not applying it at all is... automotive: 6.55389% faster consumer: 0.00048% worse networking: 0.03793% faster office: 0.07269% worse telecom: 0.00000% faster applying heuristic only to partial-partial vs. applying it in general is... automotive: 0.00674% faster consumer: 0.00076% worse networking: 0.01746% faster office: 0.00440% worse telecom: 0.00002% worse Unfortunately, there is still no word from the FSF on what they did with our Copyright Assignment. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38401
