[Bug rtl-optimization/109858] [14 Regression] r14-172 caused some SPEC2017 bmk to degrade on Power
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109858 Kewen Lin changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Resolution|--- |FIXED Assignee|unassigned at gcc dot gnu.org |crazylht at gmail dot com --- Comment #12 from Kewen Lin --- Already fixed by Hongtao's fix.
[Bug rtl-optimization/109858] [14 Regression] r14-172 caused some SPEC2017 bmk to degrade on Power
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109858 --- Comment #11 from CVS Commits --- The master branch has been updated by hongtao Liu : https://gcc.gnu.org/g:4fb66b2329319e9b47e89200d613b6f741a114fc commit r14-1252-g4fb66b2329319e9b47e89200d613b6f741a114fc Author: liuhongt Date: Tue May 16 10:36:16 2023 +0800 Only use NO_REGS in cost calculation when !hard_regno_mode_ok for GENERAL_REGS and mode. r14-172-g0368d169492017 replaces GENERAL_REGS with NO_REGS in cost calculation when the preferred register class are not known yet. It regressed powerpc PR109610 and PR109858, it looks too aggressive to use NO_REGS when mode can be allocated with GENERAL_REGS. The patch takes a step back, still use GENERAL_REGS when hard_regno_mode_ok for mode and GENERAL_REGS, otherwise uses NO_REGS. gcc/ChangeLog: PR target/109610 PR target/109858 * ira-costs.cc (scan_one_insn): Only use NO_REGS in cost calculation when !hard_regno_mode_ok for GENERAL_REGS and mode, otherwise still use GENERAL_REGS.
[Bug rtl-optimization/109858] [14 Regression] r14-172 caused some SPEC2017 bmk to degrade on Power
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109858 --- Comment #10 from Segher Boessenkool --- (In reply to Hongtao.liu from comment #8) > (In reply to Segher Boessenkool from comment #7) > > > The patch will still use GENERAL_REGS when hard_regno_mode_ok for mode and > > > GENERAL_REGS(which is the case in PR109610), hope it can also fix this > > > regression. > > > > That sounds more reasonable. But, why use any heuristics like this? Can't > > you > > just look at the actual costs of using mem and regs? > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109610#c2 That is not an answer to my question at all?
[Bug rtl-optimization/109858] [14 Regression] r14-172 caused some SPEC2017 bmk to degrade on Power
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109858 --- Comment #9 from Kewen Lin --- (In reply to Kewen Lin from comment #6) > (In reply to Hongtao.liu from comment #5) > > (In reply to Kewen Lin from comment #3) > > > (In reply to Hongtao.liu from comment #2) > > > > Does https://gcc.gnu.org/pipermail/gcc-patches/2023-May/617431.html > > > > help? > > > > > > Sorry, I just measured those degraded bmks with this fix, the results > > > showed > > > it didn't help. > > > > Sorry for the inconvience, could you try again with attached patch. > > The patch will still use GENERAL_REGS when hard_regno_mode_ok for mode and > > GENERAL_REGS(which is the case in PR109610), hope it can also fix this > > regression. > > Thanks for the prompt fix, I'll do the perf evaluation once the perf boxes > get released (they are used by others now) and get back to you. I re-evaluated all SPEC2017 bmks on Power9 and Power10 with this patch (r14-171 vs. r14-172 + this fix), and confirmed it does fix all three degradation found before and it doesn't cause any new degradation (btw, all the >1% improvements are gone as well, all the results are neutral).
[Bug rtl-optimization/109858] [14 Regression] r14-172 caused some SPEC2017 bmk to degrade on Power
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109858 --- Comment #8 from Hongtao.liu --- (In reply to Segher Boessenkool from comment #7) > > The patch will still use GENERAL_REGS when hard_regno_mode_ok for mode and > > GENERAL_REGS(which is the case in PR109610), hope it can also fix this > > regression. > > That sounds more reasonable. But, why use any heuristics like this? Can't > you > just look at the actual costs of using mem and regs? https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109610#c2
[Bug rtl-optimization/109858] [14 Regression] r14-172 caused some SPEC2017 bmk to degrade on Power
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109858 --- Comment #7 from Segher Boessenkool --- > The patch will still use GENERAL_REGS when hard_regno_mode_ok for mode and > GENERAL_REGS(which is the case in PR109610), hope it can also fix this > regression. That sounds more reasonable. But, why use any heuristics like this? Can't you just look at the actual costs of using mem and regs?
[Bug rtl-optimization/109858] [14 Regression] r14-172 caused some SPEC2017 bmk to degrade on Power
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109858 --- Comment #6 from Kewen Lin --- (In reply to Hongtao.liu from comment #5) > (In reply to Kewen Lin from comment #3) > > (In reply to Hongtao.liu from comment #2) > > > Does https://gcc.gnu.org/pipermail/gcc-patches/2023-May/617431.html help? > > > > Sorry, I just measured those degraded bmks with this fix, the results showed > > it didn't help. > > Sorry for the inconvience, could you try again with attached patch. > The patch will still use GENERAL_REGS when hard_regno_mode_ok for mode and > GENERAL_REGS(which is the case in PR109610), hope it can also fix this > regression. Thanks for the prompt fix, I'll do the perf evaluation once the perf boxes get released (they are used by others now) and get back to you.
[Bug rtl-optimization/109858] [14 Regression] r14-172 caused some SPEC2017 bmk to degrade on Power
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109858 --- Comment #5 from Hongtao.liu --- (In reply to Kewen Lin from comment #3) > (In reply to Hongtao.liu from comment #2) > > Does https://gcc.gnu.org/pipermail/gcc-patches/2023-May/617431.html help? > > Sorry, I just measured those degraded bmks with this fix, the results showed > it didn't help. Sorry for the inconvience, could you try again with attached patch. The patch will still use GENERAL_REGS when hard_regno_mode_ok for mode and GENERAL_REGS(which is the case in PR109610), hope it can also fix this regression.
[Bug rtl-optimization/109858] [14 Regression] r14-172 caused some SPEC2017 bmk to degrade on Power
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109858 --- Comment #4 from Hongtao.liu --- Created attachment 55091 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55091=edit Only use NO_REGS in cost calculation when !hard_regno_mode_ok for GENERAL_REGS and mode.
[Bug rtl-optimization/109858] [14 Regression] r14-172 caused some SPEC2017 bmk to degrade on Power
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109858 --- Comment #3 from Kewen Lin --- (In reply to Hongtao.liu from comment #2) > Does https://gcc.gnu.org/pipermail/gcc-patches/2023-May/617431.html help? Sorry, I just measured those degraded bmks with this fix, the results showed it didn't help.
[Bug rtl-optimization/109858] [14 Regression] r14-172 caused some SPEC2017 bmk to degrade on Power
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109858 --- Comment #2 from Hongtao.liu --- Does https://gcc.gnu.org/pipermail/gcc-patches/2023-May/617431.html help?
