[Bug target/94373] 548.exchange2_r run time is 7-12% worse than GCC 9 at -O2 and generic march/mtune
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94373 --- Comment #4 from Richard Biener --- Note the cited commit simply caused more complete unrolling to happen. Too much actually which is why I reverted it. Note GCC 9.2 does not have that more unrolling so the difference must be something else in the end.
[Bug target/94373] 548.exchange2_r run time is 7-12% worse than GCC 9 at -O2 and generic march/mtune
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94373 --- Comment #3 from Hongtao.liu --- (In reply to Hongtao.liu from comment #2) > I think > Change lea_cost from 2 --> 1 in skylake can fix this regressions. > > Since it's stage4 now, i hold my patch. Classify: it's for -O2 -mtune=skylake-avx512 not sure the what cause the regression for -O2 -mtune=generic.
[Bug target/94373] 548.exchange2_r run time is 7-12% worse than GCC 9 at -O2 and generic march/mtune
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94373 --- Comment #2 from Hongtao.liu --- I think Change lea_cost from 2 --> 1 in skylake can fix this regressions. Since it's stage4 now, i hold my patch.
[Bug target/94373] 548.exchange2_r run time is 7-12% worse than GCC 9 at -O2 and generic march/mtune
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94373 Andrew Pinski changed: What|Removed |Added Keywords||missed-optimization Component|tree-optimization |target --- Comment #1 from Andrew Pinski --- Seems IV related and most likely a target cost model issue too.