RFR: 8345287: C2: live in computation is broken

Mon Dec 9 08:21:43 UTC 2024

On Thu, 5 Dec 2024 08:47:31 GMT, Roberto Castañeda Lozano <rcastanedalo at openjdk.org> wrote:

> I will do a new benchmark run of jdk-24+26 with default configuration vs. jdk-24+26 with `-XX:-OptoRegScheduling` on x64 and report the results in a few days (likely early next week).

Turning off `-XX:-OptoRegScheduling` seems to have a slight overall negative effect on Renaissance (would require a more thorough analysis to confirm) and no measurable effect on DaCapo and SPECjvm2008 except for a slight improvement (around 1%) in crypto.signverify for older Coffee Lake-B machines. I agree with Vladimir that it would be worth further investigating (separately) whether to disable (or improve) `OptoRegScheduling`.

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PR Comment: https://git.openjdk.org/jdk/pull/22473#issuecomment-2527233803