RFR: 8267532: C2: Profile and prune untaken exception handlers [v5]

Wed Nov 15 17:45:36 UTC 2023

On Wed, 15 Nov 2023 04:08:38 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

> So, how do you want to move forward? Should I attempt to re-implement the current patch to prune infrequent calls instead?

I'm fine with the approach chosen in this patch. Still not done with the review though.

Please, file an RFE to explore pruning of unreached call sites.

> Missing profiling would be bad, as in that case we'd always try to prune the exception handler. i.e. it's not just a missed optimization. 

Yes, pathological recompilation is another scenario to consider. You can sprinkle `Compile::too_many_traps` checks (both as asserts and product checks) to ensure profiling information is up-to-date.

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PR Comment: https://git.openjdk.org/jdk/pull/16416#issuecomment-1812983248