RFR: 8321122: Shenandoah: Remove ShenandoahLoopOptsAfterExpansion flag

Fri Dec 1 16:55:08 UTC 2023

On Thu, 30 Nov 2023 16:00:17 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> More flags cleanup. `ShenandoahLoopOptsAfterExpansion` was added long time ago to gate more aggressive barrier optimizations in C2. It was default since then. There seem to be no reason to keep it as the flag. Just checking, @rwestrel -- you don't need it anymore, right?

It could be useful for diagnostic purposes. Say if a user reports a crash, one trouble shooting step could be to ask them to run with `ShenandoahLoopOptsAfterExpansion` off. This said, that never happened AFAIK. So I don't have a strong opinion. I'm also wondering if: they make an actual difference performance wise? with other changes that happened in the meantime, are they still doing anything useful?

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PR Comment: https://git.openjdk.org/jdk/pull/16908#issuecomment-1836454231