[jdk8u-dev] RFR: 8072422: Cleanup: Remove some unused flags/code in loop optimizations [v2]

[Yi Yang]

On Fri, 25 Mar 2022 09:55:11 GMT, Severin Gehwolf <sgehwolf at openjdk.org> wrote:

> Please use pull request title `Backport <sha-of-original-commit>` which should then let the bots do it's thing and figure out it's a backport and change the title back to the right bug description.

Thanks, I will do that.

> With that said, what are you trying to do? Looking at both bugs it sounds like if we don't introduce [JDK-8072422](https://bugs.openjdk.java.net/browse/JDK-8072422), then [JDK-8159715](https://bugs.openjdk.java.net/browse/JDK-8159715) won't be an issue? If you are seeing an issue, without it I strongly encourage you to bring in the fix _without_ the cleanup patch.

We do need the cleanup patch, because https://github.com/alibaba/dragonwell8/issues/305 reports a crash due to use of UnrollLoopLimit, this flag is not supposed to be used by end users, it could be removed by cleanup patch. As I understand, the cleanup patch introduces another problem that can be fixed by JDK-8159715, so once cleanup backport is merged, I will backport JDK-8159715 as well.

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PR: https://git.openjdk.java.net/jdk8u-dev/pull/22