RFR: 8242115: C2 SATB barriers are not safepoint-safe

[Vladimir Ivanov]

On Fri, 30 Sep 2022 21:22:47 GMT, Igor Veresov <iveresov at openjdk.org> wrote:

> Implement load pinning, use it for g1 pre-value loads, add verification that the load control dependency is kept and that there are no safepoints between the load of the pre-value and the marking check (with the exception of the CAS intrinsics where it's permitted).

Looks good. 

Did you run any performance tests?

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Marked as reviewed by vlivanov (Reviewer).

PR: https://git.openjdk.org/jdk/pull/10517