RFR: 8308469: [PPC64] Implement alternative fast-locking scheme [v2]

[Richard Reingruber]

On Thu, 25 May 2023 17:07:56 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

>> There are already some nodes which use CR0 as result which is tested for quite some time. Nodes which kill it should ideally have a "kill cr0" effect, but we don't need to rely on it. C2 doesn't place other nodes between the one which sets the ConditionRegister and the conditional branch. So, using CR0 should be reliable.
>
> It is indeed not very clear which macro assembler part kills CR0. In this case, I have made changes to support providing CR0 EQ on success and CR0 NE on failure. That is close to what other platforms do which use flags as results of lock/unlock. It is fragile, but at least, it's similar on all platforms, now.

Ok.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14069#discussion_r1205886788