RFR: 8331733: [PPC64] saving and restoring CR is not needed at most places [v2]

[Martin Doerr]

On Wed, 5 Jun 2024 07:00:26 GMT, Varada M <varadam at openjdk.org> wrote:

>> PPC64 uses save/restore CR less often. Only LR is critical, CR is mainly needed for native-to-Java calls.
>> Fastdebug: build and tier1 testing successful. [unrelated failures]
>
> Varada M has updated the pull request incrementally with one additional commit since the last revision:
> 
>   [PPC64] saving and restoring CR is not needed at most places

Thanks for the updates! Sorry, my assumption is wrong. I have found a test which runs into the `ShouldNotReachHere()`: jdk/incubator/vector/VectorMaxConversionTests.java#ZGenerational
I think we should revert all changes in `SaveLiveRegisters` (barrierSetAssembler_ppc.cpp) and `XSaveLiveRegisters` (xBarrierSetAssembler_ppc.cpp). We can keep them saving and restoring CR. Sorry for not finding this earlier.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/19494#issuecomment-2149186342