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

[Martin Doerr]

On Fri, 31 May 2024 08:56:36 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.

src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.cpp line 345:

> 343:       }
> 344:     } else if (vm_reg->is_ConditionRegister()) {
> 345:       // NOP. Conditions registers are covered by save_LR

This comment is no longer correct. I don't think that we ever save or restore condition registers at this point. So, I think we can replace this comment by `ShouldNotReachHere(); // live condition registers are unexpected at this point`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19494#discussion_r1622505227