RFR: 8323497: On x64, use 32-bit immediate moves for narrow klass base if possible [v6]

[Thomas Stuefe]

On Thu, 22 May 2025 16:57:45 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Thomas Stuefe has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   fix COH
>
> src/hotspot/cpu/x86/macroAssembler_x86.cpp line 5444:
> 
>> 5442:   }
>> 5443:   if (CompressedKlassPointers::base() != nullptr) {
>> 5444:     // Note: we use movptr to uses a 32-bit mov if the base is small enough
> 
> I think these "32-bit mov" comments are not really useful here. We also do not really know what macroAssembler would do with these. We just put the "machine pointer" in there, and let macroAssembler do the right thing.

Sure, I remove them.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17340#discussion_r2103819704