RFR: 8180450: secondary_super_cache does not scale well [v14]

[Vladimir Ivanov]

On Fri, 12 Apr 2024 22:27:17 GMT, Dean Long <dlong at openjdk.org> wrote:

>> Andrew Haley has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   JDK-8180450: secondary_super_cache does not scale well
>
> src/hotspot/cpu/x86/macroAssembler_x86.cpp line 4789:
> 
>> 4787:   // Get the first array index that can contain super_klass into r_array_index.
>> 4788:   if (bit != 0) {
>> 4789:     popcntq(r_array_index, r_array_index);
> 
> What about hardware with supports_popcnt() == false?

`VM_Version::supports_popcnt()` is a prerequisite for `UseSecondarySupersTable`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18309#discussion_r1563290039