RFR: 8282204: Use lea instructions for arithmetic operations on x86_64 [v5]

[Sandhya Viswanathan]

On Mon, 28 Feb 2022 15:01:06 GMT, Jie Fu <jiefu at openjdk.org> wrote:

>> Icelakes introduce `clwb` instruction so I use that to filter Intel cpus.
>
>> Icelakes introduce `clwb` instruction so I use that to filter Intel cpus.
> 
> I'm not sure if we can find a better way (e.g., cpuid) to filter Intel CPUs.
> However, this seems fine since gcc and llvm will generate `lea` even without `clwb`.

supports_clwb() is true on the previous Cascade Lake architecture as well so it will be good to pick some other new Icelake feature to differentiate.

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PR: https://git.openjdk.java.net/jdk/pull/7560