RFR: 8282204: Use lea instructions for arithmetic operations on x86_64 [v10]

[Quan Anh Mai]

On Sat, 12 Mar 2022 01:10:33 GMT, Sandhya Viswanathan <sviswanathan at openjdk.org> wrote:

>> Quan Anh Mai has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   remove unreached rules
>
> src/hotspot/cpu/x86/vm_version_x86.hpp line 1062:
> 
>> 1060:   static bool supports_fast_3op_lea() {
>> 1061:     return supports_fast_2op_lea() &&
>> 1062:            ((is_intel() && supports_clwb()) || // Icelake and above
> 
> 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.

I have fixed this, thank you very much.

> src/hotspot/cpu/x86/x86_64.ad line 7527:
> 
>> 7525:   predicate(VM_Version::supports_fast_2op_lea());
>> 7526:   match(Set dst (AddI base (LShiftI index scale)));
>> 7527:   match(Set dst (AddI (LShiftI index scale) base));
> 
> I think the commutativity is automatically handled by adlc.

Yes you are right, I have removed the unnecessaries.

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