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

Mon Feb 28 11:38:54 UTC 2022

On Fri, 25 Feb 2022 12:11:43 GMT, Quan Anh Mai <duke at openjdk.java.net> wrote:

>> Hi,
>> 
>> This patch adds several matching rules for x86_64 backend to use `lea` instructions for several fused arithmetic operations. Also, `lea`s don't kill flags and allow different `dst` and `src`, so it is preferred over `sll` if possible, too. 
>> 
>> Thank you very much.
>
> Quan Anh Mai has updated the pull request incrementally with one additional commit since the last revision:
> 
>   address reviews

src/hotspot/cpu/x86/x86_64.ad line 3702:

> 3700:   match(RegL);
> 3701:   match(rax_RegL);
> 3702:   match(rcx_RegL);

Why we need this change?

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