RFR: 8282204: Use lea instructions for arithmetic operations on x86_64 [v12]

[Tobias Hartmann]

On Sat, 12 Mar 2022 04:52:41 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 with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 12 additional commits since the last revision:
> 
>  - Merge branch 'master' into leaIns
>  - reviews
>  - remove unreached rules
>  - remove 0x67 prefix
>  - address reviews
>  - remove irrelevent changes
>  - reviews
>  - address reviews
>  - add benchmark
>  - add predicate
>  - ... and 2 more: https://git.openjdk.java.net/jdk/compare/90759a67...e0fd81f6

Observed some intermittent issues that are probably unrelated. Will re-run testing.

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