RFR: 8281453: New optimization: convert `~x` into `-1-x` when `~x` is used in an arithmetic expression [v9]

[Zhiqiang Zang]

On Sat, 17 Sep 2022 16:32:45 GMT, Quan Anh Mai <duke at openjdk.org> wrote:

>> Zhiqiang Zang has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   include microbenchmark.
>
> Hi, what if `~x` is also used in another context, would it duplicate this local, also how about the cases where `x` is an addition or subtraction? I think this should be an idealisation of the `XorNode`, and if you cannot really check the uses of a node during parsing, you can record them for igvn later. Thanks.

Thanks @merykitty  for the comment. Can you give an example for this?
>what if `~x` is also used in another context, would it duplicate this local

Also, I think this works.
> how about the cases where `x` is an addition or subtraction

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PR: https://git.openjdk.org/jdk/pull/7376