RFR: 8336856: Optimize String Concat [v34]

[Shaojin Wen]

On Tue, 6 Aug 2024 18:07:16 GMT, Shaojin Wen <duke at openjdk.org> wrote:

>> This PR implements the same algorithm as the current generateMHInlineCopy based on bytecode to improve startup performance.
>
> Shaojin Wen has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - copyright
>  - remove unused import

https://github.com/wenshao/jdk/actions/runs/10271363457

Thanks to @cl4es for the patch, I created a branch with highArity set to the default value of 0, and it can be built successfully.

Next we can do two things:
1. SimpleStringBuilderStrategy or need to change a name, now it is not using StringBuilder
2. Change the default value of highArity to 0

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PR Comment: https://git.openjdk.org/jdk/pull/20273#issuecomment-2271990852