RFR: 8318457: Use prefix-less prepend methods directly to reduce branches in String concat expressions

[Claes Redestad]

On Wed, 18 Oct 2023 16:04:34 GMT, Jim Laskey <jlaskey at openjdk.org> wrote:

>> In #16006 using `StringConcatFactory` seem to induce a run-to-run variance. One idea to reduce this is to generate expression trees with fewer branches by looking up and using the prefix-less `prepend` methods directly for cases where constant is null/empty so that the prefixed prepender will always deal with a non-null prefix constant.
>
> Marked as reviewed by jlaskey (Reviewer).

Thanks for the quick review, @JimLaskey! I'll await tier1-3 test results before integration.

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PR Comment: https://git.openjdk.org/jdk/pull/16244#issuecomment-1768877287