[jdk11u-dev] RFR: 8212597: Optimize String concatenation setup when using primitive operands

[Anton Bobrov]

On Tue, 25 Jun 2024 13:57:22 GMT, Anton Bobrov <abobrov at openjdk.org> wrote:

> This is a backport of b3b41df70fb5ec3187d165786b3c8ad2d4b4012b / [JDK-8212597](https://bugs.openjdk.org/browse/JDK-8212597)
> 
> This backport is needed to facilitate clean backports of various String concat improvements that are on todo list for 11 which are otherwise very complex and high risk to rework:
> 
> JDK-8212726 Replace some use of drop- and foldArguments with filtering argument combinator in StringConcatFactory
> JDK-8213035 Pack MethodHandleInlineStrategy coder and length into a long
> JDK-8213478 Reduce rebinds when applying repeated filters and conversions
> JDK-8222852 Reduce String concat combinator tree shapes by folding constants into prependers
> JDK-8223454 Reduce String concatenation shapes by folding initialLengthCoder into last mixer
> 
> This is a clean backport.
> 
> Testing: x86_64 build, tier1

after discussion with 11u maintainers this backport, as well as related backports listed in the PR description above, were deemed too risky to bring over as they are improvements and not critical bug fixes, closing this.

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PR Comment: https://git.openjdk.org/jdk11u-dev/pull/2813#issuecomment-2199788865