On Mon, 9 Jan 2023 20:04:34 GMT, Christian Wimmer <cwim...@openjdk.org> wrote:
>> The method `String.split` contains a fast-path when the regular expression
>> parameter is not really a regular expression, but just a single split
>> character.
>> This fast path vs. slow path check can be constant folded when the regular
>> expression parameter is a literal constant - a quite frequent pattern (for
>> example, all JDK usages of `String.split` have a constant expression
>> parameter). But method inlining in JIT and AOT compilers can usually not
>> inline `String.split` because the method body is too large. Factoring out
>> the actual fast-path splitting logic into a separate method solves this
>> problem: the JIT or AOT compiler can inline `String.split`, constant-fold
>> the fast/slow path check, and then only the invoke of either the fast path
>> or the slow path remains.
>
> Christian Wimmer has updated the pull request incrementally with one
> additional commit since the last revision:
>
> Add comment about method inlining
Looks good.
src/java.base/share/classes/java/lang/String.java line 3130:
> 3128: ((ch-'A')|('Z'-ch)) < 0)) &&
> 3129: (ch < Character.MIN_HIGH_SURROGATE ||
> 3130: ch > Character.MAX_LOW_SURROGATE))
Not your change, but I'd replace them with `MIN_SURROGATE` and `MAX_SURROGATE`
respectively, for readability, taking the opportunity.
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PR: https://git.openjdk.org/jdk/pull/11791
