RFR: 8321283: Reuse StringLatin1::equals in regionMatches

[Chen Liang]

On Sat, 2 Dec 2023 16:56:22 GMT, Francesco Nigro <duke at openjdk.org> wrote:

> This improvement has been found on https://github.com/vert-x3/vertx-web/pull/2526.
> 
> It can potentially affect the existing ArraysSupport.mismatch caller code-path performance ie requires investigation.

With a JBS issue, you need to change the PR title to `8321283: Reuse StringLatin1::equals in regionMatches` so that the JDK bot will recognize and link the issue.

src/java.base/share/classes/java/lang/String.java line 2185:

> 2183:         byte[] ov = other.value;
> 2184:         if (coder == otherCoder) {
> 2185:             if ((ooffset | toffset) == 0 && len == (tv.length >> coder) && ov.length == tv.length) {

Just curious, is `(ooffset | toffset) == 0` more efficient than `ooffset == 0 && toffset== 0`?

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PR Comment: https://git.openjdk.org/jdk/pull/16933#issuecomment-1873586642
PR Review Comment: https://git.openjdk.org/jdk/pull/16933#discussion_r1414224254