RFR: 8302163: Speed up various String comparison methods with ArraysSupport.mismatch

[Alan Bateman]

On Mon, 13 Feb 2023 09:59:24 GMT, Claes Redestad <redestad at openjdk.org> wrote:

> We can improve various String methods such as `startsWith`, `endsWith` and `regionMatches` by leveraging the intrinsified mismatch methods in `ArraysSupport`.

src/java.base/share/classes/java/lang/String.java line 2272:

> 2270:             toffset <<= coder;
> 2271:             return ArraysSupport.mismatch(ta, toffset,
> 2272:                     pa, 0, pc) < 0;

`offset <<= coder` is only obvious if the reader knows the value of LATIN1, maybe it would be simpler to read if you kept "int to"?

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PR: https://git.openjdk.org/jdk/pull/12528