RFR: 8315585: Optimization for decimal to string [v7]

[温绍锦]

On Fri, 8 Sep 2023 12:25:02 GMT, Claes Redestad <redestad at openjdk.org> wrote:

>> 温绍锦 has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Continue to optimize and reduce duplicate code
>
> src/java.base/share/classes/java/lang/String.java line 699:
> 
>> 697:     }
>> 698: 
>> 699:     static String newStringLatin1NoRepl(byte[] bytes) {
> 
> How much does this help compared to calling `jla.newStringNoRepl(bytes, StandardCharsets.ISO_8859_1)`? Maybe something that would be better split out to a separate enhancement and examined in isolation and apply it in other places where applicable (`java.util.UUID`, `java.util.HexFormat`)

newStringLatin1NoRepl does not significantly help performance, but it simplifies the code. 

Of course, there is another advantage: because the call will be simpler, making it easier for the caller method to implement codeSize smaller than the default value of FreqInlineSize 325, and there are more opportunities to be inlined.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15555#discussion_r1320022640