RFR: 8347009: Speed ​​up parseInt and parseLong [v9]

[Raffaello Giulietti]

On Sat, 25 Jan 2025 04:01:47 GMT, Shaojin Wen <swen at openjdk.org> wrote:

>> This is an optimization for decimal Integer.parseInt and Long.parseLong, which improves performance by about 10%. The optimization includes:
>> 1. Improve performance by parsing 2 numbers at a time, which has performance improvements for numbers with length >= 3.
>> 2. It uses charAt(0) for the first number. Assuming that the optimization can eliminate boundary checks, this will be more friendly to parsing numbers with length 1.
>> 3. It removes the reliance on the Character.digit method and eliminates the reliance on the CharacterDataLatin1#DIGITS cache array, which avoids performance degradation caused by cache misses.
>
> Shaojin Wen has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 25 commits:
> 
>  - Merge remote-tracking branch 'upstream/master' into optim_parse_int_long_202501
>    
>    # Conflicts:
>    #	src/java.base/share/classes/jdk/internal/util/DecimalDigits.java
>  - use &
>  - from @rgiulietti
>  - remove unused
>  - Update src/java.base/share/classes/jdk/internal/util/DecimalDigits.java
>    
>    Co-authored-by: Chen Liang <liach at openjdk.org>
>  - vector digit2
>  - emptyInput -> nullInput
>  - use CharacterDataLatin1.instance::isDigit
>  - add comments
>  - reduce codeSize
>  - ... and 15 more: https://git.openjdk.org/jdk/compare/f446cefe...0bacfa01

This line on a test is now failing because it's expecting a specific `NumberFormatException` message.
https://github.com/openjdk/jdk/blob/21feef32803b2593b097fb225c7a4c7cd46525da/test/jdk/com/sun/jdi/JdbExprTest.java#L114

I don't have much time to have a look during this week, though.

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PR Comment: https://git.openjdk.org/jdk/pull/22919#issuecomment-2616783945