RFR: 8349176: Speed up Integer/Long.toString via allocateUninitializedArray [v5]

[Shaojin Wen]

On Fri, 27 Jun 2025 19:09:27 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> Shaojin Wen has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 11 commits:
>> 
>>  - Merge remote-tracking branch 'upstream/master' into allocate_un_init_202501
>>    
>>    # Conflicts:
>>    #	src/java.base/share/classes/java/lang/Integer.java
>>    #	src/java.base/share/classes/java/lang/Long.java
>>  - simplify code
>>  - use Unsafe::allocateUninitializedArray
>>  - Merge remote-tracking branch 'upstream/master' into allocate_un_init_202501
>>    
>>    # Conflicts:
>>    #	src/java.base/share/classes/java/lang/Integer.java
>>    #	src/java.base/share/classes/java/lang/Long.java
>>  - use StringConcatHelper.newArray
>>  - simplify
>>  - use Unsafe.allocateUninitializedArray
>>  - revert StringConcatHelper newArray change
>>  - copyright
>>  - remove duplicate check
>>  - ... and 1 more: https://git.openjdk.org/jdk/compare/b685ea54...85e437a8
>
> Unsafe.allocateUninitializedArray has a single use at present and should not become more widely used.
> The current performance is adequate and the small improvement is not sufficient to warrant using Unsafe.

@RogerRiggs , thank you for your review. I will close this PR later.

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PR Comment: https://git.openjdk.org/jdk/pull/23353#issuecomment-3015674276