8271225: Add floorDivExact() method to java.lang.[Strict]Math

[bplb]

Add methods floorDivExact(int,int) and floorDivExact(long,long) to java.lang.Math and java.lang.StrictMath.

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Progress

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Issue

• JDK-8271225: Add floorDivExact() method to java.lang.[Strict]Math

Reviewers

• Joe Darcy (@jddarcy - Reviewer)

Reviewing

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$ git checkout pull/4941
$ git pull https://git.openjdk.java.net/jdk pull/4941/head

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$ git pr checkout 4941

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https://git.openjdk.java.net/jdk/pull/4941.diff

[bridgekeeper]

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[bplb]

The floorDivExact() methods are identical to their floorDiv() counterparts aside from that they throw an ArithmeticException when the dividend is MIN_VALUE and the divisor is -1. These methods behave with respect to the methods floorDiv() as the methods divideExact() behave with respect to the division operator /.

[openjdk]

@bplb The following label will be automatically applied to this pull request:

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[mlbridge]

Webrevs

• 02: Full (fac5107a)
• 01: Full - Incremental (7601fe9b)
• 00: Full (03e83cda)

[bplb]

/csr

[openjdk]

@bplb this pull request will not be integrated until the CSR request JDK-8271518 for issue JDK-8271225 has been approved.

[rgiulietti]

Hello @bplb,

the doc of floorDivExact() is not, well..., exact.

For example,

The floor rounding mode gives different results from truncation
when the exact result is negative.

The truth is that the results are different when the exact quotient is not an integer and is negative.
The description following this sentence is imprecise as well.

The doc seems to have been copied and adapted from the doc of floorDiv(), which is imprecise in the first place.
You might want to take a look at PR 4963 which addresses this and wait until that one is thoroughly discussed for mathematical accuracy and correct wording.

Greetings
Raffaello

[bplb]

@rgiulietti Yes, that doc was copied. I tend to agree that it would be better to get 4963 right and hold off on this PR until then.

[bplb]

CSR updated to match this PR.

[bplb]

The CSR for this PR has been approved.

[openjdk]

@bplb This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8271225: Add floorDivExact() method to java.lang.[Strict]Math

Reviewed-by: darcy

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 224 new commits pushed to the master branch:

• 0609421: 8272347: ObjectMethods::bootstrap should specify NPE if any argument except lookup is null
• 7fc8540: 8260265: UTF-8 by Default
• 3204853: 8272343: Remove MetaspaceClosure::FLAG_MASK
• fecefb8: 8271302: Regex Test Refresh
• f18c0fa: 8271560: sun/security/ssl/DHKeyExchange/LegacyDHEKeyExchange.java still fails due to "An established connection was aborted by the software in your host machine"
• 5aaa20f: 8272861: Add a micro benchmark for vector api
• 7a01ba6: 8272093: Extract evacuation failure injection from G1CollectedHeap
• 98b9d98: 8272797: Mutex with rank safepoint_check_never imply allow_vm_block
• f11e099: 8272651: G1 heap region info print order changed by JDK-8269914
• fbffa54: 8270438: "Cores to use" output in configure is misleading
• ... and 214 more: https://git.openjdk.java.net/jdk/compare/3ab95d19174100f440e2274d5b2c3119fb55e9e1...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[bplb]

/integrate

[openjdk]

Going to push as commit e551852.
Since your change was applied there have been 229 commits pushed to the master branch:

• e671255: 8237567: Refactor G1-specific code in shared VM_CollectForMetadataAllocation
• 9bc7cc5: 8273033: SerialGC: remove obsolete comments
• 841e394: 8159979: During initial mark, preparing all regions for marking may take a significant amount of time
• 98fa533: 8273100: Improve AbstractStringBuilder.append(String) when using CompactStrings
• 9732fbe: 8273153: Consolidate file_exists into os:file_exists
• 0609421: 8272347: ObjectMethods::bootstrap should specify NPE if any argument except lookup is null
• 7fc8540: 8260265: UTF-8 by Default
• 3204853: 8272343: Remove MetaspaceClosure::FLAG_MASK
• fecefb8: 8271302: Regex Test Refresh
• f18c0fa: 8271560: sun/security/ssl/DHKeyExchange/LegacyDHEKeyExchange.java still fails due to "An established connection was aborted by the software in your host machine"
• ... and 219 more: https://git.openjdk.java.net/jdk/compare/3ab95d19174100f440e2274d5b2c3119fb55e9e1...master

Your commit was automatically rebased without conflicts.

[openjdk]

@bplb Pushed as commit e551852.

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