8305783: x86_64: Optimize AbsI and AbsL

[merykitty]

Hi,

This patch optimizes the sequence emitted by AbsINode and AbsLNode to save some instructions and 1 temp register. Please take a look and kindly leave your reviews.

Thanks a lot.

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8305783: x86_64: Optimize AbsI and AbsL

Reviewers

• Jasmine Karthikeyan (@jaskarth - Author)
• Tobias Hartmann (@TobiHartmann - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/13402/head:pull/13402
$ git checkout pull/13402

Update a local copy of the PR:
$ git checkout pull/13402
$ git pull https://git.openjdk.org/jdk.git pull/13402/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 13402

View PR using the GUI difftool:
$ git pr show -t 13402

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/13402.diff

Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back qamai! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

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

• hotspot-compiler

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[merykitty]

Running the patch on org.openjdk.bench.java.lang.MathBench shows noticeable improvement:

                                        Before                    After
Benchmark           Mode  Cnt        Score       Error        Score       Error   Units   Change
MathBench.absInt   thrpt    8  2848176.368 ± 18552.810  3442310.540 ± 65838.237  ops/ms  +20.86%
MathBench.absLong  thrpt    8  2851886.891 ± 17565.736  3389983.543 ± 36466.553  ops/ms  +18.87%

[mlbridge]

Webrevs

• 01: Full - Incremental (4767979d)
• 00: Full (723eb6ce)

[jaskarth]

Patch looks nice! (I am not a reviewer.) I have one comment with the code.

I was also thinking that the unconditional usage of cmov here may lead to performance issues if the abs is part of a loop-carried dependency, as I've seen that happen before with MinI/MaxI nodes before. I did a small test to see if that was the case here and it seems there's no regression, so very nice!

[merykitty]

@jaskarth Thanks a lot for your review, I think this cannot introduce more dependency into the operation since it depends on src already. I also added more description to the format sections

[jaskarth]

Great, thank you!

[TobiHartmann]

Looks good to me.

[openjdk]

@merykitty 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:

8305783: x86_64: Optimize AbsI and AbsL

Reviewed-by: jkarthikeyan, thartmann

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 159 new commits pushed to the master branch:

• b9bdbe9: 8305524: AArch64: Fix arraycopy issue on SVE caused by matching rule vmask_gen_sub
• 82e8b03: 8305203: Simplify trimming operation in Region::Ideal
• 27cf638: 8300912: Update java/nio/MappedByteBuffer/PmemTest.java to run on x86_64 only
• 42fa000: 8305484: Compiler::init_c1_runtime unnecessarily uses an Arena that lives for the lifetime of the process
• 475e9a7: 8305809: (fs) Review obsolete Linux kernel dependency on os.version (Unix kernel 2.6.39)
• 1de772c: 8294806: jpackaged-app ignores splash screen from jar file
• d9db906: 8305368: G1 remset chunk claiming may use relaxed memory ordering
• c789d24: 8305370: Inconsistent use of for_young_only_phase parameter in G1 predictions
• c6d7cf6: 8305663: Wrong iteration order of pause array in g1MMUTracker
• ce4b995: 8305761: Resolve multiple definition of 'jvm' when statically linking with JDK native libraries
• ... and 149 more: https://git.openjdk.org/jdk/compare/d063b8964fbdd6ca1d9527dabb40fed59bbc8ad7...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.

[merykitty]

@TobiHartmann Thanks for your review, I will integrate the change

[merykitty]

/integrate

[openjdk]

Going to push as commit 99a9dbc.
Since your change was applied there have been 160 commits pushed to the master branch:

• d8af7a6: 8304725: AsyncGetCallTrace can cause SIGBUS on M1
• b9bdbe9: 8305524: AArch64: Fix arraycopy issue on SVE caused by matching rule vmask_gen_sub
• 82e8b03: 8305203: Simplify trimming operation in Region::Ideal
• 27cf638: 8300912: Update java/nio/MappedByteBuffer/PmemTest.java to run on x86_64 only
• 42fa000: 8305484: Compiler::init_c1_runtime unnecessarily uses an Arena that lives for the lifetime of the process
• 475e9a7: 8305809: (fs) Review obsolete Linux kernel dependency on os.version (Unix kernel 2.6.39)
• 1de772c: 8294806: jpackaged-app ignores splash screen from jar file
• d9db906: 8305368: G1 remset chunk claiming may use relaxed memory ordering
• c789d24: 8305370: Inconsistent use of for_young_only_phase parameter in G1 predictions
• c6d7cf6: 8305663: Wrong iteration order of pause array in g1MMUTracker
• ... and 150 more: https://git.openjdk.org/jdk/compare/d063b8964fbdd6ca1d9527dabb40fed59bbc8ad7...master

Your commit was automatically rebased without conflicts.

[openjdk]

@merykitty Pushed as commit 99a9dbc.

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