8328528: C2 should optimize long-typed parallel iv in an int counted loop

[tabjy]

Currently, parallel iv optimization only happens in an int counted loop with int-typed parallel iv's. This PR adds support for long-typed iv to be optimized.

Additionally, this ticket contributes to the resolution of JDK-8275913. Meanwhile, I'm working on adding support for parallel IV replacement for long counted loops which will depend on this PR.

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed (2 reviews required, with at least 2 Reviewers)

Issue

• JDK-8328528: C2 should optimize long-typed parallel iv in an int counted loop (Enhancement - P4)

Reviewers

• Roland Westrelin (@rwestrel - Reviewer)
• Tobias Hartmann (@TobiHartmann - Reviewer) Review applies to 04b2c6ad
• Christian Hagedorn (@chhagedorn - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/18489/head:pull/18489
$ git checkout pull/18489

Update a local copy of the PR:
$ git checkout pull/18489
$ git pull https://git.openjdk.org/jdk.git pull/18489/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 18489

View PR using the GUI difftool:
$ git pr show -t 18489

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/18489.diff

Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back kxu! 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]

@tabjy 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:

8328528: C2 should optimize long-typed parallel iv in an int counted loop

Reviewed-by: roland, chagedorn, 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 366 new commits pushed to the master branch:

• 330f2b5: 8342295: compiler/jvmci/TestJVMCISavedProperties.java fails due to garbage in output
• 1f35748: 8342102: ZGC: Optimize copy constructors in ZPhysicalMemory
• 66ddaaa: 8340241: RISC-V: Returns mispredicted
• 07f550b: 8340818: Add a new jtreg test root to test the generated documentation
• 27ef6c9: 8341470: BigDecimal.stripTrailingZeros() optimization
• 5d5d88a: 8339570: Add Tidy build support for JDK tests
• 239d84a: 8342578: GHA: RISC-V: Bootstrap using Debian snapshot is still failing
• aa060f2: 8342334: CDS: Scratch mirrors should not point to dead klasses
• 680dc5d: 8342496: C2/Shenandoah: SEGV in compiled code when running jcstress
• 8f2b23b: 8341407: C2: assert(main_limit == cl->limit() || get_ctrl(main_limit) == new_limit_ctrl) failed: wrong control for added limit
• ... and 356 more: https://git.openjdk.org/jdk/compare/fb703258774ca14a6a239fc6d47a37e021e6036a...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.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@rwestrel, @eme64, @TobiHartmann, @chhagedorn) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[openjdk]

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

• hotspot-compiler

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 25: Full - Incremental (81bce8ff)
• 24: Full - Incremental (4314d739)
• 23: Full - Incremental (c37484ab)
• 22: Full - Incremental (04b2c6ad)
• 21: Full - Incremental (845e34cc)
• 20: Full - Incremental (32bedd00)
• 19: Full - Incremental (4e2735ae)
• 18: Full - Incremental (6cad8c19)
• 17: Full - Incremental (5d1ee27a)
• 16: Full - Incremental (de6b7e20)
• 15: Full - Incremental (66b04622)
• 14: Full (5925761f)
• 13: Full - Incremental (4094231e)
• 12: Full - Incremental (2f053c5a)
• 11: Full - Incremental (64bf036e)
• 10: Full (e1e112da)
• 09: Full - Incremental (63ff69ea)
• 08: Full - Incremental (20bdc791)
• 07: Full - Incremental (596dbf9a)
• 06: Full - Incremental (6ae66d4a)
• 05: Full - Incremental (981b9600)
• 04: Full - Incremental (be0f596d)
• 03: Full - Incremental (85820dee)
• 02: Full - Incremental (dcd55681)
• 01: Full - Incremental (efc270ec)
• 00: Full (2230c7a6)

[rwestrel]

That looks good to me. A comment that shows what the transformation does with pseudo code before and pseudo code after (before/after subgraphs) would be helpful I think.

[dean-long]

Do we also handle the reverse, int-typed parallel iv in a long counted loop?

On a related topic, I noticed that checks for is_range_check_if seem to require the type to match the loop type, but I wonder if that could be relaxed.

[tabjy]

@dean-long

No, it doesn't at this stage. C2 never supported parallel iv of any type in long counted loops. However, I'm working on a patch adding supports for long and int iv in long counted loops. Since there are code dependencies, I'd prefer to have this pr merged first.

[tabjy]

/integrate

[openjdk]

@tabjy
Your change (at version 04b2c6a) is now ready to be sponsored by a Committer.

[chhagedorn]

Two suggestions but otherwise, looks good to me, too.

[rwestrel]

/sponsor

[openjdk]

@rwestrel The PR has been updated since the change author (@tabjy) issued the integrate command - the author must perform this command again.

[tabjy]

/integrate

[openjdk]

@tabjy
Your change (at version 81bce8f) is now ready to be sponsored by a Committer.

[rwestrel]

/sponsor

[openjdk]

Going to push as commit 80ec552.
Since your change was applied there have been 366 commits pushed to the master branch:

• 330f2b5: 8342295: compiler/jvmci/TestJVMCISavedProperties.java fails due to garbage in output
• 1f35748: 8342102: ZGC: Optimize copy constructors in ZPhysicalMemory
• 66ddaaa: 8340241: RISC-V: Returns mispredicted
• 07f550b: 8340818: Add a new jtreg test root to test the generated documentation
• 27ef6c9: 8341470: BigDecimal.stripTrailingZeros() optimization
• 5d5d88a: 8339570: Add Tidy build support for JDK tests
• 239d84a: 8342578: GHA: RISC-V: Bootstrap using Debian snapshot is still failing
• aa060f2: 8342334: CDS: Scratch mirrors should not point to dead klasses
• 680dc5d: 8342496: C2/Shenandoah: SEGV in compiled code when running jcstress
• 8f2b23b: 8341407: C2: assert(main_limit == cl->limit() || get_ctrl(main_limit) == new_limit_ctrl) failed: wrong control for added limit
• ... and 356 more: https://git.openjdk.org/jdk/compare/fb703258774ca14a6a239fc6d47a37e021e6036a...master

Your commit was automatically rebased without conflicts.

[openjdk]

@rwestrel @tabjy Pushed as commit 80ec552.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.