8253734: C2: Optimize Move nodes #826

iwanowww · 2020-10-23T08:27:50Z

Introduce the following transformations for Move nodes:

MoveI2F (MoveF2I x) => x
MoveI2F (LoadI mem) => LoadF mem
StoreI mem (MoveF2I x) => StoreF mem x

(The same applies to MoveL2D/MoveD2L.)

№1 eliminates redundant operations and №2/№3 avoid reg-to-reg moves in generated code:

0x000000010d09964c:   vmovss 0x20(%rsi),%xmm1
0x000000010d099651:   vmovd  %xmm1,%eax                   ;*invokestatic floatToRawIntBits

vs

0x0000000110c5a6cc:   mov    0x20(%rsi),%eax              ;*invokestatic floatToRawIntBits

(№2 and №3 are performed late (after loop opts are over) to avoid high-level optimizations passes to handle newly introduced mismatched accesses.)

Testing: tier1-5.

Progress

Change must not contain extraneous whitespace
Commit message must refer to an issue
Change must be properly reviewed

Testing

	Linux x32	Linux x64	Windows x64	macOS x64
Build	✔️ (1/1 passed)	✔️ (5/5 passed)	✔️ (2/2 passed)	✔️ (2/2 passed)
Test (tier1)		✔️ (9/9 passed)	❌ (1/9 failed)	✔️ (9/9 passed)

Failed test task

Windows x64 (hs/tier1 compiler)

Issue

JDK-8253734: C2: Optimize Move nodes

Reviewers

Tobias Hartmann (@TobiHartmann - Reviewer)
Nils Eliasson (@neliasso - Reviewer)
Vladimir Kozlov (@vnkozlov - Reviewer)
@blaquez (no known github.com user name / role)

Download

$ git fetch https://git.openjdk.java.net/jdk pull/826/head:pull/826
$ git checkout pull/826

iwanowww · 2020-10-23T08:28:23Z

/label add hotspot-compiler

bridgekeeper · 2020-10-23T08:28:32Z

👋 Welcome back vlivanov! 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 · 2020-10-23T08:30:19Z

@iwanowww
The hotspot-compiler label was successfully added.

mlbridge · 2020-10-23T08:37:49Z

Webrevs

01: Full - Incremental (878d44b)
00: Full (567c4fb)

TobiHartmann

Maybe add some comments with examples to the reinterpret methods.

TobiHartmann · 2020-10-23T09:08:56Z

src/hotspot/share/opto/movenode.hpp

  public:
-  MoveL2DNode( Node *value ) : Node(0,value) {}
+  MoveL2DNode(Node* value) : MoveNode(value) {
+    init_class_id(Class_Move);


Shouldn't init_class_id be moved to the MoveNode constructor?

TobiHartmann · 2020-10-23T09:13:36Z

src/hotspot/share/opto/movenode.hpp

+  public:
+  virtual Node* Ideal(PhaseGVN* phase, bool can_reshape);
+  virtual Node* Identity(PhaseGVN* phase);
+//  virtual const Type* Value(PhaseGVN* phase) const;


Can be removed.

iwanowww · 2020-10-23T11:08:00Z

Thanks for the quick feedback, Tobias!

Please, take a look at the updated version.

TobiHartmann

Looks good to me. Thanks for making these changes!

openjdk · 2020-10-23T12:07:11Z

@iwanowww 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:

8253734: C2: Optimize Move nodes

Reviewed-by: thartmann, neliasso, kvn

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 53 new commits pushed to the master branch:

3f6abd2: 8255330: gtest/MetaspaceGtests.java fail on 32-bit platforms
cf821b0: 8232024: Don't pollute log output with multiple errors of the same type
185c8bc: 8255338: CodeSections are never frozen
cc86113: 8255271: Avoid generating duplicate interpreter entries for subword types
5ec1b80: 8255287: aarch64: fix SVE patterns for vector shift count
12daf2b: 8255340: [s390] build failure after JDK-8255208
9007bc2: 8255129: [PPC64, s390] Check vector_size_supported and add VectorReinterpret node
df79257: 8255274: [PPC64, s390] wrong StringLatin1.indexOf version matched
55a0cad: 8254982: (tz) Upgrade time-zone data to tzdata2020c
ac1748e: 8254670: SVE test uses linux-specific api
... and 43 more: https://git.openjdk.java.net/jdk/compare/7e2640432bf4fb5115c2ff694c09937234e6d1c5...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.

neliasso

Looks good!

vnkozlov

Proposed optimization looks fine. In what cases you see the issues?

mlbridge · 2020-10-23T18:19:44Z

Mailing list message from Vladimir Ivanov on hotspot-compiler-dev:

Thanks for the reviews, Vladimir and Tobias.

Proposed optimization looks fine. In what cases you see the issues?

It was motivated by some microbenchmarks targeting Memory Access API:

https://mail.openjdk.java.net/pipermail/panama-dev/2020-September/010873.html

Best regards,
Vladimir Ivanov

mlbridge · 2020-10-23T18:23:36Z

Mailing list message from Vladimir Kozlov on hotspot-compiler-dev:

On 10/23/20 11:17 AM, Vladimir Ivanov wrote:

Thanks for the reviews, Vladimir and Tobias.

Proposed optimization looks fine. In what cases you see the issues?

It was motivated by some microbenchmarks targeting Memory Access API:

https://mail.openjdk.java.net/pipermail/panama-dev/2020-September/010873.html

Okay.

Thanks,
Vladimir K

Best regards,
Vladimir Ivanov

iwanowww · 2020-10-26T17:22:28Z

/integrate

iwanowww · 2020-10-26T17:23:29Z

Thanks for the reviews, Vladimir, Tobias, and Nils.

openjdk · 2020-10-26T17:27:21Z

@iwanowww Since your change was applied there have been 69 commits pushed to the master branch:

6666dcb: 8237363: Remove automatic is in heap verification in OopIterateClosure
fa64477: 8255301: Common and strengthen the code in ciMemberName and ciMethodHandle
9b5a2a6: 8255349: Vector API issues on Big Endian
e8b75b1: 8255393: sun/security/util/DerValue/Indefinite.java fails with ---illegal-access=deny
7cafe35: 8255352: Archive important test outputs in submit workflow
888086f: 8255373: Submit workflow artifact name is always "test-results_.zip"
6918818: 8255265: IdealLoopTree::iteration_split_impl does not use should_align
c28b011: 8255343: java/util/stream/SpliteratorTest.java fails on 32-bit platforms with "Misaligned access at address: 12"
b71b5b4: 8199062: Test javax/swing/text/Utilities/8134721/bug8134721.java is unstable
ee34fa5: 8199060: Test javax/swing/text/html/parser/Parser/6990651/bug6990651.java is unstable
... and 59 more: https://git.openjdk.java.net/jdk/compare/7e2640432bf4fb5115c2ff694c09937234e6d1c5...master

Your commit was automatically rebased without conflicts.

Pushed as commit 83a91bf.

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

8253734: Optimize Move nodes

567c4fb

iwanowww marked this pull request as draft October 23, 2020 08:27

openjdk bot added the hotspot-compiler hotspot-compiler-dev@openjdk.org label Oct 23, 2020

iwanowww marked this pull request as ready for review October 23, 2020 08:33

iwanowww marked this pull request as draft October 23, 2020 08:34

openjdk bot added the rfr Pull request is ready for review label Oct 23, 2020

iwanowww changed the title ~~8253734: Optimize Move nodes~~ 8253734: C2: Optimize Move nodes Oct 23, 2020

iwanowww marked this pull request as ready for review October 23, 2020 08:34

TobiHartmann suggested changes Oct 23, 2020

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Address review comments from Tobias.

878d44b

TobiHartmann approved these changes Oct 23, 2020

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openjdk bot added the ready Pull request is ready to be integrated label Oct 23, 2020

neliasso approved these changes Oct 23, 2020

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vnkozlov approved these changes Oct 23, 2020

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openjdk bot closed this Oct 26, 2020

openjdk bot added integrated Pull request has been integrated and removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Oct 26, 2020

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8253734: C2: Optimize Move nodes #826

8253734: C2: Optimize Move nodes #826

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8253734: C2: Optimize Move nodes #826

8253734: C2: Optimize Move nodes #826

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