8259601: AArch64: Fix reinterpretX2D match rule issue

[XiaohongGong]

Currently the "reinterpretX2D" match rule does not generate any register move instruction if the 'dst' and 'src' are the same register. This rule implements the vector reinterpretation from 16 bytes to 8 bytes. It is a kind of data truncation, which should make sure the higher 8 bytes of the 'dst' register cleared to zero. So the "mov" is always needed even if the "dst" and "src" are the same register in case of the issue mentioned in [1].

We have tested the case [3] with Arm NEON. And the issue still exists even if [1] is fixed with [2]. Removing the check (i.e. whether 'src' and 'dst' are the same register) in the rule would fix it finally.

[1] https://bugs.openjdk.java.net/browse/JDK-8259353
[2] #100
[3] https://bugs.openjdk.java.net/secure/attachment/92713/Test.java

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Progress

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Issue

• JDK-8259601: AArch64: Fix reinterpretX2D match rule issue

Reviewers

• Andrew Dinn (@adinn - Reviewer)
• Ningsheng Jian (@nsjian - Committer)

Download

$ git fetch https://git.openjdk.java.net/jdk16 pull/108/head:pull/108
$ git checkout pull/108

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[openjdk]

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[mlbridge]

Webrevs

• 00: Full (3c0d1df)

[adinn]

Yes, these changes look good.

[openjdk]

@XiaohongGong 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:

8259601: AArch64: Fix reinterpretX2D match rule issue

Reviewed-by: adinn, njian

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 6 new commits pushed to the master branch:

• 17b4db3: 8259636: Check for buffer backed by shared segment kicks in in unexpected places
• 5f9cd72: 8259645: Revert JDK-8245956 JavaCompiler still uses File API instead of Path API in a specific case
• b03880e: 8259634: MemorySegment::asByteBuffer does not respect spatial bounds
• 8a81cf1: 8259298: broken link in Stream::toList spec
• 67e1b63: 8259380: Correct pretouch chunk size to cap with actual page size
• 28ff2de: 8259237: Demo selection changes with left/right arrow key. No need to press space for selection.

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
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.

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[XiaohongGong]

/integrate

[openjdk]

@XiaohongGong
Your change (at version 3c0d1df) is now ready to be sponsored by a Committer.

[XiaohongGong]

Yes, these changes look good.

Thanks for your review @adinn !

[nsjian]

Looks good to me too.

[nsjian]

/sponsor

[openjdk]

@nsjian @XiaohongGong Since your change was applied there have been 8 commits pushed to the master branch:

• 15dd8f3: 8259275: JRuby crashes while resolving invokedynamic instruction
• 1cf2378: 8259353: VectorReinterpretNode is incorrectly optimized out
• 17b4db3: 8259636: Check for buffer backed by shared segment kicks in in unexpected places
• 5f9cd72: 8259645: Revert JDK-8245956 JavaCompiler still uses File API instead of Path API in a specific case
• b03880e: 8259634: MemorySegment::asByteBuffer does not respect spatial bounds
• 8a81cf1: 8259298: broken link in Stream::toList spec
• 67e1b63: 8259380: Correct pretouch chunk size to cap with actual page size
• 28ff2de: 8259237: Demo selection changes with left/right arrow key. No need to press space for selection.

Your commit was automatically rebased without conflicts.

Pushed as commit 793017d.

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