8350840: C2: x64 Assembler::vpcmpeqq assert: failed: XMM register should be 0-15

[jatin-bhateja]

This bug fix patch addressed an assertion failure due to unexpected register operand encoding.
AVX2 flavour of instruction "vpcmpeqq" expects to operate over XMM registers from lower register bank (0-15), in this case, the register mask associated with the destination vector operand of the matcher pattern also includes registers from the higher bank.

The issue can be reliably reproduced if we modify the static allocation order of XMM register through AD file change.
Existing bug JDK-8343294 already tracks the requirement to randomize the allocation ordering.

Kindly review and share your feedback.

Best Regards,
Jatin

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Issue

• JDK-8350840: C2: x64 Assembler::vpcmpeqq assert: failed: XMM register should be 0-15 (Bug - P3)

Reviewers

• Sandhya Viswanathan (@sviswa7 - Reviewer)
• Vladimir Kozlov (@vnkozlov - Reviewer)

Reviewing

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[openjdk]

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

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8350840: C2: x64 Assembler::vpcmpeqq assert: failed: XMM register should be 0-15

Reviewed-by: sviswanathan, kvn

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At the time when this comment was updated there had been 24 new commits pushed to the master branch:

• 02c850f: 8350982: -server|-client causes fatal exception on static JDK
• 2371696: 8303770: Remove Baltimore root certificate expiring in May 2025
• f16a742: 8351626: Update remaining icons to SVG format
• a21fa46: 8351309: test/hotspot/jtreg/runtime/posixSig/TestPosixSig.java fails on static-jdk
• 3b189e0: 8351345: [IR Framework] Improve reported disabled IR verification messages
• 95b66d5: 8351700: Remove code conditional on BarrierSetNMethod being null
• 84f87dd: 8351665: Remove unused UseNUMA in os_aix.cpp
• 4be502e: 8350642: Interpreter: Upgrade CountBytecodes to 64 bit on 64 bit platforms
• 1fe4526: 8350194: Last 2 parameters of ReturnNode::ReturnNode are swapped in the declaration
• 1d147cc: 8351484: Race condition in max stats in MonitorList::add
• ... and 14 more: https://git.openjdk.org/jdk/compare/4cf63160ad575d49dbe70f128cd36aba22b8f2ff...master

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[mlbridge]

Webrevs

• 00: Full (e41d3d42)

[sviswa7]

Looks good to me.

[vnkozlov]

Looks fine to me too. Let me test it before approval.

[vnkozlov]

My testing passed.

[jatin-bhateja]

Thanks @vnkozlov, @sviswa7

[jatin-bhateja]

/integrate

[openjdk]

Going to push as commit 41cc049.
Since your change was applied there have been 30 commits pushed to the master branch:

• a347ecd: 8350905: Shenandoah: Releasing a WeakHandle's referent may extend its lifetime
• 5502ce7: 8351699: Problem list com/sun/jdi/JdbStopInNotificationThreadTest.java with ZGC
• cdf7632: 8351444: Shenandoah: Class Unloading may encounter recycled oops
• 930455b: 8351640: Print reason for making method not entrant
• 895f64a: 8351142: Add JFR monitor deflation and statistics events
• db531bf: 8351881: Tidy complains about missing "alt" attribute
• 02c850f: 8350982: -server|-client causes fatal exception on static JDK
• 2371696: 8303770: Remove Baltimore root certificate expiring in May 2025
• f16a742: 8351626: Update remaining icons to SVG format
• a21fa46: 8351309: test/hotspot/jtreg/runtime/posixSig/TestPosixSig.java fails on static-jdk
• ... and 20 more: https://git.openjdk.org/jdk/compare/4cf63160ad575d49dbe70f128cd36aba22b8f2ff...master

Your commit was automatically rebased without conflicts.

[openjdk]

@jatin-bhateja Pushed as commit 41cc049.

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