[ci-scan] Build break: JIT assertion in ILC compiling BigMulTestSuite (lower.cpp:5605)

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Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1429604
Build error leg or test failing: linux-x64 Checked NativeAOT_Pri1 - HardwareIntrinsics_X86_ro / HardwareIntrinsics_X86_r

Error Details

ILC crashes with a JIT assertion failure in lower.cpp:5605 when compiling JIT.HardwareIntrinsics.X86.BigMulTestSuite:TestLargeRandomCalculations() during the Lowering phase. The assertion fires on both linux-x64 and windows-x64 NativeAOT builds (pipeline 265), and also in runtime-coreclr jitstress (pipeline 109) when compiling BigMulTestSuite:TestStaticFieldAccess().

Exit code 134 (SIGABRT) from ILC causes the entire NativeAOT test build to fail for HardwareIntrinsics_X86_ro and HardwareIntrinsics_X86_r projects.

ILC: src/coreclr/jit/lower.cpp:5605
ILC: Assertion failed 'varDsc->CanBeReplacedWithItsField(m_compiler) || varDsc->lvDoNotEnregister || !varDsc->lvPromoted' in 'JIT.HardwareIntrinsics.X86.BigMulTestSuite:TestLargeRandomCalculations()' during 'Lowering nodeinfo' (IL size 126; hash 0x426b9eb9; FullOpts)

Also seen in jitstress (pipeline 109, build 1429353):

Assert failure: Assertion failed 'varDsc->CanBeReplacedWithItsField(m_compiler) || varDsc->lvDoNotEnregister || !varDsc->lvPromoted' in 'JIT.HardwareIntrinsics.X86.BigMulTestSuite:TestStaticFieldAccess()' during 'Lowering nodeinfo' (IL size 80; hash 0x1a37c87b; FullOpts)

Affected legs:

• runtime-nativeaot-outerloop (def 265): linux-x64 Checked NativeAOT_Pri1, windows-x64 Checked NativeAOT_Pri1
• runtime-coreclr jitstress (def 109): linux-x64 checked Pri1

First build it occurred: 1429604 (2026-05-21) for NativeAOT pipeline. Build 1428880 (2026-05-20) did NOT have this failure. 2 occurrences in NativeAOT (1429604, 1430586).

Error Message

{
  "ErrorMessage": "Assertion failed 'varDsc->CanBeReplacedWithItsField(m_compiler) || varDsc->lvDoNotEnregister || !varDsc->lvPromoted' in 'JIT.HardwareIntrinsics.X86.BigMulTestSuite",
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Note

🔒 Integrity filter blocked 1 item

The following item was blocked because it doesn't meet the GitHub integrity level.

• #11455 search_issues: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".

To allow these resources, lower min-integrity in your GitHub frontmatter:

tools:
  github:
    min-integrity: approved  # merged | approved | unapproved | none

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