[ci-scan] Test failure: JIT/opt/Vectorization/AvxState emits forbidden vzeroupper on x64 (X64-NOT FileCheck)

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Build Information

Build: https://dev.azure.com/dnceng-public/public/_build/results?buildId=1611950
Build error leg or test failing: coreclr Pri1 Runtime Tests Run linux x64 checked @ azurelinux.3.amd64.open.rt - JIT.opt (JIT/opt/Vectorization/AvxState)

Pipeline: runtime-coreclr outerloop (definition 108), branch main. The JIT/opt/Vectorization/AvxState FileCheck test fails on the x64 checked legs (linux x64, linux_musl x64, osx x64): the JIT emits a vzeroupper instruction that the test's X64-NOT: vzeroupper directive forbids, so FileCheck reports the excluded string was found and the test exits with code 1.

This is a genuine post-fix recurrence. PR #134560 ("JIT: Track AVX state from register-producing widths") added this exact X64-NOT: vzeroupper CHECK line and the AVX-state tracking codegen; it merged 2026-09-25T01:47Z. Source build 1611950 has commit deae693 (2026-09-25T07:56Z, after the merge) yet still emits the forbidden vzeroupper on these three legs, and the failure persists into follow-up build 1612573 (2026-09-25).

KBE authoring guidance (ci-failure-scan)

• Error Details is for readers. Paste the full exception, stack trace, or build error excerpt so the failure is understandable without opening the raw log.
• Build Analysis parses only the single JSON block under Error Message.
• ErrorMessage is a case-sensitive ordinal String.Contains substring copied verbatim from the failing log.
• Set BuildRetry to true only for a clear infrastructure retry case. ExcludeConsoleLog disables Helix console-log scanning.

Error Details

__tmp1_AvxState.cs:21:14: error: X64-NOT: excluded string found in input
 // X64-NOT: vzeroupper
             ^
__jit_disasm.out:104:2: note: found here
 vzeroupper
 ^~~~~~~~~~
EXECUTION OF FILECHECK - FAILED 1
10:08:58.523 Failed test: JIT/opt/Vectorization/AvxState/AvxState.cmd

Error Message

{
  "ErrorMessage": [
    "AvxState.cs:21:14: error: X64-NOT: excluded string found in input",
    "Failed test: JIT/opt/Vectorization/AvxState/AvxState.cmd"
  ],
  "ErrorPattern": "",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Agentic workflow metadata (ci-failure-scan)

Workflow artifact: ci-failure-scan
Artifact kind: kbe-verification
Verified match count: 2 hits in failure.log

First build it occurred

This signature appears in source build 1611950 (2026-09-25, commit deae693) and follow-up build 1612573 (2026-09-25), both of which contain the merge of #134560 (merged 2026-09-25T01:47Z). The immediately prior definition-108 failures did not run the JIT.opt FileCheck with this CHECK line, so this is the introduction of the X64-NOT: vzeroupper directive that the JIT still violates on these legs.

Duplicate search

Searched open and closed Known Build Error issues, area trackers, and open/merged PRs for AvxState, vzeroupper, and the FileCheck X64-NOT signature: no existing KBE or open fix PR matches. Related: #134560 introduced both the CHECK and the codegen this failure exercises.

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Filed by ci-failure-scan (detection only). ci-failure-fix walks open [ci-scan] KBEs and either opens a small fix PR or comments here to loop in owners — it never disables the test.

Generated by CI Outer-Loop Failure Scanner · opus48 · 997.2 AIC · ⌖ 15 AIC · ⊞ 19.2K · ◷

Report

Build	Repository	Test	Pull Request
1613196	dotnet/runtime	JIT/opt/GuardedDevirtualization/badinlinee/badinlinee.cmd
1613078	dotnet/runtime	JIT/opt/Vectorization/AvxState/AvxState.cmd

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
2	2	2

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