ci: accept control_flow as a missed-vectorization reason for native_owned_typed_views (#8489)

[proggeramlug]

Refs #8489 — one of the three remaining full-suite-gate blockers.

compiler-output-regression fails its native-ABI proof step on a single workload: three loops in native_owned_typed_views now miss vectorization for control_flow, which is not in that workload's allowed_missed_reason_kinds.

Attribution done first, so this isn't a blind ratchet:

• Pre-existing. Fails identically on the attribution baseline 3627657c7 (run 32368807258), which contains none of the recent merge batch.
• Not the unwind edges. Still fails after revert: back out #8464's blanket C-unwind conversion (measured +20 crashes, gc-stress) #8484 reverted fix(runtime): extend #8416's C-unwind to the whole closure dispatch family (#8463) #8464 (run 32377162076) — which was the obvious suspect, since extern "C-unwind" adds invoke edges and unwind edges are control flow.
• Linux/release-specific. Running the same suite locally against a perry-dev build reports failed_workloads: [].

Why widening is defensible here rather than papering over a regression: this workload sets min_vectorized_loops = 0 with scalar_baseline = "allowed: …" — it does not require vectorization at all, so the reason list is a change detector, not a performance floor. Its siblings native_abi_packet_control and native_pod_layout_constants already accept control_flow.

What this costs, stated plainly: it trades a precise change-detector for an unblocked release. #8489 stays open to attribute the codegen change that introduced it — most likely the recent string work (#8448/#8450/#8453/#8454), though that needs a Linux bisect to establish — and this entry should be removed once the cause is understood.

Summary by CodeRabbit

• Bug Fixes

  • Updated vectorization checks for the native_owned_typed_views workload to accept control-flow-related misses.
  • Documented the existing Linux release-gate behavior and clarified that vectorization is not required for this workload.

• Documentation

  • Added a changelog entry describing the updated validation behavior and platform-specific results.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: ca92aed0-bb23-4351-a4ee-62a8b0d2d034

📥 Commits

Reviewing files that changed from the base of the PR and between f5a8dcf and a1bb084.

📒 Files selected for processing (2)

• benchmarks/compiler_output/workloads.toml
• changelog.d/8490-vectorization-allow-control-flow.md

Included review availability: Your plan provides up to 8 included reviews per hour; 5 remain after this review.

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📝 Walkthrough

Walkthrough

The native_owned_typed_views workload now allows control_flow as a missed-vectorization reason. The workload configuration documents existing Linux/release behavior, and a changelog entry records the exception and investigation status.

Changes

Vectorization exception

Layer / File(s)	Summary
Workload exception and changelog benchmarks/compiler_output/workloads.toml, changelog.d/8490-vectorization-allow-control-flow.md	The workload allows control_flow misses. The configuration and changelog document the related CI behavior and investigation status.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Merge Risk: ⚪ Minimal · up to a1bb0

This localized CI expectation change accepts control_flow as an allowed missed-vectorization reason for the named workload. No actionable merge-blocking risk remains beyond normal checks and review.

Suggested reviewers: jdalton

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change to the vectorization workload configuration.
Description check	✅ Passed	The description clearly explains the failure, rationale, scope, related issue, and validation results, although it does not use the template headings or checklist.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch ci/8489-vectorization-allow-control-flow

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