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Public benchmark structural-identifiability audit

Audit date: 2026-07-02

Result

Benchmark subset Tasks Functional oracle Multi-clock Usable structural intent Native CDC/RDC scoring
VerilogEval specification-to-RTL 156 156 0 (0.0%) 0 0
RTLLM v2 repository tasks 50 50 2 (4.0%) 2 0
CVDP v1.1 open-tool, non-agentic generation 302 302 10 (3.3%) 9 0
Combined descriptive inventory 508 508 12 (2.4%) 11 0

The combined row reports heuristic detector outputs, not a validated census or population estimate. The three benchmark suites differ in construction, difficulty, and task family; negative cases have not been manually censused.

Definitions

  • Functional oracle: the task ships an executable testbench or harness.
  • Multi-clock: the target module exposes at least two clock-like input ports after excluding clock-enable signals.
  • Usable structural intent: a multi-clock specification explicitly states asynchronous, synchronization, or clock-domain intent sufficient to define a reference audit. Merely using two clock names is not enough.
  • Native CDC/RDC scoring: the supplied benchmark harness includes a structural checker, structural assertions, or SDC/XDC constraints as a scored evaluation dimension.

Multiple reset-named inputs are retained as manual-review candidates but are not automatically counted as reset-domain risk. Reset-domain relationships require more intent than signal-name matching.

Manual review

The detector's two RTLLM multi-clock candidates are its asynchronous FIFO and multi-bit synchronizer. Both state synchronization intent; neither ships structural constraints or native CDC/RDC scoring.

The ten manually reviewed CVDP positives are multi-clock tasks in the audited subset: variants of asynchronous FIFOs, pulse synchronizers, mux synchronizers, clock comparison or detection, and a two-clock GFCM task. Nine explicitly state synchronization intent. The clock-jitter task exposes clk and system_clk but does not state their relationship, so it is not counted as structurally identifiable.

Reproduction

svgap audit verilog-eval /path/to/verilog-eval --output reports/audits
svgap audit rtllm /path/to/RTLLM --output reports/audits
svgap audit cvdp /path/to/cvdp_v1.1.0_nonagentic_code_generation_no_commercial.jsonl --output reports/audits

The task-level JSON and CSV files include parsed ports, evidence, and manual-review flags. Source data are not vendored.

Frozen sources

  • VerilogEval commit c498220d0a52248f8e3fdffe279075215bde2da6
  • RTLLM commit 41b26896e33b536940116a975626455eed3de65e
  • CVDP (dataset, paper) JSONL SHA-256 cbcd81295561ebb16e4d857e096f4d9908d042c33aff3b58abf236e868411857

The CVDP dataset describes non-code content as CC BY 4.0, original code as Apache-2.0, and derivative datapoints under the component licenses in its NOTICE. This audit retains identifiers and derived metadata only.

Interpretation boundary

This audit supports a narrower claim: the current heuristic detected limited multi-clock exposure and no recognizable CDC/RDC scoring artifacts in these snapshots. Parser recall and native-scoring recall have not been established on a manually reviewed negative sample, so “only 12 exist” and “none score CDC/RDC” are not yet justified. The audit does not assess the behavioral purposes of the functional tests or defect prevalence in generated RTL.