How should ICC2 inventory be reconciled with synthesis reports?
From PDVerse PnR Interview Handbook · pdVerse Mentor Guide
Short Answer
Compare like-for-like scope and object classes, accounting for known handoff transformations rather than demanding unexplained equality.
Technical Explanation
Separating registers, combinational logic, memories, and macros helps you see which part of the design changed instead of hiding everything inside one total.
What To Check
• Warning sign: Sequential or macro counts differ substantially because the wrong revision or top was loaded. • Inspect: Compare one named object across the related reports; the same object should tell a consistent story. • Correct: Identify known transformations; otherwise stop and ask synthesis ownership to reconcile the handoff.
Command Checks & Actions
• sizeof_collection [get_cells -hierarchical *]: counts exactly the objects returned by a selector
• sizeof_collection [get_ports *]: counts exactly the objects returned by a selector
Run the commands in order. Each line answers a separate part of the check.Healthy, Suspicious & Hard-stop Results
• Expected: Compare like-for-like scope and object classes, accounting for known handoff transformations rather than demanding unexplained equality. • Investigate: Sequential or macro counts differ substantially because the wrong revision or top was loaded. • Stop before floorplanning when required logic or timing coverage is missing or unexplained. Identify known transformations; otherwise stop and ask synthesis ownership to reconcile the handoff.
Common Mistake
Do not assume the check passed just because ICC2 continued: Sequential or macro counts differ substantially because the wrong revision or top was loaded. Fix or narrowly justify the named objects, then rerun the same command.
What The Interviewer Is Testing
Be ready to explain why this matters before floorplanning: Sequential or macro counts differ substantially because the wrong revision or top was loaded.
Follow-up Question & Model Response
Model response: “I would save the report, inspect one affected object in the correct block and scenario, and make or request this correction: Identify known transformations; otherwise stop and ask synthesis ownership to reconcile the handoff. Then I would reopen the clean checkpoint and rerun the same evidence.”
Practical Example
Symptom: Sequential or macro counts differ substantially because the wrong revision or top was loaded. Corrective path: Identify known transformations; otherwise stop and ask synthesis ownership to reconcile the handoff.
Continue practising