Constraints & QoR

Section goal

Synthesis SDC scope, clock-gating inference, dont-touch policy, and QoR dashboard discipline.

How to study this section

1. Start with each topic hub to understand mechanism and ownership.

2. Use reports and debug pages to build run-comparison instincts.

3. Use interview and case pages for pressure drills.

4. Close with checklist and PPA impact before merge decisions.

Topics

1. synthesis-sdc/ — Synthesis SDC Contracts

2. clock-gating-inference/ — Clock-Gating Inference

3. dont-touch-policy/ — Dont-Touch & Preserve Policy

4. qor-dashboard/ — QoR Dashboard & Trend Triage

Related topics

• Synthesis course hub

Synthesis deep dive

Constraint hygiene determines whether synthesis QoR is trustworthy.

Concept diagram

CONSTRAINT FLOW

RTL intent -> synthesis SDC -> compile checks -> QoR dashboard -> review gate

Metric graph

QOR HEALTH

constraint lint pass   ███████████████
unconstrained count    ███
policy violations      ██

Reports and artifacts

• compile QoR

• unconstrained endpoints

• constraint lint

• policy audit log

Mini case study

Nightly WNS improved but unconstrained paths jumped; strict SDC lint restored true QoR picture.

Debug branches

• Diff SDC first

• Audit dont_touch scope

• Track unconstrained trend weekly

Senior review question

Ask: what evidence proves this QoR move is real and stable?