03 / 08 · What we check

Catch closure problems before they cost you a synthesis run.

Long combinational chains and awkward fanout patterns often don't show up until place-and-route. We trace critical paths by eye and flag structures likely to blow your timing budget.

01
Combinational depth. Long logic chains between registers that risk missing your target frequency.
02
Fanout hotspots. Signals driving an unusually large number of loads without buffering.
03
Multi-cycle assumptions. Paths that implicitly assume more than one clock cycle without constraints.
04
Critical-path candidates. Arithmetic or comparison chains most likely to dominate your slack report.
05
Pipelining opportunities. Places where a retiming register would meaningfully improve Fmax.

Sample findingTiming Risks

assign result = (a + b) * (c - d) + (e * f)
                + (g >> 2) + (h << 1);
// single-cycle combinational chain, no pipeline stage

Unpipelined arithmetic chain on the datapath's critical netCritical

At the target clock this path is likely to fail timing closure. Consider a retiming register mid-expression.

Why it matters

What this check protects you from.

Avoid late re-spins

Timing failures found post-synthesis are the most expensive class of bug to fix.

Predictable Fmax

Flagging risky paths early means fewer surprises during place-and-route.

Better constraints

Understanding real critical paths helps you write tighter, more accurate SDC.

All categories

Every review covers all 8.

Timing Risks is one of eight categories in every FPGAStudio review. Explore the rest below.

Resource Optimization

DSP & Fixed-Point

Detailed Report

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