From a complex hierarchical design, the test case was derived which resulted in modifications to four flops and three output ports due to RTL changes. To rectify the logic, GOF ECO utilized four gates and occupied 2.1 in area. On the other hand, Conformal ECO used 28 gates and occupied 29.2 in area to fix the logic. Notably, all the gates in the ECO methods were driven by 'X4'.
| ECO Result | Total Cells | Non-Buffer | Invert | Buffer | Area |
| GOF | 4 | 1 | 3 | 0 | 2.1 |
| Conformal ECO | 28 | 24 | 4 | 0 | 29.2 |
GOF generates a patch having three inputs, two outputs and 5 gates in total.
Figure 1 GOF ECO patch
While Conformal ECO generates a big patch with tens inputs and outputs, total 28 gates.
Figure 2 Conformal ECO patch
The files can be downloaded to reproduce the result
gof -lib mp16.lib imp.v -ref ref.v -run eco.gpl
