Recently, circomlib updated its Poseidon hash functions to conform to the reference implementation: https://github.com/iden3/circomlib/pull/47.
With circomlib v0.2.4, which provides a script to generate Poseidion hash bytecode, the new gas costs and relevant parameters are as follows:
| Number of inputs | t |
nRoundsF |
nRoundsP |
Gas cost |
|---|---|---|---|---|
| 2 | 3 | 8 | 57 | 53189 |
| 5 | 6 | 8 | 60 | 121984 |
The code I used to obtain these measurements is here: