This repo estimates the gas cost of implementing PoseidonT3 over the alt_bn128 curve using EIP-6690 (EVMMAX).

The best PoseidonT3 implementation consumes 21,124 gas. The arithmetic represents about ~40% of the cost.

EVMMAX arithmetic is ~5x cheaper than the best normal implementation. The expected total PoseidonT3 cost with EVMMAX would be 13,659 gas. This is calculated by subtracting the difference in the arithmetic cost from the total cost above.

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alt_bn128 T3 consumed 19947 gas (normal)
    stack: 10668
    arith: 9279
alt_bn128 T3 consumed 1814 gas (EVMMAX)
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m31 T3 consumed 7949 gas (normal)
    stack: 4355
    arith: 3594
m31 T3 consumed 920 gas (EVMMAX)
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m31 T8 consumed 26344 gas (normal)
    stack: 12997
    arith: 13347
m31 T8 consumed 3326 gas (EVMMAX)
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