FullMath Code Style Findings

FMH-01C: Outdated Implementation

Description:

The FullMath contract is a copy of the homonymous Uniswap V2 library and implements an outdated version of the mulDiv function which does not contain the optimization of h == 0 as present in the Uniswap V2 equivalent.

Example:

Copy
33function mulDiv(
34    uint256 x,
35    uint256 y,
36    uint256 d
37) internal pure returns (uint256) {
38    (uint256 l, uint256 h) = fullMul(x, y);
39    uint256 mm = mulmod(x, y, d);
40    if (mm > l) h -= 1;
41    l -= mm;
42    require(h < d, 'FullMath::mulDiv: overflow');
43    return fullDiv(l, h, d);
44}

Recommendation:

We advise the optimization to be applied to reduce the gas cost involved with the library.

Alleviation:

The optimization of Uniswap V2 was properly integrated into the codebase.