Ethena Labs - evmboi32's results

Use != 0 instead of > 0 for unsigned integer comparison

Using != 0 instead of > 0 saves gas.

StakedUSDe.sol
    if (getUnvestedAmount() > 0) revert StillVesting();
    if (_totalSupply > 0 && _totalSupply < MIN_SHARES) revert MinSharesViolation();
   
EthenaMinting.sol 
    if (remainingBalance > 0) {
      token.safeTransferFrom(benefactor, addresses[addresses.length - 1], remainingBalance);
    }

https://github.com/code-423n4/2023-10-ethena/blob/ee67d9b542642c9757a6b826c82d0cae60256509/contracts/StakedUSDe.sol#L90

https://github.com/code-423n4/2023-10-ethena/blob/ee67d9b542642c9757a6b826c82d0cae60256509/contracts/StakedUSDe.sol#L193

https://github.com/code-423n4/2023-10-ethena/blob/ee67d9b542642c9757a6b826c82d0cae60256509/contracts/EthenaMinting.sol#L430-L432

Use calldata instead of memory for function arguments that do not get mutated

https://github.com/code-423n4/2023-10-ethena/blob/ee67d9b542642c9757a6b826c82d0cae60256509/contracts/EthenaMinting.sol#L111-L118

Use hardcode address instead address(this)

Instead of using address(this), it is more gas-efficient to pre-calculate and use the hardcoded address. Foundry’s script.sol and solmate’s LibRlp.sol contracts can help achieve this.

https://github.com/code-423n4/2023-10-ethena/blob/ee67d9b542642c9757a6b826c82d0cae60256509/contracts/EthenaMinting.sol#L452

A modifier used only once and not being inherited should be inlined to save gas

When a modifier is used only once and is not inherited by any other contracts, inlining it can reduce gas costs. Inlining means that the modifier’s code is directly inserted into the function where it is applied, rather than creating a separate function call for the modifier.

By inlining the modifier, you avoid the overhead of the additional function call, which results in lower gas consumption. This optimization is especially useful when the modifier’s code is short or simple.

The following two modifiers in EthenaMinting.sol are only used once:

modifier belowMaxMintPerBlock(uint256 mintAmount) {
    if (mintedPerBlock[block.number] + mintAmount > maxMintPerBlock) revert MaxMintPerBlockExceeded();
    _;
}

modifier belowMaxRedeemPerBlock(uint256 redeemAmount) {
    if (redeemedPerBlock[block.number] + redeemAmount > maxRedeemPerBlock) revert MaxRedeemPerBlockExceeded();
    _;
}

https://github.com/code-423n4/2023-10-ethena/blob/ee67d9b542642c9757a6b826c82d0cae60256509/contracts/EthenaMinting.sol#L97-L107

https://github.com/code-423n4/2023-10-ethena/blob/ee67d9b542642c9757a6b826c82d0cae60256509/contracts/EthenaMinting.sol#L167

https://github.com/code-423n4/2023-10-ethena/blob/ee67d9b542642c9757a6b826c82d0cae60256509/contracts/EthenaMinting.sol#L199

Avoid emitting storage values

Caching of a state variable replaces each Gwarmaccess (100 gas) with a much cheaper stack read. We can avoid unecessary SLOADs by caching storage values that were previously accessed and emitting those cached values.

https://github.com/code-423n4/2023-10-ethena/blob/ee67d9b542642c9757a6b826c82d0cae60256509/contracts/EthenaMinting.sol#L436-L440

https://github.com/code-423n4/2023-10-ethena/blob/ee67d9b542642c9757a6b826c82d0cae60256509/contracts/EthenaMinting.sol#L443-L447

https://github.com/code-423n4/2023-10-ethena/blob/ee67d9b542642c9757a6b826c82d0cae60256509/contracts/StakedUSDeV2.sol#L126-L134

If statements that use & can be refactored into nested if statements

This way we can save some gas

https://github.com/code-423n4/2023-10-ethena/blob/ee67d9b542642c9757a6b826c82d0cae60256509/contracts/EthenaMinting.sol#L383