Gas Optimizations

[code423n4]

Unchecked Gas Optimisation in Minter.sol

A check is already made to make sure that issuedNonInflationSupply does not exceed a certain value so an arithmetic overflow is not possible

Change issuedNonInflationSupply += amount; to unchecked { issuedNonInflationSupply += amount;}

https://github.com/code-423n4/2022-05-backd/blob/2a5664d35cde5b036074edef3c1369b984d10010/protocol/contracts/tokenomics/Minter.sol#L150-L154

Unchecked Gas Optimisations in AmmGauge.sol

We can make another unchecked addition because totalStaked will always be larger than balances[user]

Change

balances[account] += staked;
totalStaked += staked;

to

totalStaked += staked;
unchecked { balances[account] += staked; } 

https://github.com/code-423n4/2022-05-backd/blob/2a5664d35cde5b036074edef3c1369b984d10010/protocol/contracts/tokenomics/AmmGauge.sol#L112-L113

In Line 134 and 135
Change

balances[msg.sender] -= unstaked;
totalStaked -= unstaked;

to

balances[msg.sender] -= unstaked;
unchecked { totalStaked -= unstaked }

https://github.com/code-423n4/2022-05-backd/blob/2a5664d35cde5b036074edef3c1369b984d10010/protocol/contracts/tokenomics/AmmGauge.sol#L134-L135

KeeperGauge.sol

Change epoch++ to ++epoch as talked about here
https://github.com/code-423n4/2022-05-backd/blob/2a5664d35cde5b036074edef3c1369b984d10010/protocol/contracts/tokenomics/KeeperGauge.sol#L59
https://github.com/code-423n4/2022-05-backd/blob/2a5664d35cde5b036074edef3c1369b984d10010/protocol/contracts/tokenomics/KeeperGauge.sol#L98

Change

        keeperRecords[beneficiary].feesInPeriod[epoch] += amount;
        perPeriodTotalFees[epoch] += amount;

to

        perPeriodTotalFees[epoch] += amount;
        unchecked { keeperRecords[beneficiary].feesInPeriod[epoch] += amount; }
        

https://github.com/code-423n4/2022-05-backd/blob/2a5664d35cde5b036074edef3c1369b984d10010/protocol/contracts/tokenomics/KeeperGauge.sol#L87-L88

BkdLocker.sol

As we already make a value check we do not need to worry about arithmetic overflow
Wrap unchecked around

        totalStashed[msg.sender] += amount;

https://github.com/code-423n4/2022-05-backd/blob/2a5664d35cde5b036074edef3c1369b984d10010/protocol/contracts/BkdLocker.sol#L119-L123

Again we have a similar issue

Change

        totalStashed[msg.sender] -= totalAvailableToWithdraw;
        uint256 newTotal = balances[msg.sender] - totalAvailableToWithdraw;
        _userCheckpoint(msg.sender, 0, newTotal);
        totalLocked -= totalAvailableToWithdraw;

to

        totalStashed[msg.sender] -= totalAvailableToWithdraw;
        uint256 newTotal = balances[msg.sender] - totalAvailableToWithdraw;
        _userCheckpoint(msg.sender, 0, newTotal);
        unchecked { totalLocked -= totalAvailableToWithdraw; }

https://github.com/code-423n4/2022-05-backd/blob/2a5664d35cde5b036074edef3c1369b984d10010/protocol/contracts/BkdLocker.sol#L149-L152

curRewardTokenData.feeBalance will always be larger than or equal to curRewardTokenData.userShares[msg.sender] of any user so we can change Line 216 to
unchecked { curRewardTokenData.feeBalance -= claimable; }

https://github.com/code-423n4/2022-05-backd/blob/2a5664d35cde5b036074edef3c1369b984d10010/protocol/contracts/BkdLocker.sol#L214-L216

Gas Savings in _userCheckpoint() in BkdLocker.sol Contract

Variables such as boostFactors and curRewardTokenData are read multiple times throughout the contract. This requires multiple SLOAD operations which are very expensive. It is better to load the variables into memory and use those when reading while the storage variables can be used for writing.

See here for more info
i.e.

       RewardTokenData storage curRewardTokenData = rewardTokenData[rewardToken];


        // Compute the share earned by the user since they last updated
        uint256 userBalance = balances[user];
        if (userBalance > 0) {
            curRewardTokenData.userShares[user] += (curRewardTokenData.feeIntegral -
                curRewardTokenData.userFeeIntegrals[user]).scaledMul(
                    userBalance.scaledMul(boostFactors[user])
                );

can be changed to

        RewardTokenData storage curRewardTokenData = rewardTokenData[rewardToken];
        RewardTokenData memory _curRewardTokenData = curRewardTokenData


        // Compute the share earned by the user since they last updated
        uint256 userBalance = balances[user];
        if (userBalance > 0) {
            curRewardTokenData.userShares[user] += (_curRewardTokenData.feeIntegral -
                _curRewardTokenData.userFeeIntegrals[user]).scaledMul(
                    userBalance.scaledMul(boostFactors[user])
                );

This also applies to boostFactors and prevRewardTokenData

https://github.com/code-423n4/2022-05-backd/blob/2a5664d35cde5b036074edef3c1369b984d10010/protocol/contracts/BkdLocker.sol#L292-L335

[GalloDaSballo]

Unchecked Gas Optimisation in Minter.sol

Saves 20 gas per instance
3 * 20
60

## Change epoch++ to ++epoch as talked about here
5 per instance
10

Unchecked
20

Unchecked2
20

Gas Savings in _userCheckpoint() in BkdLocker.sol Contract

I don't believe this will save gas as when you copy in memory you are copying all fields once

Total Gas Savings
110

[GalloDaSballo]

Formatting can be hugely improved, as well as submission format.

We think in problems not in files, so sending the same optimization in multiple files makes it more complex to deal with.