Gas Optimizations

[code423n4]

unchecked direction can be used at mintLongShortTokens function in PrePOMarket.sol

Target codebase

mintLongShortTokens function in PrePOMarket.sol can use unchecked directory.

https://github.com/code-423n4/2022-03-prepo/blob/main/contracts/core/PrePOMarket.sol#L122

require(_amount > _fee, "Minting amount too small");
_collateral.transferFrom(msg.sender, _treasury, _fee);
_amount -= _fee;

It is obvious that _amount - _fee will not be underflown since it has require(_amount > _fee, ...). Hence, can use unchecked directory,

Proposed change

require(_amount > _fee, "Minting amount too small");
_collateral.transferFrom(msg.sender, _treasury, _fee);
unchecked {
    _amount -= _fee;
}

Gas changes with the proposed changes

Methods - average gas change

Contract	Methods	Before	After	Change
PrePOMarket	mintLongShortTokens	198115	198055	-60

Deployments - average gas change

Contract	Before	After	Change
PrePOMarketFactory	4182011	4180271	-1740

---

unchecked direction can be used at redeem function in PrePOMarket.sol

Target codebase

redeem function in PrePOMarket.sol can use unchecked directory.

https://github.com/code-423n4/2022-03-prepo/blob/main/contracts/core/PrePOMarket.sol#L169

require(_collateralOwed > _fee, "Redemption amount too small");
_collateral.transfer(_treasury, _fee);
_collateralOwed -= _fee;

It is obvious that _collateralOwed - _fee will not be underflown since it has require(_collateralOwed > _fee, ...). Hence, can use unchecked directory,

Proposed change

require(_collateralOwed > _fee, "Redemption amount too small");
_collateral.transfer(_treasury, _fee);
unchecked {
    _collateralOwed -= _fee;
}

Gas changes with the proposed changes

Methods - average gas change

Contract	Methods	Before	After	Change
PrePOMarket	mintLongShortTokens	100708	100653	-55

Deployments - average gas change

Contract	Before	After	Change
PrePOMarketFactory	4182011	4180271	-1740

---

Target codebase

Proposed change

Gas changes with the proposed changes

Methods - average gas change

Contract	Methods	Before	After	Change
PrePOMarket	extractRewards	135652	131459	-4193

Deployments - average gas change

Contract	Before	After	Change
ExecutorManager	548814	536945	-11869

---

Unchecked can be used at deposit function in Collateral.sol

Target codebase

https://github.com/code-423n4/2022-03-prepo/blob/main/contracts/core/Collateral.sol#L73

require(_amountToDeposit > _fee, "Deposit amount too small");
_baseToken.safeTransfer(_treasury, _fee);
_amountToDeposit -= _fee;

_amountToDeposit - _fee will not be underflown since require(_amountToDeposit > _fee, ...).

Proposed change

require(_amountToDeposit > _fee, "Deposit amount too small");
_baseToken.safeTransfer(_treasury, _fee);
unchecked {
    _amountToDeposit -= _fee;
}

Gas changes with the proposed changes

Methods - average gas change

Contract	Methods	Before	After	Change
PrePOMarket	extractRewards	135652	131459	-4193

Deployments - average gas change

Contract	Before	After	Change
ExecutorManager	548814	536945	-11869

---

uint256 _shares does not need to be initialized with 0 at deposit function in Collateral.sol

Target codebase

https://github.com/code-423n4/2022-03-prepo/blob/main/contracts/core/Collateral.sol#L81

uint256 _shares = 0;

Proposed change

uint256 _shares;

Gas changes with the proposed changes

Methods - average gas change

Contract	Methods	Before	After	Change
Collateral	deposit	273176	273117	-59

Deployments - average gas change

Contract	Before	After	Change
TestCollateral	3383940	3382344	-1596

---

unchecked can be used at withdraw function at Collateral.sol

Target codebase

https://github.com/code-423n4/2022-03-prepo/blob/main/contracts/core/Collateral.sol#L171

require(_amountWithdrawn > _fee, "Withdrawal amount too small");
_baseToken.safeTransfer(_treasury, _fee);
_amountWithdrawn -= _fee;

It is obvious that _amountWithdrawn - _fee will not be underflown since it has require(_amountWithdrawn > _fee, ...).

Proposed change

require(_amountWithdrawn > _fee, "Withdrawal amount too small");
_baseToken.safeTransfer(_treasury, _fee);
unchecked {
    _amountWithdrawn -= _fee;
}

Gas changes with the proposed changes

Methods - average gas change

Contract	Methods	Before	After	Change
Collateral	withdraw	162848	162788	-60

Deployments - average gas change

Contract	Before	After	Change
TestCollateral	3383940	3382200	-1740

---

Unchecked can be used at recordDeposit function in CollateralDepositRecord.sol

Target codebase

https://github.com/code-423n4/2022-03-prepo/blob/main/contracts/core/CollateralDepositRecord.sol#L37-L38

require(
    _amount + _globalDepositAmount <= _globalDepositCap,
    "Global deposit cap exceeded"
);
require(
    _amount + _accountToNetDeposit[_sender] <= _accountDepositCap,
    "Account deposit cap exceeded"
);
_globalDepositAmount += _amount;
_accountToNetDeposit[_sender] += _amount;

Both _globalDepositAmount + _amount and _accountToNetDeposit[_sender] + _amount will not be overflown because it checks _amount + _globalDepositAmount <= _globalDepositCap and _amount + _accountToNetDeposit[_sender] <= _accountDepositCap before.

Proposed change

require(
    _amount + _globalDepositAmount <= _globalDepositCap,
    "Global deposit cap exceeded"
);
require(
    _amount + _accountToNetDeposit[_sender] <= _accountDepositCap,
    "Account deposit cap exceeded"
);
unchecked {
    _globalDepositAmount += _amount;
    _accountToNetDeposit[_sender] += _amount;
}

Gas changes with the proposed changes

Methods - average gas change

Contract	Methods	Before	After	Change
CollateralDepositRecord	recordDeposit	66022	65298	-724

Deployments - average gas change

Contract	Before	After	Change
CollateralDepositRecord	750519	744047	-6472

---

Unchecked can be used at recordWithdrawal function in CollateralDepositRecord.sol

Target codebase

https://github.com/code-423n4/2022-03-prepo/blob/main/contracts/core/CollateralDepositRecord.sol#L47
https://github.com/code-423n4/2022-03-prepo/blob/main/contracts/core/CollateralDepositRecord.sol#L52

if (_globalDepositAmount > _amount) {
    _globalDepositAmount -= _amount;
} else {
    _globalDepositAmount = 0;
}
if (_accountToNetDeposit[_sender] > _amount) {
    _accountToNetDeposit[_sender] -= _amount;
} else {
    _accountToNetDeposit[_sender] = 0;
}

_globalDepositAmount - _amount and _accountToNetDeposit[_sender] - _amount will not be underflown since they are wrapped by the if statement _globalDepositAmount > _amount or _accountToNetDeposit[_sender] > _amount.

Proposed change

if (_globalDepositAmount > _amount) {
    unchecked {
        _globalDepositAmount -= _amount;
    }
} else {
    _globalDepositAmount = 0;
}
if (_accountToNetDeposit[_sender] > _amount) {
    unchecked {
        _accountToNetDeposit[_sender] -= _amount;
    }
} else {
    _accountToNetDeposit[_sender] = 0;
}

Gas changes with the proposed changes

Methods - average gas change

Contract	Methods	Before	After	Change
CollateralDepositRecord	recordWithdrawal	33023	32895	-128

Deployments - average gas change

Contract	Before	After	Change
CollateralDepositRecord	750519	736492	-14027

---

Unchecked can be used at allowAccounts function in AccountAccessController.sol

Target codebase

https://github.com/code-423n4/2022-03-prepo/blob/main/contracts/core/AccountAccessController.sol#L44

for (uint256 _i = 0; _i < _accounts.length; _i++) {
    _allowedAccounts[_allowedAccountsIndex][_accounts[_i]] = true;
    emit AccountAllowed(_accounts[_i]);
}

Proposed change

for (uint256 _i = 0; _i < _accounts.length; ) {
    _allowedAccounts[_allowedAccountsIndex][_accounts[_i]] = true;
    emit AccountAllowed(_accounts[_i]);
    unchecked {
        _i++;
    }
}

Gas changes with the proposed changes

Methods - average gas change

Contract	Methods	Before	After	Change
MockAccountAccessController	allowAccounts	115094	114786	-308

Deployments - average gas change

Contract	Before	After	Change
MockAccountAccessController	948869	946721	-2148

---

Unchecked can be used at blockAccounts function in AccountAccessController.sol

Target codebase

https://github.com/code-423n4/2022-03-prepo/blob/main/contracts/core/AccountAccessController.sol#L55-L58

for (uint256 _i = 0; _i < _accounts.length; _i++) {
    _blockedAccounts[_blockedAccountsIndex][_accounts[_i]] = true;
    emit AccountBlocked(_accounts[_i]);
}

Proposed change

for (uint256 _i = 0; _i < _accounts.length; ) {
    _blockedAccounts[_blockedAccountsIndex][_accounts[_i]] = true;
    emit AccountBlocked(_accounts[_i]);
    unchecked {
        _i++;
    }
}

Gas changes with the proposed changes

Methods - average gas change

Contract	Methods	Before	After	Change
MockAccountAccessController	blockAccounts	115120	114812	-308

Deployments - average gas change

Contract	Before	After	Change
MockAccountAccessController	948869	946721	-2148

[ramenforbreakfast]

Excellent submission, well documented and clearly outlines gas savings.
This report and #5 will be referenced as the source submissions for common optimization duplicates.