Gas Optimizations

[code423n4]

G-01 USING BOTH NAMED RETURNS AND A RETURN STATEMENT ISN'T NECESSARY

Number of Instances Identified: 5

Removing unused named returns variables can reduce gas usage (MSTOREs/MLOADs) and improve code clarity. To save gas and improve code quality: consider using only one of those.

https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JB721GlobalGovernance.sol

37: returns (uint256 units)
123: function balanceOf(address _owner) public view override returns (uint256 balance) {

https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JBTiered721Delegate.sol

617: ) internal returns (uint256 leftoverAmount) {

https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JBTiered721DelegateProjectDeployer.sol

119: returns (uint256 configuration)
162: returns (uint256 configuration)

G-02 X += Y COSTS MORE GAS THAN X = X + Y FOR STATE VARIABLES

Number of Instances Identified: 7

https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JBTiered721DelegateStore.sol

354: supply += _storedTier.initialQuantity - _storedTier.remainingQuantity;
409: units += _balance * _storedTierOf[_nft][_i].votingUnits;
506: balance += tierBalanceOf[_nft][_owner][_i];
534: weight += _storedTierOf[_nft][tierIdOfToken(_tokenIds[_i])].contributionFloor;
563: weight +=...
827: numberOfReservesMintedFor[msg.sender][_tierId] += _count;

https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/libraries/JBIpfsDecoder.sol

62: carry += uint256(digits[j]) * 256;

G-03 ++I or I++ SHOULD BE UNCHECKED{++I} or UNCHECKED{I++} WHEN IT IS NOT POSSIBLE FOR THEM TO OVERFLOW, AS IS THE CASE WHEN USED IN FOR- AND WHILE-LOOPS

the unchecked keyword is new in solidity version 0.8.0, so this only applies to that version or higher, which these instances are.

Number of Instances Identified: 5

https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/libraries/JBIpfsDecoder.sol

49: for (uint256 i = 0; i < _source.length; ++i) {
51: for (uint256 j = 0; j < digitlength; ++j) {
68: for (uint256 i = 0; i < _length; i++) {
76: for (uint256 i = 0; i < _input.length; i++) {
84: for (uint256 i = 0; i < _indices.length; i++) {

G-04 ++I COSTS LESS GAS COMPARED TO I++ OR I += 1 (SAME FOR --I VS I-- OR I -= 1)

Number of Instances Identified: 6

Pre-increments and pre-decrements are cheaper.

For a uint256 i variable, the following is true with the Optimizer enabled at 10k:

Increment:

• i += 1 is the most expensive form
• i++ costs 6 gas less than i += 1
• ++i costs 5 gas less than i++ (11 gas less than i += 1)

Decrement:

• i -= 1 is the most expensive form
• i-- costs 11 gas less than i -= 1
• --i costs 5 gas less than i-- (16 gas less than i -= 1)

https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/libraries/JBIpfsDecoder.sol

59: digitlength++;
68: for (uint256 i = 0; i < _length; i++) {
76: for (uint256 i = 0; i < _input.length; i++) {
84: for (uint256 i = 0; i < _indices.length; i++) {

https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JBTiered721DelegateStore.sol

1106: numberOfBurnedFor[msg.sender][_tierId]++;
1108: _storedTierOf[msg.sender][_tierId].remainingQuantity++;

G-05 IT COSTS MORE GAS TO INITIALIZE VARIABLES WITH THEIR DEFAULT VALUE THAN LETTING THE DEFAULT VALUE BE APPLIED

Number of Instances Identified: 5

If a variable is not set/initialized, it is assumed to have the default value (0 for uint, false for bool, address(0) for address…). Explicitly initializing it with its default value is an anti-pattern and wastes gas.

As an example: for (uint256 i = 0; i < numIterations; ++i) { should be replaced with for (uint256 i; i < numIterations; ++i) {

https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/libraries/JBIpfsDecoder.sol

49: for (uint256 i = 0; i < _source.length; ++i) {
51: for (uint256 j = 0; j < digitlength; ++j) {
68: for (uint256 i = 0; i < _length; i++) {
76: for (uint256 i = 0; i < _input.length; i++) {
84: for (uint256 i = 0; i < _indices.length; i++) {

G-06 INTERNAL FUNCTIONS ONLY CALLED ONCE CAN BE INLINED TO SAVE GAS

Number of Instances Identified: 4

Not inlining costs 20 to 40 gas because of two extra JUMP instructions and additional stack operations needed for function calls.

https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JB721TieredGovernance.sol

194: function _getTierVotingUnits(address _account, uint256 _tierId)
242: function _transferTierVotingUnits

https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JBTiered721Delegate.sol

524: function _processPayment(JBDidPayData calldata _data) internal override {  
598: function _didBurn(uint256[] memory _tokenIds) internal override {

[Picodes]

Most findings are invalid or out of scope with the automated report

[c4-judge]

Picodes marked the issue as grade-b