Gas Optimizations

[code423n4]

Gas Optimizations

[G01] uint256 default value is 0 so we can remove = 0:

BaseRewardPool.sol
  66,33:     uint256 public periodFinish = 0;
  67,31:     uint256 public rewardRate = 0;
  70,34:     uint256 public queuedRewards = 0;
  71,35:     uint256 public currentRewards = 0;
  72,38:     uint256 public historicalRewards = 0;
  176,24:         for (uint256 i = 0; i < extraRewards.length; i++) {
  199,24:         for (uint256 i = 0; i < extraRewards.length; i++) {
  218,24:         for (uint256 i = 0; i < extraRewards.length; i++) {
  245,24:         for (uint256 i = 0; i < extraRewards.length; i++) {
  282,28:             for (uint256 i = 0; i < extraRewards.length; i++) {

Booster.sol
  329,24:         for (uint256 i = 0; i < poolInfo.length; i++) {

ExtraRewardStashV1.sol
  29,38:     uint256 public historicalRewards = 0;

ExtraRewardStashV2.sol
  71,28:             for (uint256 i = 0; i < length; i++) {
  78,28:             for (uint256 i = 0; i < length; i++) {
  137,24:         for (uint256 i = 0; i < maxRewards; i++) {
  181,24:         for (uint256 i = 0; i < tokenCount; i++) {
  213,24:         for (uint256 i = 0; i < tokenCount; i++) {

ExtraRewardStashV3.sol
  84,24:         for (uint256 i = 0; i < maxRewards; i++) {
  126,24:         for (uint256 i = 0; i < tokenCount; i++) {

RewardFactory.sol
  49,24:         for (uint256 i = 0; i < length; i++) {
  66,24:         for (uint256 i = 0; i < length; i++) {

VE3DLocker.sol
  286,24:         for (uint256 i = 0; i < userRewards.length; i++) {
  315,51:         for (uint256 i = locks.length - 1; i + 1 != 0; i--) {
  360,51:         for (uint256 i = locks.length - 1; i + 1 != 0; i--) {
  387,49:         for (uint256 i = epochindex - 1; i + 1 != 0; i--) {
  406,41:         for (uint256 i = _epoch; i + 1 != 0; i--) {
  420,21:         uint256 min = 0;
  425,24:         for (uint256 i = 0; i < 128; i++) {
  613,24:         uint256 reward = 0;
  803,28:             for (uint256 i = 0; i < rewardTokens.length; i++) {

VE3DRewardPool.sol
  148,24:         for (uint256 i = 0; i < rewardTokens.length(); i++) {
  214,24:         for (uint256 i = 0; i < length; i++) {
  238,24:         for (uint256 i = 0; i < length; i++) {
  257,24:         for (uint256 i = 0; i < length; i++) {
  281,24:         for (uint256 i = 0; i < rewardTokens.length(); i++) {
  326,28:             for (uint256 i = 0; i < length; i++) {

VeAssetDepositor.sol
  28,37:     uint256 public incentiveVeAsset = 0;

VirtualBalanceRewardPool.sol
  74,33:     uint256 public periodFinish = 0;
  75,31:     uint256 public rewardRate = 0;
  78,34:     uint256 public queuedRewards = 0;
  79,35:     uint256 public currentRewards = 0;
  80,38:     uint256 public historicalRewards = 0;

VoterProxy.sol
  217,28:             for (uint256 i = 0; i < _tokenVote.length; i++) {
  227,26:         uint256 _balance = 0;

[G02] ++i use less gas than i++:

++i costs less gas compared to i++. about 5 gas per iteration.

BaseRewardPool.sol
  176,54:         for (uint256 i = 0; i < extraRewards.length; i++) {
  199,54:         for (uint256 i = 0; i < extraRewards.length; i++) {
  218,54:         for (uint256 i = 0; i < extraRewards.length; i++) {
  245,54:         for (uint256 i = 0; i < extraRewards.length; i++) {
  282,58:             for (uint256 i = 0; i < extraRewards.length; i++) {

Booster.sol
  329,50:         for (uint256 i = 0; i < poolInfo.length; i++) {

ExtraRewardStashV2.sol
  71,45:             for (uint256 i = 0; i < length; i++) {
  78,45:             for (uint256 i = 0; i < length; i++) {
  137,45:         for (uint256 i = 0; i < maxRewards; i++) {
  181,45:         for (uint256 i = 0; i < tokenCount; i++) {
  213,45:         for (uint256 i = 0; i < tokenCount; i++) {

ExtraRewardStashV3.sol
  84,45:         for (uint256 i = 0; i < maxRewards; i++) {
  126,45:         for (uint256 i = 0; i < tokenCount; i++) {

RewardFactory.sol
  49,41:         for (uint256 i = 0; i < length; i++) {
  66,41:         for (uint256 i = 0; i < length; i++) {

VE3DLocker.sol
  207,50:         for (uint256 i; i < rewardTokens.length; i++) {
  286,53:         for (uint256 i = 0; i < userRewards.length; i++) {
  425,38:         for (uint256 i = 0; i < 128; i++) {
  457,61:         for (uint256 i = nextUnlockIndex; i < locks.length; i++) {
  640,59:             for (uint256 i = nextUnlockIndex; i < length; i++) {
  720,50:         for (uint256 i; i < rewardTokens.length; i++) {
  803,58:             for (uint256 i = 0; i < rewardTokens.length; i++) {

VE3DRewardPool.sol
  148,56:         for (uint256 i = 0; i < rewardTokens.length(); i++) {
  214,41:         for (uint256 i = 0; i < length; i++) {
  238,41:         for (uint256 i = 0; i < length; i++) {
  257,41:         for (uint256 i = 0; i < length; i++) {
  281,56:         for (uint256 i = 0; i < rewardTokens.length(); i++) {
  326,45:             for (uint256 i = 0; i < length; i++) {

VoterProxy.sol
  217,56:             for (uint256 i = 0; i < _tokenVote.length; i++) {

[G03] Use Custom Errors to save Gas:

Custom errors from Solidity 0.8.4 are cheaper than require messages.
https://blog.soliditylang.org/2021/04/21/custom-errors/

[G04] SafeMath is not needed when using Solidity version 0.8:

Solidity version 0.8.* already implements overflow and underflow checks by default.
Using the SafeMath library from OpenZeppelin (which is more gas expensive than the 0.8.* overflow checks) is therefore redundant.

Recommended Mitigation Steps:

Use arithmetics instead of SafeMath lib.

[GalloDaSballo]

Less than 500 gas saved