Gas Optimizations

[code423n4]

State variables should not be initialized to their default values

Initializing uint variables to their default value of 0 is unnecessary and costs gas

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VotingEscrow.sol: L298

        uint256 blockSlope = 0; // dblock/dt

Change to:

        uint256 blockSlope; // dblock/dt

Similarly for the additional instances below

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min is initialized to zero in both the following lines:

VotingEscrow.sol: L714

VotingEscrow.sol: L737

        uint256 min = 0;

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VotingEscrow.sol: L793

        uint256 dBlock = 0;

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dTime is initialized to zero in both the following lines:

VotingEscrow.sol: L794

VotingEscrow.sol: L889

        uint256 dTime = 0;

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Use ++i instead of i++ to increase count in a for loop

Since use of i++ (or equivalent counter) costs more gas, it is better to use ++i in the four for loops referenced below:

VotingEscrow.sol: L309-347

VotingEscrow.sol: L717-725

VotingEscrow.sol: L739-748

VotingEscrow.sol: L834-855

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Avoid use of default "checked" behavior in a for loop

Underflow/overflow checks are made every time ++i (or i++ or equivalent counter) is called. Such checks are unnecessary since i is already limited. Therefore, use unchecked {++i}/unchecked {i++} instead

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VotingEscrow.sol: L717-725

        for (uint256 i = 0; i < 128; i++) {
            if (min >= max) break;
            uint256 mid = (min + max + 1) / 2;
            if (pointHistory[mid].blk <= _block) {
                min = mid;
            } else {
                max = mid - 1;
            }
        }

Suggestion:

        for (uint256 i = 0; i < 128;) {
            if (min >= max) break;
            uint256 mid = (min + max + 1) / 2;
            if (pointHistory[mid].blk <= _block) {
                min = mid;
            } else {
                max = mid - 1;
            }

            unchecked {
              ++i;
          }
        }

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Similarly for the three for loops referenced below:

VotingEscrow.sol: L309-347

VotingEscrow.sol: L739-748

VotingEscrow.sol: L834-855

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