FIAT DAO veFDT contest - 0xackermann's results

Gas Report

Use != 0 instead of > 0 for Unsigned Integer Comparison

Locations:

Blocklist.sol::42 => return size > 0;
VotingEscrow.sol::176 => if (delegatee != _addr && value > 0) {
VotingEscrow.sol::236 => if (_oldLocked.end > block.timestamp && _oldLocked.delegated > 0) {
VotingEscrow.sol::244 => if (_newLocked.end > block.timestamp && _newLocked.delegated > 0) {
VotingEscrow.sol::288 => if (epoch > 0) {
VotingEscrow.sol::412 => require(_value > 0, "Only non zero amount");
VotingEscrow.sol::448 => require(_value > 0, "Only non zero amount");
VotingEscrow.sol::449 => require(locked_.amount > 0, "No lock");
VotingEscrow.sol::469 => require(locked_.amount > 0, "Delegatee has no lock");
VotingEscrow.sol::502 => require(locked_.amount > 0, "No lock");
VotingEscrow.sol::529 => require(locked_.amount > 0, "No lock");
VotingEscrow.sol::564 => require(locked_.amount > 0, "No lock");
VotingEscrow.sol::587 => require(toLocked.amount > 0, "Delegatee has no lock");
VotingEscrow.sol::621 => if (newLocked.amount > 0) {
VotingEscrow.sol::635 => require(locked_.amount > 0, "No lock");

Impact

It is cheaper to deal with unsigned integers by using != 0 than > 0.

Use Shift Right/Left instead of Division/Multiplication if possible

Locations:

VotingEscrow.sol::719 => uint256 mid = (min + max + 1) / 2;
VotingEscrow.sol::743 => uint256 mid = (min + max + 1) / 2;

Impact

It costs cheaper to use >> 1 instead of dividing by 2.

Need to Have Specific Compiler Version for Pragma

Locations:

Blocklist.sol::2 => pragma solidity ^0.8.3;
IBlocklist.sol::2 => pragma solidity ^0.8.3;
IERC20.sol::2 => pragma solidity ^0.8.3;
IERC20Permit.sol::4 => pragma solidity ^0.8.3;
IVotingEscrow.sol::2 => pragma solidity ^0.8.3;
VotingEscrow.sol::2 => pragma solidity ^0.8.3;

Impact

It is suggested to use a concrete compiler version. This is because a new version compiler may be vulnerable and cause fall back in older version of compiler.