First gas optimization - OR (||) conditions cost less than their equivalent AND (&&) conditions ("not(something is false) cost less than ("everything is true")
Remember that the equivalent of (a && b) is !(!a || !b), even with the 10k Optimizer enabled: OR (||) (conditions cost less than their equivalent AND (&&) conditions.
Fourth gas optimization - No need to explicitly initialize variables with default values
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.
First gas optimization - OR (||) conditions cost less than their equivalent AND (&&) conditions ("not(something is false) cost less than ("everything is true")
Remember that the equivalent of (a && b) is !(!a || !b), even with the 10k Optimizer enabled: OR (||) (conditions cost less than their equivalent AND (&&) conditions.
https://github.com/code-423n4/2022-08-olympus/blob/b5e139d732eb4c07102f149fb9426d356af617aa/src/modules/INSTR.sol 61: -} else if (instruction.action == Actions.ChangeExecutor && i != length - 1) { 61: +} } else if (!(instruction.action != Actions.ChangeExecutor || i = length - 1) {
https://github.com/code-423n4/2022-08-olympus/blob/b5e139d732eb4c07102f149fb9426d356af617aa/src/modules/RANGE.sol 133: -if (capacity_ < _range.high.threshold && range.high.active) { 133: +if !(!(capacity < _range.high.threshold) || !_range.high.active) {
145: -if (capacity_ < _range.low.threshold && range.low.active) { 145: +if !(!(capacity < _range.low.threshold) || !_range.low.active) {
221: -if (market == type(uint256).max && marketCapacity != 0) revert RANGEInvalidParams(); 221: +if (!(market != type(uint256).max || marketCapacity_ = 0) revert RANGE_InvalidParams();
Second gas optimization - ++ should be unchecked, when it is not possible for them to overflow
https://github.com/code-423n4/2022-08-olympus/blob/b5e139d732eb4c07102f149fb9426d356af617aa/src/modules/INSTR.sol it's hardly to believe that a cache for storing a list of instructions to be executed in the future, can get greater than uint256 and overflow. 44: -uint256 instructionsId = ++totalInstructions; 44: +unchecked { uint256 instructionsId = ++totalInstructions; }
Third gas optimization - Usage of uints/ints smaller than 32 bytes (256 bits) incurs in overhead
https://github.com/code-423n4/2022-08-olympus/blob/b5e139d732eb4c07102f149fb9426d356af617aa/src/modules/PRICE.sol 44: uint32 public nextObsIndex; 47: uint32 public numObservations; 50: uint48 public observationFrequency; 53: uint48 public movingAverageDuration; 56: uint48 public lastObservationTime;
https://github.com/code-423n4/2022-08-olympus/blob/b5e139d732eb4c07102f149fb9426d356af617aa/src/policies/Operator.sol 83: uint8 public immutable ohmDecimals; 86: uint8 public immutable reserveDecimals;
Fourth gas optimization - No need to explicitly initialize variables with default values
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.
https://github.com/code-423n4/2022-08-olympus/blob/b5e139d732eb4c07102f149fb9426d356af617aa/src/utils/KernelUtils.sol 43: -for (uint256 i = 0; i < 5; ) { 43: +for (uint256 i; i < 5; ) {
58: -for (uint256 i = 0; i < 32; ) { 58: +for (uint256 i; i < 32; ) {
https://github.com/code-423n4/2022-08-olympus/blob/b5e139d732eb4c07102f149fb9426d356af617aa/src/Kernel.sol 397: -for (uint256 i = 0; i < reqLength; ) { 397: +for (uint256 i; i < reqLength; ) {
Fifth gas optimization - <=/>= cost less gas than </>
https://github.com/code-423n4/2022-08-olympus/blob/b5e139d732eb4c07102f149fb9426d356af617aa/src/utils/KernelUtils.sol 43: -for (uint256 i = 0; i < 5; ) { 43: +for (uint256 i = 0; i <= 4; ) {
58: -for (uint256 i = 0; i < 32; ) { 58: +for (uint256 i = 0; i <= 31; ) {