Olympus DAO contest - Noah3o6's results

-> X = X + Y IS CHEAPER THAN X += Y (same for X = X - Y IS CHEAPER THAN X -= Y)

https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/TRSRY.sol#:~:text=reserveDebt%5Btoken_%5D%5Bmsg.sender%5D%20%2B%3D%20amount_%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/TRSRY.sol#:~:text=totalDebt%5Btoken_%5D%20%2B%3D%20amount_%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/TRSRY.sol#:~:text=reserveDebt%5Btoken_%5D%5Bmsg.sender%5D%20%2D%3D%20received%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/TRSRY.sol#:~:text=totalDebt%5Btoken_%5D%20%2D%3D%20received%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/TRSRY.sol#:~:text=oldDebt%20%3C%20amount_)-,totalDebt%5Btoken_%5D%20%2B%3D%20amount_,-%2D%20oldDebt%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/TRSRY.sol#:~:text=totalDebt%5Btoken_%5D%20%2D%3D%20oldDebt https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/PRICE.sol#:~:text=_movingAverage%20%2B%3D%20(currentPrice%20%2D%20earliestPrice)%20/%20numObs%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/PRICE.sol#:~:text=_movingAverage%20%2D%3D%20(earliestPrice%20%2D%20currentPrice)%20/%20numObs%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/PRICE.sol#:~:text=total%20%2B%3D%20startObservations_%5Bi%5D%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/VOTES.sol#:~:text=balanceOf%5Bfrom_%5D%20%2D%3D%20amount_%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/VOTES.sol#:~:text=balanceOf%5Bto_%5D%20%2B%3D%20amount_%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/BondCallback.sol#:~:text=_amountsPerMarket%5Bid_%5D%5B0%5D%20%2B%3D%20inputAmount_%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/BondCallback.sol#:~:text=_amountsPerMarket%5Bid_%5D%5B1%5D%20%2B%3D%20outputAmount_%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Heart.sol#:~:text=lastBeat%20%2B%3D%20frequency()%3B

->STATE VARIABLES ONLY SET IN THE CONSTRUCTOR SHOULD BE DECLARED IMMUTABLE

Avoids a Gsset (20000 gas) in the constructor, and replaces each Gwarmacces (100 gas) with a PUSH32 (3 gas)

https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/PRICE.sol#:~:text=uint256%20internal%20immutable%20_scaleFactor%3B

-> ++i costs less gas compared to i++ or i += 1 (Also --i costs less gas compared to i-- or i -= 1)

https://github.com/code-423n4/2022-08-olympus/blob/main/src/utils/KernelUtils.sol#:~:text=A%2DZ%20only-,unchecked%20%7B,i%2B%2B%3B,-%7D https://github.com/code-423n4/2022-08-olympus/blob/main/src/utils/KernelUtils.sol#:~:text=%7D-,unchecked%20%7B,i%2B%2B%3B,-%7D https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=/%2010%3B-,decimals%2B%2B,-%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=%3D%20true%3B-,_status.low.count%2B%2B,-%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=%3D%20false%3B-,_status.low.count%2D%2D,-%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=_status.high.count%2B%2B https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=_status.high.count%2D%2D

-> USAGE OF UINTS/INTS SMALLER THAN 32 BYTES (256 BITS) INCURS OVERHEAD When using elements that are smaller than 32 bytes, your contract’s gas usage may be higher. This is because the EVM operates on 32 bytes at a time. Therefore, if the element is smaller than that, the EVM must use more operations in order to reduce the size of the element from 32 bytes to the desired size.

https://github.com/code-423n4/2022-08-olympus/blob/main/src/Kernel.sol#:~:text=%3D%3E%20mapping(-,bytes4,-%3D%3E%20bool))) https://github.com/code-423n4/2022-08-olympus/blob/main/src/utils/KernelUtils.sol#:~:text=)%20pure%20returns-,(bytes5),-%7B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/TRSRY.sol#:~:text=override%20returns%20(-,uint8%20major%2C,-uint8%20minor)%20%7B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/TRSRY.sol#:~:text=uint8%20major%2C-,uint8%20minor),-%7B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/PRICE.sol#:~:text=by%20the%20contract.-,uint8,-public%20constant%20decimals https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/PRICE.sol#:~:text=_ohmEthPriceFeed%20%3D%20ohmEthPriceFeed_%3B-,uint8,-ohmEthDecimals%20%3D%20_ohmEthPriceFeed https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/INSTR.sol#:~:text=override%20returns%20(-,uint8%20major,-%2C%20uint8%20minor https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/INSTR.sol#:~:text=uint8%20major%2C-,uint8%20minor),-%7B https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=public%20immutable%20ohm%3B-,uint8,-public%20immutable%20ohmDecimals https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=public%20immutable%20reserve%3B-,uint8,-public%20immutable%20reserveDecimals https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=is%20the%20priceDecimal%20value-,int8,-priceDecimals%20%3D%20_getPriceDecimals(range https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=cushion.high.price)%3B-,int8,-scaleAdjustment%20%3D%20int8 https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=int8%20scaleAdjustment%20%3D-,int8,-(ohmDecimals)%20%2D https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=(ohmDecimals)%20%2D-,int8,-(reserveDecimals)%20%2B https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=uint256%20bondScale%20%3D%2010%20**-,uint8(,-36%20%2B%20scaleAdjustment%20%2B%20int8(reserveDecimals https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=the%20low%20side-,uint8,-oracleDecimals%20%3D%20PRICE https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=is%20the%20priceDecimal%20value-,int8,-priceDecimals%20%3D%20_getPriceDecimals(invCushionPrice https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=_getPriceDecimals(invCushionPrice)%3B-,int8,-scaleAdjustment%20%3D%20int8 https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=int8%20scaleAdjustment%20%3D-,int8,-(reserveDecimals)%20%2D https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=(reserveDecimals)%20%2D-,int8,-(ohmDecimals)%20%2B https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=%3D%2010**-,uint8,-(int8(oracleDecimals https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=**uint8(-,int8,-(oracleDecimals)%20%2D https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=%2B%20scaleAdjustment%20%2B-,int8,-(ohmDecimals)%20%2D https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=(ohmDecimals)%20%2D-,int8,-(reserveDecimals)%20%2D https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=return%20decimals%20%2D-,int8,-(PRICE.decimals

->IT COSTS MORE GAS TO INITIALIZE NON-CONSTANT/NON-IMMUTABLE VARIABLES TO ZERO THAN TO LET THE DEFAULT OF ZERO BE APPLIED

https://github.com/code-423n4/2022-08-olympus/blob/main/src/utils/KernelUtils.sol#:~:text=for%20(-,uint256%20i%20%3D%200%3B,-i%20%3C%205 https://github.com/code-423n4/2022-08-olympus/blob/main/src/utils/KernelUtils.sol#:~:text=for-,(uint256%20i%20%3D%200,-%3B%20i%20%3C%2032

->USING BOOLS FOR STORAGE INCURS OVERHEAD

https://github.com/code-423n4/2022-08-olympus/blob/main/src/Kernel.sol#:~:text=mapping(bytes4%20%3D%3E%20bool))) https://github.com/code-423n4/2022-08-olympus/blob/main/src/Kernel.sol#:~:text=mapping(Role%20%3D%3E%20bool)) https://github.com/code-423n4/2022-08-olympus/blob/main/src/Kernel.sol#:~:text=if%20role%20exists.-,mapping(Role%20%3D%3E%20bool),-public%20isRole%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/modules/PRICE.sol#:~:text=and%20therefore%20active).-,bool,-public%20initialized%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=bool%20public%20initialized%3B https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Operator.sol#:~:text=Operator%20is%20active-,bool%20public%20active%3B,-///%20Modules https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/BondCallback.sol#:~:text=mapping(uint256%20%3D%3E%20bool) https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Heart.sol#:~:text=stopped%2C%20true%20%3D%20beating-,bool%20public%20active%3B,-///%20%40notice%20Timestamp%20of https://github.com/code-423n4/2022-08-olympus/blob/main/src/policies/Governance.sol#:~:text=mapping(address%20%3D%3E%20bool)