Mimo August 2022 contest - ignacio's results

1) <ARRAY>.LENGTH SHOULD NOT BE LOOKED UP IN EVERY LOOP OF A FOR-LOOP and Increments can be unchecked

The overheads outlined below are PER LOOP, excluding the first loop

storage arrays incur a Gwarmaccess (100 gas) memory arrays use MLOAD (3 gas) calldata arrays use CALLDATALOAD (3 gas) ++I COSTS LESS GAS THAN I++ Caching the length changes each of these to a DUP<N> (3 gas), and gets rid of the extra DUP<N> needed to store the stack offset https://github.com/code-423n4/2022-08-mimo/blob/main/contracts/proxy/MIMOProxy.sol#L132

2 Use != 0 instead of > 0 at the above mentioned codes. The variable is uint, so it will not be below 0 so it can just check != 0.

!= 0 costs less gas compared to > 0 for unsigned integers in require statements with the optimizer enabled https://github.com/code-423n4/2022-08-mimo/blob/main/contracts/actions/MIMOLeverage.sol#L50 https://github.com/code-423n4/2022-08-mimo/blob/main/contracts/actions/MIMORebalance.sol#L135 https://github.com/code-423n4/2022-08-mimo/blob/main/contracts/actions/MIMOSwap.sol#L56

3 USING CALLDATA INSTEAD OF MEMORY FOR READ-ONLY ARGUMENTS IN EXTERNAL FUNCTIONS SAVES GAS

When a function with a memory array is called externally, the abi.decode() step has to use a for-loop to copy each index of the calldata to the memory index. Each iteration of this for-loop costs at least 60 gas (i.e. 60 * <mem_array>.length). Using calldata directly, obliviates the need for such a loop in the contract code and runtime execution. https://github.com/code-423n4/2022-08-mimo/blob/main/contracts/actions/MIMOLeverage.sol#L45 https://github.com/code-423n4/2022-08-mimo/blob/main/contracts/actions/MIMOLeverage.sol#L75 https://github.com/code-423n4/2022-08-mimo/blob/main/contracts/actions/MIMORebalance.sol#L45 https://github.com/code-423n4/2022-08-mimo/blob/main/contracts/actions/MIMORebalance.sol#L70 https://github.com/code-423n4/2022-08-mimo/blob/main/contracts/actions/MIMOEmptyVault.sol#L45

4 )MULTIPLE ADDRESS MAPPINGS CAN BE COMBINED INTO A SINGLE MAPPING OF AN ADDRESS TO A STRUCT, WHERE APPROPRIATE

Saves a storage slot for the mapping. Depending on the circumstances and sizes of types, can avoid a Gsset (20000 gas) per mapping combined. ### Reads and subsequent writes can also be cheaper when a function requires both values and they both fit in the same storage slot

https://github.com/code-423n4/2022-08-mimo/blob/main/contracts/actions/managed/MIMOManagedAction.sol#L15