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)
Caching the length changes each of these to a DUP (3 gas), and gets rid of the extra DUP needed to store the stack offset
GalloDaSballo
commented
2 years ago
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) Caching the length changes each of these to a DUP (3 gas), and gets rid of the extra DUP needed to store the stack offset
( ++I/I++ ) SHOULD BE UNCHECKED{++I}/UNCHECKED{I++} WHEN IT IS NOT POSSIBLE FOR THEM TO OVERFLOW, AS IS THE CASE WHEN USED IN FOR- AND WHILE-LOOPS https://github.com/code-423n4/2022-10-blur/blob/main/contracts/BlurExchange.sol#L199 https://github.com/code-423n4/2022-10-blur/blob/main/contracts/BlurExchange.sol#L476 https://github.com/code-423n4/2022-10-blur/blob/main/contracts/lib/EIP712.sol#L77