`++i` is more gas efficient than `i++` or `i += i` (if x = 1)

[0xpr0f]

++i is more gas efficient than i++ or i += x (if x = 1)

Severity

Which severity would you assign to this Issue?

• Gas Optimization
• Non-Critical
• Low Risk
• Med Risk
• High Risk

Description

writing a value to a slot that doesn’t have one will be more expensive than writing to one that does.
when incrementing an integer, ++i (return old value, then add 1) is cheaper than i++ (add 1, then return new value)

Example

🤦 Bad:

/// @dev Consumes ~21586 gas on average.
function war() external pure returns (uint256 result) {
         uint i = 1;
        result += i;
    }

or

/// @dev Consumes ~21557 gas on average.
function bar() external pure returns (uint256 result) {
     result ++;
    }

🚀 Good:

 /// @dev Consumes ~21530 gas on average. 
function foo() external pure returns (uint256 result) {
        ++ result;
    }

Background Information

https://m1guelpf.blog/d0gBiaUn48Odg8G2rhs3xLIjaL8MfrWReFkjg8TmDoM

[0xpr0f]

Tagging @pmerkleplant for visibility

[merkleplant]

Many thanks! ❤️