Comparison Operators

In the Ethereum Virtual Machine (EVM), the selection of comparison operators influences the efficiency and gas consumption of smart contracts. Opting for < (less than) and > (greater than) over ≤ (less than or equal to) and ≥ (greater than or equal to) is notably more gas-efficient. This is due to the absence of direct opcode instructions for ≤ and ≥ in the EVM's design, which requires additional operations to achieve these comparisons.

Given that iszero consumes 3 units of gas, utilizing ≤ and ≥ in contracts that frequently perform comparisons can lead to increased gas expenditures.

代码演示

Below are examples of code achieving the same result using < and <=, respectively.

contract CompareLessThan {
    // gas: 247
    function isSmallerThan(uint256 value) external pure returns (bool) {
        return value < 8;
    }
}

contract CompareLessThanOrEqual {
    // gas: 250
    function isSmallerThanOrEqual(uint256 value) external pure returns (bool) {
        return value <= 7;
    }
}

Assuming value is 7, both functions will return the same result. However, the < operator will be more gas-efficient than the <= operator.

关于 gas 优化的建议：

🌟 Using the < and > operators is more gas-efficient than <= and >= in smart contracts.