🌗Gas Saving Technique 22: >= is cheaper than >

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Introduction: In the meticulous world of Solidity programming, the nuances between strict and non-strict comparisons might seem trivial. However, these minute details can play a significant role in gas efficiency. This tutorial aims to shed light on the advantages of using non-strict comparisons over their strict counterparts in terms of gas optimization.

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Concept: When it comes to inequality comparisons in Solidity, non-strict inequalities like >= are often cheaper in gas than their strict counterparts, such as >. This gas differential arises from the supplementary checks (like ISZERO) associated with strict inequalities. Hence, a small shift in programming practice—favoring non-strict comparisons where applicable—can lead to gas savings.

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Underlying Problem:

1. Supplementary Opcodes: Strict inequalities involve extra operations like the ISZERO opcode, which costs an additional 3 gas units.

2. Minor Overhead Accumulates: In contracts with frequent calls or in high-traffic protocols, these seemingly minuscule gas costs can accumulate rapidly, leading to more expensive interactions over time.

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Example:

Using Strict Inequality:

solidityCopy codereturn principal > calculatedDebt ? principal : calculatedDebt;

Optimized with Non-Strict Inequality:

solidityCopy codereturn principal >= calculatedDebt ? principal : calculatedDebt + 1;

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Recommendation:

1. Scan your contracts to identify occurrences of strict inequalities, like >.

2. Consider if the logic allows for replacement with non-strict comparisons, such as >=, without compromising functionality.

3. Modify the code and adjust any affected logic accordingly.

4. Conduct rigorous testing to verify that the change hasn't introduced any unwanted behaviors.

5. As a best practice, always favor non-strict comparisons when writing new contracts, unless strictness is necessary for the contract's logic.

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Conclusion: The world of smart contracts is one where the difference of a few gas units can have a sizable impact, especially over numerous transactions. Embracing non-strict comparisons offers a simple yet effective method to optimize for gas efficiency. As developers, focusing on such minute details ensures the development of cost-effective and efficient smart contracts, benefiting both the end-users and the network.