Zokyo Gas Savings
  • โ›ฝZokyo Gas Savings
  • ๐Ÿ“šTutorials
    • โœ”๏ธGas Saving Technique 1: Unchecked Arithmetic
    • โ›“๏ธGas Saving Technique 2: Immutable Variable
    • โœจGas Saving Technique 3: Double star ** inefficiency
    • ๐Ÿ’ฐGas Saving Technique 4: Cache Array Length
    • โฌ…๏ธGas Saving Technique 5: ++i costs less gas compared to i++
    • โš–๏ธGas Saving Technique 6: NOT operator ! cheaper than boolean FALSE
    • ๐ŸชกGas Saving Technique 7: Using Short Reason Strings
    • ๐ŸชตGas Saving Technique 8: Use Custom Errors instead of Revert Strings to save Gas
    • โœ’๏ธGas Saving Technique 9: Use Custom Errors instead of Revert Strings to save Gas
    • ๐Ÿ‘พGas Saving Technique 10: Calldata cheaper than memory
    • โ›”Gas Saving Technique 11: > 0 is less efficient than != 0 for unsigned integers
    • โž—Gas Saving Technique 12: SafeMath no longer needed
    • ๐Ÿ˜ฎGas Saving Technique 13: variables default to 0
    • ๐ŸงฑGas Saving Technique 14: struct layout/ variable packing
    • ๐Ÿ“žGas Saving Technique 15: Cache External Call
    • โœ๏ธGas Saving Technique 16: Early Validation before external call
    • ๐Ÿ˜ŽGas Saving Technique 17: Donโ€™t cache value that is used once
    • ๐Ÿ˜งGas Saving Technique 18: Redundant code
    • โœ…Gas Saving Technique 19: Early Validation before external call
    • โ›๏ธGas Saving Technique 20: Storage vs Memory read optimizations
    • โœ’๏ธGas Saving Technique 21: Unneeded If statements
    • ๐ŸŒ—Gas Saving Technique 22: >= is cheaper than >
    • ๐ŸŽ’Gas Saving Technique 23: Public to private constants
    • โน๏ธGas Saving Technique 24: Make unchanged variables constant/immutable
    • โฑ๏ธGas Saving Techniques 25: Redundant Access Control Checks
    • โžก๏ธGas Saving Technique 26: Shift Right instead of Dividing by 2
    • ๐ŸชƒGas Saving Tutorial 27: Efficient Boolean Comparison
    • ๐ŸคGas Saving Technique 28: && operator uses more gas
    • ๐Ÿ‘“Gas Saving Technique 29: x = x + y is cheaper than x += y
    • ๐Ÿ‘‚Gas Saving Technique 30: Using 1 and 2 rather than 0 and 1 saves gas
    • โšฝGas Saving Technique 31: Optimize Storage by Avoiding Booleans
    • ๐Ÿ”™Gas Saving Technique 32: Optimal Use of Named Return Variables in Solidity
    • ๐Ÿ›ข๏ธGas Saving Technique 33: Making Functions Payable for Optimized Gas Costs
    • โœ๏ธGas Saving Technique 34: Optimizing Storage References in Smart Contracts
    • โ›ฐ๏ธGas Saving Technique 35: Usage of uints/ints smaller than 32 bytes (256 bits) incurs overhead
    • ๐ŸŒช๏ธGas Saving Technique 36: Inlining Single Use Internal Functions for Savings
    • โ˜„๏ธGas Saving Technique 37: Switching from Public to External Functions for Savings
    • ๐ŸŽ†Gas Saving Technique 38: Upgrading Solidity Compiler to Improve Gas Efficiency and Security
    • ๐Ÿ•ถ๏ธGas Saving Technique 39: Avoiding Duplicated Code for Gas Savings
    • ๐Ÿ˜„Gas Saving Technique 40: Removal of Unused Internal Functions for Gas Savings
    • ๐Ÿ–‹๏ธGas Saving Tutorial 41: In-lining Single Use Modifiers For Gas Saving
    • โ›๏ธGas Saving Technique 42: `require` vs`assert`
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Gas Saving Technique 13: variables default to 0

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Last updated 1 year ago

Introduction

In the realm of smart contract development, every gas unit saved is crucial. One straightforward yet often overlooked optimization technique is avoiding redundant initialization of variables. By understanding and leveraging the default values of variable types in Solidity, developers can write cleaner code and achieve minor gas savings.

Impact & Details

Understanding Gas Consumption

  • Redundant Initialization Cost: Initializing variables to their default values, like setting bool variables to false or uint256 variables to 0, introduces unnecessary operations and thereby consumes extra gas.

  • Default Values: In Solidity, uninitialized bool variables default to false, and uint256 variables default to 0. Being aware of these defaults allows for cleaner and more gas-efficient code.

How to Avoid Redundant Initialization for Gas Savings

Practical Example: Removing Redundant Initialization

Consider the following smart contract snippet before and after optimization:

Before Optimization:

solidityCopy code// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract MyContract {
    bool transferSuccess = false;  // Redundant initialization
    uint256 public periodFinish = 0;  // Redundant initialization
    uint256 public rewardRate = 0;  // Redundant initialization
}

After Optimization:

solidityCopy code// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract MyContract {
    bool transferSuccess;  // Defaults to false
    uint256 public periodFinish;  // Defaults to 0
    uint256 public rewardRate;  // Defaults to 0
}

In the optimized version, redundant initializations are removed, and the contract relies on default values, resulting in slightly less gas consumption and cleaner code.

Recommended Mitigation Steps

  1. Identify Redundant Initializations: Scan your smart contracts for variables being initialized to default values.

  2. Remove Redundant Initializations: Omit explicit initialization for variables when you intend to set them to their default values.

  3. Test: Conduct rigorous testing to ensure that the removal of explicit initializations does not affect the contractโ€™s expected behavior while facilitating minor gas savings.

Conclusion

Avoiding redundant initializations by relying on variable default values is a straightforward and effective optimization technique for gas saving in smart contract development. Although the savings per transaction might be minor, the overall savings across many transactions can be more significant. After making these changes, always ensure to test the smart contract meticulously to ensure it functions as expected while consuming slightly less gas.

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