Gas Optimizations - Githubissues

G-01 Multiple address mappings can be combined into a single mapping of an address to a struct, where appropriate (16 instances) G-02 State variables only set in the constructor should be declared immutable (1 instance) G-03 Using calldata instead of memory for read-only arguments in external functions saves gas (27 instances) G-04 += costs more gas than = + for state variables (6 instances) G-05 Use simple comparison in trinary logic / in if statement (2 instances)

Total: 52 instances in 5 issues

G-01 Multiple address mappings can be combined into a single mapping of an address to a struct, where appropriate

Saves a storage slot for the mapping. Depending on the circumstances and sizes of types, can avoid a Gsset (20000 gas) per mapping combined. Reads and subsequent writes can also be cheaper when a function requires both values and they both fit in the same storage slot.

16 instances in 1 file:

G-02 State variables only set in the constructor should be declared immutable

Avoids a Gsset (20000 gas) in the constructor, and replaces each Gwarmacces (100 gas) with a PUSH32 (3 gas).

1 instance in 1 file:

JBTiered721Delegate.sol https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JBTiered721Delegate.sol#L48

G-03 Using calldata instead of memory for read-only arguments in external functions saves gas

When a function with a memory array is called externally, the abi.decode() step has to use a for-loop to copy each index of the calldata to the memory index. Each iteration of this for-loop costs at least 60 gas (i.e. 60 * .length). Using calldata directly, obliviates the need for such a loop in the contract code and runtime execution. Structs have the same overhead as an array of length one

27 instances in 5 files:

JB721TieredGovernance.sol https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JB721TieredGovernance.sol#L147 https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JB721TieredGovernance.sol#L313

JBTiered721DelegateDeployer.sol https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JBTiered721DelegateDeployer.sol#L71

JB721GlobalGovernance.sol https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JB721GlobalGovernance.sol#L55

G-04 += costs more gas than = + for state variables

6 instances in 1 file:

G-05 Use simple comparison in trinary logic / in if statement

The comparison operators >= and <= use more gas than >, <, or ==. Replacing the >= and ≤ operators with a comparison operator that has an opcode in the EVM saves gas. Recommended Mitigation Steps: Replace the comparison operator and reverse the logic to save gas using the suggestions above.

2 instances in 2 files:

JBTiered721DelegateStore.sol https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JBTiered721DelegateStore.sol#L903

JB721TieredGovernance.sol https://github.com/jbx-protocol/juice-nft-rewards/blob/f9893b1497098241dd3a664956d8016ff0d0efd0/contracts/JB721TieredGovernance.sol#L133

code-423n4 / 2022-10-juicebox-findings

Gas Optimizations #223

G-01 Multiple address mappings can be combined into a single mapping of an address to a struct, where appropriate

G-02 State variables only set in the constructor should be declared immutable

G-03 Using calldata instead of memory for read-only arguments in external functions saves gas

G-04 += costs more gas than = + for state variables

G-05 Use simple comparison in trinary logic / in if statement