Caviar contest - lukris02's results

Gas Optimizations Report for Caviar contest

Overview

During the audit, 2 gas issues were found.
Total savings ~280.

Gas Optimizations Findings(2)

G-1. Use unchecked blocks for incrementing i

Description

In Solidity 0.8+, there’s a default overflow and underflow check on unsigned integers. In the loops, "i" will not overflow because the loop will run out of gas before that.

Instances

• https://github.com/code-423n4/2022-12-caviar/blob/main/src/Pair.sol#L238
• https://github.com/code-423n4/2022-12-caviar/blob/main/src/Pair.sol#L258
• https://github.com/code-423n4/2022-12-caviar/blob/main/src/Pair.sol#L468
• https://github.com/code-423n4/2022-12-caviar/blob/main/src/lib/SafeERC20Namer.sol#L13
• https://github.com/code-423n4/2022-12-caviar/blob/main/src/lib/SafeERC20Namer.sol#L22
• https://github.com/code-423n4/2022-12-caviar/blob/main/src/lib/SafeERC20Namer.sol#L33
• https://github.com/code-423n4/2022-12-caviar/blob/main/src/lib/SafeERC20Namer.sol#L39

Recommendation

Change:

for (uint256 i; i < n; ++i) {
 // ...
}

to:

for (uint256 i; i < n;) { 
 // ...
 unchecked { ++i; }
}

Saved

This saves ~30-40 gas per iteration.
So, ~35*7 = 245

G-2. Use unchecked blocks for subtractions where underflow is impossible

Description

In Solidity 0.8+, there’s a default overflow and underflow check on unsigned integers. When an overflow or underflow isn’t possible (after require or if-statement), some gas can be saved by using unchecked blocks.

Instances

• https://github.com/code-423n4/2022-12-caviar/blob/main/src/Pair.sol#L168

Saved

This saves ~35.