Submission Details
Severity:
Use assembly for math
Summary
Use assembly for math instead of Solidity. You can check for overflow/underflow in assembly to ensure safety. If using Solidity versions < 0.8.0 and you are using Safemath, you can gain significant gas savings by using assembly to calculate values and checking for overflow/underflow.
Recommendations
contract ThisContract {
//addition in assembly
function addFunction(uint256 a, uint256 b) public pure {
assembly {
let c := add(a, b)
if lt(c, a) {
mstore(0x00, "overflow")
revert(0x00, 0x20)
}
}
}
}
//Without assembly
| src/gas.sol:Contract0 contract | |||||
|---|---|---|---|---|---|
| Deployment Cost | Deployment Size | ||||
| 40693 | 234 | ||||
| Function Name | min | avg | median | max | # calls |
| addTest | 308 | 308 | 308 | 308 | 1 |
// With assemebly
| src/gas.sol:Contract1 contract | |||||
|---|---|---|---|---|---|
| Deployment Cost | Deployment Size | ||||
| 37087 | 216 | ||||
| Function Name | min | avg | median | max | # calls |
| addAssemblyTest | 263 | 263 | 263 | 263 | 1 |
Prize pool breakdown
Total prize
40,000 USDC
nSLOC
186215
USDC / LOC
37,000 USDC
3,000 USDC
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