ENS Contest - saneryee's results

Gas Optimizations Report

Report Date: 2023-04-20 06:00:54

[G-01] Multiple accesses of a mapping/array should use a local variable cache

Impact

The instances below point to the second+ access of a value inside a mapping/array, 1within a function. Caching a mapping's value in a local storage or calldata variable when the value is accessed multiple times, saves ~42 gas per access due to not having to recalculate the key's keccak256 hash (Gkeccak256 - 30 gas) and that calculation's associated stack operations. Caching an array's struct avoids recalculating the array offsets into memory/calldata

Findings

Total:1

contracts/dnssec-oracle/DNSSECImpl.sol#L46 contracts/dnssec-oracle/DNSSECImpl.sol#L415-L425

46:     mapping(uint8 => Digest) public digests;
......
415:    function verifyDSHash(
416:         uint8 digesttype,
417:         bytes memory data,
418:         bytes memory digest
419:     ) internal view returns (bool) {
420:         if (address(digests[digesttype]) == address(0)) {
421:             return false;
422:         }
423:         return digests[digesttype].verify(data, digest);
424:     }
425: }