Caching badger and badgerSett can save 400 gas in redeemToken()

[code423n4]

Handle

0xRajeev

Vulnerability details

Impact

State variables badger and badgerSett addresses are read three times each in redeemToken(). Caching them in local variables at the beginning of the function and using those local variables can save 400 gas from avoiding 2 repeated SLOADs for each of them.

Impact: Gas savings of 400

Proof of Concept

Three badger reads:

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/yield-source/BadgerYieldSource.sol#L64

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/yield-source/BadgerYieldSource.sol#L75

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/yield-source/BadgerYieldSource.sol#L79

Three badgerSett reads:

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/yield-source/BadgerYieldSource.sol#L58

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/yield-source/BadgerYieldSource.sol#L61

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/yield-source/BadgerYieldSource.sol#L73

Tools Used

Manual Analysis

Recommended Mitigation Steps

Cache badger and badgerSett state variables in local variables at the beginning of the function and use those local variables instead.

[asselstine]

Duplicate of: #38

However, they've both identified unique reads. Need to combine them.