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

[code423n4]

Handle

0xRajeev

Vulnerability details

Impact

State variables badger and badgerSett addresses are read two and four times respectively in supplyTokenTo(). Caching them in local variables at the beginning of the function and using those local variables can save 400 gas from avoiding 3 repeated SLOADs for badgerSett and 1 repeated SLOAD for badger.

Impact: Gas savings of 400

Proof of Concept

Two badger reads: https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/yield-source/BadgerYieldSource.sol#L44-L45

Four badgerSett reads:

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/yield-source/BadgerYieldSource.sol#L45

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/yield-source/BadgerYieldSource.sol#L47

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/yield-source/BadgerYieldSource.sol#L48

https://github.com/code-423n4/2021-06-pooltogether/blob/85f8d044e7e46b7a3c64465dcd5dffa9d70e4a3e/contracts/yield-source/BadgerYieldSource.sol#L49

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.

[kamescg]

• https://github.com/pooltogether/badger-yield-source/pull/new/fix/38
• Fix/38 gas optimization pooltogether/badger-yield-source#8