Gas Optimizations

[code423n4]

Gas Optimization for PoolTogether Apr-2022 by PeritoFlores

[G-01] Remove OZ SafeMath library to save gas

As you are using the version 0.8 of solidity compiler there is no need to use OZ SafeMath library.

The built-in checks of overflow/underflow in the compiler is much cheaper.

Sample issue

https://issueantenna.com/repo/code-423n4/2022-01-insure-findings/issues/38

Recommended

Make the following changes

#L14

[-] import { SafeMath } from "@openzeppelin/contracts/utils/math/SafeMath.sol";

#L26

 [-] using SafeMath for uint256; 

#L262

[-] uint256 _balanceDiff = _afterBalance.sub(_beforeBalance);
[+] uint256 _balanceDiff = _afterBalance-_beforeBalance;

#L361

[-] return _supply == 0 ? _tokens : _tokens.mul(_supply).div(aToken.balanceOf(address(this)));
[+] return _supply == 0 ? _tokens : _tokens*_supply/aToken.balanceOf(address(this));

#L373

[-]    return _supply == 0 ? _shares : _shares.mul(aToken.balanceOf(address(this))).div(_supply); 
[+]    return _supply == 0 ? _shares : _shares*(aToken.balanceOf(address(this))/_supply;

[PierrickGT]

Duplicate of #11