selfBalanceCheaperThanBalance.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity =0.8.19;

contract Gas {
    // 20
    function notOptimized() external view returns(uint gasUsed){        
        uint startGas = gasleft();
        uint256 callStatus;
        callStatus = address(this).balance;
        gasUsed = startGas - gasleft();
    }
    
    // 20
    function compilerOptimized() public view returns (uint gasUsed) {
        uint startGas = gasleft();
        uint256 callStatus;
        callStatus = address(this).balance;
        gasUsed = startGas - gasleft();
    }

    // 117
    function optimized() external view returns(uint gasUsed){        
        uint startGas = gasleft();
        uint256 callStatus;
        assembly {
            callStatus :=balance(address())
        }
        gasUsed = startGas - gasleft();
    }    
}