内存优化：Hash

contract ExpensiveHasher {
    bytes32 public hash;
    struct Values {
        uint256 a;
        uint256 b;
        uint256 c;
    }
    Values values;
    // cost: 113155function setOnchainHash(Values calldata _values) external {
        hash = keccak256(abi.encode(_values));
        values = _values;
    }
 }
contract CheapHasher {
    bytes32 public hash;
    struct Values {
        uint256 a;
        uint256 b;
        uint256 c;
    }
    Values values;
    // cost: 112107
    function setOnchainHash(Values calldata _values) external {
        assembly {
            // cache the free memory pointer because we are about to override it 
            let fmp := mload(0x40)
            
            // use 0x00 to 0x60
            calldatacopy(0x00, 0x04, 0x60)
            sstore(hash.slot, keccak256(0x00, 0x60))
            // restore the cache value of free memory pointer
            mstore(0x40, fmp)
        }
        values = _values;
    }
 }

src/assembly/MemoryExp.sol
test/assembly/MemoryExp.t.sol

forge test --gas-report --mt test_memexp_hasher_ -vvv --optimize