pragma solidity ^0.4.24;


contract FreeMemory2 {
    struct Increase {
        uint dist;
        uint src;
    }
    
    function callFuncMemoryCheck(uint a, bool _memoryUse) public pure returns(uint) {
        uint res = a;
        Increase memory increase;
        increase.src = a;
        for(uint i=0; i<a; i++) {
          if(_memoryUse) {
              increase = doExec(increase);
          } else {
            res = addFunc(res, 5);
          }
        }
        assembly {
            res := mload(0x40)
        }
        return res;
    }
    
    function addFunc(uint a, uint b) internal pure returns(uint) {
      return a + b;
    }
    
    function doExec(Increase memory inc) internal pure returns(Increase memory) {
        inc.dist += inc.src;
        return inc;
    }
}

Compile and Run ▶