VTVL contest - dharma09's results

1.Require statements including conditions with the && operator can be broken down in multiple require statements to save gas.

PROOF OF CONCEPT

Instances include: VTVLVesting.sol#L344

Change :

require(_startTimestamps.length == length ,"ARRAY_LENGTH_MISMATCH");
require( _endTimestamps.length == length ,"ARRAY_LENGTH_MISMATCH");
require( _cliffReleaseTimestamps.length == length  ,"ARRAY_LENGTH_MISMATCH");
require(_releaseIntervalsSecs.length == length ,"ARRAY_LENGTH_MISMATCH");
require(_linearVestAmounts.length == length ,"ARRAY_LENGTH_MISMATCH");
require(_cliffAmounts.length == length,  "ARRAY_LENGTH_MISMATCH");

VTVLVesting.sol#L270

I suggest changing > 0 with != 0 here:

require((_cliffReleaseTimestamp =! 0 , "INVALID_CLIFF");
require( _cliffAmount =! 0 , "INVALID_CLIFF");
require(_cliffReleaseTimestamp <= _startTimestamp, "INVALID_CLIFF");

2.DEFAULT VALUE INITIALIZATION

PROBLEM

If a variable is not set/initialized, it is assumed to have the default value (0, false, 0x0 etc depending on the data type). Explicitly initializing it with its default value is an anti-pattern and wastes gas.

PROOF OF CONCEPT

Instances include: VTVLVesting.sol#L353

AND we can use unchecked which can save Gas For above instances:

 for (uint256 i; i < length; ) {
         _createClaimUnchecked(_recipients[i], _startTimestamps[i], _endTimestamps[i], _cliffReleaseTimestamps[i], _releaseIntervalsSecs[i], _linearVestAmounts[i], _cliffAmounts[I]);
unchecked {
	    ++i;
           }
        }

3.COMPARISONS: != IS MORE EFFICIENT THAN > IN REQUIRE (6 GAS LESS)

!= 0 costs less gas compared to > 0 for unsigned integers in require statements with the optimizer enabled (6 gas)

For uints the minimum value would be 0 and never a negative value. Since it cannot be a negative value, then the check > 0 is essentially checking that the value is not equal to 0 therefore >0 can be replaced with !=0 which saves gas.

While it may seem that > 0 is cheaper than !=, this is only true without the optimizer enabled and outside a require statement. If you enable the optimizer at 10k AND you’re in a require statement, this will save gas.

PROOF OF CONCEPT

Instances include: VTVLVesting.sol#L449 VTVLVesting.sol#L256 VTVLVesting.sol#L257 VTVLVesting.sol#L263

VariableSupplyERC20Token.sol#L27

4.USING PRIVATE RATHER THAN PUBLIC FOR immutable, SAVES GAS

Instances: VTVLVesting.sol#L17

IERC20 public immutable tokenAddress;