Gas Optimizations

[code423n4]

Title: Using multiple require instead && can save gas

Proof of Concept:
AllowList.sol#L96-L101

Recommended Mitigation Steps:
Change to:

        require(callersLength == _targets.length, "yw");
        require(callersLength == _functionSigs.length, "yw");
        require(callersLength == _enables.length, "yw");

---

Title: Expression for constant values such as a call to keccak256(), should use immutable rather than constant

Proof of Concept:
L2ContractHelper.sol#L24

Recommended Mitigation Steps:
Change from constant to immutable
reference: here

---

Title: Using != in require statement is more gas efficient

Proof of Concept:
L1ERC20Bridge.sol#L117
L1ERC20Bridge.sol#L210

Recommended Mitigation Steps:
Change > 0 to != 0

---

[c4-judge]

GalloDaSballo marked the issue as grade-c