Minor gas optimizations

src/libraries/MathLib.sol

@@ -7,10 +7,7 @@ uint256 constant WAD = 1e18;
 /// @author Morpho Labs
 /// @custom:contact [email protected]
 /// @notice Library to manage fixed-point arithmetic.
-/// @dev Inspired by https://github.com/morpho-org/morpho-utils.
 library MathLib {
-    uint256 internal constant MAX_UINT256 = 2 ** 256 - 1;
-
     /// @dev (x * y) / WAD rounded down.
     function wMulDown(uint256 x, uint256 y) internal pure returns (uint256) {
         return mulDivDown(x, y, WAD);
@@ -32,39 +29,21 @@ library MathLib {
     }
 
     /// @dev (x * y) / denominator rounded down.
-    function mulDivDown(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 z) {
-        // Division by zero if denominator == 0.
-        // Overflow if
-        //     x * y > type(uint256).max
-        // <=> y > 0 and x > type(uint256).max / y
-        assembly {
-            if or(mul(y, gt(x, div(MAX_UINT256, y))), iszero(denominator)) { revert(0, 0) }
-
-            z := div(mul(x, y), denominator)
-        }
+    function mulDivDown(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256) {
+        return (x * y) / denominator;
     }
 
     /// @dev (x * y) / denominator rounded up.
-    function mulDivUp(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 z) {
-        // Underflow if denominator == 0.
-        // Division by 0 if denominator == 0 (this case cannot occur since the above underflow happens before).
-        // Overflow if
-        //     x * y + denominator - 1 > type(uint256).max
-        // <=> x * y > type(uint256).max - denominator + 1
-        // <=> y > 0 and x > (type(uint256).max - denominator + 1) / y
-        assembly {
-            if or(mul(y, gt(x, div(sub(MAX_UINT256, sub(denominator, 1)), y))), iszero(denominator)) { revert(0, 0) }
-
-            z := div(add(mul(x, y), sub(denominator, 1)), denominator)
-        }
+    function mulDivUp(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256) {
+        return (x * y + (denominator - 1)) / denominator;
     }
 
     /// @dev The sum of the last three terms in a four term taylor series expansion
     ///      to approximate a continuous compound interest rate: e^(nx) - 1.
     function wTaylorCompounded(uint256 x, uint256 n) internal pure returns (uint256) {
         uint256 firstTerm = x * n;
-        uint256 secondTerm = wMulDown(firstTerm, firstTerm) / 2;
-        uint256 thirdTerm = wMulDown(secondTerm, firstTerm) / 3;
+        uint256 secondTerm = mulDivDown(firstTerm, firstTerm, 2 * WAD);
+        uint256 thirdTerm = mulDivDown(secondTerm, firstTerm, 3 * WAD);
 
         return firstTerm + secondTerm + thirdTerm;
     }