gas savings from unchecked math

Uniswap · Sep 5, 2023 · cf82527 · cf82527
1 parent 607ea3b
commit cf82527
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Showing 9 changed files with 47 additions and 43 deletions.
diff --git a/.forge-snapshots/RouterBytecode.snap b/.forge-snapshots/RouterBytecode.snap
@@ -1 +1 @@
-4829
+4676
diff --git a/.forge-snapshots/RouterExactIn1Hop.snap b/.forge-snapshots/RouterExactIn1Hop.snap
@@ -1 +1 @@
-194162
+193938
diff --git a/.forge-snapshots/RouterExactIn2Hops.snap b/.forge-snapshots/RouterExactIn2Hops.snap
@@ -1 +1 @@
-271461
+271014
diff --git a/.forge-snapshots/RouterExactIn3Hops.snap b/.forge-snapshots/RouterExactIn3Hops.snap
@@ -1 +1 @@
-348765
+348095
diff --git a/.forge-snapshots/RouterExactInSingle.snap b/.forge-snapshots/RouterExactInSingle.snap
@@ -1 +1 @@
-192195
+192194
diff --git a/.forge-snapshots/RouterExactOut1Hop.snap b/.forge-snapshots/RouterExactOut1Hop.snap
@@ -1 +1 @@
-187374
+193086
diff --git a/.forge-snapshots/RouterExactOut2Hops.snap b/.forge-snapshots/RouterExactOut2Hops.snap
@@ -1 +1 @@
-271562
+271039
diff --git a/.forge-snapshots/RouterExactOut3Hops.snap b/.forge-snapshots/RouterExactOut3Hops.snap
@@ -1 +1 @@
-349804
+349020
diff --git a/contracts/Routing.sol b/contracts/Routing.sol
@@ -110,46 +110,50 @@ abstract contract Routing {
     }
 
     function _swapExactInput(ExactInputParams memory params, address msgSender) private {
-        for (uint256 i = 0; i < params.path.length; i++) {
-            (PoolKey memory poolKey, bool zeroForOne) = _getPoolAndSwapDirection(params.path[i], params.currencyIn);
-            uint128 amountOut = uint128(
-                -_swapExactPrivate(
-                    poolKey,
-                    zeroForOne,
-                    int256(int128(params.amountIn)),
-                    0,
-                    msgSender,
-                    i == 0,
-                    i == params.path.length - 1
-                )
-            );
-
-            params.amountIn = amountOut;
-            params.currencyIn = params.path[i].tradeCurrency;
+        unchecked {
+            for (uint256 i = 0; i < params.path.length; i++) {
+                (PoolKey memory poolKey, bool zeroForOne) = _getPoolAndSwapDirection(params.path[i], params.currencyIn);
+                uint128 amountOut = uint128(
+                    -_swapExactPrivate(
+                        poolKey,
+                        zeroForOne,
+                        int256(int128(params.amountIn)),
+                        0,
+                        msgSender,
+                        i == 0,
+                        i == params.path.length - 1
+                    )
+                );
+
+                params.amountIn = amountOut;
+                params.currencyIn = params.path[i].tradeCurrency;
+            }
+
+            if (params.amountIn < params.amountOutMinimum) revert TooLittleReceived();
         }
-
-        if (params.amountIn < params.amountOutMinimum) revert TooLittleReceived();
     }
 
     function _swapExactOutput(ExactOutputParams memory params, address msgSender) private {
-        for (uint256 i = params.path.length; i > 0; i--) {
-            (PoolKey memory poolKey, bool oneForZero) = _getPoolAndSwapDirection(params.path[i - 1], params.currencyOut);
-            uint128 amountIn = uint128(
-                _swapExactPrivate(
-                    poolKey,
-                    !oneForZero,
-                    -int256(int128(params.amountOut)),
-                    0,
-                    msgSender,
-                    i == 1,
-                    i == params.path.length
-                )
-            );
-
-            params.amountOut = amountIn;
-            params.currencyOut = params.path[i - 1].tradeCurrency;
+        unchecked {
+            for (uint256 i = params.path.length; i > 0; i--) {
+                (PoolKey memory poolKey, bool oneForZero) = _getPoolAndSwapDirection(params.path[i - 1], params.currencyOut);
+                uint128 amountIn = uint128(
+                    _swapExactPrivate(
+                        poolKey,
+                        !oneForZero,
+                        -int256(int128(params.amountOut)),
+                        0,
+                        msgSender,
+                        i == 1,
+                        i == params.path.length
+                    )
+                );
+
+                params.amountOut = amountIn;
+                params.currencyOut = params.path[i - 1].tradeCurrency;
+            }
+            if (params.amountOut > params.amountInMaximum) revert TooMuchRequested();
         }
-        if (params.amountOut > params.amountInMaximum) revert TooMuchRequested();
     }
 
     function _swapExactPrivate(