Move balance delta assignment into unchecked block in Pool.donate (#…

…643) * Move balance delta assignment into unchecked block in `Pool.donate` The balance delta calculation has been moved inside an unchecked block in the 'donate' function since overflow isn't possible. * Add comment
Uniswap · May 13, 2024 · 0f5d739 · 0f5d739
1 parent 30671fd
commit 0f5d739
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Showing 4 changed files with 5 additions and 4 deletions.
diff --git a/.forge-snapshots/donate gas with 1 token.snap b/.forge-snapshots/donate gas with 1 token.snap
@@ -1 +1 @@
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+108741
diff --git a/.forge-snapshots/donate gas with 2 tokens.snap b/.forge-snapshots/donate gas with 2 tokens.snap
@@ -1 +1 @@
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+149236
diff --git a/.forge-snapshots/poolManager bytecode size.snap b/.forge-snapshots/poolManager bytecode size.snap
@@ -1 +1 @@
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+23579
diff --git a/src/libraries/Pool.sol b/src/libraries/Pool.sol
@@ -473,8 +473,9 @@ library Pool {
     function donate(State storage state, uint256 amount0, uint256 amount1) internal returns (BalanceDelta delta) {
         uint128 liquidity = state.liquidity;
         if (liquidity == 0) revert NoLiquidityToReceiveFees();
-        delta = toBalanceDelta(-(amount0.toInt128()), -(amount1.toInt128()));
         unchecked {
+            // negation safe as amount0 and amount1 are always positive
+            delta = toBalanceDelta(-(amount0.toInt128()), -(amount1.toInt128()));
             if (amount0 > 0) {
                 state.feeGrowthGlobal0X128 += FullMath.mulDiv(amount0, FixedPoint128.Q128, liquidity);
             }