Optimize fee pips calculation in SwapMath

Refactored the SwapMath module to optimize fee pips calculation. This was achieved by caching the feePips value to prevent redundant typecasts. This reduces computational overhead and may improve performance.
Aperture-Finance · May 27, 2024 · 41b4ce6 · 41b4ce6
1 parent 83a5278
commit 41b4ce6
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Showing 2 changed files with 19 additions and 12 deletions.
diff --git a/.gas-snapshot b/.gas-snapshot
@@ -145,12 +145,12 @@ SqrtPriceMathTest:testGas_GetNextSqrtPriceFromInput() (gas: 303466)
 SqrtPriceMathTest:testGas_GetNextSqrtPriceFromInput_Og() (gas: 285701)
 SqrtPriceMathTest:testGas_GetNextSqrtPriceFromOutput() (gas: 286328)
 SqrtPriceMathTest:testGas_GetNextSqrtPriceFromOutput_Og() (gas: 269021)
-SwapMathTest:testFuzz_ComputeSwapStep(uint160,uint160,uint128,int256,uint24) (runs: 65546, μ: 27026, ~: 27110)
-SwapMathTest:testFuzz_ComputeSwapStepExactIn(uint160,uint160,uint128,uint256,uint24) (runs: 65546, μ: 29078, ~: 29027)
-SwapMathTest:testFuzz_ComputeSwapStepExactOut(uint160,uint160,uint128,uint256,uint24) (runs: 65546, μ: 28605, ~: 28507)
+SwapMathTest:testFuzz_ComputeSwapStep(uint160,uint160,uint128,int256,uint24) (runs: 65546, μ: 27023, ~: 27110)
+SwapMathTest:testFuzz_ComputeSwapStepExactIn(uint160,uint160,uint128,uint256,uint24) (runs: 65546, μ: 29070, ~: 29020)
+SwapMathTest:testFuzz_ComputeSwapStepExactOut(uint160,uint160,uint128,uint256,uint24) (runs: 65546, μ: 28608, ~: 28507)
 SwapMathTest:testFuzz_getSqrtPriceTarget(bool,uint160,uint160) (runs: 65546, μ: 3503, ~: 3503)
-SwapMathTest:testGas_ComputeSwapStep() (gas: 514575)
-SwapMathTest:testGas_ComputeSwapStepExactIn() (gas: 534678)
+SwapMathTest:testGas_ComputeSwapStep() (gas: 514269)
+SwapMathTest:testGas_ComputeSwapStepExactIn() (gas: 533978)
 SwapMathTest:testGas_ComputeSwapStepExactIn_Og() (gas: 563266)
 SwapMathTest:testGas_ComputeSwapStepExactOut() (gas: 482433)
 SwapMathTest:testGas_ComputeSwapStepExactOut_Og() (gas: 557512)

diff --git a/src/SwapMath.sol b/src/SwapMath.sol
@@ -52,19 +52,23 @@ library SwapMath {
         uint24 feePips
     ) internal pure returns (uint160 sqrtRatioNextX96, uint256 amountIn, uint256 amountOut, uint256 feeAmount) {
         unchecked {
+            uint256 _feePips = feePips; // cast once and cache
             bool zeroForOne = sqrtRatioCurrentX96 >= sqrtRatioTargetX96;
-            uint256 feeComplement = MAX_FEE_PIPS - feePips;
             bool exactOut = amountRemaining < 0;
 
             if (!exactOut) {
-                uint256 amountRemainingLessFee = FullMath.mulDiv(uint256(amountRemaining), feeComplement, MAX_FEE_PIPS);
+                uint256 amountRemainingLessFee = FullMath.mulDiv(
+                    uint256(amountRemaining),
+                    MAX_FEE_PIPS - _feePips,
+                    MAX_FEE_PIPS
+                );
                 amountIn = zeroForOne
                     ? SqrtPriceMath.getAmount0Delta(sqrtRatioTargetX96, sqrtRatioCurrentX96, liquidity, true)
                     : SqrtPriceMath.getAmount1Delta(sqrtRatioCurrentX96, sqrtRatioTargetX96, liquidity, true);
                 if (amountRemainingLessFee >= amountIn) {
                     // `amountIn` is capped by the target price
                     sqrtRatioNextX96 = sqrtRatioTargetX96;
-                    feeAmount = FullMath.mulDivRoundingUp(amountIn, feePips, feeComplement);
+                    feeAmount = FullMath.mulDivRoundingUp(amountIn, _feePips, MAX_FEE_PIPS - _feePips);
                 } else {
                     // exhaust the remaining amount
                     amountIn = amountRemainingLessFee;
@@ -100,7 +104,7 @@ library SwapMath {
                 amountIn = zeroForOne
                     ? SqrtPriceMath.getAmount0Delta(sqrtRatioNextX96, sqrtRatioCurrentX96, liquidity, true)
                     : SqrtPriceMath.getAmount1Delta(sqrtRatioCurrentX96, sqrtRatioNextX96, liquidity, true);
-                feeAmount = FullMath.mulDivRoundingUp(amountIn, feePips, feeComplement);
+                feeAmount = FullMath.mulDivRoundingUp(amountIn, _feePips, MAX_FEE_PIPS - _feePips);
             }
         }
     }
@@ -123,16 +127,19 @@ library SwapMath {
         uint256 feePips
     ) internal pure returns (uint160 sqrtRatioNextX96, uint256 amountIn, uint256 amountOut) {
         bool zeroForOne = sqrtRatioCurrentX96 >= sqrtRatioTargetX96;
-        uint256 feeComplement = UnsafeMath.sub(MAX_FEE_PIPS, feePips);
-        uint256 amountRemainingLessFee = FullMath.mulDiv(amountRemaining, feeComplement, MAX_FEE_PIPS);
+        uint256 amountRemainingLessFee = FullMath.mulDiv(
+            amountRemaining,
+            UnsafeMath.sub(MAX_FEE_PIPS, feePips),
+            MAX_FEE_PIPS
+        );
         amountIn = zeroForOne
             ? SqrtPriceMath.getAmount0Delta(sqrtRatioTargetX96, sqrtRatioCurrentX96, liquidity, true)
             : SqrtPriceMath.getAmount1Delta(sqrtRatioCurrentX96, sqrtRatioTargetX96, liquidity, true);
         if (amountRemainingLessFee >= amountIn) {
             // `amountIn` is capped by the target price
             sqrtRatioNextX96 = sqrtRatioTargetX96;
             // add the fee amount
-            amountIn = FullMath.mulDivRoundingUp(amountIn, MAX_FEE_PIPS, feeComplement);
+            amountIn = FullMath.mulDivRoundingUp(amountIn, MAX_FEE_PIPS, UnsafeMath.sub(MAX_FEE_PIPS, feePips));
         } else {
             // exhaust the remaining amount
             amountIn = amountRemaining;