diff --git a/benchmark/CMakeLists.txt b/benchmark/CMakeLists.txt
index bf43145b7c690..30f3b9ce46900 100644
--- a/benchmark/CMakeLists.txt
+++ b/benchmark/CMakeLists.txt
@@ -41,6 +41,7 @@ set(SWIFT_BENCH_MODULES
     single-source/ArraySetElement
     single-source/ArraySubscript
     single-source/AsyncTree
+    single-source/AutoDiffBuildingSimulator
     single-source/BinaryFloatingPointConversionFromBinaryInteger
     single-source/BinaryFloatingPointProperties
     single-source/BitCount
diff --git a/benchmark/single-source/AutoDiffBuildingSimulator.swift b/benchmark/single-source/AutoDiffBuildingSimulator.swift
new file mode 100644
index 0000000000000..5b73153403bbe
--- /dev/null
+++ b/benchmark/single-source/AutoDiffBuildingSimulator.swift
@@ -0,0 +1,253 @@
+//===--- AutoDiffBuildingSimulator.swift ----------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import TestsUtils
+import _Differentiation
+
+public let benchmarks = [
+  BenchmarkInfo(
+    name: "AutoDiffBuildingSimulator.Forward",
+    runFunction: run_AutoDiffBuildingSimulatorForward,
+    tags: [.validation, .api, .algorithm]),
+  BenchmarkInfo(
+    name: "AutoDiffBuildingSimulator.Reverse",
+    runFunction: run_AutoDiffBuildingSimulatorReverse,
+    tags: [.validation, .api, .algorithm]),
+  
+]
+
+// Simulation parameters
+let trials = 100
+let timesteps = 20
+let dTime: Float = 0.1
+let printGradToCompare = false
+
+// Definitions
+let π = Float.pi
+
+struct SimParams: Differentiable {
+    var tube: TubeType = .init()
+    var slab: SlabType = .init()
+    var quanta: QuantaType = .init()
+    var tank: TankType = .init()
+    var startingTemp: Float
+}
+
+struct TubeType: Differentiable {
+    var tubeSpacing: Float = 0.50292 // meters
+    var diameter: Float = 0.019 // m  (3/4")
+    var thickness: Float = 0.001588 // m (1/16")
+    var resistivity: Float = 2.43 // (K/W)m
+}
+
+struct SlabType: Differentiable {
+    var temp: Float = 21.1111111 // °C
+    var area: Float = 100.0 // m^2
+    var Cp: Float = 0.2
+    var density: Float = 2242.58 // kg/m^3
+    var thickness: Float = 0.101 // m
+}
+
+struct QuantaType: Differentiable {
+    var power: Float = 0.0 // Watt
+    var temp: Float = 60.0 // °C
+    var flow: Float = 0.0006309 // m^3/sec
+    var density: Float = 1000.0 // kg/m^3
+    var Cp: Float = 4180.0 // ws/(kg • K)
+}
+
+struct TankType: Differentiable {
+    var temp: Float = 70.0
+    var volume: Float = 0.0757082
+    var Cp: Float = 4180.000
+    var density: Float = 1000.000
+    var mass: Float = 75.708
+}
+
+// Computations
+
+@differentiable(reverse)
+func computeResistance(floor: SlabType, tube: TubeType, quanta _: QuantaType) -> Float {
+    let geometry_coeff: Float = 10.0
+    // let f_coff = 0.3333333
+
+    let tubingSurfaceArea = (floor.area / tube.tubeSpacing) * π * tube.diameter
+    let resistance_abs = tube.resistivity * tube.thickness / tubingSurfaceArea
+
+    let resistance_corrected = resistance_abs * geometry_coeff // * (quanta.flow * f_coff)
+
+    return resistance_corrected
+}
+
+struct QuantaAndPower: Differentiable {
+    var quanta: QuantaType
+    var power: Float
+}
+
+
+extension Differentiable {
+    /// Applies the given closure to the derivative of `self`.
+    ///
+    /// Returns `self` like an identity function. When the return value is used in
+    /// a context where it is differentiated with respect to, applies the given
+    /// closure to the derivative of the return value.
+    @inlinable
+    @differentiable(reverse, wrt: self)
+    func withDerivative(_: @escaping (inout TangentVector) -> Void) -> Self {
+        return self
+    }
+
+    @inlinable
+    @derivative(of: withDerivative)
+    func _vjpWithDerivative(
+        _ body: @escaping (inout TangentVector) -> Void
+    ) -> (value: Self, pullback: (TangentVector) -> TangentVector) {
+        return (self, { grad in
+            var grad = grad
+            body(&grad)
+            return grad
+        })
+    }
+}
+
+@differentiable(reverse)
+func computeLoadPower(floor: SlabType, tube: TubeType, quanta: QuantaType) -> QuantaAndPower {
+    let resistance_abs = computeResistance(floor: floor, tube: tube, quanta: quanta)
+
+    let conductance: Float = 1 / resistance_abs
+    let dTemp = floor.temp - quanta.temp
+    let power = dTemp * conductance
+
+    var updatedQuanta = quanta
+    updatedQuanta.power = power
+    let loadPower = -power
+
+    return QuantaAndPower(quanta: updatedQuanta, power: loadPower)
+}
+
+@differentiable(reverse)
+func updateQuanta(quanta: QuantaType) -> QuantaType {
+    let workingVolume = (quanta.flow * dTime)
+    let workingMass = (workingVolume * quanta.density)
+    let workingEnergy = quanta.power * dTime
+    let TempRise = workingEnergy / quanta.Cp / workingMass
+    var updatedQuanta = quanta
+    updatedQuanta.temp = quanta.temp + TempRise
+
+    updatedQuanta.power = 0
+    return updatedQuanta
+}
+
+@differentiable(reverse)
+func updateBuildingModel(power: Float, floor: SlabType) -> SlabType {
+    var updatedFloor = floor
+
+    let floorVolume = floor.area * floor.thickness
+    let floorMass = floorVolume * floor.density
+
+    updatedFloor.temp = floor.temp + ((power * dTime) / floor.Cp / floorMass)
+    return updatedFloor
+}
+
+struct TankAndQuanta: Differentiable {
+    var tank: TankType
+    var quanta: QuantaType
+}
+
+@differentiable(reverse)
+func updateSourceTank(store: TankType, quanta: QuantaType) -> TankAndQuanta {
+    var updatedStore = store
+    var updatedQuanta = quanta
+
+    let massPerTime = quanta.flow * quanta.density
+    let dTemp = store.temp - quanta.temp
+    let power = dTemp * massPerTime * quanta.Cp
+
+    updatedQuanta.power = power
+
+    let tankMass = store.volume * store.density
+    let TempRise = (power * dTime) / store.Cp / tankMass
+    updatedStore.temp = store.temp + TempRise
+
+    return TankAndQuanta(tank: updatedStore, quanta: updatedQuanta)
+}
+
+var simParams = SimParams(startingTemp: 33.3)
+
+@differentiable(reverse)
+@inlinable public func absDifferentiable(_ value: Float) -> Float {
+    if value < 0 {
+        return -value
+    }
+    return value
+}
+
+func lossCalc(pred: Float, gt: Float) -> Float {
+    let diff = pred - gt
+    return absDifferentiable(diff)
+}
+
+// Simulations
+
+@differentiable(reverse)
+func simulate(simParams: SimParams) -> Float {
+    let pexTube = simParams.tube
+    var slab = simParams.slab
+    var tank = simParams.tank
+    var quanta = simParams.quanta
+
+    slab.temp = simParams.startingTemp
+    for _ in 0 ..< timesteps {
+        let tankAndQuanta = updateSourceTank(store: tank, quanta: quanta)
+        tank = tankAndQuanta.tank
+        quanta = tankAndQuanta.quanta
+
+        quanta = updateQuanta(quanta: quanta)
+
+        let quantaAndPower = computeLoadPower(floor: slab, tube: pexTube, quanta: quanta)
+        quanta = quantaAndPower.quanta
+        let powerToBuilding = quantaAndPower.power
+        quanta = updateQuanta(quanta: quanta)
+
+        slab = updateBuildingModel(power: powerToBuilding, floor: slab)
+    }
+    return slab.temp
+}
+
+var blackHole: Any?
+@inline(never)
+func dontLetTheCompilerOptimizeThisAway<T>(_ x: T) {
+    blackHole = x
+}
+
+@differentiable(reverse)
+func fullPipe(simParams: SimParams) -> Float {
+    let pred = simulate(simParams: simParams)
+    let loss = lossCalc(pred: pred, gt: 27.344767)
+    return loss
+}
+
+@inline(never)
+public func run_AutoDiffBuildingSimulatorForward(n: Int) {
+  for _ in 0 ..< n {
+    let forwardOnly = fullPipe(simParams: simParams)
+    dontLetTheCompilerOptimizeThisAway(forwardOnly)
+  }
+}
+
+@inline(never)
+public func run_AutoDiffBuildingSimulatorReverse(n: Int) {
+  for _ in 0 ..< n {
+    let grad = gradient(at: simParams, of: fullPipe)
+    dontLetTheCompilerOptimizeThisAway(grad)
+  }
+}
diff --git a/benchmark/utils/main.swift b/benchmark/utils/main.swift
index 869a782053138..ccccaf10ee80a 100644
--- a/benchmark/utils/main.swift
+++ b/benchmark/utils/main.swift
@@ -29,6 +29,7 @@ import ArrayRemoveAll
 import ArraySetElement
 import ArraySubscript
 import AsyncTree
+import AutoDiffBuildingSimulator
 import BinaryFloatingPointConversionFromBinaryInteger
 import BinaryFloatingPointProperties
 import BitCount
@@ -229,6 +230,7 @@ register(ArrayRemoveAll.benchmarks)
 register(ArraySetElement.benchmarks)
 register(ArraySubscript.benchmarks)
 register(AsyncTree.benchmarks)
+register(AutoDiffBuildingSimulator.benchmarks)
 register(BinaryFloatingPointConversionFromBinaryInteger.benchmarks)
 register(BinaryFloatingPointProperties.benchmarks)
 register(BitCount.benchmarks)