diff --git a/neuralnetworks/1.3/IDevice.hal b/neuralnetworks/1.3/IDevice.hal
index 9afd778..8dc41f7 100644
--- a/neuralnetworks/1.3/IDevice.hal
+++ b/neuralnetworks/1.3/IDevice.hal
@@ -48,9 +48,14 @@
     /**
      * Gets the supported operations in a model.
      *
-     * getSupportedOperations indicates which operations of a model are fully
-     * supported by the vendor driver. If an operation may not be supported for
-     * any reason, getSupportedOperations must return false for that operation.
+     * getSupportedOperations indicates which operations of the top-level
+     * subgraph are fully supported by the vendor driver. If an operation may
+     * not be supported for any reason, getSupportedOperations must return
+     * false for that operation.
+     *
+     * The {@link OperationType::IF} and {@link OperationType::WHILE}
+     * operations may only be fully supported if the vendor driver fully
+     * supports all operations in the referenced subgraphs.
      *
      * @param model A model whose operations--and their corresponding operands--
      *     are to be verified by the driver.
diff --git a/neuralnetworks/1.3/types.hal b/neuralnetworks/1.3/types.hal
index bb924c2..a6d274a 100644
--- a/neuralnetworks/1.3/types.hal
+++ b/neuralnetworks/1.3/types.hal
@@ -17,7 +17,6 @@
 package android.hardware.neuralnetworks@1.3;
 
 import @1.0::DataLocation;
-import @1.0::OperandLifeTime;
 import @1.0::PerformanceInfo;
 import @1.0::RequestArgument;
 import @1.2::Model.ExtensionNameAndPrefix;
@@ -42,6 +41,13 @@
      */
     TENSOR_QUANT8_ASYMM_SIGNED = 14,
 
+    /**
+     * A reference to a subgraph.
+     *
+     * Must have the lifetime {@link OperandLifeTime::SUBGRAPH}.
+     */
+    SUBGRAPH = 15,
+
     /*
      * DEPRECATED. Since HAL version 1.2, extensions are the preferred
      * alternative to OEM operation and data types.
@@ -70,7 +76,7 @@
 enum OperandTypeRange : uint32_t {
     BASE_MIN        = 0,
     FUNDAMENTAL_MIN = 0,
-    FUNDAMENTAL_MAX = 14,
+    FUNDAMENTAL_MAX = 15,
     OEM_MIN         = 10000,
     OEM_MAX         = 10001,
     BASE_MAX        = 0xFFFF,
@@ -4879,6 +4885,92 @@
     QUANTIZED_LSTM = 95,
 
     /**
+     * Executes one of the two referenced subgraphs as determined by a boolean
+     * value.
+     *
+     * The inputs and outputs of the two referenced subgraphs must agree with the
+     * signature of this operation. That is, if the operation has (3 + n) inputs
+     * and m outputs, both subgraphs must have n inputs and m outputs with the same
+     * types as the corresponding operation inputs and outputs.
+     *
+     * Inputs:
+     * * 0: A value of type {@link OperandType::TENSOR_BOOL8} and shape [1]
+     *      that determines which of the two referenced subgraphs to execute.
+     * * 1: A {@link OperandType::SUBGRAPH} reference to the subgraph to be
+     *      executed if the condition is true.
+     * * 2: A {@link OperandType::SUBGRAPH} reference to the subgraph to be
+     *      executed if the condition is false.
+     * * 3 ~ (n + 2): Inputs to be passed to the subgraph selected for execution.
+     *
+     * Outputs:
+     * * 0 ~ (m - 1): Outputs produced by the selected subgraph.
+     */
+    IF = 96,
+
+    /**
+     * Executes the body subgraph until the condition subgraph outputs false.
+     *
+     * The inputs to this operation are the condition subgraph, the body subgraph,
+     * and operand values for the first iteration of the loop. The values are
+     * implicitly split into three groups of input-output, state-only, and
+     * input-only values, as described below.
+     *
+     * The outputs of this operation are the final values of input-output
+     * operands.
+     *
+     * Both the condition and body subgraph receive (m + k + n) inputs.
+     * * The first m (m >= 1) inputs are input-output operands. For the first
+     *   iteration, these are initialized from the corresponding inputs of the
+     *   WHILE operation. In subsequent iterations, their values come from the
+     *   corresponding outputs of the body subgraph produced during the previous
+     *   iteration.
+     * * The next k (k >= 0) inputs are state-only operands. They are similar to
+     *   the input-output operands, except that their values are no longer
+     *   available after the loop terminates.
+     * * The last n (n >= 0) inputs are input-only operands. Their values come
+     *   from the corresponding inputs of the WHILE operation.
+     *
+     * The body subgraph produces (m + k) outputs.
+     * * The first m outputs are input-output operands. They become the outputs
+     *   of the WHILE operation when a termination condition is reached.
+     * * The last k outputs are state-only operands. Their values are no longer
+     *   available after the loop terminates.
+     *
+     * The numbers m, k, and n are inferred by the driver as follows:
+     *     m = (WHILE operation output count)
+     *     k = (body subgraph output count) - m
+     *     n = (body subgraph input count) - m - k
+     *
+     * The pseudo-code below illustrates the flow of a WHILE operation with
+     * inputs condition, body, initial_input_output, initial_state, input_only
+     * (m = 1, k = 1, n = 1):
+     *
+     *     input_output = initial_input_output
+     *     state = initial_state
+     *     while condition(input_output, state, input_only):
+     *         input_output, state = body(input_output, state, input_only)
+     *     return input_output
+     *
+     * Inputs:
+     * * 0: A {@link OperandType::SUBGRAPH} reference to the condition
+     *      subgraph. The subgraph must have (m + k + n) inputs with
+     *      the same types as the corresponding inputs of the WHILE operation
+     *      and exactly one output of {@link OperandType::TENSOR_BOOL8}
+     *      and shape [1].
+     * * 1: A {@link OperandType::SUBGRAPH} reference to the body subgraph.
+     *      The subgraph must have (m + k + n) inputs and (m + k) outputs with
+     *      the same types as the corresponding inputs and outputs of the WHILE
+     *      operation.
+     * * (m inputs): Initial values for input-output operands.
+     * * (k inputs): Initial values for state-only operands.
+     * * (n inputs): Values for input-only operands.
+     *
+     * Outputs:
+     * * 0 ~ (m - 1): Outputs produced by the loop.
+     */
+    WHILE = 97,
+
+    /**
      * DEPRECATED. Since NNAPI 1.2, extensions are the preferred alternative to
      * OEM operation and data types.
      *
@@ -4900,13 +4992,12 @@
 enum OperationTypeRange : uint32_t {
     BASE_MIN        = 0,
     FUNDAMENTAL_MIN = 0,
-    FUNDAMENTAL_MAX = 95,
+    FUNDAMENTAL_MAX = 97,
     OEM_MIN         = 10000,
     OEM_MAX         = 10000,
     BASE_MAX        = 0xFFFF,
 };
 
-
 /**
  * The capabilities of a driver.
  *
@@ -4968,6 +5059,59 @@
 };
 
 /**
+ * How an operand is used.
+ */
+enum OperandLifeTime : int32_t {
+    /**
+     * The operand is internal to the model. It's created by an operation and
+     * consumed by other operations. It must be an output operand of
+     * exactly one operation.
+     */
+    TEMPORARY_VARIABLE,
+
+    /**
+     * The operand is an input of a subgraph. It must not be an output
+     * operand of any operation.
+     *
+     * An operand can't be both input and output of a subgraph.
+     */
+    SUBGRAPH_INPUT,
+
+    /**
+     * The operand is an output of a subgraph. It must be an output
+     * operand of exactly one operation.
+     *
+     * An operand can't be both input and output of a subgraph.
+     */
+    SUBGRAPH_OUTPUT,
+
+    /**
+     * The operand is a constant found in Model.operandValues. It must
+     * not be an output operand of any operation.
+     */
+    CONSTANT_COPY,
+
+    /**
+     * The operand is a constant that was specified via a Memory
+     * object. It must not be an output operand of any operation.
+     */
+    CONSTANT_REFERENCE,
+
+    /**
+     * The operand does not have a value. This is valid only for optional
+     * arguments of operations.
+     */
+    NO_VALUE,
+
+    /**
+     * The operand is a reference to a subgraph. It must be an input to one
+     * or more {@link OperationType::IF} or {@link OperationType::WHILE}
+     * operations.
+     */
+    SUBGRAPH,
+};
+
+/**
  * Describes one operand of the model's graph.
  */
 struct Operand {
@@ -5003,7 +5147,7 @@
      *     . The operand has lifetime CONSTANT_COPY or
      *       CONSTANT_REFERENCE.
      *
-     *     . The operand has lifetime MODEL_INPUT. Fully
+     *     . The operand has lifetime SUBGRAPH_INPUT. Fully
      *       specified dimensions must either be present in the
      *       Operand or they must be provided in the corresponding
      *       RequestArgument.
@@ -5051,8 +5195,8 @@
 
     /**
      * Where to find the data for this operand.
-     * If the lifetime is TEMPORARY_VARIABLE, MODEL_INPUT, MODEL_OUTPUT, or
-     * NO_VALUE:
+     * If the lifetime is TEMPORARY_VARIABLE, SUBGRAPH_INPUT, SUBGRAPH_OUTPUT,
+     * or NO_VALUE:
      * - All the fields must be 0.
      * If the lifetime is CONSTANT_COPY:
      * - location.poolIndex is 0.
@@ -5062,6 +5206,11 @@
      * - location.poolIndex is set.
      * - location.offset is the offset in bytes into the specified pool.
      * - location.length is set.
+     * If the lifetime is SUBGRAPH:
+     * - location.poolIndex is 0.
+     * - location.offset is the index of the referenced subgraph in
+     *   {@link Model::referenced}.
+     * - location.length is 0.
      */
     DataLocation location;
 
@@ -5100,32 +5249,19 @@
  */
 struct Model {
     /**
-     * All operands included in the model.
+     * The top-level subgraph.
      */
-    vec<Operand> operands;
+    Subgraph main;
 
     /**
-     * All operations included in the model.
+     * Referenced subgraphs.
      *
-     * The operations are sorted into execution order. Every operand
-     * with lifetime MODEL_OUTPUT or TEMPORARY_VARIABLE must be
-     * written before it is read.
-     */
-    vec<Operation> operations;
-
-    /**
-     * Input indexes of the model. There must be at least one.
+     * Each subgraph is referenced by the main subgraph or at least one other
+     * referenced subgraph.
      *
-     * Each value corresponds to the index of the operand in "operands".
+     * There must be no reference cycles.
      */
-    vec<uint32_t> inputIndexes;
-
-    /**
-     * Output indexes of the model. There must be at least one.
-     *
-     * Each value corresponds to the index of the operand in "operands".
-     */
-    vec<uint32_t> outputIndexes;
+    vec<Subgraph> referenced;
 
     /**
      * A byte buffer containing operand data that were copied into the model.
@@ -5178,6 +5314,39 @@
 };
 
 /**
+ * An excerpt of the execution graph.
+ */
+struct Subgraph {
+    /**
+     * All operands included in the subgraph.
+     */
+    vec<Operand> operands;
+
+    /**
+     * All operations included in the subgraph.
+     *
+     * The operations are sorted into execution order. Every operand
+     * with lifetime SUBGRAPH_OUTPUT or TEMPORARY_VARIABLE must be
+     * written before it is read.
+     */
+    vec<Operation> operations;
+
+    /**
+     * Input indexes of the subgraph. There must be at least one.
+     *
+     * Each value corresponds to the index of the operand in "operands".
+     */
+    vec<uint32_t> inputIndexes;
+
+    /**
+     * Output indexes of the subgraph. There must be at least one.
+     *
+     * Each value corresponds to the index of the operand in "operands".
+     */
+    vec<uint32_t> outputIndexes;
+};
+
+/**
  * A buffer descriptor. Describes the properties of a buffer.
  */
 struct BufferDesc {
diff --git a/neuralnetworks/1.3/types.t b/neuralnetworks/1.3/types.t
index b4c3769..f3319e5 100644
--- a/neuralnetworks/1.3/types.t
+++ b/neuralnetworks/1.3/types.t
@@ -19,7 +19,6 @@
 package android.hardware.neuralnetworks@1.3;
 
 import @1.0::DataLocation;
-import @1.0::OperandLifeTime;
 import @1.0::PerformanceInfo;
 import @1.0::RequestArgument;
 import @1.2::Model.ExtensionNameAndPrefix;
@@ -90,7 +89,6 @@
     BASE_MAX        = 0xFFFF,
 };
 
-
 /**
  * The capabilities of a driver.
  *
@@ -152,6 +150,59 @@
 };
 
 /**
+ * How an operand is used.
+ */
+enum OperandLifeTime : int32_t {
+    /**
+     * The operand is internal to the model. It's created by an operation and
+     * consumed by other operations. It must be an output operand of
+     * exactly one operation.
+     */
+    TEMPORARY_VARIABLE,
+
+    /**
+     * The operand is an input of a subgraph. It must not be an output
+     * operand of any operation.
+     *
+     * An operand can't be both input and output of a subgraph.
+     */
+    SUBGRAPH_INPUT,
+
+    /**
+     * The operand is an output of a subgraph. It must be an output
+     * operand of exactly one operation.
+     *
+     * An operand can't be both input and output of a subgraph.
+     */
+    SUBGRAPH_OUTPUT,
+
+    /**
+     * The operand is a constant found in Model.operandValues. It must
+     * not be an output operand of any operation.
+     */
+    CONSTANT_COPY,
+
+    /**
+     * The operand is a constant that was specified via a Memory
+     * object. It must not be an output operand of any operation.
+     */
+    CONSTANT_REFERENCE,
+
+    /**
+     * The operand does not have a value. This is valid only for optional
+     * arguments of operations.
+     */
+    NO_VALUE,
+
+    /**
+     * The operand is a reference to a subgraph. It must be an input to one
+     * or more {@link OperationType::IF} or {@link OperationType::WHILE}
+     * operations.
+     */
+    SUBGRAPH,
+};
+
+/**
  * Describes one operand of the model's graph.
  */
 struct Operand {
@@ -187,7 +238,7 @@
      *     . The operand has lifetime CONSTANT_COPY or
      *       CONSTANT_REFERENCE.
      *
-     *     . The operand has lifetime MODEL_INPUT. Fully
+     *     . The operand has lifetime SUBGRAPH_INPUT. Fully
      *       specified dimensions must either be present in the
      *       Operand or they must be provided in the corresponding
      *       RequestArgument.
@@ -235,8 +286,8 @@
 
     /**
      * Where to find the data for this operand.
-     * If the lifetime is TEMPORARY_VARIABLE, MODEL_INPUT, MODEL_OUTPUT, or
-     * NO_VALUE:
+     * If the lifetime is TEMPORARY_VARIABLE, SUBGRAPH_INPUT, SUBGRAPH_OUTPUT,
+     * or NO_VALUE:
      * - All the fields must be 0.
      * If the lifetime is CONSTANT_COPY:
      * - location.poolIndex is 0.
@@ -246,6 +297,11 @@
      * - location.poolIndex is set.
      * - location.offset is the offset in bytes into the specified pool.
      * - location.length is set.
+     * If the lifetime is SUBGRAPH:
+     * - location.poolIndex is 0.
+     * - location.offset is the index of the referenced subgraph in
+     *   {@link Model::referenced}.
+     * - location.length is 0.
      */
     DataLocation location;
 
@@ -284,32 +340,19 @@
  */
 struct Model {
     /**
-     * All operands included in the model.
+     * The top-level subgraph.
      */
-    vec<Operand> operands;
+    Subgraph main;
 
     /**
-     * All operations included in the model.
+     * Referenced subgraphs.
      *
-     * The operations are sorted into execution order. Every operand
-     * with lifetime MODEL_OUTPUT or TEMPORARY_VARIABLE must be
-     * written before it is read.
-     */
-    vec<Operation> operations;
-
-    /**
-     * Input indexes of the model. There must be at least one.
+     * Each subgraph is referenced by the main subgraph or at least one other
+     * referenced subgraph.
      *
-     * Each value corresponds to the index of the operand in "operands".
+     * There must be no reference cycles.
      */
-    vec<uint32_t> inputIndexes;
-
-    /**
-     * Output indexes of the model. There must be at least one.
-     *
-     * Each value corresponds to the index of the operand in "operands".
-     */
-    vec<uint32_t> outputIndexes;
+    vec<Subgraph> referenced;
 
     /**
      * A byte buffer containing operand data that were copied into the model.
@@ -362,6 +405,39 @@
 };
 
 /**
+ * An excerpt of the execution graph.
+ */
+struct Subgraph {
+    /**
+     * All operands included in the subgraph.
+     */
+    vec<Operand> operands;
+
+    /**
+     * All operations included in the subgraph.
+     *
+     * The operations are sorted into execution order. Every operand
+     * with lifetime SUBGRAPH_OUTPUT or TEMPORARY_VARIABLE must be
+     * written before it is read.
+     */
+    vec<Operation> operations;
+
+    /**
+     * Input indexes of the subgraph. There must be at least one.
+     *
+     * Each value corresponds to the index of the operand in "operands".
+     */
+    vec<uint32_t> inputIndexes;
+
+    /**
+     * Output indexes of the subgraph. There must be at least one.
+     *
+     * Each value corresponds to the index of the operand in "operands".
+     */
+    vec<uint32_t> outputIndexes;
+};
+
+/**
  * A buffer descriptor. Describes the properties of a buffer.
  */
 struct BufferDesc {
diff --git a/neuralnetworks/1.3/vts/functional/CompilationCachingTests.cpp b/neuralnetworks/1.3/vts/functional/CompilationCachingTests.cpp
index fe8d907..5cb466f 100644
--- a/neuralnetworks/1.3/vts/functional/CompilationCachingTests.cpp
+++ b/neuralnetworks/1.3/vts/functional/CompilationCachingTests.cpp
@@ -308,7 +308,7 @@
                 model,
                 [&fullySupportsModel, &model](ErrorStatus status, const hidl_vec<bool>& supported) {
                     ASSERT_EQ(ErrorStatus::NONE, status);
-                    ASSERT_EQ(supported.size(), model.operations.size());
+                    ASSERT_EQ(supported.size(), model.main.operations.size());
                     fullySupportsModel = std::all_of(supported.begin(), supported.end(),
                                                      [](bool valid) { return valid; });
                 });
diff --git a/neuralnetworks/1.3/vts/functional/GeneratedTestHarness.cpp b/neuralnetworks/1.3/vts/functional/GeneratedTestHarness.cpp
index 4f747f4..805d5b5 100644
--- a/neuralnetworks/1.3/vts/functional/GeneratedTestHarness.cpp
+++ b/neuralnetworks/1.3/vts/functional/GeneratedTestHarness.cpp
@@ -59,7 +59,6 @@
 using implementation::PreparedModelCallback;
 using V1_0::DataLocation;
 using V1_0::ErrorStatus;
-using V1_0::OperandLifeTime;
 using V1_0::RequestArgument;
 using V1_1::ExecutionPreference;
 using V1_2::Constant;
@@ -269,10 +268,10 @@
         }
     }
 
-    return {.operands = std::move(operands),
-            .operations = std::move(operations),
-            .inputIndexes = testModel.inputIndexes,
-            .outputIndexes = testModel.outputIndexes,
+    return {.main = {.operands = std::move(operands),
+                     .operations = std::move(operations),
+                     .inputIndexes = testModel.inputIndexes,
+                     .outputIndexes = testModel.outputIndexes},
             .operandValues = std::move(operandValues),
             .pools = std::move(pools),
             .relaxComputationFloat32toFloat16 = testModel.isRelaxed};
@@ -290,8 +289,8 @@
 }
 
 static void makeOutputDimensionsUnspecified(Model* model) {
-    for (auto i : model->outputIndexes) {
-        auto& dims = model->operands[i].dimensions;
+    for (auto i : model->main.outputIndexes) {
+        auto& dims = model->main.operands[i].dimensions;
         std::fill(dims.begin(), dims.end(), 0);
     }
 }
diff --git a/neuralnetworks/1.3/vts/functional/ValidateModel.cpp b/neuralnetworks/1.3/vts/functional/ValidateModel.cpp
index 8395111..cc86264 100644
--- a/neuralnetworks/1.3/vts/functional/ValidateModel.cpp
+++ b/neuralnetworks/1.3/vts/functional/ValidateModel.cpp
@@ -25,7 +25,6 @@
 
 using implementation::PreparedModelCallback;
 using V1_0::ErrorStatus;
-using V1_0::OperandLifeTime;
 using V1_1::ExecutionPreference;
 using V1_2::SymmPerChannelQuantParams;
 using HidlToken =
@@ -83,22 +82,22 @@
 }
 
 static uint32_t addOperand(Model* model) {
-    return hidl_vec_push_back(&model->operands,
+    return hidl_vec_push_back(&model->main.operands,
                               {
                                       .type = OperandType::INT32,
                                       .dimensions = {},
                                       .numberOfConsumers = 0,
                                       .scale = 0.0f,
                                       .zeroPoint = 0,
-                                      .lifetime = OperandLifeTime::MODEL_INPUT,
+                                      .lifetime = OperandLifeTime::SUBGRAPH_INPUT,
                                       .location = {.poolIndex = 0, .offset = 0, .length = 0},
                               });
 }
 
 static uint32_t addOperand(Model* model, OperandLifeTime lifetime) {
     uint32_t index = addOperand(model);
-    model->operands[index].numberOfConsumers = 1;
-    model->operands[index].lifetime = lifetime;
+    model->main.operands[index].numberOfConsumers = 1;
+    model->main.operands[index].lifetime = lifetime;
     return index;
 }
 
@@ -112,13 +111,13 @@
 };
 
 static void mutateOperandTypeTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operand = 0; operand < model.operands.size(); ++operand) {
+    for (size_t operand = 0; operand < model.main.operands.size(); ++operand) {
         for (uint32_t invalidOperandType : invalidOperandTypes) {
             const std::string message = "mutateOperandTypeTest: operand " +
                                         std::to_string(operand) + " set to value " +
                                         std::to_string(invalidOperandType);
             validate(device, message, model, [operand, invalidOperandType](Model* model) {
-                model->operands[operand].type = static_cast<OperandType>(invalidOperandType);
+                model->main.operands[operand].type = static_cast<OperandType>(invalidOperandType);
             });
         }
     }
@@ -150,15 +149,15 @@
 }
 
 static void mutateOperandRankTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operand = 0; operand < model.operands.size(); ++operand) {
-        const uint32_t invalidRank = getInvalidRank(model.operands[operand].type);
+    for (size_t operand = 0; operand < model.main.operands.size(); ++operand) {
+        const uint32_t invalidRank = getInvalidRank(model.main.operands[operand].type);
         if (invalidRank == 0) {
             continue;
         }
         const std::string message = "mutateOperandRankTest: operand " + std::to_string(operand) +
                                     " has rank of " + std::to_string(invalidRank);
         validate(device, message, model, [operand, invalidRank](Model* model) {
-            model->operands[operand].dimensions = std::vector<uint32_t>(invalidRank, 0);
+            model->main.operands[operand].dimensions = std::vector<uint32_t>(invalidRank, 0);
         });
     }
 }
@@ -190,12 +189,12 @@
 }
 
 static void mutateOperandScaleTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operand = 0; operand < model.operands.size(); ++operand) {
-        const float invalidScale = getInvalidScale(model.operands[operand].type);
+    for (size_t operand = 0; operand < model.main.operands.size(); ++operand) {
+        const float invalidScale = getInvalidScale(model.main.operands[operand].type);
         const std::string message = "mutateOperandScaleTest: operand " + std::to_string(operand) +
                                     " has scale of " + std::to_string(invalidScale);
         validate(device, message, model, [operand, invalidScale](Model* model) {
-            model->operands[operand].scale = invalidScale;
+            model->main.operands[operand].scale = invalidScale;
         });
     }
 }
@@ -229,15 +228,15 @@
 }
 
 static void mutateOperandZeroPointTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operand = 0; operand < model.operands.size(); ++operand) {
+    for (size_t operand = 0; operand < model.main.operands.size(); ++operand) {
         const std::vector<int32_t> invalidZeroPoints =
-                getInvalidZeroPoints(model.operands[operand].type);
+                getInvalidZeroPoints(model.main.operands[operand].type);
         for (int32_t invalidZeroPoint : invalidZeroPoints) {
             const std::string message = "mutateOperandZeroPointTest: operand " +
                                         std::to_string(operand) + " has zero point of " +
                                         std::to_string(invalidZeroPoint);
             validate(device, message, model, [operand, invalidZeroPoint](Model* model) {
-                model->operands[operand].zeroPoint = invalidZeroPoint;
+                model->main.operands[operand].zeroPoint = invalidZeroPoint;
             });
         }
     }
@@ -310,11 +309,11 @@
 
 static bool mutateOperationOperandTypeSkip(size_t operand, OperandType type, const Model& model) {
     // Do not test OEM types
-    if (type == model.operands[operand].type || type == OperandType::OEM ||
+    if (type == model.main.operands[operand].type || type == OperandType::OEM ||
         type == OperandType::TENSOR_OEM_BYTE) {
         return true;
     }
-    for (const Operation& operation : model.operations) {
+    for (const Operation& operation : model.main.operations) {
         // Skip mutateOperationOperandTypeTest for the following operations.
         // - LSH_PROJECTION's second argument is allowed to have any type.
         // - ARGMIN and ARGMAX's first argument can be any of
@@ -401,7 +400,7 @@
 }
 
 static void mutateOperationOperandTypeTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operand = 0; operand < model.operands.size(); ++operand) {
+    for (size_t operand = 0; operand < model.main.operands.size(); ++operand) {
         for (OperandType invalidOperandType : hidl_enum_range<OperandType>{}) {
             if (mutateOperationOperandTypeSkip(operand, invalidOperandType, model)) {
                 continue;
@@ -410,7 +409,7 @@
                                         std::to_string(operand) + " set to type " +
                                         toString(invalidOperandType);
             validate(device, message, model, [operand, invalidOperandType](Model* model) {
-                mutateOperand(&model->operands[operand], invalidOperandType);
+                mutateOperand(&model->main.operands[operand], invalidOperandType);
             });
         }
     }
@@ -425,13 +424,13 @@
 };
 
 static void mutateOperationTypeTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operation = 0; operation < model.operations.size(); ++operation) {
+    for (size_t operation = 0; operation < model.main.operations.size(); ++operation) {
         for (uint32_t invalidOperationType : invalidOperationTypes) {
             const std::string message = "mutateOperationTypeTest: operation " +
                                         std::to_string(operation) + " set to value " +
                                         std::to_string(invalidOperationType);
             validate(device, message, model, [operation, invalidOperationType](Model* model) {
-                model->operations[operation].type =
+                model->main.operations[operation].type =
                         static_cast<OperationType>(invalidOperationType);
             });
         }
@@ -441,14 +440,14 @@
 ///////////////////////// VALIDATE MODEL OPERATION INPUT OPERAND INDEX /////////////////////////
 
 static void mutateOperationInputOperandIndexTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operation = 0; operation < model.operations.size(); ++operation) {
-        const uint32_t invalidOperand = model.operands.size();
-        for (size_t input = 0; input < model.operations[operation].inputs.size(); ++input) {
+    for (size_t operation = 0; operation < model.main.operations.size(); ++operation) {
+        const uint32_t invalidOperand = model.main.operands.size();
+        for (size_t input = 0; input < model.main.operations[operation].inputs.size(); ++input) {
             const std::string message = "mutateOperationInputOperandIndexTest: operation " +
                                         std::to_string(operation) + " input " +
                                         std::to_string(input);
             validate(device, message, model, [operation, input, invalidOperand](Model* model) {
-                model->operations[operation].inputs[input] = invalidOperand;
+                model->main.operations[operation].inputs[input] = invalidOperand;
             });
         }
     }
@@ -457,14 +456,15 @@
 ///////////////////////// VALIDATE MODEL OPERATION OUTPUT OPERAND INDEX /////////////////////////
 
 static void mutateOperationOutputOperandIndexTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operation = 0; operation < model.operations.size(); ++operation) {
-        const uint32_t invalidOperand = model.operands.size();
-        for (size_t output = 0; output < model.operations[operation].outputs.size(); ++output) {
+    for (size_t operation = 0; operation < model.main.operations.size(); ++operation) {
+        const uint32_t invalidOperand = model.main.operands.size();
+        for (size_t output = 0; output < model.main.operations[operation].outputs.size();
+             ++output) {
             const std::string message = "mutateOperationOutputOperandIndexTest: operation " +
                                         std::to_string(operation) + " output " +
                                         std::to_string(output);
             validate(device, message, model, [operation, output, invalidOperand](Model* model) {
-                model->operations[operation].outputs[output] = invalidOperand;
+                model->main.operations[operation].outputs[output] = invalidOperand;
             });
         }
     }
@@ -485,17 +485,17 @@
 }
 
 static void removeOperand(Model* model, uint32_t index) {
-    hidl_vec_removeAt(&model->operands, index);
-    for (Operation& operation : model->operations) {
+    hidl_vec_removeAt(&model->main.operands, index);
+    for (Operation& operation : model->main.operations) {
         removeValueAndDecrementGreaterValues(&operation.inputs, index);
         removeValueAndDecrementGreaterValues(&operation.outputs, index);
     }
-    removeValueAndDecrementGreaterValues(&model->inputIndexes, index);
-    removeValueAndDecrementGreaterValues(&model->outputIndexes, index);
+    removeValueAndDecrementGreaterValues(&model->main.inputIndexes, index);
+    removeValueAndDecrementGreaterValues(&model->main.outputIndexes, index);
 }
 
 static bool removeOperandSkip(size_t operand, const Model& model) {
-    for (const Operation& operation : model.operations) {
+    for (const Operation& operation : model.main.operations) {
         // Skip removeOperandTest for the following operations.
         // - SPLIT's outputs are not checked during prepareModel.
         if (operation.type == OperationType::SPLIT) {
@@ -520,7 +520,7 @@
 }
 
 static void removeOperandTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operand = 0; operand < model.operands.size(); ++operand) {
+    for (size_t operand = 0; operand < model.main.operands.size(); ++operand) {
         if (removeOperandSkip(operand, model)) {
             continue;
         }
@@ -533,14 +533,14 @@
 ///////////////////////// REMOVE OPERATION /////////////////////////
 
 static void removeOperation(Model* model, uint32_t index) {
-    for (uint32_t operand : model->operations[index].inputs) {
-        model->operands[operand].numberOfConsumers--;
+    for (uint32_t operand : model->main.operations[index].inputs) {
+        model->main.operands[operand].numberOfConsumers--;
     }
-    hidl_vec_removeAt(&model->operations, index);
+    hidl_vec_removeAt(&model->main.operations, index);
 }
 
 static void removeOperationTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operation = 0; operation < model.operations.size(); ++operation) {
+    for (size_t operation = 0; operation < model.main.operations.size(); ++operation) {
         const std::string message = "removeOperationTest: operation " + std::to_string(operation);
         validate(device, message, model,
                  [operation](Model* model) { removeOperation(model, operation); });
@@ -615,9 +615,9 @@
 }
 
 static void removeOperationInputTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operation = 0; operation < model.operations.size(); ++operation) {
-        for (size_t input = 0; input < model.operations[operation].inputs.size(); ++input) {
-            const Operation& op = model.operations[operation];
+    for (size_t operation = 0; operation < model.main.operations.size(); ++operation) {
+        for (size_t input = 0; input < model.main.operations[operation].inputs.size(); ++input) {
+            const Operation& op = model.main.operations[operation];
             if (removeOperationInputSkip(op, input)) {
                 continue;
             }
@@ -625,9 +625,9 @@
                                         std::to_string(operation) + ", input " +
                                         std::to_string(input);
             validate(device, message, model, [operation, input](Model* model) {
-                uint32_t operand = model->operations[operation].inputs[input];
-                model->operands[operand].numberOfConsumers--;
-                hidl_vec_removeAt(&model->operations[operation].inputs, input);
+                uint32_t operand = model->main.operations[operation].inputs[input];
+                model->main.operands[operand].numberOfConsumers--;
+                hidl_vec_removeAt(&model->main.operations[operation].inputs, input);
             });
         }
     }
@@ -636,13 +636,14 @@
 ///////////////////////// REMOVE OPERATION OUTPUT /////////////////////////
 
 static void removeOperationOutputTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operation = 0; operation < model.operations.size(); ++operation) {
-        for (size_t output = 0; output < model.operations[operation].outputs.size(); ++output) {
+    for (size_t operation = 0; operation < model.main.operations.size(); ++operation) {
+        for (size_t output = 0; output < model.main.operations[operation].outputs.size();
+             ++output) {
             const std::string message = "removeOperationOutputTest: operation " +
                                         std::to_string(operation) + ", output " +
                                         std::to_string(output);
             validate(device, message, model, [operation, output](Model* model) {
-                hidl_vec_removeAt(&model->operations[operation].outputs, output);
+                hidl_vec_removeAt(&model->main.operations[operation].outputs, output);
             });
         }
     }
@@ -669,15 +670,15 @@
 }
 
 static void addOperationInputTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operation = 0; operation < model.operations.size(); ++operation) {
-        if (addOperationInputSkip(model.operations[operation])) {
+    for (size_t operation = 0; operation < model.main.operations.size(); ++operation) {
+        if (addOperationInputSkip(model.main.operations[operation])) {
             continue;
         }
         const std::string message = "addOperationInputTest: operation " + std::to_string(operation);
         validate(device, message, model, [operation](Model* model) {
-            uint32_t index = addOperand(model, OperandLifeTime::MODEL_INPUT);
-            hidl_vec_push_back(&model->operations[operation].inputs, index);
-            hidl_vec_push_back(&model->inputIndexes, index);
+            uint32_t index = addOperand(model, OperandLifeTime::SUBGRAPH_INPUT);
+            hidl_vec_push_back(&model->main.operations[operation].inputs, index);
+            hidl_vec_push_back(&model->main.inputIndexes, index);
         });
     }
 }
@@ -685,13 +686,13 @@
 ///////////////////////// ADD OPERATION OUTPUT /////////////////////////
 
 static void addOperationOutputTest(const sp<IDevice>& device, const Model& model) {
-    for (size_t operation = 0; operation < model.operations.size(); ++operation) {
+    for (size_t operation = 0; operation < model.main.operations.size(); ++operation) {
         const std::string message =
                 "addOperationOutputTest: operation " + std::to_string(operation);
         validate(device, message, model, [operation](Model* model) {
-            uint32_t index = addOperand(model, OperandLifeTime::MODEL_OUTPUT);
-            hidl_vec_push_back(&model->operations[operation].outputs, index);
-            hidl_vec_push_back(&model->outputIndexes, index);
+            uint32_t index = addOperand(model, OperandLifeTime::SUBGRAPH_OUTPUT);
+            hidl_vec_push_back(&model->main.operations[operation].outputs, index);
+            hidl_vec_push_back(&model->main.outputIndexes, index);
         });
     }
 }