Rescale sub int16 correctly

backends/arm/operators/op_sub.py

@@ -50,7 +50,7 @@ def define_node(
         validate_valid_dtype(
             self.target,
             [*inputs, output],
-            [ts.DType.INT8, ts.DType.INT32],
+            [ts.DType.INT8, ts.DType.INT16, ts.DType.INT32],
             output.tosa_spec,
         )
 
@@ -59,12 +59,18 @@ def define_node(
             rescaled_inputs, scale_back = tqutils.insert_rescale_ops_to_int32_maxscale(
                 tosa_graph, inputs, node, self.tosa_spec
             )
+        elif inputs[0].dtype == ts.DType.INT16:
+            rescaled_inputs, scale_back = (
+                tqutils.insert_rescale_ops_int16_to_int32_maxscale(
+                    tosa_graph, inputs, node, self.tosa_spec
+                )
+            )
         else:
             # input[0].dtype == ts.DType.INT32
             # Non quantized input, natively support by TOSA.SUB
             rescaled_inputs = inputs
 
-        if output.dtype == ts.DType.INT8:
+        if output.dtype in [ts.DType.INT8, ts.DType.INT16]:
             broadcasted_shape = tutils.tosa_shape(output.shape, output.dim_order)
             sub_output = tosa_graph.addIntermediate(broadcasted_shape, ts.DType.INT32)
         else:
@@ -95,6 +101,15 @@ def define_node(
                 compute_rescale=False,
                 tosa_spec=self.tosa_spec,
             )  # type: ignore[possibly-undefined]
+        elif output.dtype == ts.DType.INT16:
+            tqutils.insert_rescale_op_to_int16(
+                tosa_graph,
+                sub_output,
+                scale_back,
+                node,
+                compute_rescale=False,
+                tosa_spec=self.tosa_spec,
+            )  # type: ignore[possibly-undefined]
 
 
 @register_node_visitor

backends/arm/test/ops/test_sub.py

@@ -10,15 +10,21 @@
 from typing import Tuple
 
 import torch
+from executorch.backends.arm.quantizer.arm_quantizer import (
+    get_symmetric_a16w8_quantization_config,
+    TOSAQuantizer,
+)
 
-from executorch.backends.arm.test import common
+from executorch.backends.arm.test import common, conftest
 from executorch.backends.arm.test.tester.test_pipeline import (
     EthosU55PipelineINT,
     EthosU85PipelineINT,
     TosaPipelineFP,
     TosaPipelineINT,
     VgfPipeline,
 )
+from executorch.backends.arm.tosa import TosaSpecification
+from executorch.backends.xnnpack.test.tester import Quantize
 
 aten_op = "torch.ops.aten.sub.Tensor"
 exir_op = "executorch_exir_dialects_edge__ops_aten_sub_Tensor"
@@ -242,3 +248,96 @@ def test_sub_tensor_vgf_INT_2(test_data: Tuple[torch.Tensor, torch.Tensor]):
         tosa_version="TOSA-1.0+INT",
     )
     pipeline.run()
+
+
+def get_symmetric_a16w8_sub_quantizer(per_channel_quantization=False):
+    tosa_version = conftest.get_option("tosa_version")
+    tosa_profiles = {
+        "1.0": TosaSpecification.create_from_string("TOSA-1.0+INT+int16"),
+    }
+
+    quantizer = TOSAQuantizer(tosa_profiles[tosa_version])
+    quantizer.set_global(
+        get_symmetric_a16w8_quantization_config(is_per_channel=per_channel_quantization)
+    )
+
+    return Quantize(
+        quantizer,
+        get_symmetric_a16w8_quantization_config(
+            is_per_channel=per_channel_quantization
+        ),
+    )
+
+
+@common.parametrize("test_data", sub_test_data)
+def test_sub_tensor_16a8w_tosa_INT(test_data: input_t1):
+    """Test sub operation with 16A8W quantization (16-bit activations, 8-bit weights)"""
+    per_channel_quantization = False
+
+    pipeline = TosaPipelineINT[input_t1](
+        Sub(),
+        test_data(),
+        aten_op,
+        exir_op=[],
+        per_channel_quantization=per_channel_quantization,
+        use_to_edge_transform_and_lower=True,
+        tosa_extensions=["int16"],
+    )
+
+    pipeline.change_args(
+        "quantize",
+        get_symmetric_a16w8_sub_quantizer(
+            per_channel_quantization=per_channel_quantization
+        ),
+    )
+    pipeline.run()
+
+
+@common.parametrize("test_data", sub_test_data)
+@common.XfailIfNoCorstone300
+def test_sub_tensor_16a8w_u55_INT16(test_data: input_t1):
+    """Test sub operation with 16A8W quantization on U55 (16-bit activations, 8-bit weights)"""
+    per_channel_quantization = False
+
+    pipeline = EthosU55PipelineINT[input_t1](
+        Sub(),
+        test_data(),
+        aten_op,
+        exir_op,
+        per_channel_quantization=per_channel_quantization,
+        use_to_edge_transform_and_lower=True,
+        run_on_fvp=True,
+    )
+
+    pipeline.change_args(
+        "quantize",
+        get_symmetric_a16w8_sub_quantizer(
+            per_channel_quantization=per_channel_quantization
+        ),
+    )
+    pipeline.run()
+
+
+@common.parametrize("test_data", sub_test_data)
+@common.XfailIfNoCorstone320
+def test_sub_tensor_16a8w_u85_INT16(test_data: input_t1):
+    """Test sub operation with 16A8W quantization on U85 (16-bit activations, 8-bit weights)"""
+    per_channel_quantization = False
+
+    pipeline = EthosU85PipelineINT[input_t1](
+        Sub(),
+        test_data(),
+        aten_op,
+        exir_op,
+        per_channel_quantization=per_channel_quantization,
+        use_to_edge_transform_and_lower=True,
+        run_on_fvp=True,
+    )
+
+    pipeline.change_args(
+        "quantize",
+        get_symmetric_a16w8_sub_quantizer(
+            per_channel_quantization=per_channel_quantization
+        ),
+    )
+    pipeline.run()

backends/arm/test/targets.bzl

@@ -22,6 +22,7 @@ def define_arm_tests():
         "ops/test_mul.py",
         "ops/test_slice.py",
         "ops/test_sigmoid.py",
+        "ops/test_sub.py",
         "ops/test_tanh.py",
         "ops/test_view.py",
         "ops/test_cos.py",