Fix depthwise conv detection for groups==in_channels==1

backends/cadence/aot/BUCK

@@ -132,6 +132,7 @@ fbcode_target(_kind = runtime.python_library,
     typing = True,
     deps = [
         "fbcode//caffe2:torch",
+        "fbcode//executorch/backends/cadence/aot:utils",
         "fbcode//executorch/exir:scalar_type",
         "fbcode//executorch/kernels/quantized:custom_ops_generated_lib",
     ],
@@ -374,6 +375,7 @@ fbcode_target(_kind = runtime.python_library,
     deps = [
         "//caffe2:torch",
         "//executorch/backends/cadence/aot:pass_utils",
+        "//executorch/backends/cadence/aot:utils",
         "//executorch/exir:pass_base",
     ],
 )

backends/cadence/aot/ops_registrations.py

@@ -14,6 +14,7 @@
     get_conv1d_output_size,
     get_conv2d_output_size,
     get_im2row_output_size,
+    is_depthwise_conv,
 )
 from executorch.exir.scalar_type import ScalarType
 from torch._meta_registrations import _linalg_svd_meta
@@ -1034,11 +1035,8 @@ def quantized_conv2d_nhwc_meta(
     assert len(in_size) < 6
 
     # Determine weight layout based on depthwise vs regular conv.
-    # Depthwise is defined by in_channels == groups, where in_channels
-    # is the last dim of the NHWC input.
     in_channels = in_size[-1]
-    is_depthwise = in_channels == groups
-    if is_depthwise:
+    if is_depthwise_conv(groups, in_channels):
         # Depthwise conv: weight is [*kernel_size, OC]
         *kernel_size, out_channels = weight.shape
     else:
@@ -1177,12 +1175,8 @@ def quantized_conv2d_nhwc_per_tensor_meta(
     assert len(in_size) < 6
 
     # Determine weight layout based on depthwise vs regular conv.
-    # Depthwise is defined by in_channels == groups, where in_channels
-    # is the last dim of the NHWC input.
     in_channels = in_size[-1]
-    is_depthwise = in_channels == groups
-    if is_depthwise:
-        # Depthwise conv: weight is [*kernel_size, OC]
+    if is_depthwise_conv(groups, in_channels):
         *kernel_size, out_channels = weight.shape
     elif len(in_size) == 3:
         # 1D conv: weight is [OC, K, IC]
@@ -1336,12 +1330,9 @@ def quantized_conv2d_nhwc_asym8sxsym8s_asym8s_per_tensor_meta(
     assert len(in_size) > 2
     assert len(in_size) < 6
 
-    # Determine weight layout based on input and weight dimensions:
-    # - Depthwise conv: input is 3D/4D, weight is 2/3D [K, OC]/[KH, KW, OC]
-    # - 1D conv: input is 3D, weight is 3D [OC, K, IC]
-    # - 2D regular conv: input is 4D, weight is 4D [OC, KH, KW, IC]
-    if len(weight.shape) == 3:
-        # 2D depthwise conv: weight is [KH, KW, OC]
+    # Determine weight layout based on depthwise vs regular conv.
+    in_channels = in_size[-1]
+    if is_depthwise_conv(groups, in_channels):
         *kernel_size, out_channels = weight.shape
     elif len(in_size) == 3:
         # 1D conv: weight is [OC, K, IC]
@@ -1397,12 +1388,9 @@ def quantized_conv2d_nhwc_asym8uxsym8u_asym8u_per_tensor_meta(
     assert len(in_size) > 2
     assert len(in_size) < 6
 
-    # Determine weight layout based on input and weight dimensions:
-    # - Depthwise conv: input is 3D/4D, weight is 3D [KH, KW, OC]
-    # - 1D conv: input is 3D, weight is 3D [OC, K, IC]
-    # - 2D regular conv: input is 4D, weight is 4D [OC, KH, KW, IC]
-    if len(weight.shape) == 3:
-        # 2D depthwise conv: weight is [KH, KW, OC]
+    # Determine weight layout based on depthwise vs regular conv.
+    in_channels = in_size[-1]
+    if is_depthwise_conv(groups, in_channels):
         *kernel_size, out_channels = weight.shape
     elif len(in_size) == 3:
         # 1D conv: weight is [OC, K, IC]

backends/cadence/aot/ref_implementations.py

@@ -12,6 +12,7 @@
 import torch
 import torch.nn as nn
 import torch.nn.functional as F
+from executorch.backends.cadence.aot.utils import is_depthwise_conv
 from executorch.exir.scalar_type import ScalarType
 from torch.library import impl, Library
 
@@ -1104,17 +1105,12 @@ def quantized_conv2d_nhwc_per_tensor(
 
     # Convert to NCHW format to reuse the existing implementation
     in_channels = input_tensor.shape[-1]
-    # Depthwise weights have one fewer dimension than the input because the IC
-    # dimension (always 1) was squeezed out during the NCHW->NHWC conversion in
-    # replace_ops.py.  E.g. 2D depthwise: weight is [KH, KW, OC] (3D) while
-    # input is [N, H, W, C] (4D).  A regular conv with in_channels==groups==1
-    # still has 4D weights [OC, KH, KW, IC].
-    is_depthwise = in_channels == groups and weight.dim() < input_tensor.dim()
+    depthwise = is_depthwise_conv(groups, in_channels)
 
     if len(input_tensor.shape) == 3:
         # 1D conv: input is [N, L, C] -> [N, C, L]
         input_tensor = input_tensor.movedim(-1, 1).contiguous()
-        if is_depthwise:
+        if depthwise:
             # 1D depthwise: weight is [K, OC] -> [OC, 1, K]
             weight = weight.permute(1, 0).unsqueeze(1).contiguous()
         else:
@@ -1124,7 +1120,7 @@ def quantized_conv2d_nhwc_per_tensor(
     else:
         # 2D conv: input is [N, H, W, C] -> [N, C, H, W]
         input_tensor = input_tensor.movedim(-1, -3)
-        if is_depthwise:
+        if depthwise:
             # 2D depthwise: weight is [KH, KW, OC] -> [OC, 1, KH, KW]
             weight = weight.permute(2, 0, 1).unsqueeze(1).contiguous()
         else:

backends/cadence/aot/replace_ops.py

@@ -26,6 +26,7 @@
     register_cadence_pass,
     RemoveOrReplacePassInterface,
 )
+from executorch.backends.cadence.aot.utils import is_depthwise_conv
 from executorch.backends.transforms.replace_scalar_with_tensor import (
     ReplaceScalarWithTensorArgPass,
 )
@@ -1138,19 +1139,19 @@ def maybe_remove_or_replace(self, node: torch.fx.Node) -> bool:
 
         # Check if this is a depthwise convolution (groups == input_channels)
         # and weight is 4D with shape [OC, 1, KH, KW]
-        groups = node.args[6]
+        groups = cast(int, node.args[6])
         input_shape = input_node.meta["val"].shape
         weight_shape = weight_node.meta["val"].shape
         input_channels = input_shape[1]  # NCHW format, channels at index 1
-        # Depthwise conv has 4D weight [OC, 1, KH, KW] where the IC dim is 1
-        is_depthwise = groups == input_channels and weight_shape[1] == 1
+        # NCHW: also verify weight IC dim == 1.
+        depthwise = is_depthwise_conv(groups, input_channels) and weight_shape[1] == 1
         is_2d = len(input_shape) == 4
         # Insert transpose operations before the node
         with graph.inserting_before(node):
             # Convert input from NCHW to NHWC
             input_nhwc = self._change_nchw_to_nhwc(graph, input_node)
             # Convert weight from NCHW to the appropriate format
-            if is_depthwise:
+            if depthwise:
                 # For depthwise: [OC, 1, KH, KW] -> [KH, KW, OC] for NNLib
                 weight_nhwc = self._change_depthwise_weight_to_hwc(
                     graph, weight_node, is_2d

backends/cadence/aot/tests/test_ref_implementations.py

@@ -14,6 +14,7 @@
 import numpy as np
 import torch
 from executorch.backends.cadence.aot.typing_stubs import expand
+from executorch.backends.cadence.aot.utils import is_depthwise_conv
 
 from executorch.exir.scalar_type import ScalarType
 
@@ -942,12 +943,22 @@ def test_quantized_conv_per_tensor(
         assert memory_format in [torch.contiguous_format, torch.channels_last]
 
         if memory_format == torch.channels_last:
+            in_channels = input_tensor.shape[1]  # NCHW still at this point
+            depthwise = is_depthwise_conv(groups, in_channels)
             if input_tensor.ndim == 3:
                 input_tensor = input_tensor.movedim(1, -1)
-                weight = weight.movedim(1, -1)
+                if depthwise:
+                    # [OC, 1, K] -> [K, OC] (squeeze IC, move OC to end)
+                    weight = weight.squeeze(1).movedim(0, -1)
+                else:
+                    weight = weight.movedim(1, -1)
             else:
                 input_tensor = input_tensor.movedim(-3, -1)
-                weight = weight.movedim(-3, -1)
+                if depthwise:
+                    # [OC, 1, KH, KW] -> [KH, KW, OC] (squeeze IC, move OC to end)
+                    weight = weight.squeeze(1).movedim(0, -1)
+                else:
+                    weight = weight.movedim(-3, -1)
 
         convs = [
             (