Fix missing .items() in duplicate consant node

exir/backend/canonical_partitioners/duplicate_constant_node_pass.py

@@ -107,19 +107,14 @@ def duplicate_constant_node(
                             for arg in users[ith].args
                         ]
                     )
-                    new_kwargs = dict(
-                        {
-                            (
-                                key,
-                                (
-                                    value
-                                    if value != constant_or_attribute_node
-                                    else copied_constant_or_attribute_node
-                                ),
-                            )
-                            for key, value in users[ith].kwargs
-                        }
-                    )
+                    new_kwargs = {
+                        key: (
+                            value
+                            if value != constant_or_attribute_node
+                            else copied_constant_or_attribute_node
+                        )
+                        for key, value in users[ith].kwargs.items()
+                    }
                     users[ith].args = new_args
                     users[ith].kwargs = new_kwargs
                     if old_input_spec.kind == InputKind.CONSTANT_TENSOR:

exir/backend/test/test_passes.py

@@ -46,3 +46,43 @@ def forward(self, x):
         FileCheck().check("b_const_copy_0").run(
             edge.exported_program().graph_module.code
         )
+
+    def test_duplicate_constant_node_with_kwargs_users(self) -> None:
+        """
+        Test that duplicate_constant_node correctly handles nodes where users
+        reference the constant via kwargs (not just args).
+        """
+
+        class ModelWithBuffer(torch.nn.Module):
+            def __init__(self):
+                super().__init__()
+                self.register_buffer("const_buffer", torch.tensor([1.0, 2.0, 3.0]))
+
+            def forward(self, x: torch.Tensor) -> torch.Tensor:
+                return x + self.const_buffer + x * self.const_buffer
+
+        model = export(ModelWithBuffer(), (torch.randn(3),), strict=True).module()
+        edge = exir.to_edge(torch.export.export(model, (torch.randn(3),), strict=True))
+
+        # Find the buffer node
+        buffer_node = None
+        for node in edge.exported_program().graph.nodes:
+            if node.op == "placeholder" and is_buffer(edge.exported_program(), node):
+                buffer_node = node
+                break
+
+        # Move buffer reference from args to kwargs for one user
+        users = list(buffer_node.users.keys())
+        user = users[1]
+        user.args = tuple(a for a in user.args if a is not buffer_node)
+        user.kwargs = {"other": buffer_node}
+
+        # Patch validation since we modified the graph
+        edge.exported_program()._validate = lambda: None
+
+        copied_nodes = duplicate_constant_node(
+            edge.exported_program(), buffer_node.name
+        )
+
+        self.assertEqual(len(copied_nodes), 1)
+        self.assertNotEqual(user.kwargs["other"], buffer_node)