Handle new dims for repeat in pass

backends/arm/_passes/arm_pass_manager.py

@@ -41,6 +41,9 @@
     ScalarsToAttributePass,
 )
 from executorch.backends.arm._passes.size_adjust_conv2d_pass import SizeAdjustConv2DPass
+from executorch.backends.arm._passes.unsqueeze_before_repeat_pass import (
+    UnsqueezeBeforeRepeatPass,
+)
 from executorch.backends.arm._passes.unsqueeze_scalar_placeholders_pass import (
     UnsqueezeScalarPlaceholdersPass,
 )
@@ -66,6 +69,7 @@ def transform_to_backend_pipeline(
         self.add_pass(RemoveClonePass())
         self.add_pass(ConvertExpandCopyToRepeatPass())
         self.add_pass(DecomposeLayerNormPass())
+        self.add_pass(UnsqueezeBeforeRepeatPass())
         self.add_pass(DecomposeVarPass())
         self.add_pass(ConvertMeanDimToAveragePool())
         self.add_pass(DecomposeMeanDimPass())

backends/arm/_passes/unsqueeze_before_repeat_pass.py

@@ -0,0 +1,62 @@
+# Copyright 2024 Arm Limited and/or its affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+# pyre-unsafe
+import torch
+import torch.fx
+from executorch.backends.arm._passes.arm_pass_utils import (
+    create_node,
+    get_first_fake_tensor,
+)
+from executorch.exir.dialects._ops import ops as exir_ops
+from executorch.exir.pass_base import ExportPass, PassResult
+
+
+class UnsqueezeBeforeRepeatPass(ExportPass):
+    """
+    A TOSA TILE op only supports rank(in) == rank(out).
+    To support Pytorch's repeat which can also add dimensions,
+    we add an explicit view op before which adds the new dimensions.
+    New dimensions are appendend at the front, see
+    https://pytorch.org/docs/stable/generated/torch.Tensor.expand.html
+
+    Original:
+        repeat(multiples)
+    After pass:
+        view(shape = [1]*num_new_dims + old_shape)
+        repeat(multiples)
+    """
+
+    def call(self, graph_module: torch.fx.GraphModule):
+        modified_graph = False
+        for node in graph_module.graph.nodes:
+            if node.op != "call_function":
+                continue
+            if node.target != exir_ops.edge.aten.repeat.default:
+                continue
+
+            old_shape = list(get_first_fake_tensor(node.all_input_nodes[0]).shape)
+            old_rank = len(old_shape)
+            multiples = node.args[1]
+            new_rank = len(multiples)
+            if old_rank == new_rank:
+                continue
+
+            num_new_dims = new_rank - old_rank
+            new_shape = [1] * num_new_dims + old_shape
+
+            with graph_module.graph.inserting_before(node):
+                view_node = create_node(
+                    graph_module.graph,
+                    exir_ops.edge.aten.view_copy.default,
+                    (node.all_input_nodes[0], new_shape),
+                )
+                node.replace_input_with(node.all_input_nodes[0], view_node)
+            modified_graph = True
+
+        if modified_graph:
+            graph_module.recompile()
+            graph_module = super().call(graph_module).graph_module
+        return PassResult(graph_module, modified_graph)

backends/arm/operators/op_repeat.py

@@ -32,37 +32,8 @@ def define_node(
         is_quant_node: bool,
     ) -> None:
 
-        item_name = inputs[0].name
-        shape = inputs[0].shape
-        rank = len(shape)
         multiples = inputs[1].special
-        new_rank = len(multiples)
-
-        assert new_rank >= rank
-
-        # TILE only supports rank(in) == rank(out). To add more dims, we need a reshape first.
-        if new_rank > rank:
-            # Add length 1 dimensions to shape to match multiples
-            num_new_dims = new_rank - rank
-            expanded_shape = tuple(
-                1 if i < num_new_dims else shape[i - num_new_dims]
-                for i in range(new_rank)
-            )
-            expanded_shape = tosa_shape(expanded_shape, output.dim_order)
-            dtype = (
-                ts.dtype_str_to_val("INT8")
-                if is_quant_node
-                else ts.dtype_str_to_val("FP32")
-            )
-
-            rescale_out = tosa_graph.addIntermediate(expanded_shape, dtype)
-            rescale_attr = ts.TosaSerializerAttribute()
-            rescale_attr.ReshapeAttribute(expanded_shape)
-            tosa_graph.addOperator(
-                TosaOp.Op().RESHAPE, [item_name], [rescale_out.name], rescale_attr
-            )
-            item_name = rescale_out.name
 
         attr = ts.TosaSerializerAttribute()
         attr.TileAttribute(tosa_shape(multiples, output.dim_order))
-        tosa_graph.addOperator(TosaOp.Op().TILE, [item_name], [output.name], attr)
+        tosa_graph.addOperator(TosaOp.Op().TILE, [inputs[0].name], [output.name], attr)

backends/arm/test/ops/test_repeat.py

@@ -37,6 +37,7 @@ class Repeat(torch.nn.Module):
             (torch.randn(3), (2, 2)),
             (torch.randn(3), (1, 2, 3)),
             (torch.randn((3, 3)), (2, 2, 2)),
+            (torch.randn((3, 3, 3)), (2, 1, 2, 4)),
         ]
 
         def forward(self, x: torch.Tensor, multiples: Sequence):
@@ -106,12 +107,20 @@ def test_repeat_tosa_MI(self, test_input, multiples):
     def test_repeat_tosa_BI(self, test_input, multiples):
         self._test_repeat_tosa_BI_pipeline(self.Repeat(), (test_input, multiples))
 
-    @parameterized.expand(Repeat.test_parameters)
+    @parameterized.expand(Repeat.test_parameters[:-1])
     def test_repeat_u55_BI(self, test_input, multiples):
         self._test_repeat_ethosu_pipeline(
             common.get_u55_compile_spec(), self.Repeat(), (test_input, multiples)
         )
 
+    # Final test requires transpose which is not supported on u55.
+    @parameterized.expand(Repeat.test_parameters[-1:])
+    @unittest.expectedFailure
+    def test_repeat_u55_BI_xfails(self, test_input, multiples):
+        self._test_repeat_ethosu_pipeline(
+            common.get_u55_compile_spec(), self.Repeat(), (test_input, multiples)
+        )
+
     @parameterized.expand(Repeat.test_parameters)
     def test_repeat_u85_BI(self, test_input, multiples):
         self._test_repeat_ethosu_pipeline(

backends/arm/test/passes/test_unsqueeze_before_repeat_pass.py

@@ -0,0 +1,74 @@
+# Copyright 2024 Arm Limited and/or its affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+import unittest
+
+import torch
+from executorch.backends.arm._passes.unsqueeze_before_repeat_pass import (
+    UnsqueezeBeforeRepeatPass,
+)
+from executorch.backends.arm.test import common
+from executorch.backends.arm.test.tester.arm_tester import ArmTester
+from executorch.backends.xnnpack.test.tester.tester import RunPasses
+
+
+class Repeat(torch.nn.Module):
+    """
+    Basic repeat model.
+    """
+
+    def forward(self, x: torch.Tensor):
+        return x.repeat(2, 2, 2, 2)
+
+
+class TestUnsqueezeBeforeRepeatPass(unittest.TestCase):
+    def test_tosa_MI_insert_view(self):
+        """
+        When rank(input) != number of repeated dimensions (=4 in Repeat module),
+        insert view.
+        """
+        module = Repeat()
+        inputs = (torch.rand((2, 3, 4)),)
+        test_pass_stage = RunPasses([UnsqueezeBeforeRepeatPass])
+        (
+            (
+                ArmTester(
+                    module,
+                    example_inputs=inputs,
+                    compile_spec=common.get_tosa_compile_spec("TOSA-0.80.0+MI"),
+                )
+                .export()
+                .to_edge()
+                .check(["aten_repeat_default"])
+                .check_not(["aten_view_copy_default"])
+                .run_passes(test_pass_stage)
+                .check(["aten_repeat_default", "aten_view_copy_default"])
+            )
+        )
+
+    def test_tosa_MI_dont_insert_view(self):
+        """
+        When rank(input) == number of repeated dimensions (=4 in Repeat module),
+        DON'T insert view.
+        """
+        module = Repeat()
+        inputs = (torch.rand((2, 3, 4, 1)),)
+        test_pass_stage = RunPasses([UnsqueezeBeforeRepeatPass])
+        (
+            (
+                ArmTester(
+                    module,
+                    example_inputs=inputs,
+                    compile_spec=common.get_tosa_compile_spec("TOSA-0.80.0+MI"),
+                )
+                .export()
+                .to_edge()
+                .check(["aten_repeat_default"])
+                .check_not(["aten_view_copy_default"])
+                .run_passes(test_pass_stage)
+                .check(["aten_repeat_default"])
+                .check_not(["aten_view_copy_default"])
+            )
+        )