Arm backend: Remove redundant pass insertions (#19448)

Decompositions of GRU, LSTM and RNN were inserted in the Arm backend
pass pipeline even though these operators would have been decomposed in
the core-ATen legalization. Also moves tests from test/passes/ to
test/modules/ as the tests are end-to-end tests rather than isolated
pass tests.


cc @digantdesai @freddan80 @per @zingo @mansnils @Sebastian-Larsson
@robell

Signed-off-by: Oscar Andersson <oscar.andersson@arm.com>

Author: oscarandersson8218

backends/arm/_passes/arm_pass_manager.py

@@ -399,9 +399,6 @@ def _tosa_pipeline(
                 ConvertToClampPass(),
                 DecomposeTOSAUnsupportedClampPass(),
                 DecomposeGroupNormPass(),
-                DecomposeGruPass(),
-                DecomposeLstmPass(),
-                DecomposeRnnPass(),
                 DecomposeLayerNormPass(),
                 DecomposeVarPass(),
                 DecomposeMeanDimPass(exported_program.graph_module, self.tosa_spec),

backends/arm/_passes/decompose_gru_pass.py

@@ -1,5 +1,6 @@
 # Copyright (c) Meta Platforms, Inc. and affiliates.
 # All rights reserved.
+# Copyright 2026 Arm Limited and/or its affiliates.
 #
 # This source code is licensed under the BSD-style license found in the
 # LICENSE file in the root directory of this source tree.
@@ -13,7 +14,6 @@
     create_node,
     get_getitem_users,
 )
-from executorch.backends.arm._passes.insert_table_ops import InsertTableOpsPass
 from executorch.exir.pass_base import ExportPass, PassResult
 
 
@@ -34,7 +34,7 @@ class DecomposeGruPass(ArmPass):
 
     """
 
-    _passes_required_after: Set[Type[ExportPass]] = {InsertTableOpsPass}
+    _passes_required_after: Set[Type[ExportPass]] = set()
 
     _TARGET = torch.ops.aten.gru.input
 

backends/arm/_passes/decompose_lstm_pass.py

@@ -1,5 +1,6 @@
 # Copyright (c) Meta Platforms, Inc. and affiliates.
 # All rights reserved.
+# Copyright 2026 Arm Limited and/or its affiliates.
 #
 # This source code is licensed under the BSD-style license found in the
 # LICENSE file in the root directory of this source tree.
@@ -13,7 +14,6 @@
     create_node,
     get_getitem_users,
 )
-from executorch.backends.arm._passes.insert_table_ops import InsertTableOpsPass
 from executorch.exir.pass_base import ExportPass, PassResult
 
 
@@ -36,7 +36,7 @@ class DecomposeLstmPass(ArmPass):
 
     """
 
-    _passes_required_after: Set[Type[ExportPass]] = {InsertTableOpsPass}
+    _passes_required_after: Set[Type[ExportPass]] = set()
 
     _TARGET = torch.ops.aten.lstm.input
 

backends/arm/_passes/decompose_rnn_pass.py

@@ -1,5 +1,6 @@
 # Copyright (c) Meta Platforms, Inc. and affiliates.
 # All rights reserved.
+# Copyright 2026 Arm Limited and/or its affiliates.
 #
 # This source code is licensed under the BSD-style license found in the
 # LICENSE file in the root directory of this source tree.
@@ -13,7 +14,6 @@
     create_node,
     get_getitem_users,
 )
-from executorch.backends.arm._passes.insert_table_ops import InsertTableOpsPass
 from executorch.exir.pass_base import ExportPass, PassResult
 
 
@@ -30,7 +30,7 @@ class DecomposeRnnPass(ArmPass):
 
     """
 
-    _passes_required_after: Set[Type[ExportPass]] = {InsertTableOpsPass}
+    _passes_required_after: Set[Type[ExportPass]] = set()
 
     _TARGETS = {
         torch.ops.aten.rnn_tanh.input,