From abadaa6eccc68a9ebe8f4d3d19eb89cb96fa923c Mon Sep 17 00:00:00 2001
From: Github Executorch <github_executorch@arm.com>
Date: Wed, 11 Feb 2026 16:44:33 -0800
Subject: [PATCH] Reverts the addition of `RemoveNoopPass` to the Cortex-M pass
 manager (introduced in #17300) which broke 8 quantization tests.

After #17300 merged, the following tests started failing:
- `test_shared_qspec_quantizer[input_fork_x_shared]`
- `test_shared_qspec_quantizer[input_fork_y_shared]`
- `test_shared_qspec_quantizer[surrounded_quantized_op]`
- `test_shared_qspec_quantizer[output_fork_shared]`
- `test_shared_qspec_quantizer[many_forks]`
- `test_dialect_mv2[mobilenet_v2]` (+ 2 more)

`RemoveNoopPass` removes `clone_dim_order` operators that are functionally necessary for shared quantization specs. It only checks dtype equality, not dim_order/layout changes, causing it to incorrectly remove clones needed for:
- Tensor forking in quantized graphs
- Shared quantization parameter propagation
- Correct quantization fusion

Remove `RemoveNoopPass` from the Cortex-M pass pipeline. The MobileNetV2 `clone_dim_order` issue it was meant to address needs a more targeted solution.

```bash
pytest -c backends/arm/test/pytest.ini backends/cortex_m/test/misc/test_quantization.py::test_shared_qspec_quantizer -v
pytest -c backends/arm/test/pytest.ini backends/cortex_m/test/models/test_mobilenet_v2.py::test_dialect_mv2 -v
---
 backends/cortex_m/passes/cortex_m_pass_manager.py  | 2 --
 backends/cortex_m/test/models/test_mobilenet_v2.py | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/backends/cortex_m/passes/cortex_m_pass_manager.py b/backends/cortex_m/passes/cortex_m_pass_manager.py
index 850b1e106d0..43be3f77fd5 100644
--- a/backends/cortex_m/passes/cortex_m_pass_manager.py
+++ b/backends/cortex_m/passes/cortex_m_pass_manager.py
@@ -8,7 +8,6 @@
 
 from executorch.backends.arm._passes import (
     FoldAndAnnotateQParamsPass,
-    RemoveNoopPass,
     ScalarsToAttributePass,
 )
 from executorch.backends.transforms.remove_getitem_op import RemoveGetItemPass
@@ -35,7 +34,6 @@ class CortexMPassManager(PassManager):
         # Run before folding so qparams attach to max_pool2d values, not tuple + getitem.
         RemoveGetItemPass,
         FoldAndAnnotateQParamsPass,
-        RemoveNoopPass,
         ReplaceScalarWithTensorArgPass,
         ReplaceQuantNodesPass,
         ActivationFusionPass,
diff --git a/backends/cortex_m/test/models/test_mobilenet_v2.py b/backends/cortex_m/test/models/test_mobilenet_v2.py
index 792a0e3800b..9260864618b 100644
--- a/backends/cortex_m/test/models/test_mobilenet_v2.py
+++ b/backends/cortex_m/test/models/test_mobilenet_v2.py
@@ -34,6 +34,7 @@
     "executorch_exir_dialects_edge__ops_cortex_m_quantized_conv2d_default": 35,
     "executorch_exir_dialects_edge__ops_cortex_m_quantized_depthwise_conv2d_default": 17,
     "executorch_exir_dialects_edge__ops_cortex_m_quantized_linear_default": 1,
+    "executorch_exir_dialects_edge__ops_dim_order_ops__clone_dim_order_default": 1,
 }
 
 # Use larger sample set for calibration to get better quantization