Reverts the addition of RemoveNoopPass to the Cortex-M pass manager…

[psiddh]

… (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.

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

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/17407

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❌ 2 New Failures, 84 Pending

As of commit abadaa6 with merge base 429925d ():

NEW FAILURES - The following jobs have failed:

• pull / test-multimodal-linux (gemma3-4b) / linux-job (gh)
  RuntimeError: Command docker exec -t 7dfead63317d8e8d0670b6aa61f4f8ac1103d2e3225460814e79b796067772a3 /exec failed with exit code 139
• trunk / test-mcu-cortex-m-backend / linux-job (gh)
  RuntimeError: Command docker exec -t a8f7eb531c01bcb0ca54f64c79e3a83db6d1d16bed2875f00a356def2e121ace /exec failed with exit code 1

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[Copilot]

Pull request overview

Reverts the recently-added RemoveNoopPass from the Cortex-M pass pipeline to prevent incorrect removal of _clone_dim_order ops that are required for shared quantization spec behavior (fixing the quantization test regressions introduced in #17300).

Changes:

• Remove RemoveNoopPass from CortexMPassManager to preserve necessary clone_dim_order ops.
• Update the MobileNetV2 Cortex-M dialect test expectations to include one remaining clone_dim_order op after transforms.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
backends/cortex_m/passes/cortex_m_pass_manager.py	Drops RemoveNoopPass from the Cortex-M pass list to avoid stripping required dim-order clones.
backends/cortex_m/test/models/test_mobilenet_v2.py	Updates expected op counts to reflect that clone_dim_order is no longer removed by the pass pipeline.

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[psiddh]

Failing mcu test will be fixed by this #17405

[AdrianLundell]

Hi, have you considered adding cortex-m unittests to your CI?

[AdrianLundell]

Now the mv2 test is failing instead...

[psiddh]

Now the mv2 test is failing instead...

Should be fixed by #17405.

Yes adding unittests in the next PR, moreover enabling test-mcu-cortex-m-backend / linux-job to run on diff times