Qualcomm AI Engine Direct - Adding QNN backend support for var core ATen ops

[qti-horodnic]

Summary

Added support for the core ATen ops var.correction and var.dim via a decomposition pass using:

var(x, dim) = mean((x - mean(x, dim, keepdim=True))^2, dim, keepdim) * N / (N - correction)

Where var.correction is an optional scalar (default=1) and for var.dim unbiased=True -> correction=1, unbiased=False -> correction=0.

Also added a couple of test cases for the select_scatter op per a suggestion in another pr.

Test plan

python backends/qualcomm/tests/test_qnn_delegate.py -k TestQNNQuantizedOperator.test_qnn_backend_var --model SM8750 --host aisw-vm15-labsd --device 545ee4aa --build_folder build-android

python backends/qualcomm/tests/test_qnn_delegate.py -k TestQNNFloatingPointOperator.test_qnn_backend_var --model SM8750 --host aisw-vm15-labsd --device 545ee4aa --build_folder build-android

cc @cccclai @cbilgin @abhinaykukkadapu

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/19722

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❌ 5 New Failures

As of commit c54f8ca with merge base af92b60 ():

NEW FAILURES - The following jobs have failed:

• pull / android / run-emulator (gh)
  The process '/usr/local/lib/android/sdk/platform-tools/adb' failed with exit code 224
• pull / test-qnn-wheel-packages-linux (3.10) / linux-job (gh)
  RuntimeError: Command docker exec -t 38eb716db90d924e845ce5186086d014a51c771993d0b4264476dea86191ed57 /exec failed with exit code 1
• pull / test-qnn-wheel-packages-linux (3.11) / linux-job (gh)
  RuntimeError: Command docker exec -t c445cfbcf066cfd3344290246704ab3733552a8d8572463c1facb49338559a30 /exec failed with exit code 1
• pull / test-qnn-wheel-packages-linux (3.12) / linux-job (gh)
  RuntimeError: Command docker exec -t e9a5c85898106e1082aa03508683dbaad892d6747e97764e5bfefc94fd587156 /exec failed with exit code 1
• pull / test-qnn-wheel-packages-linux (3.13) / linux-job (gh)
  RuntimeError: Command docker exec -t 04c5af6f041348c8a59ecca3e44a8ef39a2ff64227573320eb8b66b044dc8fb7 /exec failed with exit code 1

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[qti-horodnic]

@pytorchbot label "release notes: qualcomm"

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: qti-horodnic / name: Arik Horodniceanu (4df3d21)

[qti-horodnic]

The committers listed above are authorized under a signed CLA.

• ✅ login: qti-horodnic / name: Arik Horodniceanu (93d7f6f)

[psiddh]

The committers listed above are authorized under a signed CLA.

• ✅ login: qti-horodnic / name: Arik Horodniceanu (c54f8ca)

[qti-horodnic]

Hi @psiddh

The CLA has been signed for this PR and the other open ones, feel free to merge them at your earliest convenience:
#19785
#19826

[psiddh]

Lint failures on the PR, pls check

[qti-horodnic]

Lint failures on the PR, pls check

@psiddh

Resolved now, thanks

[qti-horodnic]

@psiddh

Hi, can we merge this pr or did you want any other changes?

[psiddh]

Lgtm, I will merge it once the CI passes basic sanity tests.