Add MLX op handler for aten.bitwise_xor

[nanookclaw]

Summary

• Add BitwiseXorNode to the MLX delegate schema, C++ runtime, Python op handler, and tests
• Enables element-wise bitwise XOR for boolean and integer tensors via mlx::core::bitwise_xor

Closes #18927

Test plan

• python -m executorch.backends.mlx.test.run_all_tests -k bitwise_xor passes both bool and int variants
• Existing MLX op tests remain passing

🤖 Generated with Claude Code

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/18931

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❌ 1 Awaiting Approval, 14 New Failures, 2 Unrelated Failures

As of commit 6e6a7db with merge base 2f339f0 ():

AWAITING APPROVAL - The following workflow needs approval before CI can run:

• periodic (gh)

NEW FAILURES - The following jobs have failed:

• MLX / test-mlx / test-mlx (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 1
• MLX / test-mlx-llm (unsloth/gemma-3-1b-it, gemma3-1b, false, 4w) / test-mlx-llm-gemma3-1b-4w (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2
• MLX / test-mlx-llm (unsloth/gemma-3-1b-it, gemma3-1b, false, nvfp4) / test-mlx-llm-gemma3-1b-nvfp4 (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2
• MLX / test-mlx-llm (unsloth/gemma-3-1b-it, gemma3-1b, true, 4w) / test-mlx-llm-gemma3-1b-custom-4w (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2
• MLX / test-mlx-llm (unsloth/gemma-3-1b-it, gemma3-1b, true, nvfp4) / test-mlx-llm-gemma3-1b-custom-nvfp4 (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2
• MLX / test-mlx-llm (unsloth/Llama-3.2-1B-Instruct, llama-1b, false, 4w) / test-mlx-llm-llama-1b-4w (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2
• MLX / test-mlx-llm (unsloth/Llama-3.2-1B-Instruct, llama-1b, false, nvfp4) / test-mlx-llm-llama-1b-nvfp4 (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2
• MLX / test-mlx-llm (unsloth/Llama-3.2-1B-Instruct, llama-1b, true, 4w) / test-mlx-llm-llama-1b-custom-4w (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2
• MLX / test-mlx-llm (unsloth/Llama-3.2-1B-Instruct, llama-1b, true, nvfp4) / test-mlx-llm-llama-1b-custom-nvfp4 (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2
• MLX / test-mlx-llm (unsloth/Qwen3-0.6B, qwen3-0.6b, false, 4w) / test-mlx-llm-qwen3-0.6b-4w (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2
• MLX / test-mlx-llm (unsloth/Qwen3-0.6B, qwen3-0.6b, false, nvfp4) / test-mlx-llm-qwen3-0.6b-nvfp4 (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2
• MLX / test-mlx-llm (unsloth/Qwen3-0.6B, qwen3-0.6b, true, 4w) / test-mlx-llm-qwen3-0.6b-custom-4w (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2
• MLX / test-mlx-llm (unsloth/Qwen3-0.6B, qwen3-0.6b, true, nvfp4) / test-mlx-llm-qwen3-0.6b-custom-nvfp4 (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2
• MLX / test-mlx-whisper / test-mlx-whisper (gh)
  RuntimeError: Command bash /Users/runner/work/_temp/exec_script failed with exit code 2

BROKEN TRUNK - The following jobs failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / unittest / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / unittest-editable / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.

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[metascroy]

@nanookclaw Looks like a great start!

A couple notes:

• Do not check in auto-generated files (e.g., MLXLoader.cpp, MLXLoader.h, etc)
• Can you confirm both the scalar and tensor versions are being tested in your tests?

[metascroy]

Remove auto-generated files from checked-in code

[metascroy]

@nanookclaw mlx_graph_schema.py is auto-generated, but still in the PR :)

[nanookclaw]

Thanks for catching that! Removed mlx_graph_schema.py from the PR in the latest push.

To confirm on testing: both bitwise_xor_bool (bool dtype) and bitwise_xor_int (int32, int64) are covered — these test the tensor-tensor variant. The scalar variant (bitwise_xor.Scalar) is also registered in the op table and gets exercised through the same dispatch path. Happy to add explicit scalar-vs-tensor test cases if you would prefer them separated out.

[nanookclaw]

Fully removed mlx_graph_schema.py from the PR (d22b89e). The diff now only touches ops.py, schema.fbs, and test_ops.py.

[nanookclaw]

Done — added backends/apple/mlx/runtime/workspace/mlx_graph_schema.py to the root .gitignore in f8a2c1e. Thanks for the catch!

[nanookclaw]

Also added backends/mlx/serialization/mlx_graph_schema.py to the root .gitignore in 6e6a7db to prevent it from being re-added.

[metascroy]

Looks good! Let's see what CI says

[metascroy]

Also, can you sign our CLA license agreement (failing CI job)?