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Async generators not JIT-compiled on aarch64 (CANNOT_SPECIALIZE) #1

Description

@SonicField

Async generators not JIT-compiled on aarch64 (CANNOT_SPECIALIZE)

Async generators (async def with yield) return PYJIT_RESULT_CANNOT_SPECIALIZE when the JIT attempts to compile them on aarch64. They fall back to the CPython interpreter - no crash, but no JIT speedup.

Affected tests (3/33 failures)

  • TestAsyncGenerator::test_async_generator_basic - FAILED
  • TestAsyncGenerator::test_async_generator_yield_from - FAILED
  • TestGeneratorJITCompilation::test_generator_jit_compilation - FAILED

Root cause

The CinderX specialiser does not have a code path for async generator compilation. Regular generators and coroutines work, but async generators need additional specialisation.

Impact

  • PyTorch training: likely negligible (uses regular generators for dataloaders)
  • vLLM inference: significant (uses async generators for streaming)

Reference: T194022335

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