test/jit/test_fuser_common.py

import torch
from torch.testing._internal.jit_utils import JitTestCase

class TestFuserCommon(JitTestCase):
    def test_autodiff_fallback(self):
        for rq in [True, False]:
            @torch.jit.script
            def fn(x):
                return torch.max(x**2.0, x**3.0)

            x = torch.randn(5, requires_grad=not rq)
            # cause optimization to be created
            for i in range(5):
                fn(x)
            # test fallback when optimization is not applicable
            y = fn(torch.randn(5, requires_grad=rq))
            self.assertEqual(y.requires_grad, rq)