Throw on data dependent ops (#83567)
Previously, we would trace through the following with no error:
```
from torch.fx.experimental.proxy_tensor import make_fx
import torch
def f(x, y):
return x[0, y:]
```
Even though the output shape is dependent on the data of `y`. Now, throw on the conversion of `y` to an integer.
It would be nice to not break on constant tensors but I'll do that as the next PR (Edit: done with https://github.com/pytorch/pytorch/pull/84387). Sketching out how that would work (and keep in mind this is applicable Dynamo tracing and not just AOT Autograd)
I think to do that you would need to :
- hold strong refs to a set of constant tensors, and only allow them to be captured from `lift_fresh.copy`
- when you run a mutable op, either remove it from the set of constant tensors or run the operator for real
- limit to small constant tensors
Anything else ?
Pull Request resolved: https://github.com/pytorch/pytorch/pull/83567
Approved by: https://github.com/ezyang
