This PR moves the definitions for:
* `sym_int`
* `sym_ceil` (used only for `sym_int`)
* `sym_floor` (used only for `sym_int`)
* `sym_float`
from `torch/fx/experimental/symbolic_shapes.py` to `torch/__init__.py`, where `SymInt` and `SymFloat` are already defined.
This removes the need for several in-line imports, and enables proper JIT script gating for #91318. I'm very open to doing this in a better way!
Pull Request resolved: https://github.com/pytorch/pytorch/pull/91317
Approved by: https://github.com/ezyang, https://github.com/anijain2305
**Introduces symbolic shape guards into dynamo.**
In this PR, we take the existing fake tensor infra and plumbing in dynamo and we start passing a shape_env around. This shape_env does not get plumbed down to middle layers / backend yet - it only collects expressions from frontend invocations at the moment. We then translate these expressions into guards at the point where we take other guards installed throughout dynamo - and add them to check_fn.
Part 1 of https://docs.google.com/document/d/1QJ-M4zfMkD-fjHIqW089RptjLl9EgozZGCceUbvmgfY/edit#
cc @jansel @lezcano @fdrocha @mlazos @soumith @yanboliang @penguinwu @anijain2305
Pull Request resolved: https://github.com/pytorch/pytorch/pull/87570
Approved by: https://github.com/ezyang
