Bound shape inference for c2 (#16081)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/16081
A simple version of bound shape inference, conditioned on batch size. In addition to doing normal shape inference, it will change the batch size (1st dim of the shape) of the inputs as well as batch size modulating ops such as `SparseLengthsSum`. Probably support to more ops is needed, such as `SparseToDense`. We can build on this.
Reviewed By: jackm321, rdzhabarov
Differential Revision: D13661968
fbshipit-source-id: 6a724a647e109757c26e3e26e15a49725ecc75cc
