Add handling of symbolic shapes (#55925)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/55925
This sets up the initial handling of symbolic shapes. As in the test, it doesn't work perfectly yet because it needs a couple other optimization passes. The basic description is pretty simple: we resolve tensor dimension indices to the same Value *, and before extracting out the output Tensor shape we substitute in symbolic shapes. We don't substitute during optimization because they are represented as negative numbers so we don't want them inadvertently used in Constant prop or something else.
Test Plan: Imported from OSS
Reviewed By: ZolotukhinM
Differential Revision: D27750996
Pulled By: eellison
fbshipit-source-id: 6984e7276b578f96b00fc2025cef0e13f594b6e6
