Completely redo how ShapeEnv guards are generated (#90528)
Instead of inferring shape mappings from a bunch of data structures that were plumbed in InstructionTranslator, we instead work out mappings by just iterating over the GraphArgs and mapping symbols to arguments as they show up. If multiple argument sizes/strides/offset map to the same symbol, this means they are duck sized, so we also generate extra equality tests that they must be equal. Finally, we generate 0/1 specialization guards. The resulting code is much shorter, and I think also easier to understand.
TODO: Delete all the tensor ref tracking code, it's unnecessary
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/90528
Approved by: https://github.com/voznesenskym
