Hoisting common expressions out of If blocks (#59492)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/59492
Adding code to find common expressions from the two subblocks of an if
operation and hoist them before the if block.
This also allows Dead Code Elimination to
then eliminate some if blocks.
Also eliminated some dead code in the codebase.
Test Plan:
python test_jit.py TestIfHoisting
Imported from OSS
Reviewed By: ngimel
Differential Revision: D29399533
fbshipit-source-id: 9336b9dc48c02c38862f98f98cd72fc1767a1802
