[TensorExpr] simplification of round + mod pattern. (#35683)
Summary:
Adds capabilities to the TensorExpr IR Simplifier to simplify down Round + Mod patterns (e.g. `(x/y)*y + x%y => x`) via means of lifting integer rounding into a temporary `RoundOff` node.
This integrates with existing simplification mechanisms (folding, factorization, reordering, etc) to allow simplification of compound expressions: e.g. `20 * (x / (16 / 2)) * 2 + (11 % 6) * (x % (7+1)) => 5 * x.`.
Tests: ran tensorexpr cpp and python tests, ran a hpc benchmark and verified results and time didn't regress.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/35683
Differential Revision: D20811316
Pulled By: nickgg
fbshipit-source-id: 0cd6a517fb9548b3bc689768304b97375df5ac58
