This patch involves boolean ring to simplify logical operations. We can treat `&` as ring multiplication and `^` as ring addition.
So we need to canonicalize all other operations to `*` `+`. Like:
```
a & b -> a * b
a ^ b -> a + b
~a -> a + 1
a | b -> a * b + a + b
c ? a : b -> c * a + (c + 1) * b
```
In the code, we use a mask set to represent an expression. Every value that is not comes from logical operations could be a bit in the mask.
The mask itself is a multiplication chain. The mask set is an addiction chain.
We can calculate two expressions based on boolean algebras.
For now, the initial patch only enabled on and/or/xor, Later we can enhance the code step by step.
Reference: https://en.wikipedia.org/wiki/Boolean_ring
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D142803
97dcbea63e