Consider removing Shl and Shr from SSA IR

[kevaundray]

Problem

Shift left and Shift right are converted into multiplication or division by a power two. Unlike normal CPU architectures where shift left and shift right are efficient, it is not the case for the SNARK context.

Happy Case

We can convert the shifts into multiplications and divisions and add a pow binary operator.

The pow binary operator would allow us to do x^y. We can use it for shift left and shift right where x=2.

In ACIR gen we will still need to figure out how to handle the case where y is a witness. See #1478 and #1479 for more context.

Alternatives Considered

No response

Additional Context

No response

Would you like to submit a PR for this Issue?

No

Support Needs

No response

[guipublic]

Closing as completed by #2072