Constrain statements are inefficient to Acir Gen

[kevaundray]

Problem

Currently constrain statements are seen as constrain <boolean>.

As an example, lets say we want to generate constraints for the following code:

constrain a == b

Ideally this uses 1 constraint which will approximately be a - b == 0.

In our case, it generates the following code:

let z = a == b;
constrain z;

The first line will generate constraints which will create a variable z which will indicate whether z is equal to b. This in turn creates an extra 2 constraints per equality used in a constrain statement.

Happy Case

There are many ways to solve this:

• We can add a pass after Acir Gen which optimizes this out
• We can change constrain bool to be constrain <expr> op <expr> so that when we process a constrain statement, we can apply the correct constraint.
• Possibly have the SSA IR handle this (needs more thought)

Alternatives Considered

No response

Additional Context

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Would you like to submit a PR for this Issue?

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