ACIR gen / ACVM: Handle predicates in non-inlined ACIR

[vezenovm]

Problem

We currently don't handle predicates in ACIR calls. For example this program where enable is false and input is not equal to 42 will fail.

fn main(
    value: Field,
    enable: bool
) -> pub Field {
    let mut result = 0;
    if enable { 
        result = assert_is_42(value);
    }
    result
}

#[fold]
fn assert_is_42(input: Field) -> Field {
    assert_eq(input, 42);
    input
}

Happy Case

We should handle predicates in ACIR function calls as we would expect if they were normally inlined. Simply adding a predicate to an ACIR Call opcode should be sufficient. This is because we expect the person proving the circuit to also be the one executing. The pseudocode in this comment is attempting to solve something that is not an issue for us. Needing to guarantee some certain call stack order is only necessary if we had someone else executing our circuit for us. In this case we would need a full VM to differentiate between incorrect execution and a malicious prover, which we do not need for an individual who is performing the proving themselves, as you trust yourself.

Project Impact

None

Impact Context

No response

Workaround

None

Workaround Description

No response

Additional Context

No response

Would you like to submit a PR for this Issue?

None

Support Needs

No response

[vezenovm]

Resolved by AztecProtocol/aztec-packages#5616