Method join

cranelift/codegen/src/remove_constant_phis.rs:83–100

(self, other: AbstractValue)

impl AbstractValue {
    fn join(self, other: AbstractValue) -> AbstractValue {
        match (self, other) {
            // Joining with `None` has no effect
            (AbstractValue::None, p2) => p2,
            (p1, AbstractValue::None) => p1,
            // Joining with `Many` produces `Many`
            (AbstractValue::Many, _p2) => AbstractValue::Many,
            (_p1, AbstractValue::Many) => AbstractValue::Many,
            // The only interesting case
            (AbstractValue::One(v1), AbstractValue::One(v2)) => {
                if v1 == v2 {
                    AbstractValue::One(v1)
                } else {
                    AbstractValue::Many
                }
            }
        }
    }

    fn is_one(self) -> bool {
        matches!(self, AbstractValue::One(_))