Method decode_from_value

cranelift/codegen/src/ir/instructions.rs:234–244

Decode a raw `Value` encoding of this block argument.

(v: Value)

    /// Decode a raw `Value` encoding of this block argument.
    fn decode_from_value(v: Value) -> Self {
        let raw = v.as_u32();
        let tag = raw >> 30;
        let payload = raw & ((1 << 30) - 1);
        match tag {
            0 => BlockArg::Value(Value::from_bits(payload)),
            1 => BlockArg::TryCallRet(payload),
            2 => BlockArg::TryCallExn(payload),
            _ => unreachable!(),
        }
    }

    /// Return this argument as a `Value`, if it is one, or `None`
    /// otherwise.