pub fn ext2felt_circuit(&mut self, value: Ext<C::F, C::EF>) -> [Felt<C::F>; 4] {
        let a = self.uninit();
        let b = self.uninit();
        let c = self.uninit();
        let d = self.uninit();
        self.push_op(DslIr::CircuitExt2Felt([a, b, c, d], value));
        [a, b, c, d]
    }
Converts an ext to a slice of felts inside a circuit.
crates/recursion/compiler/src/ir/utils.rs