问如何使用llvm::IRBuilder Create Add/Sub/Mul/Div？

EN

using System;
namespace ConsoleApp1
{
    class Program
    {

        public static int Addition(int value1, int value2)
        {
            return value1 + value2;
        }
        public static int Subtraction(int value1, int value2)
        {
            return value1 - value2;
        }
        public static int Multiplication(int value1, int value2)
        {
            return value1 * value2;
        }
        public static double Division(double value1, double value2)
        {
            return value1 / value2;
        }

        static void Main(string[] args)
        {
            while (true)
            {
                Console.Write("\nEnter Value 1 : ");
                int a = Convert.ToInt32(Console.ReadLine());
                Console.Write("Enter Value 2 : ");
                int b = Convert.ToInt32(Console.ReadLine());

                Console.WriteLine("Please Enter action to be performed :");
                Console.WriteLine("1. Addition");
                Console.WriteLine("2. Subtraction");
                Console.WriteLine("3. Multiplication");
                Console.WriteLine("4. Division");

                int action = Convert.ToInt32(Console.ReadLine());
                string _operation = "";
                double result = 0;
                switch (action)
                {
                    case 1:
                        {
                            result = Addition(a, b);
                            _operation = "+";
                            break;
                        }
                    case 2:
                        {
                            result = Subtraction(a, b);
                            _operation = "-";
                            break;
                        }
                    case 3:
                        {
                            result = Multiplication(a, b);
                            _operation = "*";
                            break;
                        }
                    case 4:
                        {
                            result = Division(a, b);
                            _operation = "/";
                            break;
                        }
                }
                Console.WriteLine("Result A {0} B = {1}", _operation, result);

                char theKey = Console.ReadKey().KeyChar;

                if (theKey == 'y' || theKey == 'Y')
                {
                    Console.Clear();
                    continue;
                }
                else
                {
                    break;
                }
            }


        } 
    }
}