Load a register value into an LLVM value.
          Example: v = load_reg(IntType(32), "eax")

def load_reg(self, reg_type, reg_name, name=''):
        """
        Load a register value into an LLVM value.
          Example: v = load_reg(IntType(32), "eax")
        """
        ftype = types.FunctionType(reg_type, [])
        return self.asm(ftype, "", "={%s}" % reg_name, [], False, name)