In my experience, international students have a natural advantage with comp lit programs if their native language is a language that they want to study and/or they've received their undergrad education in a country that speaks one of the languages they study. But if you're just an international student whose home country/country where you studied has no relation to what you study then it probably doesn't make much of a difference (barring the recruitment of "diversity," whatever that means).
Also I think adcoms probably prefer known quantities, so if your undergrad was from a very obscure program in a country whose educational system they aren't familiar with, it might be a disadvantage. If you're from Canada or England or somewhere else known for great schools, then they have probably accepted people from your school before, so it's almost the same as being American.