Can modern compilers unroll `for` loops expressed using begin and end iterators

Consider the following code

 vector<double> v;
 // fill v
 const vector<double>::iterator end =v.end();
 for(vector<double>::iterator i = v.bgin(); i != end; ++i) {
   // do stuff
 }

Are compilers like g++, clang++, icc able to unroll loops like this. Unfortunately I do not know assembly to be able verify from the output whether the loop gets unrolled or not. (and I only have access to g++.)

To me it seems that this will require more smartness than usual on behalf of the compiler, first to deduce that the iterator is a random access iterator, and then figure out the number of times the loop is executed. Can compilers do this when optimization is enabled ?

Thanks for your replies, and before some of you start lecturing about premature optimization, this is an excercise in curiosity.