compilation error with const_reverse_iterator

Consider the following program:

#include <iostream>
#include <map>
#include <string>
#include <utility>
#include <algorithm>

using namespace std;

int main()
{
map<string, int> si;

string word;

while (cin >> word)
    ++si[word];

multimap<int, string> is;

for (map<string, int>::const_iterator i = si.begin(); i != si.end(); +
+i)
    is.insert(make_pair(i->second, i->first));

for (multimap<int, string>::const_reverse_iterator r = is.rbegin(); r !
= is.rend(); ++r)
    cout << r->second << " " << r->first << endl;

return 0;
}

Under g++, I get compilation error for the line

for (multimap<int, string>::const_reverse_iterator r = is.rbegin(); r !
= is.rend(); ++r)

The actual error message is

error: no match for 'operator!=' in 'r != std::multimap<_Key, _Tp,
_Compare, _Alloc>::rend() [with _Key = int, _Tp = std::string,
_Compare = std::less<int>, _Alloc = std::allocator<std::pair<const
int, std::string> >]()'

However this program compiles fine under VC++ 2005 Express Edition.

I use the following compilation command under g++.

g++ -std=c++98 -pedantic -Wall -Wextra word_count.cpp

Kindly explain why I am getting error for the above mentioned line
under g++ only.

Thanks
V.Subramanian