What an Interesting question, who know why?

[zhangsi]

Add the code below and save it into a test.cpp.
Open test.cpp by Qt Creator 3.5.1 (Qt Version: 5.5.1, VS2010, WIN7), then CPU...

#include <map>
using namespace std;
static map<int, int> testMap;
void test()
{
    map<int, int>::iterator it;
    for (it = testMap.begin(); it != testMap.end(); ++it)
    {
        int value = it->second;
    }
}

[aha_1980]

Hi @zhangsi

QtCreator 3.5.1 is quite old and will not get any more fixes. Try updating to 4.5. If the problem still exists, create a bugreport at bugreports.qt.io

Thanks