[Bug libstdc++/61166] New: overflow when parse number in std::duration operator""

[kan.liu.229 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61166

            Bug ID: 61166
           Summary: overflow when parse number in std::duration operator""
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kan.liu.229 at gmail dot com

overflow may occur when using a number whose size exceeds sizeof(unsigned) in
chrono_literals. Because the parse classes in include/bits/parse_number.h just
use *unsigned* for member type. However, it should accept *unsigned long long*
I think. This issue also exists in trunk I think.

#include <chrono>

using namespace std;
using namespace std::chrono;

int main() {
    // std::numeric_limits<unsigned>::max() == 4294967295
    cout << 429496729510 << endl;
    cout << (429496729510h).count() << endl;
    return 0;
}

And the result is

429496729510 
926648584