condition_variable::wait_for doesn't wait if duration is large

[gnbond]

Bugzilla Link	47074
Version	10.0
OS	All
Attachments	Test cases with sample findings for various versions
CC	@mclow

Extended Description

The following code should wait forever, but it does not, it returns immediately:

#include <chrono>
#include <iostream>
#include <condition_variable>

using namespace std::chrono;

int main() {
    std::mutex m;
    std::unique_lock l(m);
    std::condition_variable cv;

    std::cout << "sleeping forever" << std::endl;
    cv.wait_for(l, milliseconds::max(), []() { return false; });
    std::cout << "returned!" << std::endl;
}

Tested on FreeBSD, Ubuntu16 & MacOS, clang version 6, 8 & 10

Behaviour is somewhat variable, depending on OS and compiler version (at least for the small sample I have access to). Basically, given a duration past a certain size (somewhere around 1<<52 units of any duration type), wait_for() no longer waits at all. On some versions/platforms, the 2-argument wait_for() does not appear to wait at all, even for small durations.

This looks like some kind of overflow in the duration conversion.

Bug filed under libraries, but problem may be in the compiler intrinsics.

See attached somewhat more detailed test cases and notes on the limits I have discovered.

[mclow]

I wonder if this is related to #14093