flat_multimap::emplace not sorting elements under GCC

[Paris Oplopoios]

Hello!

I have attached a code snippet.
main.txt

If you build it like this:

g++ -O3 main.cpp

The output is not sorted, next timestamp should be 6000.

Next timestamp: 10000
Time: 6000, TaskType: 0
Time: 10000, TaskType: 1

Next timestamp should be 6000.

If you compile with O2 using g++, or you compile using clang++ however, the issue is fixed:

clang++ -O3 main.cpp

Next timestamp: 6000
Time: 6000, TaskType: 0
Time: 10000, TaskType: 1

[Paris Oplopoios]

accidentally opened twice, closing