I already had Cygwin installed, but I just ran the installer to get a later version of GCC.
Previously I was running GCC 4.9, I am now running 9.3. However, my code now runs approximately 20% slower.
To confirm the GCC version is the cause I would like to be able to compile it with GCC 4.9 again.
How do I do switch between using GCC 4.9 and 9.3?
