8 ms·

First and foremost, an easy way to grab a bunch of undefined behavior.

• eru 2y ago
  That's a bit sloppy. The undefined behaviour is already in the C standard. But you are right that enabling -O3 is generally going to make your compiler more aggressive about exploiting the undefined behaviour in the pursuit of speed. In general, if you want to avoid being the guy to run into new and exciting bugs, you want to run with options that are as close as possible to what everyone else is using.