Comment by drob518
Exactly. A lot of people didn’t understand the contract between the programmer and the compiler that is required to use -O3.
Exactly. A lot of people didn’t understand the contract between the programmer and the compiler that is required to use -O3.
That's a little vague, I'd put that more pointedly: they don't understand how the C and C++ languages are defined, have a poor grasp of undefined behaviour in particular, and mistakenly believe their defective code to be correct.
Of course, even with a solid grasp of the language(s), it's still by no means easy to write correct C or C++ code, but if your plan it to go with this seems to work, you're setting yourself up for trouble.