How to deal with the different result when executing UB programs?

[Jonathan Wakely]

On Fri, 22 May 2020 at 06:54, Haoxin Tu via Gcc <gcc@gcc.gnu.org> wrote:
>
> Hi, there!
>
> I am new for using GCC mail list, please forgive me if something is wrong.

You're using the wrong mailing list, see
https://gcc.gnu.org/lists.html which says this question should be on
the gcc-help list. Please send any replies there instead.

> I have some issues about how GCC deal with the different optimizations in a
> UB program.

It's undefined. Anything can happen. We're not going to define the
behaviour of undefined behaviour, because it's undefined.

https://en.wikipedia.org/wiki/Undefined_behavior
https://en.cppreference.com/w/cpp/language/ub