[Bug c/84121] optimizer breaks code without -frwapv, but -Wall -Wextra show no warnings

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84121

--- Comment #2 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Marc Glisse from comment #1)
> You can compile with -fsanitize=undefined then run your code, to understand
> the issue.

Oups, sorry, that doesn't show anything for your code, the problem is not what
I thought, ignore my message.