[Bug c++/63140] wrong code generation probably due to optimization problem

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63140

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
You might want to try -fsanitize=undefined and/or -fno-strict-overflow as it
sounds like you may be invoking undefined behavior.