On Sat, Sep 22, 2018 at 1:33 AM Chí-Thanh Christopher Nguyễn <chith...@gentoo.org> wrote: > > Richard Yao schrieb: > > >> To make code behave differently it needs substantial amount of code > >> to provide you an example. You need to him O2<->O3 behaviour delta > >> after all. But I will try (for a different warning, it should not matter > >> much). > > Thanks. I had been incorrect about -O3 giving not us some additional > > information for warnings. My apologies for the confusion. > >> > >> Below is a reduced example of a larger C++ program. > >> Many thanks to Ulya for providing recent example! > > Not that it matters now, but there are examples of packages building at -O2 > but failing to build at -O3 optimization levels, due to -Werror. > > One is dev-libs/libcss: https://bugs.gentoo.org/626752 >
It is matter, and shows that for selected packages in which upstream has strict policy of no warning, each warning should be investigated as it may be a true issue. The tool compiler provide to find these edge condition should not be ignored nor overridden. The fact that a package "builds" does not mean it is free of bugs. Regards, Alon
