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From: Alon Bar-Lev <alonbl@gentoo.org>
Date: Sat, 22 Sep 2018 08:57:56 +0300
Message-ID: <CAOazyz0gPD1FfTdkO3mM2Zo8hpX1fs59PLtnP0Kt56NyfjH4wQ@mail.gmail.com>
Subject: Re: [gentoo-dev] Changing policy about -Werror
To: gentoo-dev@lists.gentoo.org
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On Sat, Sep 22, 2018 at 1:33 AM Ch=C3=AD-Thanh Christopher Nguy=E1=BB=85n
<chithanh@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 matt=
er
> >> much).
> > Thanks. I had been incorrect about -O3 giving not us some additional in=
formation 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