[Bug tree-optimization/79828] missing div-by-zero warning

["arnd at linaro dot org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79828

--- Comment #8 from Arnd Bergmann <arnd at linaro dot org> ---
(In reply to Jakub Jelinek from comment #6)
> If the warning has false positives, then I'm sure the kernel will turn it
> off anyway like it does with tons of other warnings.

That is well possible. I try to catch new warnings early by building lots of
kernels with random configurations and sending kernel fixes, but if there are
more than a few dozen instances and none of them are interesting kernel bugs,
I'd also turn off that warning.

I have started going through all available warnings to see how much output they
generate (97GB on an allmodconfig kernel build when turning them all on with
gcc, more with clang), with the intention of re-enabling the more useful ones,
but will take a while to get there as I can only enable them after having fixed
all the warnings we get.