[cfarm-users] GCC 8.2 UBsan and runtime error: signed integer overflow

[Jeffrey Walton]

On Tue, Nov 27, 2018 at 4:17 PM Jerry James <loganjerry at gmail.com> wrote:
>
> On Tue, Nov 27, 2018 at 1:53 PM Jeffrey Walton via cfarm-users
> <cfarm-users at lists.tetaneutral.net> wrote:
> > ppc_simd.h:965 is a vec_add, and it happens on a unsigned int vector.
> > We don't use signed vector types. I don't believe overflow can happen
> > and the algorithm depends on unsigned wrap.
>
> Does building with -fwrapv help?

Thanks. Jerry.

-fwrapv clears the UBsan findings. The problem is, governance does not
allow us to use it. -fwrapv is for defective programs. The defective
program must be fixed.

-fwrapv does not clear the failed self tests.

Jeff