On Sat, Feb 26, 2022 at 1:42 PM Segher Boessenkool
<segher@xxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, Feb 23, 2022 at 11:23:39AM -0800, Linus Torvalds wrote:
> > That said, we seem to only have two cases of it in the kernel, at
> > least by a x86-64 allmodconfig build. So we could examine the types
> > there, or we could just add '-Wno-shift-negative-value".
>
> Yes.
>
> The only reason the warning exists is because it is undefined behaviour
> (not implementation-defined or anything). The reason it is that in the
> standard is that it is hard to implement and even describe for machines
> that are not two's complement. However relevant that is today :-)
Could gcc follow the clang behavior then and skip the warning and
sanitizer for this case when -fno-strict-overflow or -fwrapv are used?
Arnd
