https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120604
--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to David Binderman from comment #5)
> (In reply to Uroš Bizjak from comment #4)
> > Unfortunately I
> > have very limited knowledge on how to fix signed overflow, so I would really
> > appreciate some help here.
>
> Suggest use a type with more bits in it. I have seen wide-ints
> used for situations like this, but I don't know if they are suitable
> here.
>
> See trunk/gcc/wide-int.h
Simply do
diff = (unsigned HOST_WIDE_INT)ct - (unsigned HOST_WIDE_INT)cf;
(and in the other place), or use unsigned for 'diff' in the first place.
