Hi I do not have a strong preference for wheezy. Long term I agree with you.
/ Ola Sent from a phone Den 4 apr 2017 11:33 skrev "Hugo Lefeuvre" <h...@debian.org>: > Hi Ben, Ola, > > > This seems to be a correct optimisation. Overflow/underflow on signed > > arithmetic has undefined behaviour, therefore standard C code will not > > allow it to happen and the compiler may rely on that. If the code does > > actually cause an overflow, literally anything can result. > > > > Thankfully gcc does have an option to support code that relies on > > two's-complement wrapping behaviour on signed arithmetic, which is > > -fwrapv. See also the -fno-strict-overflow option. > > You're right ! Compiling with -fwrapv fixes the problem. > > Alternatively we could use the attached patch that also seems to fix the > problem. > > This patch should be sufficient because in this case an integer overflow > can > only occur if there is a x with > > * x < bm->w > > and > > * x + BM_WORDBITS > INT_MAX > > thus only if bm->w > INT_MAX - BM_WORDBITS. > > I don't know which solution is the best, but the second solution is > probably > better for future maintainance. > > Cheers, > Hugo > > -- > Hugo Lefeuvre (hle) | www.owl.eu.com > 4096/ ACB7 B67F 197F 9B32 1533 431C AC90 AC3E C524 065E >
