"3.4.2. Time Bombs. Undefined behavior also leads to time bombs: code that works under today's compilers, but breaks unpredictably in the future as optimization technology improves. The Internet is rife with stories about problems caused by GCC’s ever-increasing power to exploit signed overflows. For example, in 2005 a principal PostgreSQL developer was annoyed that his code was broken by a recent version of GCC: 'It seems that gcc is up to some creative reinterpretation of basic C semantics again; specifically, you can no longer trust that traditional C semantics of integer overflow hold'"
Relying on overflow and edge case behaviors seems like a terrible idea in the first place. Unless the edge case behaviors are part of the language standard, they cannot be relied upon especially if the code is meant to be portable across compilers and architectures.