The issue of creeping optimizations causing problems far in the future is one of the reasons that I suggested using unsigned intergers in C as much as possible:

The issue of creeping optimizations causing problems far in the future is one of the reasons that I suggested using unsigned intergers in C as much as possible: "Compiler authors will likely support this as long as possible, but the peer pressure of needing things to go faster and faster will likely push them to exploit more and more undefined behaviour to their advantage in the future. Their argument will be: 'After all, who has sympathy for those who don't follow the standard?'." From: http://blog.robertelder.org/signed-or-unsigned-part-2/ http://blog.robertelder.org/signed-or-unsigned-part-2/ Lots of people disagree with me, but its nice to have less UB issues to worry about far in the future.