It's worth mentioning that x86 CPUs had a single instruction overflow test that would raise a hardware interrupt in response to an integer overflow. This allowed for extremely low cost integer overflow tests.
Unfortunately, this capability was deleted from x86-64 and we're now stuck with either accepting the risks of integer overflows or suffering a performance hit to test for them by using multiple instructions.
Another extremely useful instruction deleted from x86-64 tested if an array access was in bounds. Determining how many buffer overflow exploits could have been prevented if this instruction was widely used--and carried over to x64--is left as an exercise for the reader.
Unfortunately, this capability was deleted from x86-64 and we're now stuck with either accepting the risks of integer overflows or suffering a performance hit to test for them by using multiple instructions.
Another extremely useful instruction deleted from x86-64 tested if an array access was in bounds. Determining how many buffer overflow exploits could have been prevented if this instruction was widely used--and carried over to x64--is left as an exercise for the reader.