I don’t know about studies and statistics, but yes, there are definitely optimizations taking this into account that compilers actually do. And yes, they are very important (tldr loop vectorization for example). Besides the compiler optimizations, there is another aspect to be taken into account. With UB you get C/C++ signed integers to behave arithmetically … Read more
Math.addExact throws exception on overflow Since Java 8 there is a set of methods in the Math class: toIntExact(long) addExact(int,int) subtractExact(int,int) multiplyExact(int,int) …and versions for long as well. Each of these methods throws ArithmeticException if overflow happens. Otherwise they return the proper result if it fits within the range. Example of addition: int x = … Read more
This is not a bug. int.MinValue * -1 is 1 greater than int.MaxValue can hold. Thus, the number wraps around back to int.MinValue. This is basically caused by an integer overflow. Int32.MinValue: The value of this constant is -2,147,483,648 Int32.MaxValue: The value of this constant is 2,147,483,647 So, -2,147,483,648 * -1 = 2,147,483,648 which is … Read more
In C#, it was a question of performance. Specifically, out-of-box benchmarking. When C# was new, Microsoft was hoping a lot of C++ developers would switch to it. They knew that many C++ folks thought of C++ as being fast, especially faster than languages that “wasted” time on automatic memory management and the like. Both potential … Read more
You misunderstand the reason for undefined behavior. The reason is not memory corruption around the integer – it will always occupy the same size which integers occupy – but the underlying arithmetics. Since signed integers are not required to be encoded in 2’s complement, there can not be specific guidance on what is going to … Read more
XOR will never go out of bounds because it combines bits and doesn’t create new bits where no bits were set before. The result 5 is correct. Look at the binary representation of your value and the XOR result 10 00001010 20 00010100 30 00011110 5 00000101 20 00010100 10 00001010 30 00011110 ————– 00000101 … Read more
There is no theoretical limit. The BigInteger class allocates as much memory as it needs for all the bits of data it is asked to hold. There are, however, some practical limits, dictated by the memory available. And there are further technical limits, although you’re very unlikely to be affected: some methods assume that the … Read more
As Miles hinted: The C++ code text is bound by the rules of the C++ language (integer overflow = bad), but the compiler is only bound by the rules of the cpu (overflow=ok). It is allowed to make optimizations that the code isn’t allowed to. But don’t take this as an excuse to get lazy. … Read more
Known bug. Related to http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6196102 http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6357214 and others. I think they’re considered low-priority to fix because they don’t come up in the real world.
According to the standard So, from your quote: argv[argc] is required to be a null pointer Therefore, argc cannot overflow, because then the above statement would not be true. In practice In practice, the total size of the arguments passed to a program is limited. On my Linux/x64 system: $ getconf ARG_MAX 2097152 Therefore, the … Read more