Dangerous Optimizations and the Loss of Causality in C and C++ (2010) [pdf](pubweb.eng.utah.edu)

    [0]: https://reviews.llvm.org/D26196

    #include <fmt.h>
    #include <cstdio>

    int main() {
        int a{}, b{};
        int64_t c{};
        fmt::print("Please enter two numbers: ");
        scanf("%d %d", &a, &b);
        c = a + b;
        fmt::printf("The sum of the numbers you entered is {}\n", c);
        return 0;
    }

    #include <stdio.h>

    int main() {
        int a, b, c;
        printf("Please enter two numbers: ");
        scanf("%d %d", &a, &b);
        if(__builtin_add_overflow(a, b, &c)) 
        { 
          printf("The sum of the numbers you entered is %d\n", c); 
        }
        else 
        {
          printf("You are in a twisty maze of compiler features, all different"); 
          exec("/usr/bin/0ad");
        }
        return 0;
    }