And yet C is still the dominant language. Undefined behavior is actually the reason why: any defined behavior is expensive to implement in the compiler and possibly incurs a cost at runtime. The language design intentionally trades programmer’s sanity for ease of implementation.
For a real prominent counterexample: the Linux kernel is intentionally programmed in a C dialect (defined by a myriad of GCC compiler flags) that removes a lot of UB.
If they craved the Faustian bargain of UB for speed, they could immediately move in that direction by dropping some GCC options.
Legacy reasons, most embedded devs and UNIX clones won't use anything else.
In many other domains, other languages have taken their place, and this will keep on going, even if it takes a couple of generations, or goverment cybersecurity mandatates to make it happen.
> The language design intentionally trades programmer’s sanity for ease of implementation.
There's nothing "easy" at all about UB-exploiting performance optimizations in modern C compilers, and "ease of implementation" is absolutely not why those optimization passes have been included. In fact, the easiest thing for the compiler to do, when it sees an int * int operation, is to emit an IMUL assembly instruction (or the equivalent for your CPU architecture) and not worry about deleting overflow checking code. Which is what C compilers did before the extent of UB exploitation became excessive.
I agree on the top compilers but there are dozens if not hundreds architectures with their own proprietary C compilers maintained by a dinosaur and a couple intern dino chicks if they’re lucky. I postulate any other language wouldn’t be implemented or would be defanged to C-level of (non)safety anyway in a way similar to mrustc.
