I'm afraid the author as usual confuses the cases when UB produces strange results and when the compiler actively and deliberately exacerbates the results. He also claims gcc interpretation of UB provides a lot of performance. Ironically gcc or clang already do experiments on different interpretation of UB like signed integer overflow and implicit initialization.
But these are options, it's not a big deal to me that compiler offers special options for special use cases.
It's not clear to me if you are saying that the *default* for clang and GCC differs, aren't they both using `fno-wrapv` by default?
These options provide a different interpretation of UB like signed integer overflow and implicit initialization. It's in reference to Ralf's blog post:
>I honestly think trying to write a highly optimizing compiler based on a different interpretation of UB would be a worthwhile experiment. We sorely lack data on how big the performance gain of exploiting UB actually is. However, I strongly doubt that the result would even come close to the most widely used compilers today—and programmers that can accept such a big performance hit would probably not use C to begin with. Certainly, any proposal for requiring compilers to curtail their exploitation of UB must come with evidence that this would even be possible while keeping C a viable language for performance-sensitive code.
He doesn't know such interpretations are implemented by widely used C compilers.
