I watched the video and didn't learn anything new. I know UB pretty well.
> Compilers generaly do not abuse UB
It's disheartening to see this take from the guy who said that one word broke C.
It is also false, in my experience because some people, including compiler developers, think that compiler freedom is the definition of UB, not a side effect of that one-word change:
https://gavinhoward.com/2023/08/the-scourge-of-00ub/
So your claim in the video that such things are scary to compiler developers is sad. They have broken existing code; they are not afraid to.
I used to be somewhat confident (https://gavinhoward.com/2024/05/a-grateful-open-letter-to-je...) in the direction of C with you and JeanHeyd Meneide on WG14. But if you sincerely believe what you just said, then it seems you have changed your mind since you wrote that one word changed C. So I am not as confident anymore.