As the author of the first blog post, I think you got my conclusion wrong because I'm writing a language without such UB. So I would like to have a better language.
But I was also talking about UB in the context of already existing code! My argument is that compiler writers are breaking existing code when they could very well avoid breaking it.
We have tried to convince compiler writers to not do this, but they have refused. So that's why I said that users must do something: because compiler writers won't.
And yes, I knew compilers would take every advantage that they could before that; my surprise was that someone considered UB's sole purpose to be for the benefit of compiler writers at the expense of everyone else, including non-programmers who suffer catastrophic consequences for security bugs.
But I was also talking about UB in the context of already existing code! My argument is that compiler writers are breaking existing code when they could very well avoid breaking it.
We have tried to convince compiler writers to not do this, but they have refused. So that's why I said that users must do something: because compiler writers won't.
And yes, I knew compilers would take every advantage that they could before that; my surprise was that someone considered UB's sole purpose to be for the benefit of compiler writers at the expense of everyone else, including non-programmers who suffer catastrophic consequences for security bugs.