ISO standards as a baseline, not a target

Small misunderstanding on your side. Please read what you actually wrote (not what you wanted to write):

The critical part (change in actual toolchain) was omitted. Thus you proposal sounded like you offered to change the documentation and then fix Windows 8, somehow, without making new toolchain which would treat EBX differently.

I, too, interpreted it like that and wanted to object. Because it's entirely not clear to me how can you “document and fix” that “bug” without changes to the toolchain. But then saw your clarification and understood what you meant. But mb wrote his answer before seeing it this he, like me, assumed you are saying that it's bug in Windows (but not in toolchain) and can be fixed, somehow, without changing toolchain (and definition of language that toolchain handles).

No. What I'm saying that what you are proposing is not what “we code for the hardware” crowd is proposing. They don't plant to document anything. Just read that damn document that was already referenced here. It's an ode to the resourcefulness of programmers and proclamation that if these pesky compilers would stop breaking “perfectly valid programs” and are “only just exploiting things that hardware does, but that compiler doesn't know about” then would get much better result than with current compilers that are “abusing UB”.

But, notably, what that “perfect plan” doesn't include are any proposals to change the list of UBs, any plans to define and document anything. It says that documentation should remain the same with some small addition like “compilers should magically stop breaking our programs”. Similarly to how Yodaiken claims that UB treatment in the compilers is “wrong” and demands that compilers should treat UBs differently, but, notably, doesn't propose to document anything.

But we are not talking about something documented, but more of the spectre between “you want to say that our compiler always did that in these situations… wow, had no idea” and “yeah, we never promised to always do this and always wanted to do that, but had no resources” cases.

Cases where there were explicitly no promises, but where investigation of compiler and/or other system revealed that they always behave in a certain way (even if it was never documented).

How do you propose to handle that without adding anything to documentation? Remember: all these “we code for the hardware” guys don't talk about changes to the language specification or expansion to it, or anything like that, they all “want to change the way compiler interprets UB” while still keeping the exact behavior undocumented!

Because changing and documenting things is ongoing work and they don't want that. They want some magical solution which would ensure that compiler would stop breaking their programs that rely on something that's officially defined as UB! Not would stop breaking any particular thing, but will “stop doing nasty things” (without even trying to describe these things that shouldn't be broken).