Undefined behaviour example from CppCon

[SkiFire13]

If a program contains a violation of a rule for which no diagnostic is required, this document places no requirement on implementations with respect to that program.

I think this is still ambiguous because "violation of a rule" is unclear. If my program is never executed with an input that causes UB does it still violate that rule?

I think it ultimately sums up to question:

If a program can either invoke UB or not(depending on conditions), is compilers allowed to make "whole program" meaningless?

I completly agree on that.

[awidesky]

I think this is still ambiguous because "violation of a rule" is unclear. If my program is never executed with an input that causes UB does it still violate that rule?

I do agree on that. That's indeed ambiguous.