>the problem is with compilers (and their developers) who think UB really means they can do anything
But that's exactly what undefined behavior means.
The actual problem is that programmers are surprised-- that is, programmers' expectations are not aligned with the actual behavior of the system. More precisely, the misalignment is not between the actual behavior and the specified behavior (any actual behavior is valid when the specified behavior is undefined, by definition), but between the specified behavior and the programmers' expectations.
In other words, the compiler is not at fault for doing surprising things in cases where the behavior is undefined; that's the entire point of undefined behavior. It's the language that's at fault for specifying the behavior as undefined.
In other other words, if programmers need to be able to rely on certain behaviors, then those behaviors should be part of the specification.
But that's exactly what undefined behavior means.
The actual problem is that programmers are surprised-- that is, programmers' expectations are not aligned with the actual behavior of the system. More precisely, the misalignment is not between the actual behavior and the specified behavior (any actual behavior is valid when the specified behavior is undefined, by definition), but between the specified behavior and the programmers' expectations.
In other words, the compiler is not at fault for doing surprising things in cases where the behavior is undefined; that's the entire point of undefined behavior. It's the language that's at fault for specifying the behavior as undefined.
In other other words, if programmers need to be able to rely on certain behaviors, then those behaviors should be part of the specification.