Let\'s pretend my program contains a specific construct the C++ Standard states to be unspecified behavior. This basically means the implementation has to do something reasonabl
Unspecified and undefined behavior are not guaranteed to be consistent between separate runs of an already compiled program. That alone already makes the notion of consistency between separate compiles totally meaningless.
Also, it is probably worth adding that undefined behavior can manifest itself at compilation stage by preventing the program from compiling at all.