> From: Robert Dewar <[EMAIL PROTECTED]> > .. there is no requirement that optimization preserve the behavior of > undefined programs ... It is fine to argue that defining the semantics > is useful in a particular case, but arguing solely from the point of > view of trying to preserve observed behaviort is a poor argument. > > Indeed the point is that optimization is not changing the behavior, the > behavior is non-deterministic, and can change from one compilation to > the next even if optimization does not change.
- observable program behavior is the only thing that's significant. - yes, it's understood that a language's specification may consider multiple program implementations having differing observable behaviors as being logically equivalent when their observable differences are restricted to differing implementations of under/undefined language semantics; however this does not imply observable behavior modifying optimizations are generally innocuous and/or desirable, as in fact any optimization which may alter a programs observable behavior which was otherwise deemed desirable is clearly arguably counterproductive, as neither observable behavior is warranted to be portable or more correct. - however as promised I'll abstain from further debate as the community seems satisfied with accepting the consequences of such optimizations.
