Move the emission of strict enum range metadata behind a flag (the same
flag as GCC uses: -fstrict-enums). There is a *lot* of code making unwarranted assumptions about the underlying type of enums, and it doesn't seem entirely reasonable to eagerly break all of it. Much more importantly, the current state of affairs is *very* good at optimizing based upon this information, which causes failures that are very distant from the actual enum. Before we push for enabling this by default, I think we need to implement -fcatch-undefined-behavior support for instrumenting and trapping whenever we store or load a value outside of the range. That way we can track down the misbehaving code very quickly. I discussed this with Rafael, and currently the only important cases he is aware of are the bool range-based optimizations which are staying hard enabled. We've not seen any issue with those either, and they are much more important for performance. llvm-svn: 153550
Loading
Please register or sign in to comment