dberlin added a comment. In https://reviews.llvm.org/D30538#690699, @hans wrote:
> +1 for documenting this, but I have to leave it to the language lawyers for > how to fomulate it. > > > Enables/disables the strict aliasing assumption, which assumes that objects > > of different types do not share the same location in memory. > > I think it needs to say incompatible types at least (and `char` and `unsigned > char` are also special). And isn't it really about pointers -- the compiler > assumes that when dereferncing two pointers of incompatible types, those > pointers do not refer to the same memory? > > > clang does not allow "type-punning" by writing and reading from different > > union members > > I thought clang does allow type-punning through unions, as long as it's in a > single function, but that it fails when things get more complicated. The limitation is really "union accesses must be visibly through a union, and if you try to trick the compiler, you will lose". That is what we meant to allow, it just is still broken *anyway* > +dannyb who enjoys this stuff ;) You are so mean :) https://reviews.llvm.org/D30538 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
