On Thu, Mar 17, 2016 at 05:56:17PM +0000, JF Bastien via cfe-commits wrote: > C++ atomics are explicitly designed to avoid problems with touching > adjacent bytes: if `atomic<T>` where `sizeof(T) == 1` requires a 4-byte > `cmpxchg` then it's up to the frontend to make sure `sizeof<atomic<T>> >= 4` > (or something equivalent such as making it non-lock-free).
That's not completely relevant for the code at hand. At least the __sync_* builtins only ever required appropiate alignment of the base type, not necessarily extra alignment to avoid padding for stupid codegen. I also believe that access to extra data is completely harmless for all but one use case. If you are directly accessing memory mapped devices using compiler atomics, you should really know what you are doing. That's about the only case where it matters. Joerg _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
