lebedev.ri added a comment. In https://reviews.llvm.org/D33826#772676, @aaron.ballman wrote:
> How does this check compare with the -Wcast-align diagnostic in the Clang > frontend? I believe that warning already covers these cases, so I'm wondering > what extra value is added with this check? In https://reviews.llvm.org/D33826#856887, @rjmccall wrote: > In https://reviews.llvm.org/D33826#856652, @lebedev.ri wrote: > > > In https://reviews.llvm.org/D33826#856619, @Eugene.Zelenko wrote: > > > > > In https://reviews.llvm.org/D33826#856610, @lebedev.ri wrote: > > > > > > > Any status update here? :) > > > > I generally do see a benefit in this check, because `-Wcast-align` (at > > > > least currently?) does not warn on `reinterpret_cast<>()`. > > > > > > > > > I think will be good idea to extend -Wcast-align. > > > > > > Hm, are you *sure* `reinterpret_cast<>()` is not allowed to increase > > alignment? > > There was a commit that intentionally removed that warning: (by @rjmccall, > > i believe) > > > > https://github.com/llvm-mirror/clang/commit/35a38d95da89d48778019c37b5f8c9a20f7e309c > > > One of the fundamental design principles to keep in mind when implementing > warnings like -Wcast-align is that we're trying to warn users about having > written something dangerous, not scold them for writing code a particular > way. Users do need to do these casts sometimes, and there has to be some way > of doing them without a warning. So the question of when to warn has to > consider whether the code is explicitly acknowledging the danger. It would, > for example, be a mistake to warn in C about double-casts through (void*), > because that is not something that people do accidentally; it is very likely > that it is an attempt to suppress the warning. In C++, it seemed to me that > a reinterpret_cast is by its nature explicitly acknowledging the danger, so > it is never really appropriate to warn. So we are back from where we have started, and this check does make sense. Repository: rL LLVM https://reviews.llvm.org/D33826 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
