rjmccall added a comment. 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. 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
