hliao added a comment. In D61458#1488981 <https://reviews.llvm.org/D61458#1488981>, @rjmccall wrote:
> In D61458#1488972 <https://reviews.llvm.org/D61458#1488972>, @hfinkel wrote: > > > In D61458#1488970 <https://reviews.llvm.org/D61458#1488970>, @jlebar wrote: > > > > > Here's one for you: > > > > > > __host__ float bar(); > > > __device__ int bar(); > > > __host__ __device__ auto foo() -> decltype(bar()) {} > > > > > > > > > What is the return type of `foo`? :) > > > > > > I don't believe the right answer is, "float when compiling for host, int > > > when compiling for device." > > > > > > So, actually, I wonder if that's not the right answer. We generally allow > > different overloads to have different return types. > > > Only if they also differ in some other way. C++ does not (generally) have > return-type-based overloading. The two functions described would even mangle > the same way if CUDA didn't include host/device in the mangling. > > (Function templates can differ only by return type, but if both return types > successfully instantiate for a given set of (possibly inferred) template > arguments then the templates can only be distinguished when taking their > address, not when calling.) > > I think I've said before that adding this kind of overloading is not a good > idea, but since it's apparently already there, you should consult the > specification (or at least existing practice) to figure out what you're > supposed to do. BTW, just check similar stuff with nvcc, with more than one candidates, it accepts the following code float bar(); // This line could be replaced by appendig `__host` or `__device__`, all of them are accepted. __host__ __device__ auto foo() -> decltype(bar()) {} however, if there are more than one candidates differenct on the return type (without or with CUDA attibute difference), it could raise the error foo.cu(4): error: cannot overload functions distinguished by return type alone it seems to me that that's also an acceptable policy to handle the issue after we allow different-side candidates in type-only context. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D61458/new/ https://reviews.llvm.org/D61458 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
