jdoerfert marked an inline comment as done. jdoerfert added inline comments.
================ Comment at: clang/test/OpenMP/barrier_codegen.cpp:22 +// CLANGCG-NOT: readonly +// IRBUILDER: ; Function Attrs: nofree nosync nounwind readonly +// IRBUILDER-NEXT: declare i32 @__kmpc_global_thread_num(%struct.ident_t*) ---------------- ABataev wrote: > jdoerfert wrote: > > ABataev wrote: > > > Not sure about correct use of `nosync` and `readonly` attributes. OpenMP > > > runtime uses lazy initialization of the runtime library and when any > > > runtime function is called, the inner parts of the OpenMP runtime are > > > initialized automatically. It may use some sync primitives and may modify > > > memory, I assume. Same about `nofree`. > > There are two versions of these functions, host and device. I assume host > > functions are not inlined but device functions might be. This is basically > > all the modes we support right now. > > > > If we do not inline the function (host) we don't necessarily care what they > > do but what effect the user can expect. > > The user can not expect to synchronize through `__kmpc_global_thread_num` > > calls in a defined way, thus `nosync`. > > Similarly, from the users perspective there is no way to determine if > > something was written or freed, no matter how many of these calls I issue > > and under which control conditions, all I see is the number as a result. > > Thus, `readonly` and `nofree`. I believe `readnone` is even fine here but > > it might not work for the device version (see below) so I removed it. > > > > If we do inline the function (device) we need to make sure the attributes > > are compatible with the inlined code to not cause UB. The code of > > `__kmpc_global_thread_num` at least does not write anything and only reads > > stuff (as far as I can tell). > > > > Please correct me if I overlooked something. > But someone may try to inline the host-based runtime or try to use LTO with > it. > The question is not about the user expectations but about the optimizations > which can be triggered with these attributes. This is our runtime and we have supported and unsupported usage models. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D69922/new/ https://reviews.llvm.org/D69922 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
