https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121760
--- Comment #21 from Benjamin Schulz <schulz.benjamin at googlemail dot com> --- Created attachment 62287 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=62287&action=edit datastruct_gpu_memory_functions.h Hi there, thank you for your advice jacub. I now have looked at the code a bit longer... It turned out that in the offload helper, there was a variable, which was not stored as reference. If I changed datastruct<T> pdL; into datastruct<T> &pdL; in the code below, then gcc would compile the correct code and not try to map structs that were already on device. It was not the datafields, and not the code in the strassen algorithm. these it could eat. I have now changed the files into template<typename T> class Datastruct_GPU_Memory_Functions { public: class OffloadHelper { protected: bool pupdate_host; datastruct<T> &pdL; int pdevicenum; public: inline OffloadHelper(datastruct<T>& dL, int devicenum, bool just_alloc, bool update_host_on_exit) :pupdate_host(update_host_on_exit), pdL(dL),pdevicenum(devicenum) { #if !defined(Unified_Shared_Memory) if (just_alloc) Datastruct_GPU_Memory_Functions::create_out_struct(dL, devicenum); else Datastruct_GPU_Memory_Functions::create_in_struct(dL, devicenum); #endif } inline ~OffloadHelper() { #if !defined(Unified_Shared_Memory) if (pupdate_host) { Datastruct_GPU_Memory_Functions::update_host(pdL, pdevicenum); } Datastruct_GPU_Memory_Functions::release_struct(pdL, pdevicenum); #endif } OffloadHelper(const OffloadHelper&) = delete; OffloadHelper& operator=(const OffloadHelper&) = delete; };and ive changed strassen_multiply_h and winograd_multiply_h such that they only want device pointers for the pdata fields and that the structs themselves are mapped properly. But that was not really the problem, the problem was the that it stored a copy and then tried to map that which confused it... Now the strassen and Winograd algorithms work on device and host
