Hi, we've installed gcc-9.2 with offloading capability to Nvidia GPUs on our system. A short example in either C++ or Fortran using OpenACC pragmas does generate code that successfully performs offloading to the GPU. This is verified by setting GOMP_DEBUG=1 or running nvprof. The examples are compiled with either gfortran -fopenacc test_oacc.F90 or g++ -fopenacc test_oacc.cpp nvprof in both cases then show a line like GPU activities: 100.00% 3.22929s [...] MAIN__$_omp_fn$0 However, said short examples in neither C++ nor Fortran are successfully built when using OpenMP pragmas for offloading. The compile commands are gfortran -fopenmp test_omp.F90 or g++ -fopenmp test_omp.cpp and in both cases result in unresolved symbol __nvptx_uni collect2: error: ld returned 1 exit status mkoffload: fatal error: x86_64-pc-linux-gnu-accel-nvptx-none-gcc returned 1 exit status compilation terminated. lto-wrapper: fatal error: [...]/mkoffload returned 1 exit status compilation terminated. [...]/ld: error: lto-wrapper failed collect2: error: ld returned 1 exit status Linker and compiler are from different versions since we've installed gcc-9.2 on-top of our existing setup. Adding -fno-lto as compile flag does successfully compile a binary, but skips any offloading. GOMP_DEBUG shows no OpenMP activity and nvprof only shows API calls, no actual kernels. Adding --save-temps and checking test.s I can see the lines // BEGIN GLOBAL VAR DECL: __nvptx_uni .extern .shared .u32 __nvptx_uni[32]; Running strace along with the compiler, I can see mkoffload failing and various accesses to crt*.o but not crt0.o which is where I suspect the missing symbol comes from? This is, however, clutching at straws since the OpenACC case also doesn't seem to touch crt0.o. What are we missing here? Any hint appreciated, thanks, Dirk
