This appears to come from NNPACK, one of the libraries that are still bundled. These functions seem to be generated by Python scripts that use PeachPy, such as NNPACK/src/x86_64-fma/2d-fourier-8x8.py: --8<---------------cut here---------------start------------->8--- for post_operation in ["stream", "store"]: fft8x8_arguments = (arg_t_pointer, arg_f_pointer, arg_t_stride, arg_f_stride, arg_row_count, arg_column_count, arg_row_offset, arg_column_offset) with Function("nnp_fft8x8_with_offset_and_{post_operation}__avx2".format(post_operation=post_operation), fft8x8_arguments, target=uarch.default + isa.fma3 + isa.avx2): […] --8<---------------cut here---------------end--------------->8--- The ‘__local’ bit in the name comes from PeachPy, in peachpy/name.py: --8<---------------cut here---------------start------------->8--- suffixed_name = "__local" + str(suffix) for name_object in iter(unnamed_objects): # Generate a non-conflicting name by appending a suffix while suffixed_name in self.names: suffix += 1 suffixed_name = "__local" + str(suffix) --8<---------------cut here---------------end--------------->8--- So the problem may be that these things get generated in parallel, and thus numbering is non-deterministic. NNPACK/CMakeLists.txt has this bit to generate targets to build all that: --8<---------------cut here---------------start------------->8--- ADD_CUSTOM_COMMAND( OUTPUT ${obj} COMMAND "PYTHONPATH=${PEACHPY_PYTHONPATH}" ${PYTHON_EXECUTABLE} -m peachpy.x86_64 -mabi=sysv -g4 -mimage-format=${PEACHPY_IMAGE_FORMAT} "-I${PROJECT_SOURCE_DIR}/src" "-I${PROJECT_SOURCE_DIR}/src/x86_64-fma" "-I${FP16_SOURCE_DIR}/include" -o ${obj} "${PROJECT_SOURCE_DIR}/${src}" DEPENDS ${NNPACK_BACKEND_PEACHPY_OBJS}) --8<---------------cut here---------------end--------------->8--- It might be that building just those targets sequentially would solve the problem. To be continued… Ludo’.