Build error on Ubuntu 16.04 and Cuda 7.5

[FabbyD]

As the title says, I fail to build the source files.

$ git clone https://github.com/NVIDIA/nccl.git
$ cd ncll
$ make CUDA_HOME=/usr/local/cuda test
Compiling src/libwrap.cu                      > /home/fabrice/nccl/build/obj/libwrap.o
/usr/include/string.h: In function ‘void* __mempcpy_inline(void*, const void*, size_t)’:
/usr/include/string.h:652:42: error: ‘memcpy’ was not declared in this scope
   return (char *) memcpy (__dest, __src, __n) + __n;
                                          ^
Makefile:109: recipe for target '/home/fabrice/nccl/build/obj/libwrap.o' failed
make: *** [/home/fabrice/nccl/build/obj/libwrap.o] Error 1

My setup:

• Ubuntu 16.04
• Cuda 7.5
• gcc 5.4

Anyone else had that error before?

EDIT:
It seems like others had similar issues (here, here and here). Adding the magic flag CXXFLAGS += -D_FORCE_INLINES allows me to go a bit further but then I get this error:

$ make CUDA_HOME=/usr/local/cuda test
Compiling src/core.cu                         > /home/fabrice/nccl/build/obj/core.o
Compiling src/all_gather.cu                   > /home/fabrice/nccl/build/obj/all_gather.o
Compiling src/all_reduce.cu                   > /home/fabrice/nccl/build/obj/all_reduce.o
Compiling src/broadcast.cu                    > /home/fabrice/nccl/build/obj/broadcast.o
Compiling src/reduce.cu                       > /home/fabrice/nccl/build/obj/reduce.o
Compiling src/reduce_scatter.cu               > /home/fabrice/nccl/build/obj/reduce_scatter.o
Linking   libnccl.so.1.3.3                    > /home/fabrice/nccl/build/lib/libnccl.so.1.3.3
/usr/bin/ld: /home/fabrice/nccl/build/obj/libwrap.o: relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC
/home/fabrice/nccl/build/obj/libwrap.o: error adding symbols: Bad value
collect2: error: ld returned 1 exit status
Makefile:93: recipe for target '/home/fabrice/nccl/build/lib/libnccl.so.1.3.3' failed
make: *** [/home/fabrice/nccl/build/lib/libnccl.so.1.3.3] Error 1

EDIT2:
Adding -D_FORCE_LINES to NVCUFLAGS (line 26) instead of CXXFLAGS made it work:
NVCUFLAGS := -D_FORCE_INLINES -ccbin $(CXX) $(NVCC_GENCODE) -lineinfo -std=c++11 -maxrregcount 96

Output:

$ make CUDA_HOME=/usr/local/cuda test
Grabbing  src/nccl.h                          > /home/fabrice/nccl/build/include/nccl.h
Compiling src/libwrap.cu                      > /home/fabrice/nccl/build/obj/libwrap.o
Compiling src/core.cu                         > /home/fabrice/nccl/build/obj/core.o
Compiling src/all_gather.cu                   > /home/fabrice/nccl/build/obj/all_gather.o
Compiling src/all_reduce.cu                   > /home/fabrice/nccl/build/obj/all_reduce.o
Compiling src/broadcast.cu                    > /home/fabrice/nccl/build/obj/broadcast.o
Compiling src/reduce.cu                       > /home/fabrice/nccl/build/obj/reduce.o
Compiling src/reduce_scatter.cu               > /home/fabrice/nccl/build/obj/reduce_scatter.o
Linking   libnccl.so.1.3.3                    > /home/fabrice/nccl/build/lib/libnccl.so.1.3.3
Building  test/single/all_gather_test.cu      > /home/fabrice/nccl/build/test/single/all_gather_test
Building  test/single/all_gather_scan.cu      > /home/fabrice/nccl/build/test/single/all_gather_scan
Building  test/single/all_reduce_test.cu      > /home/fabrice/nccl/build/test/single/all_reduce_test
Building  test/single/all_reduce_scan.cu      > /home/fabrice/nccl/build/test/single/all_reduce_scan
Building  test/single/broadcast_test.cu       > /home/fabrice/nccl/build/test/single/broadcast_test
Building  test/single/broadcast_scan.cu       > /home/fabrice/nccl/build/test/single/broadcast_scan
Building  test/single/reduce_test.cu          > /home/fabrice/nccl/build/test/single/reduce_test
Building  test/single/reduce_scan.cu          > /home/fabrice/nccl/build/test/single/reduce_scan
Building  test/single/reduce_scatter_test.cu  > /home/fabrice/nccl/build/test/single/reduce_scatter_test
Building  test/single/reduce_scatter_scan.cu  > /home/fabrice/nccl/build/test/single/reduce_scatter_scan

Don't ask me why. Magic.

[hsaputra]

Any update on this?

[sjeaugey]

From what I can see searching for this online, this is a general issue with recent gcc versions which break the older nvcc in cuda 7.5.

So I would think that it should be a general Ubuntu 16.04+CUDA7.5 recipe to add -D_FORCE_INLINES to nvcc for all situations, not specifically for NCCL. Maybe defining an alias with : alias nvcc='nvcc -D_FORCE_INLINES' would solve the issue on such systems. It seems to me it would be a more sensible solution than adding this define in every CUDA project.

Let me know if you disagree or if I missed a use case.