[Openmp-dev] clang-7: warning: No library 'libomptarget-nvptx-sm_35.bc'

Siegmar Gross via Openmp-dev openmp-dev at lists.llvm.org
Mon Jul 2 06:26:38 PDT 2018


Hi,

today I've built the latest version of llvm-trunk using Cmake on my "SUSE
Linux Enterprise Server 12.3 (x86_64)". I get the following warnings, if I
compile a small program.

loki introduction 162 \clang --cuda-gpu-arch=sm_50 -fopenmp 
-fopenmp-targets=nvptx64-nvidia-cuda dot_prod_accelerator_OpenMP.c -lomptarget
clang-7: warning: No library 'libomptarget-nvptx-sm_35.bc' found in the default 
clang lib directory or in LIBRARY_PATH. Expect degraded performance due to no 
inlining of runtime functions on target devices. [-Wopenmp-target]
clang-7: warning: argument unused during compilation: '--cuda-gpu-arch=sm_50' 
[-Wunused-command-line-argument]
loki introduction 163


Why does the compiler ignore "--cuda-gpu-arch=sm_50". How can I create
"libomptarget-nvptx-sm_35.bc" and probably "libomptarget-nvptx-sm_50.bc"?


Why do I get different numbers of devices, if I compile the program with
different options. I use a machine with two "Intel Xeon E5-2620 v3"
processors (6 cores and 12 hwthreads each) and one Nvidia Quadro K2200
device.


loki introduction 183 clang -fopenmp -fopenmp-targets=x86_64-pc-linux-gnu \
? dot_prod_accelerator_OpenMP.c -lomptarget
loki introduction 184 a.out
Number of processors:     24
Number of devices:        4
Default device:           0
sum = 6.000000e+08

loki introduction 185 clang -fopenmp -fopenmp-targets=nvptx64-nvidia-cuda \
? dot_prod_accelerator_OpenMP.c -lomptarget
clang-7: warning: No library 'libomptarget-nvptx-sm_35.bc' found in the default 
clang lib directory or in LIBRARY_PATH. Expect degraded performance due to no 
inlining of runtime functions on target devices. [-Wopenmp-target]
loki introduction 186 a.out
Number of processors:     24
Number of devices:        1
Default device:           0
sum = 6.000000e+08
loki introduction 187


Thank you very much for any answers in advance.


Kind regards

Siegmar


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