clang 5 and 7 + omp
Hi there and thx for reading and answering if you can.
I'm trying to compile a cpp project using omp. It works fine with gcc 7.3 on linux x64 but failed with both clang 5 and 7: the linker shrieks because there is no reference to __kmpc_barrier and other symbols of the same kind.
However, when I issue an:
clang++ -openmp myfile.cpp
works, myfile.cpp containing omp pragmas. So, a project with multiple files using make or cmake needs something more.
Any hint ?
c++ openmp
asked Nov 20 at 18:44
skylendar
93
|
show 5 more comments
Hi there and thx for reading and answering if you can.
I'm trying to compile a cpp project using omp. It works fine with gcc 7.3 on linux x64 but failed with both clang 5 and 7: the linker shrieks because there is no reference to __kmpc_barrier and other symbols of the same kind.
However, when I issue an:
clang++ -openmp myfile.cpp
works, myfile.cpp containing omp pragmas. So, a project with multiple files using make or cmake needs something more.
Any hint ?
c++ openmp
asked Nov 20 at 18:44
skylendar
93
Have you tried -fopenmp=libomp to use gcc OpenMP implementation?
– Matthieu Brucher
Nov 20 at 18:56
Ok, it works ! Thx for your help and I have a last question: Why is clang-7 so slooow ? I have got it compiled with gcc 7.3, but clang is 10x slower than gcc for the same source...
– skylendar
Nov 21 at 16:01
Compiled in release mode or debug?
– Matthieu Brucher
Nov 21 at 16:01
In debug mode of course...
– skylendar
Nov 21 at 16:44
I made the same mistake a few months ago ;)
– Matthieu Brucher
Nov 21 at 16:45
|
show 5 more comments
Hi there and thx for reading and answering if you can.
I'm trying to compile a cpp project using omp. It works fine with gcc 7.3 on linux x64 but failed with both clang 5 and 7: the linker shrieks because there is no reference to __kmpc_barrier and other symbols of the same kind.
However, when I issue an:
clang++ -openmp myfile.cpp
works, myfile.cpp containing omp pragmas. So, a project with multiple files using make or cmake needs something more.
Any hint ?
c++ openmp
asked Nov 20 at 18:44
skylendar
93
Hi there and thx for reading and answering if you can.
I'm trying to compile a cpp project using omp. It works fine with gcc 7.3 on linux x64 but failed with both clang 5 and 7: the linker shrieks because there is no reference to __kmpc_barrier and other symbols of the same kind.
However, when I issue an:
clang++ -openmp myfile.cpp
works, myfile.cpp containing omp pragmas. So, a project with multiple files using make or cmake needs something more.
Any hint ?
c++ openmp
c++ openmp
asked Nov 20 at 18:44
skylendar
93
asked Nov 20 at 18:44
skylendar
93
asked Nov 20 at 18:44
skylendar
93
asked Nov 20 at 18:44
skylendar
93
asked Nov 20 at 18:44
skylendar
93
93
Have you tried -fopenmp=libomp to use gcc OpenMP implementation?
– Matthieu Brucher
Nov 20 at 18:56
Ok, it works ! Thx for your help and I have a last question: Why is clang-7 so slooow ? I have got it compiled with gcc 7.3, but clang is 10x slower than gcc for the same source...
– skylendar
Nov 21 at 16:01
Compiled in release mode or debug?
– Matthieu Brucher
Nov 21 at 16:01
In debug mode of course...
– skylendar
Nov 21 at 16:44
I made the same mistake a few months ago ;)
– Matthieu Brucher
Nov 21 at 16:45
|
show 5 more comments
Have you tried -fopenmp=libomp to use gcc OpenMP implementation?
– Matthieu Brucher
Nov 20 at 18:56
Ok, it works ! Thx for your help and I have a last question: Why is clang-7 so slooow ? I have got it compiled with gcc 7.3, but clang is 10x slower than gcc for the same source...
– skylendar
Nov 21 at 16:01
Compiled in release mode or debug?
– Matthieu Brucher
Nov 21 at 16:01
In debug mode of course...
– skylendar
Nov 21 at 16:44
I made the same mistake a few months ago ;)
– Matthieu Brucher
Nov 21 at 16:45
Have you tried -fopenmp=libomp to use gcc OpenMP implementation?
– Matthieu Brucher
Nov 20 at 18:56
Have you tried -fopenmp=libomp to use gcc OpenMP implementation?
– Matthieu Brucher
Nov 20 at 18:56
Ok, it works ! Thx for your help and I have a last question: Why is clang-7 so slooow ? I have got it compiled with gcc 7.3, but clang is 10x slower than gcc for the same source...
– skylendar
Nov 21 at 16:01
Ok, it works ! Thx for your help and I have a last question: Why is clang-7 so slooow ? I have got it compiled with gcc 7.3, but clang is 10x slower than gcc for the same source...
– skylendar
Nov 21 at 16:01
Compiled in release mode or debug?
– Matthieu Brucher
Nov 21 at 16:01
Compiled in release mode or debug?
– Matthieu Brucher
Nov 21 at 16:01
In debug mode of course...
– skylendar
Nov 21 at 16:44
In debug mode of course...
– skylendar
Nov 21 at 16:44
I made the same mistake a few months ago ;)
– Matthieu Brucher
Nov 21 at 16:45
I made the same mistake a few months ago ;)
– Matthieu Brucher
Nov 21 at 16:45
|
show 5 more comments
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Have you tried -fopenmp=libomp to use gcc OpenMP implementation?
– Matthieu Brucher
Nov 20 at 18:56
Ok, it works ! Thx for your help and I have a last question: Why is clang-7 so slooow ? I have got it compiled with gcc 7.3, but clang is 10x slower than gcc for the same source...
– skylendar
Nov 21 at 16:01
Compiled in release mode or debug?
– Matthieu Brucher
Nov 21 at 16:01
In debug mode of course...
– skylendar
Nov 21 at 16:44
I made the same mistake a few months ago ;)
– Matthieu Brucher
Nov 21 at 16:45