Search code examples
c++gccopenmp

OpenMP offloading says 'fatal error: could not find accel/nvptx-none/mkoffload'

I'm trying to compile the following simple OpenMP GPU offloading program with G++ 9.3.0:

#include <iostream>

int main(){
  const int N=1000;
  int d[N];

  for(auto i=0;i<N;i++)
    d[i] = 1;

  #pragma omp target teams distribute parallel for map(tofrom:d[0:N])
  for(size_t i=0;i<N;i++){
    d[i] *= 3*i+1;
  }

  for(int i=0;i<N;i++)
    std::cout<<d[i]<<" ";
  std::cout<<std::endl;
}

I'm compiling with

g++ -fopenmp -O3 gpu_test.cpp

However, when I try to compile, I get the following error message:

lto-wrapper: fatal error: could not find accel/nvptx-none/mkoffload in /usr/lib/gcc/x86_64-linux-gnu/9/:/usr/lib/gcc/x86_64-linux-gnu/9/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/9/:/usr/lib/gcc/x86_64-linux-gnu/ (consider using ‘-B’)

How can I fix this?

Solution

  • You haven't installed GCC's offloading capabilities. On Ubuntu/Debian systems you can do so with:

    sudo apt install gcc-offload-nvptx

    Or install for a specific version of GCC with, e.g.

    sudo apt install gcc-9-offload-nvptx