[Bug 1907812] [NEW] Can't build simple OpenMP offloading programs on Ubuntu 20.10

[Mehdi Chinoune]

Public bug reported:

$cat prod.f90
program main
  implicit none
  integer, parameter :: sp = selected_real_kind(6,37)
  integer, parameter :: n = 4096
  real(sp), allocatable :: a(:), b(:), c(:), c2(:)
  integer :: i

  allocate( a(n), b(n), c(n) )
  
  c = 0._sp
  call random_number(a)
  call random_number(b)

  !$omp target teams map(to: a, b) map(from: c)
  !$omp distribute parallel do
  do i = 1, n
    c(i) = a(i)*b(i)
  end do
  !$omp end target teams
  
  c2 = a*b
  
  print*, maxval( abs(c2-c) )
  
end program

$ gfortran -O3 -flto -fopenmp -foffload=nvptx-none prod.f90 -o test.x
/usr/bin/ld: /tmp/ccyvMF16.crtoffloadtable.o: warning: relocation against `__offload_vars_end' in read-only section `.rodata'
/usr/bin/ld: warning: creating DT_TEXTREL in a PIE

Ubuntu 20.10 x86_64
Xeon E3-1505m-v6
Nvidia Quadro M2200

That doesn't happen on Ubuntu 20.04

** Affects: gcc-10 (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: offloading openmp

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https://bugs.launchpad.net/bugs/1907812

Title:
  Can't build simple OpenMP offloading programs on Ubuntu 20.10

Status in gcc-10 package in Ubuntu:
  New

Bug description:
  $cat prod.f90
  program main
    implicit none
    integer, parameter :: sp = selected_real_kind(6,37)
    integer, parameter :: n = 4096
    real(sp), allocatable :: a(:), b(:), c(:), c2(:)
    integer :: i

    allocate( a(n), b(n), c(n) )
    
    c = 0._sp
    call random_number(a)
    call random_number(b)

    !$omp target teams map(to: a, b) map(from: c)
    !$omp distribute parallel do
    do i = 1, n
      c(i) = a(i)*b(i)
    end do
    !$omp end target teams
    
    c2 = a*b
    
    print*, maxval( abs(c2-c) )
    
  end program

  $ gfortran -O3 -flto -fopenmp -foffload=nvptx-none prod.f90 -o test.x
  /usr/bin/ld: /tmp/ccyvMF16.crtoffloadtable.o: warning: relocation against `__offload_vars_end' in read-only section `.rodata'
  /usr/bin/ld: warning: creating DT_TEXTREL in a PIE

  Ubuntu 20.10 x86_64
  Xeon E3-1505m-v6
  Nvidia Quadro M2200

  That doesn't happen on Ubuntu 20.04

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