[llvm-branch-commits] [llvm] [OpenMPOpt] Make parallel regions reachable from new DeviceRTL loop functions (PR #150927)

[Sergio Afonso via llvm-branch-commits]

skatrak wrote:

After a recent rebase of this work, a backend assert ("Getting frame offset for a dead object?") started triggering for some of the offload tests added here, even with OpenMPOpt disabled. I was able to create a more concise reproducer for this issue:

```f90
! flang -O0 -fopenmp -fopenmp-version=52 --offload-arch=gfx1100 test.f90
program main
  integer :: i, counter

  !$omp target teams distribute
  do i=1, 10
  end do

  counter = 0
  !$omp target map(tofrom: counter)
    !$omp parallel do reduction(+:counter)
    do i=1, 10
      counter = counter + 1
    end do
  !$omp end target
end program
```

Changes to PrologEpilogInserter.cpp implement an AI-assisted backend tweak that successfully works around it, but I am not at all familiar with it to have any confidence about that being the right way to address that problem. I'd be grateful if an expert in that area could take a look.

https://github.com/llvm/llvm-project/pull/150927