[flang] [OpenMP] flang-new crashes (omp taskgroup)

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Test code:

$ cat test.f90
program taskgroup_example
  use omp_lib
  implicit none
  integer :: i

  !$omp parallel
  !$omp single
  !$omp taskgroup
  do i=1,5
    !$omp task
    call do_work(i)
    !$omp end task
  end do
  !$omp end taskgroup
  !$omp end single
  !$omp end parallel

contains

  subroutine do_work(i)
    integer, intent(in) :: i
    print*, "Task ", i, " started"
    ! Do some work here
    print*, "Task ", i, " finished"
  end subroutine do_work

end program taskgroup_example

Stack dump:

 #0 0x000055a3abe9dbac llvm::sys::PrintStackTrace(llvm::raw_ostream&, int)
 #1 0x000055a3abe9e1ee SignalHandler(int) Signals.cpp:0:0
 #2 0x00007f16043ef520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #3 0x000055a3ac27dc2b Fortran::frontend::CodeGenAction::executeAction()
 #4 0x000055a3abebd344 Fortran::frontend::FrontendAction::execute()
 #5 0x000055a3abeb57b1 Fortran::frontend::CompilerInstance::executeAction(Fortran::frontend::FrontendAction&)
 #6 0x000055a3abebf9c0 Fortran::frontend::executeCompilerInvocation(Fortran::frontend::CompilerInstance*)
 #7 0x000055a3abb9a7b2 fc1_main(llvm::ArrayRef<char const*>, char const*)
 #8 0x000055a3abb98980 main
 #9 0x00007f16043d6d90 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
#10 0x00007f16043d6e40 call_init ./csu/../csu/libc-start.c:128:20
#11 0x00007f16043d6e40 __libc_start_main ./csu/../csu/libc-start.c:379:5
#12 0x000055a3abb97f05 _start
flang-new: error: unable to execute command: Segmentation fault
flang-new: error: flang frontend command failed due to signal (use -v to see invocation)
flang-new version 17.0.0 (https://github.com/llvm/llvm-project.git 7fff3bfe783953eee18446d30de2f17fe1b68bab)
Target: x86_64-unknown-linux-gnu
Thread model: posix

Program arguments:

flang-new -fc1 -triple x86_64-unknown-linux-gnu -emit-obj -fopenmp -fcolor-diagnostics -mrelocation-model pic -pic-level 2 -pic-is-pie -target-cpu x86-64 -o test.o -x f95-cpp-input test.f90

cf.

$ gfortran -fopenmp test.f90
$ ./a.out
 Task            1  started
 Task            1  finished
 Task            5  started
 Task            5  finished
 Task            2  started
 Task            2  finished
 Task            4  started
 Task            4  finished
 Task            3  started
 Task            3  finished

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@llvm/issue-subscribers-openmp

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@llvm/issue-subscribers-flang-frontend

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[tblah]

This appears to be fixed with current flang main