I've found we claim to support non-rectangular loops, but don't actually
support those in Fortran, as can be seen on:
integer i, j
!$omp parallel do collapse(2)
do i = 0, 10
do j = 0, i
end do
end do
end
To support this, the Fortran FE needs to allow the valid forms of
non-rectangular loops and disallow others, so mainly it needs its
updated version of c-omp.c c_omp_check_loop_iv etc., plus for non-rectangular
lb or ub expressions emit a TREE_VEC instead of normal expression as the C/C++ FE
do, plus testsuite coverage.
2021-10-27 Jakub Jelinek <jakub@redhat.com>
* libgomp.texi (OpenMP 5.0): Mention that Non-rectangular loop nests
aren't implemented for Fortran yet.