Internal compiler error with OpenMP code in version 2026.0

caplanr — Thu, 07 May 2026 21:03:38 GMT

Hi,

I am getting an internal compiler error with one of our OpenMP codes:

getpb_reproducer.f90: error #5633: **Internal compiler error: segmentation violation signal raised** Please report this error along with the circumstances in which it occurred in a Software Problem Report. Note: File and line given may not be explicit cause of this error. compilation aborted for getpb_reproducer.f90 (code 3)

The error did not happen with 2025 or 2024.

If I compile without "-fopenmp" it works correctly.

I have created a small reproducer:

! ============================================================================= ! GETPB OpenMP ICE Reproducer for Intel 2026 ! Compiles with: gfortran -O3 -fopenmp getpb_reproducer.f90 -o repro ! ============================================================================= module constants use, intrinsic :: iso_fortran_env, only: real64 implicit none integer, parameter :: r_typ = real64 real(r_typ), parameter :: pi = 3.141592653589793_r_typ real(r_typ), parameter :: twopi = 2.0_r_typ * pi real(r_typ), parameter :: halfpi = pi * 0.5_r_typ real(r_typ), parameter :: degtorad = pi / 180.0_r_typ real(r_typ), parameter :: au_in_rs = 214.939469_r_typ end module constants module params use constants implicit none integer :: nx, ny real(r_typ) :: x0, x1, y0, y1 real(r_typ) :: rocc, int_rmin, int_rmax real(r_typ) :: r_obs, r_obs_rs logical :: r_obs_set real(r_typ) :: dsmult logical :: compute_pb, compute_b logical :: do_integral_weighting logical :: verbose end module params module image_region use constants implicit none real(r_typ), allocatable :: elong(:), alt(:) end module image_region module image_fields use constants implicit none real(r_typ), allocatable :: r_min(:,:), pb(:,:) end module image_fields ! ============================================================================= program repro_getpb ! ============================================================================= use constants use params use image_region use image_fields implicit none integer :: i real(r_typ) :: dummy_val logical :: twodee_local = .false. ! --------------------- Setup --------------------- nx = 101 ny = 101 x0 = -3.0_r_typ; x1 = 3.0_r_typ y0 = -3.0_r_typ; y1 = 3.0_r_typ rocc = 1.0_r_typ int_rmin = 1.0_r_typ int_rmax = 20.0_r_typ r_obs = 1.0_r_typ r_obs_set = .true. r_obs_rs = r_obs * au_in_rs dsmult = 1.0_r_typ compute_pb = .true. compute_b = .false. do_integral_weighting = .false. verbose = .true. allocate(r_min(nx,ny)) allocate(pb(nx,ny)) pb = 0.0_r_typ r_min = 0.0_r_typ allocate(elong(nx)) allocate(alt(ny)) if (verbose) then write(*,'(A)') '=== GETPB minimal reproducer (Intel 2026 ICE test) ===' write(*,'(A,I0,A,I0)') 'Image: ',nx,' x ',ny end if call get_image_obs_distance_specified dummy_val = pb(1,1) + pb(nx/2,ny/2) + pb(nx,ny) write(*,'(A,ES12.4)') 'Sample pB sum = ', dummy_val write(*,'(A)') 'SUCCESS: Reproducer compiled and ran.' deallocate(r_min, pb, elong, alt) contains subroutine transform_position(x, y, z, r, t, p) !$acc routine seq real(r_typ), intent(in) :: x, y, z real(r_typ), intent(out) :: r, t, p r = 5.0_r_typ; t = 0.0_r_typ; p = 0.0_r_typ end subroutine subroutine interp_field_ds(d1,d2,r,t,p,fv,drtp,d3,d4) !$acc routine seq real(r_typ), intent(in) :: d1,d2,r,t,p,d3,d4 real(r_typ), intent(out) :: fv real(r_typ), dimension(3), intent(out) :: drtp fv = 1.0_r_typ drtp = 0.01_r_typ end subroutine subroutine get_kernels(rmin_loc, rv, ne, cp_pb, cp_b, pb_loc, b_loc) !$acc routine seq real(r_typ), intent(in) :: rmin_loc, rv, ne logical, intent(in) :: cp_pb, cp_b real(r_typ), intent(out) :: pb_loc, b_loc if (cp_pb) then pb_loc = (rmin_loc / rv)**2 * ne * 1.0e-15_r_typ else pb_loc = 0.0_r_typ end if b_loc = 0.0_r_typ end subroutine function ds_s2c(r, t, drtp, axisymmetric) result(res) !$acc routine seq real(r_typ), intent(in) :: r, t real(r_typ), dimension(3), intent(in) :: drtp logical, intent(in) :: axisymmetric real(r_typ) :: res res = 0.01_r_typ end function ds_s2c ! =================================================================== ! Critical subroutine (this is what triggers the Intel ICE) ! =================================================================== subroutine get_image_obs_distance_specified use constants use params use image_region use image_fields implicit none real(r_typ), parameter :: zero = 0.0_r_typ real(r_typ), parameter :: half = 0.5_r_typ real(r_typ), parameter :: one = 1.0_r_typ integer :: i, j, nstop real(r_typ) :: dx, dy, s0, s1, dmax, s, t, ds, dsm, ds_local real(r_typ) :: e_rad, a_rad, cos_a, t_r_min, rv, tv, pv, pb_local real(r_typ), dimension(3) :: v_obs, v_ref, v_los, v_r_min real(r_typ) :: ds_fac real(r_typ), dimension(3) :: ex, ey, ez real(r_typ) :: n_e real(r_typ), dimension(3) :: drtp ! Build image axes if (nx == 1) then elong(1) = x0 else dx = (x1-x0)/real(nx-1,r_typ) do i=1,nx; elong(i)=x0+(i-1)*dx; enddo endif if (ny == 1) then alt(1) = y0 else dy = (y1-y0)/real(ny-1,r_typ) do j=1,ny; alt(j)=y0+(j-1)*dy; enddo endif v_obs(1) = r_obs_rs v_obs(2:3) = 0.0_r_typ ! ==================== CRITICAL PARALLEL REGION ==================== !$omp parallel do & !$omp& shared(pb, r_min, v_obs) & !$omp& private(i,j, e_rad,a_rad,cos_a, v_ref,t_r_min,v_r_min) & !$omp& private(s,s0,s1,dmax, t,ds,dsm,ds_local,nstop,v_los,rv,tv,pv) & !$omp& private(pb_local, n_e, drtp, ds_fac) & !$omp& private(ex,ey,ez) & !$omp& collapse(2) schedule(dynamic,10) !$acc parallel loop collapse(2) & !$acc& private(i,j, e_rad,a_rad,cos_a, v_ref,t_r_min,v_r_min) & !$acc& private(s,s0,s1,dmax, t,ds,dsm,ds_local,nstop,v_los,rv,tv,pv) & !$acc& private(pb_local, n_e, drtp) & !$acc& private(ex,ey,ez) do j = 1, ny do i = 1, nx e_rad = degtorad * elong(i) a_rad = degtorad * alt(j) cos_a = cos(a_rad) v_ref(1) = r_obs_rs * (one - cos(e_rad)*cos_a) v_ref(2) = r_obs_rs * sin(e_rad) * cos_a v_ref(3) = r_obs_rs * sin(a_rad) t_r_min = -(v_obs(1)*(v_ref(1)-v_obs(1)) + & v_obs(2)*(v_ref(2)-v_obs(2)) + & v_obs(3)*(v_ref(3)-v_obs(3))) / (r_obs_rs**2) v_r_min = t_r_min*v_ref + (one-t_r_min)*v_obs r_min(i,j) = sqrt(dot_product(v_r_min, v_r_min)) if (abs(e_rad) <= halfpi .and. r_min(i,j) <= rocc) then pb(i,j) = -1.0_r_typ cycle end if if (r_min(i,j) >= int_rmax) cycle dmax = sqrt(int_rmax**2 - r_min(i,j)**2) s0 = t_r_min*r_obs_rs - dmax s1 = t_r_min*r_obs_rs + dmax if (s1 <= zero) cycle s0 = max(s0, zero) s = s0 dsm = 0.0_r_typ nstop = 0 do t = s / r_obs_rs v_los = t*v_ref + (one-t)*v_obs call transform_position(v_los(1),v_los(2),v_los(3), rv,tv,pv) rv = max(int_rmin, min(rv, int_rmax)) call interp_field_ds(0.0_r_typ,0.0_r_typ,rv,tv,pv,n_e,drtp,0.0_r_typ,0.0_r_typ) ds_local = ds_s2c(rv, tv, drtp, twodee_local) call get_kernels(r_min(i,j), rv, n_e, compute_pb, compute_b, pb_local, pb_local) ds = ds_local * dsmult s = s + ds if (s >= s1) then ds = ds - (s - s1) s = s1 nstop = nstop + 1 end if ds_fac = 0.5_r_typ * (dsm + ds) pb(i,j) = pb(i,j) + ds_fac * pb_local dsm = ds if (nstop >= 2) exit end do end do end do !$acc end parallel !$omp end parallel do end subroutine get_image_obs_distance_specified end program repro_getpb

Re: Internal compiler error with OpenMP code in version 2026.0

Harald_S_Intel — Fri, 08 May 2026 08:16:22 GMT

Hello,

we're taking a look at the issue. In the meantime, I think I found a workaround for it. Can you try using a do-while construct in your inner loop (lines 223-248) rather than using a do construct? I tried the following and it worked on my end using 2026.0

do while (nstop < 2) t = s / r_obs_rs v_los = t*v_ref + (one-t)*v_obs call transform_position(v_los(1),v_los(2),v_los(3), rv,tv,pv) rv = max(int_rmin, min(rv, int_rmax)) call interp_field_ds(0.0_r_typ,0.0_r_typ,rv,tv,pv,n_e,drtp,0.0_r_typ,0.0_r_typ) ds_local = ds_s2c(rv, tv, drtp, twodee_local) call get_kernels(r_min(i,j), rv, n_e, compute_pb, compute_b, pb_local, pb_local) ds = ds_local * dsmult s = s + ds if (s >= s1) then ds = ds - (s - s1) s = s1 nstop = nstop + 1 end if ds_fac = 0.5_r_typ * (dsm + ds) pb(i,j) = pb(i,j) + ds_fac * pb_local dsm = ds ! if (nstop >= 2) exit end do

Best,

Re: Internal compiler error with OpenMP code in version 2026.0

caplanr — Mon, 11 May 2026 20:29:50 GMT

Hi,

It looks like this work-around works!

It would still be good to have this fixed within the next couple of releases though so we don't have to change the code.

- Ron

Re: Internal compiler error with OpenMP code in version 2026.0

Harald_S_Intel — Tue, 12 May 2026 07:44:25 GMT

@caplanr -- there is another workaround available. If you remove the "collapse(2)" clause from line 182, it also works on my end.

Re: Internal compiler error with OpenMP code in version 2026.0

caplanr — Tue, 12 May 2026 16:04:29 GMT

I think that would reduce performance since the inner loop would not be parallelized?

Re: Internal compiler error with OpenMP code in version 2026.0

Harald_S_Intel — Tue, 12 May 2026 19:40:09 GMT

Yes -- using this latter WA, performance will likely depend now on the parallelization over ny rather than ny*nx, and that could be impactful depending on the value of ny and nx. If you want a more performant solution, you could go with the first WA. If you want a less intrusive solution, you can go with the second. That said, compiler colleagues are taking a look at the bug.

topic Re: Internal compiler error with OpenMP code in version 2026.0 in Intel® Fortran Compiler

Internal compiler error with OpenMP code in version 2026.0

Re: Internal compiler error with OpenMP code in version 2026.0

Re: Internal compiler error with OpenMP code in version 2026.0

Re: Internal compiler error with OpenMP code in version 2026.0

Re: Internal compiler error with OpenMP code in version 2026.0

Re: Internal compiler error with OpenMP code in version 2026.0