a component of an array element mapped tofrom does not come back (CCE 21, both memory modes)

Legality: not independently confirmed. no independent review yet How this is checked

Same issue as oop/cce-element-component-map-lost; this program is another reproducer of it.

map(tofrom: vk(4)%g(3)), an element of a component of an element of an array of structures: the target region's write is lost on CCE 21.0.3 and 21.0.4 with separate and with unified memory. Mapping the whole element vk(5) works. AFAR and GCC are correct.

Affected variants

Compiler	MI300A gfx942 unified memory (XNACK 1)	MI300A gfx942 copy (XNACK 0)	MI250X gfx90a copy (XNACK 0)	MI300X gfx942 copy (XNACK 0)	MI350X gfx950 copy (XNACK 0)	A100 sm_80 separate memory	A100 sm_80 managed memory
AFAR 24.3.0	correct	correct	unknown not run	correct	correct	n/a	n/a
CCE 19.0.0	correct	behaves incorrectly	unknown not run	unknown not run	unknown not run	n/a	n/a
CCE 20.0.2	correct	behaves incorrectly	unknown not run	unknown not run	unknown not run	n/a	n/a
CCE 21.0.3	behaves incorrectly	behaves incorrectly	unknown not run	unknown not run	unknown not run	n/a	n/a
CCE 21.0.4	behaves incorrectly	behaves incorrectly	unknown not run	unknown not run	unknown not run	n/a	n/a
NVHPC 25.11	n/a	n/a	n/a	n/a	n/a	correct	correct
NVHPC 26.9	n/a	n/a	n/a	n/a	n/a	correct	correct
GCC 16.2.0	correct	correct	correct	correct	correct	correct	n/a

"behaves incorrectly" / "not supported": this issue, confirmed in up to four environments (another build directory, another node, a repeat). "fails another way": a different failure, not counted as this issue. "unknown": not run there, or the runs disagree.

Messages

Result	Compiler and GPU	Message
behaves incorrectly	CCE 19.0.0, MI300A copy CCE 20.0.2, MI300A copy CCE 21.0.3, MI300A unified CCE 21.0.3, MI300A copy CCE 21.0.4, MI300A unified CCE 21.0.4, MI300A copy	show r1= 0 r2= 0 RESULT ran_on_host=0 check=fail

Reproduce

CCE 19.0.0, MI300A copy

module load cce/19.0.0 craype-accel-amd-gfx942 rocm/6.4.3
module unload cray-mpich
ftn -fopenmp -O2 repro.f90 -o repro
HSA_XNACK=0 OMP_TARGET_OFFLOAD=mandatory ./repro

CCE 20.0.2, MI300A copy

module load cce/20.0.2 craype-accel-amd-gfx942 rocm/6.4.3
module unload cray-mpich
ftn -fopenmp -O2 repro.f90 -o repro
HSA_XNACK=0 OMP_TARGET_OFFLOAD=mandatory ./repro

CCE 21.0.3, MI300A unified

module load cce/21.0.3 craype-accel-amd-gfx942 rocm/7.2.0
module unload cray-mpich
ftn -fopenmp -O2 repro.f90 -o repro
HSA_XNACK=1 OMP_TARGET_OFFLOAD=mandatory ./repro

CCE 21.0.4, MI300A unified

module load cce/21.0.4 craype-accel-amd-gfx942 rocm/7.2.0
module unload cray-mpich
ftn -fopenmp -O2 repro.f90 -o repro
HSA_XNACK=1 OMP_TARGET_OFFLOAD=mandatory ./repro

AFAR 24.3.0, MI300A unified (runs correctly)

$AFAR/bin/amdflang -fopenmp --offload-arch=gfx942 -O2 repro.f90 -o repro
HSA_XNACK=1 OMP_TARGET_OFFLOAD=mandatory ./repro

Program (54 lines)

! # Finding (fortran-oop): map(tofrom: vk(4)%g(3)) of a component of an array element does not reach the host (CCE 21, both modes)
!
! - toolchains and modes that fail: cce21 (CCE 21.0.3: copy, unified), cce21_4 (CCE 21.0.4: copy, unified); -O2
! - build: ftn -fopenmp -O2 (module load cce/<v> craype-accel-amd-gfx942 rocm/<r>; OpenACC: ftn -h acc)
! - failure: wrong_answer (check=fail); OMP_TARGET_OFFLOAD=mandatory
! - observed: `r1= 0 r2= 0` on CCE 21.0.3 and 21.0.4 at HSA_XNACK=0 and 1; the same for a section vk(5)%g(3:5). The nested form
!   vk(4)%h%c(8) is an internal compiler error on CCE 21 instead, linked to fuzz/s1-3463-cce21.f90 by the confirmer and not
!   counted here
! - expected: `r1= 74 r2= 74`
! - rule: 5.2 §5.8.3 p.151 l.13; §5.8.3 p.154 exit step 1a
! - same-compiler control: the whole element map(tofrom: vk(5)) (controls/elemsec-element.f90): correct on CCE 21 in both modes
!   (results/oop/main/rows.part*.jsonl)
! - other families: AFAR and GCC 16.2 correct; CCE 19 and 20 fail at HSA_XNACK=0 only
! - gate and confirmer: 8 cells, 8 confirmed in the gate's four environments (a-d; results/oop/main/gate_reruns*.jsonl); confirmer
!   (results/oop/main/confirm.jsonl): needs_human (R22-expected-weak) 8; R22-expected-weak means the expected value has one
!   source, the generator's Python model; the values follow from the program's arithmetic (checked by hand), and AFAR, GCC 16.2
!   (gfx90a), GCC 16.2 (sm_80), NVHPC 25.11, NVHPC 26.9 print them on this program
! - programs (2): oop-elemsec-comp-element, oop-elemsec-comp-section (offload/engine/oop_gen.py; this file is the first one)
! - legality: for the cce cells: the rules (offload.engine.rules, with the fortran-oop restrictions) and AFAR's flang front end
!   (-fsyntax-only) and NVHPC 26.9 nvfortran (compile only) (tools/campaigns/oop.py legality, results/oop/main/legality.json)
module oop_m
  implicit none
  integer, parameter :: n = 64
  type dc
    integer :: g(20) = 0
    integer :: i = 0
  end type dc
end module oop_m

program oop
  use omp_lib
  use oop_m
  implicit none
  integer :: host_flag
  logical :: ok
  integer :: r1, r2
  type(dc) :: vk(5)
  integer :: l
  host_flag = 1
  !$omp target map(from: host_flag)
  host_flag = merge(1, 0, omp_is_initial_device())
  !$omp end target
  !$omp target map(tofrom: vk(4)%g(3))
  vk(4)%g(3) = 74
  !$omp end target
  r1 = vk(4)%g(3)
  r2 = sum(vk(4)%g)
  ok = .true.
  ok = ok .and. (r1 == 74)
  ok = ok .and. (r2 == 74)
  print '(a,i0)', 'r1= ', r1
  print '(a,i0)', 'r2= ', r2
  print '(a,i0,a,a)', 'RESULT ran_on_host=', host_flag, ' check=', merge('pass', 'fail', ok)
end program oop

Source in the repository

Something to add? Dispute its legality · Report it fixed in a newer release · Report a mistake on this page

Expected and observed

Expected

r1= 74

Observed where it behaves incorrectly

r1= 0
r2= 0
RESULT ran_on_host=0 check=fail

What the specification requires

The specification text this program relies on and the compiler is expected to support.

OpenMP 5.2 §5.8.3 p.151 l.13

OpenMP 5.2 §5.8.3 p.154

Evidence

Same compiler, one change

the whole array element instead of a component of it: not run yet

Control program

! control (fortran-oop family program oop-elemsec-element, correct on every CCE in both modes)
! fortran-oop elemsec/element (OpenMP 5.2, free-form Fortran):
! map(tofrom: vk(5)): one element of an array of structures
! spec: OpenMP 5.2 §5.8.3 p.151 l.13 (structure elements and array sections are list items); §5.8.3
!   p.157 l.21-22; OpenMP 5.2 §5.8.3 p.151-155 (map clause)
! legality: defined
! expected (computed by compliance/oop_gen.py): r1= 610, r2= 40, r3= 0
module oop_m
  implicit none
  integer, parameter :: n = 64
  type dc
    integer :: g(20) = 0
    integer :: i = 0
  end type dc
end module oop_m

program oop
  use omp_lib
  use oop_m
  implicit none
  integer :: host_flag
  logical :: ok
  integer :: r1, r2, r3
  type(dc) :: vk(5)
  integer :: l
  host_flag = 1
  !$omp target map(from: host_flag)
  host_flag = merge(1, 0, omp_is_initial_device())
  !$omp end target
  !$omp target map(tofrom: vk(5))
  do l = 1, 20
    vk(5)%g(l) = 20 + l
  end do
  vk(5)%i = 40
  !$omp end target
  r1 = sum(vk(5)%g)
  r2 = vk(5)%i
  r3 = sum(vk(4)%g)
  ok = .true.
  ok = ok .and. (r1 == 610)
  ok = ok .and. (r2 == 40)
  ok = ok .and. (r3 == 0)
  print '(a,i0)', 'r1= ', r1
  print '(a,i0)', 'r2= ', r2
  print '(a,i0)', 'r3= ', r3
  print '(a,i0,a,a)', 'RESULT ran_on_host=', host_flag, ' check=', merge('pass', 'fail', ok)
end program oop

Other compilers run it correctly

AFAR 24.3.0, NVHPC 25.11, NVHPC 26.9, GCC 16.2.0