Appears to behave incorrectlyCompiler crash · Fortran · OpenMP · Open

ftn/craycc: constructs documented as unsupported in offload regions (single, masked, task, ordered, scan) give internal compiler errors or device link failures instead of a diagnostic

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

Same issue as cce19-target-parallel-single-ice; this program is another reproducer of it.

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	behaves incorrectly	behaves incorrectly	unknown not run	unknown not run	unknown not run	n/a	n/a
CCE 20.0.2	behaves incorrectly	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 unified CCE 19.0.0, MI300A copy	show Warning: Headers and libraries from cray-libsci/25.03.0 will be ignored because depends on PE_MPICH which is unavailable.. MT_CONTEXT_MASTER Error message :: unhandled construct type Error detected :: File '/workspace/crayftn/pdgcs/v_openmp.c', line 7617 Initiated from :: Line 660 (v_main.c) Optimizer built :: 2025-02-07 (production) File :: fuzz-2224-cce19.f90
behaves incorrectly	CCE 20.0.2, MI300A unified CCE 20.0.2, MI300A copy	show Warning: Headers and libraries from cray-libsci/25.09.0 will be ignored because depends on PE_MPICH which is unavailable.. MT_CONTEXT_MASKED Error message :: unhandled acc construct type Error detected :: File '/workspace/crayftn/pdgcs/v_openmp.c', line 7881 Initiated from :: Line 660 (v_main.c) Optimizer built :: 2025-11-17 (production) File :: fuzz-2224-cce19.f90
behaves incorrectly	CCE 21.0.3, MI300A unified CCE 21.0.3, MI300A copy	show Warning: Headers and libraries from cray-libsci/26.03.0 will be ignored because depends on PE_MPICH which is unavailable.. MT_CONTEXT_MASKED Error message :: unhandled acc construct type Error detected :: File '/workspace/crayftn/pdgcs/v_openmp.c', line 8265 Initiated from :: Line 732 (v_main.c) Optimizer built :: 2026-07-14 (production) File :: fuzz-2224-cce19.f90
behaves incorrectly	CCE 21.0.4, MI300A unified CCE 21.0.4, MI300A copy	show Warning: Headers and libraries from cray-libsci/26.03.0 will be ignored because depends on PE_MPICH which is unavailable.. MT_CONTEXT_MASKED Error message :: unhandled acc construct type Error detected :: File '/workspace/crayftn/pdgcs/v_openmp.c', line 8265 Initiated from :: Line 732 (v_main.c) Optimizer built :: 2026-09-24 (production) File :: fuzz-2224-cce19.f90

Reproduce

CCE 19.0.0, MI300A unified

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=1 OMP_TARGET_OFFLOAD=mandatory ./repro

CCE 20.0.2, MI300A unified

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=1 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 (25 lines)

! Minimized by compliance.fuzz_min from fuzz seed 2224 (fuzz-1).
! toolchain: cce19 (-O2, HSA_XNACK=1, OMP_TARGET_OFFLOAD=mandatory)
! failure: ice (ice: INTERNAL COMPILER ERROR: "unhandled construct type" (v_openmp.c, line 7617, version <v>))
! expected: compiles
! observed: internal compiler error: ice: INTERNAL COMPILER ERROR:  "unhandled construct type" (/workspace/crayftn/pdgcs/v_openmp.c,
!   line 7617, version cc4d36e4ff3377d45f0e6e892b5dacd82009a0ca)
! Legal OpenMP 5.2: offload.engine.prerun.check accepts it (rerun: offload.engine.rules with the
!   race rule and the restriction checks, and the AFAR flang front end, not under test here); no
!   compiler under test, gfortran or gcc is a legality witness.
! also fails on: cce20, cce21
program fuzz_prog
  use omp_lib, only: omp_is_initial_device
  implicit none
  integer, parameter :: n = 32, m = 2
  integer :: i, j
  integer(8) :: cs
  ! fuzz: kernels
  !$omp target
    !$omp masked
    !$omp end masked
  !$omp end target
  ! fuzz: checksum
  cs = 0
  print '(a,i0,a,i0)', 'RESULT checksum=', cs, ' ran_on_host=', 0
end program fuzz_prog

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

Observed where it behaves incorrectly

Warning:
 Headers and libraries from cray-libsci/25.03.0 will be ignored because depends on PE_MPICH which is unavailable..
MT_CONTEXT_MASTER
   Error message      ::  unhandled construct type
   Error detected     ::  File '/workspace/crayftn/pdgcs/v_openmp.c', line 7617
   Initiated from     ::  Line 660 (v_main.c)
   Optimizer built    ::  2025-02-07 (production)
   File               ::  fuzz-2224-cce19.f90

What the specification requires

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

The same requirement as the issue cce19-target-parallel-single-ice.

OpenMP 5.2 §11.1 p.241 l.2-3

The single construct specifies that the associated structured block is executed by only one of the threads in the team

OpenMP 5.2 §11.1 p.241 l.5-6

An implicit barrier occurs at the end of a single region if the nowait clause is not specified.

Evidence

Other compilers run it correctly

AFAR 24.3.0, NVHPC 25.11, NVHPC 26.9, GCC 16.2.0