https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112338
Bug ID: 112338
Summary: ieee_set_halting_mode only affects the master thread
outside of an OpenMP parallel region
Product: gcc
Version: 13.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: vladimir.fuka at gmail dot com
Target Milestone: ---
Calling ieee_set_halting_mode only affects the master thread if other threads
already exist and the call is done outside of a parallel region. I am not sure
what the Fortran standard and the OpenMP specifications prescribe, but the
following code produces different results with GCC and with Intel.
use ieee_exceptions
implicit none
integer, parameter :: n = 100
real :: nom(n)
integer :: denom(n)
logical :: saved_fpe_mode(size(ieee_all))
integer :: i
nom = 1
denom = 0
call ieee_set_halting_mode(ieee_overflow, .true.)
call ieee_set_halting_mode(ieee_invalid, .true.)
call ieee_set_halting_mode(ieee_divide_by_zero, .true.)
!$omp parallel
print *,"hello from a thread"
!$omp end parallel
call ieee_get_halting_mode(ieee_all, saved_fpe_mode)
call ieee_set_halting_mode(ieee_all, .false.)
!$omp parallel do
do i = 1, n
nom(i) = nom(i) / denom(i)
end do
!$omp end parallel do
nom = min(max(0., nom), 1.)
!$omp parallel
call ieee_set_halting_mode(ieee_all, saved_fpe_mode)
!$omp end parallel
print *, nom
end
With GCC
gfortran-13 -fopenmp -g fpe.f90
the code halts on line 28 (nom(i) = nom(i) / denom(i)) with SIGFPE:
Floating-point exception - erroneous arithmetic operation.
With Intel
ifx -qopenmp -g fpe.f90
the code does not halt and prints all 1.000000s.
