https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69128
Bug ID: 69128
Summary: [4.9/5/6 Regression] OpenMP workshare problem with
SUM()
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: anlauf at gmx dot de
Target Milestone: ---
Reported in
https://gcc.gnu.org/ml/fortran/2015-12/msg00112.html
% gfc-trunk workshare-sum.f90 -fopenmp
workshare-sum.f90:16:0:
!$omp parallel workshare
Error: work-sharing region may not be closely nested inside of work-sharing,
'critical', 'ordered', 'master', explicit 'task' or 'taskloop' region
The error shows up with 4.7/4.8/4.9/5/6. No error with 4.6.
The error appears for SUM(), but not e.g. for MAXVAL().
The code is accepted by ifort, sunf95, crayftn.
Testcase:
% cat workshare-sum.f90
program test
implicit none
real, allocatable :: a(:,:), b(:)
integer :: dim1, dim2, i,j
dim1=10000
dim2=500
allocate(a(dim1,dim2),b(dim1))
call random_number(a)
!$omp parallel do
do i=1,dim1
b(i) = sum(a(i,:), dim=1)
end do
!$omp end parallel do
!$omp parallel workshare
! b(:) = maxval(a(:,:), dim=2) ! No problem with maxval()
b(:) = sum(a(:,:), dim=2) ! Failure with sum()
!$omp end parallel workshare
end program
