https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104864
Bug ID: 104864
Summary: fortran openmp taskloop firstprivate and lastprivate
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: han...@compiler-dev.com
Target Milestone: ---
program main
use omp_lib
Implicit None
Logical :: init
Integer accum1,accum2,answer,i
Integer :: x(50)
Do i=1,Size(x,1)
x(i) = i
End Do
Call omp_set_schedule(1,10)
!$OMP PARALLEL NUM_THREADS(15) DEFAULT(none) SHARED(accum1,answer,x)
PRIVATE(init,accum2)
accum1 = -555
!$OMP BARRIER
accum2 = 0
init = .True.
!$OMP taskloop LASTPRIVATE(accum1) FIRSTPRIVATE(accum1)
Do i=1,Size(x,1)
If (init) Then
If (accum1/=-555) Stop 'FAIL firstpriv'
accum1 = 0
init = .False.
End If
accum1 = accum1 + x(i)
accum2 = accum2 + x(i)
If (accum1/=accum2) Stop 'FAIL accum incon'
If (i==Size(x,1)) answer = accum1
End Do
!$OMP END taskloop
If (accum1/=answer) Stop 'FAIL accum1 lastprivate'
!$OMP END PARALLEL
Print *,'ok'
End Program
gfortran-10 a.f90 -fopenmp
run a.out many times， most of the time run ok, but some time run result like
this:
./a.out
STOP STOP STOP FAIL firstpriv
FAIL firstpriv
FAIL firstpriv
I think one thread the firstpriv assignment statement really execute after
some
threads execute some do loop and return the lastprivate value to the original
list item accum1.
can taskloop construct should add a BARRIER after task_dup initial value of
accum1 from the original list?
