[PATCH] D92732: [Flang][OpenMP 4.5] Add semantic check for OpenMP Do Loop Constructs

[Yashaswini Hegde via Phabricator via llvm-commits]

yhegde added inline comments.


================
Comment at: flang/lib/Semantics/resolve-directives.cpp:1039
   }
+  ClearThreadPrivateSymbols();
   PopContext();
----------------
kiranchandramohan wrote:
> yhegde wrote:
> > kiranchandramohan wrote:
> > > Will this work if there are two omp do loops having threadprivate iteration variables?
> > For the the following test case
> > 
> > program omp_do1
> >   integer, save:: i, j, k, n
> >   !$omp  threadprivate(i)
> >   !$omp  do
> >   !ERROR: Loop iteration variable i is not allowed in THREADPRIVATE.
> >   do i = 1, 10
> >     !!$omp  threadprivate(j)
> >     !$omp  do
> >     do j = 1, 10
> >       print *, "Hello"
> >     end do
> >   end do
> >   !$omp end do
> > 
> >   !$omp  do
> >   !ERROR: Loop iteration variable i is not allowed in THREADPRIVATE.
> >   do i = 1, 10
> >     !!$omp  threadprivate(j)
> >     !$omp  do
> >     do j = 1, 10
> >       print *, "Hello"
> >     end do
> >   end do
> >   !$omp end do
> > 
> > end program omp_do1
> > 
> > the error is 
> > 
> > ./kcmtp3.f90:6:6: error: Loop iteration variable i is not allowed in THREADPRIVATE.
> >     do i = 1, 10
> >        ^
> > ./kcmtp3.f90:8:12: error: A worksharing region may not be closely nested inside a worksharing, explicit task, taskloop, critical, ordered, atomic, or master region
> >       !$omp  do
> >              ^^
> > ./kcmtp3.f90:17:6: error: Loop iteration variable i is not allowed in THREADPRIVATE.
> >     do i = 1, 10
> >        ^
> > ./kcmtp3.f90:19:12: error: A worksharing region may not be closely nested inside a worksharing, explicit task, taskloop, critical, ordered, atomic, or master region
> >       !$omp  do
> >              ^^
> > 
> > and if I uncomment !$omp  threadprivate(j) , I get parse errors. 
> > 
> > and the gfortran error is
> > 
> > kcmtp3.f90:6:14:
> > 
> >     6 |   do i = 1, 10
> >       |              1
> > Error: !$OMP DO iteration variable must not be THREADPRIVATE at (1)
> > kcmtp3.f90:17:14:
> > 
> >    17 |   do i = 1, 10
> >       |              1
> > Error: !$OMP DO iteration variable must not be THREADPRIVATE at (1)
> > 
> I got that slightly wrong. What i meant is that if we clear the symbols after visiting a block construct then we will miss the error on a following loop construct. For e.g.
> 
> ```
> integer, save:: i, j, k, n
> !$omp  threadprivate(i)
> 
> !$omp parallel
> print *, "parallel"
> !$omp end parallel
> 
> !$omp  do
> do i = 1, 10
>   do j = 1, 10
>     print *, "Hello"
>   end do
> end do
> !$omp end do
> 
> end program
> ```
Probably I can call ClearThreadPrivateSymbols() in bool Pre(const parser::ModuleSubprogram &) ?

For the test case 
program test
integer, save:: i, j, k, n
!$omp  threadprivate(i)

!$omp parallel
print *, "parallel"
!$omp end parallel

!$omp  do
do i = 1, 10
  do j = 1, 10
    print *, "Hello"
  end do
end do
!$omp end do

end program test

the error message is -
./tp4.f90:10:4: error: Loop iteration variable i is not allowed in THREADPRIVATE.
  do i = 1, 10
     ^

and for the test case  

program omp_do2
  !$omp threadprivate(k,i)
  !$omp threadprivate(j)
  !$omp  threadprivate(i)
  call compute()
  contains
  subroutine compute()
  !$omp  do ordered(2) collapse(2)
  !ERROR: Loop iteration variable k is not allowed in THREADPRIVATE.
  foo: do k = 1, 10
    do i = 1, 10
      print *, "Hello"
    end do
  end do foo
  !$omp end do
  end subroutine

end program omp_do2

program omp_do3
  !$omp  threadprivate(j)
  !$omp parallel
  print *, "parallel"
  !$omp end parallel
  !$omp  do
  !ERROR: Loop iteration variable i is not allowed in THREADPRIVATE.
  do j = 1, 10
    do i = 1, 10
      print *, "Hello"
    end do
  end do
  !$omp end do

end program omp_do3

 the error message is 
./tp5.f90:10:11: error: Loop iteration variable k is not allowed in THREADPRIVATE.
    foo: do k = 1, 10
            ^
./tp5.f90:11:8: error: Loop iteration variable i is not allowed in THREADPRIVATE.
      do i = 1, 10
         ^
./tp5.f90:27:6: error: Loop iteration variable j is not allowed in THREADPRIVATE.
    do j = 1, 10
       ^




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