| Issue |
181270
|
| Summary |
[Flang][OpenMP] The earlier DECLARE REDUCTION declaration within a different scope takes precedence, so the execution result is incorrect
|
| Labels |
flang:openmp
|
| Assignees |
|
| Reporter |
ohno-fj
|
```
Version of flang : 23.0.0(a563e6bb7ed485e0ab88717bb4a8c5e8522d9792)/AArch64
```
According to `OpenMP 6.0 : 7.6.14 declare_reduction Directive`, `the visibility and accessibility of a user-defined reduction are the same as those of a variable declared at the same location in the program.`
However, as seen in the attached program (`sngg487e_22.f90`), it appears that the declaration of the `DECLARE REDUCTION directive` takes effect not only within the same scope in the program, but also within a different scope. This results in incorrect execution results being output.
The following are the test program, Flang, Gfortran and ifx compilation/execution results.
sngg487e_22.f90:
```fortran
module m
contains
subroutine dummy
!$omp declare reduction (a:integer:omp_out=omp_out+omp_in) initializer(omp_priv=10000)
end subroutine dummy
subroutine test
!$omp declare reduction (a:integer:omp_out=omp_out+omp_in) initializer(omp_priv=0)
integer::x1,i
x1=0
!$omp parallel do reduction(a:x1)
do i=1,10
x1=x1+1
end do
!$omp end parallel do
write(6,*) "x1 = ", x1
end subroutine test
end module m
program main
use m
implicit none
call test()
end program main
```
```
$ export OMP_NUM_THREADS=2; flang -fopenmp sngg487e_22.f90; ./a.out
x1 = 20010
$
```
```
$ export OMP_NUM_THREADS=2; gfortran -fopenmp sngg487e_22.f90; ./a.out
x1 = 10
$
```
```
$ export OMP_NUM_THREADS=2; ifx -qopenmp sngg487e_22.f90; ./a.out
x1 = 10
$
```
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