Reproducer
logical :: l
! logical :: l(3)
integer, dimension(3) :: a
integer :: ia(1)
a = [ 0, -1, 3 ]
l = .true.
ia = minloc(a, mask=l)
print *, ia(1)
end
$ flang-new minloc.f90 ; a.out
2
$ flang-new -O minloc.f90 ; a.out
0
If the mask l is an array, the result is correct.