10.1.3.4 Indirect Addressing

Loop dependencies can result from stores into arrays that are indexed in the loop by subscripts whose values are not known. For example, indirect addressing could be order dependent if there are repeated values in the index array:

   DO L = 1,NW
     A(ID(L)) = A(L) + B(L)
   END DO

In the example, repeated values in ID cause elements in A to be overwritten. In the serial case, the last store is the final value. In the parallel case, the order is not determined. The values of A(L) that are used, old or updated, are order dependent.