------- Additional Comments From eedelman at acclab dot helsinki dot fi 2005-05-06 16:59 ------- (In reply to comment #2) > Reduced testcase (I tried not to reduce it too much): > subroutine difq3 (jmax, ngmax, ams) > implicit none > integer*4 :: jmax, ngmax > real*8, dimension(32) :: ams > real*8, dimension(32) :: edd > integer*4 :: j > forall (j=2:jmax) > ams(1:ngmax)= edd(j-1) > end forall > end > > > But note I get a warning with ICC: > fortcom: Warning: t.f, line 8: All active combinations of index-names are not used within the variable > being defined (i.e., leftside) of this assignment-stmt. [AMS] > ams(1:ngmax)= edd(j-1) > .........^ > > So I don't know if this code is valid or not.
I don't think it is valid; from the F2003 (draft) standard, section 7.4.4.4: "A many-to-one assignment is more than one assignment to the same object, or association of more than one target with the same pointer, whether the object is referenced directly or indirectly through a pointer. A many-to-one assignment shall not occur within a single statement in a FORALL construct or statement." In any case, that code does not make much sense to me: different values are assigned to the same variable in undefined order (or even simultaneously). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21409
