Intel has a nice feature to find bad array definitions.
Somehow thinking of C I wrote:
real :: coord(N,3)
rather than coord(3,N). Using "ifort -check arg_temp_created" this gave then
such information at run time (in my example below 20 times):
"forrtl: warning (402): fort: (1): In call to DISTANCE, an array temporary was
created for argument #1"
While one can sometimes not prevent the need for a array temporary, one often
can and should do so to speed up the program.
Example program:
---------------------------------
program tmp
implicit none
integer, parameter :: N = 20
real :: coord(N,3) ! better: (3,N)
integer :: i
real :: d
coord = 0.0
do i=1,N
d = distance(coord(i,:))
end do
contains
function distance(a)
real :: a(3)
real :: distance
distance = sqrt(a(1)**2 + a(2)**2 + a(3)**2)
end function distance
end program tmp
--
Summary: Flag to give runtime information " array temporary was
created for argument"
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: fortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: burnus at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29952
