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Date: Thu, 23 Nov 2006 09:49:00 -0000
Subject: [Bug fortran/29952]  New: Flag to give runtime information " array temporary was created for argument"
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From: "burnus at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
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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