gcc/testsuite/gfortran.dg/negative_stride_1.f90

   1 ! { dg-do run }
   2 !
   3 ! PR fortran/102043
   4 ! The middle-end used to conclude from array indexing that the index
   5 ! should be non-negative and thus that array accesses to reversed arrays
   6 ! (i.e. with negative strides) only access the last element of the array,
   7 ! as the access involves a pointer to array that is initialized to point
   8 ! to the last element in the case of a reversed array.
   9
  10 program main
  11    implicit none
  12    integer :: a(3, 3)
  13    integer :: i
  14    a = 0
  15    call s(a(3:1:-1,:))
  16    if (any(a(:,1) /= (/  7,  5,  3 /))) stop 1
  17    if (any(a(:,2) /= (/ 17, 13, 11 /))) stop 2
  18    if (any(a(:,3) /= (/ 29, 23, 19 /))) stop 3
  19 contains
  20   subroutine s(b)
  21     implicit none
  22     integer, dimension(:,:) :: b
  23     b = reshape((/ 3, 5, 7, 11, 13, 17, 19, 23, 29 /), (/ 3, 3 /))
  24   end subroutine s
  25 end program main