gcc/testsuite/gfortran.dg/do_1.f90

   1 ! { dg-do run }
   2 ! { dg-options "-Wall" }
   3 ! Program to check corner cases for DO statements.
   4 program do_1
   5   implicit none
   6   integer i, j
   7
   8   ! limit=HUGE(i), step > 1
   9   j = 0
  10   do i = HUGE(i) - 10, HUGE(i), 2
  11     j = j + 1
  12   end do
  13   if (j .ne. 6) call abort
  14   j = 0
  15   do i = HUGE(i) - 9, HUGE(i), 2
  16     j = j + 1
  17   end do
  18   if (j .ne. 5) call abort
  19
  20   ! Same again, but unknown loop step
  21   if (test1(10, 1) .ne. 11) call abort
  22   if (test1(10, 2) .ne. 6) call abort
  23   if (test1(9, 2) .ne. 5) call abort
  24
  25   ! Zero iterations
  26   j = 0
  27   do i = 1, 0, 1 ! { dg-warning "executed zero times" }
  28     j = j + 1
  29   end do
  30   if (j .ne. 0) call abort
  31   j = 0
  32   do i = 1, 0, 2 ! { dg-warning "executed zero times" }
  33     j = j + 1
  34   end do
  35   if (j .ne. 0) call abort
  36   j = 0
  37   do i = 1, 2, -1 ! { dg-warning "executed zero times" }
  38     j = j + 1
  39   end do
  40   if (j .ne. 0) call abort
  41   call test2 (0, 1)
  42   call test2 (0, 2)
  43   call test2 (2, -1)
  44   call test2 (2, -2)
  45
  46   ! Bound near smallest value
  47   j = 0;
  48   do i = -HUGE(i), -HUGE(i), 10
  49     j = j + 1
  50   end do
  51   if (j .ne. 1) call abort
  52 contains
  53 ! Returns the number of iterations performed.
  54 function test1(r, step)
  55   implicit none
  56   integer test1, r, step
  57   integer k, n
  58   k = 0
  59   do n = HUGE(n) - r, HUGE(n), step
  60     k = k + 1
  61   end do
  62   test1 = k
  63 end function
  64
  65 subroutine test2 (lim, step)
  66   implicit none
  67   integer lim, step
  68   integer k, n
  69   k = 0
  70   do n = 1, lim, step
  71     k = k + 1
  72   end do
  73   if (k .ne. 0) call abort
  74 end subroutine
  75 end program