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) STOP 1
  14   j = 0
  15   do i = HUGE(i) - 9, HUGE(i), 2
  16     j = j + 1
  17   end do
  18   if (j .ne. 5) STOP 2
  19
  20   ! Same again, but unknown loop step
  21   if (test1(10, 1) .ne. 11) STOP 3
  22   if (test1(10, 2) .ne. 6) STOP 4
  23   if (test1(9, 2) .ne. 5) STOP 5
  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) STOP 6
  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) STOP 7
  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) STOP 8
  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) STOP 9
  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) STOP 10
  74 end subroutine
  75 end program