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