gcc/testsuite/gfortran.dg/do_1.f90

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