gcc/testsuite/c-c++-common/attr-fallthrough-1.c

   1 /* PR c/7652 */
   2 /* { dg-do compile } */
   3 /* { dg-options "-Wall -Wextra -Wpedantic" } */
   4
   5 extern void bar (int);
   6 void
   7 fn (int i)
   8 {
   9   __attribute__((fallthrough)) int j = 0; /* { dg-warning "ignored|attribute not followed" } */
  10
  11   if (j)
  12     __attribute__((fallthrough));  /* { dg-error "invalid use" } */
  13
  14   __attribute__((fallthrough));  /* { dg-error "invalid use" } */
  15   switch (i)
  16   {
  17     __attribute__((fallthrough)); /* { dg-warning "statement will never" } */
  18   case 1:
  19    i++;
  20    __attribute__((fallthrough));
  21   case 2:
  22     if (i) /* { dg-warning "statement may fall through" } */
  23       bar (2);
  24     else
  25       __attribute__((fallthrough));
  26   case 3:
  27     if (i > 1)
  28       __attribute__((fallthrough));
  29     else
  30       return;
  31   case 4:
  32     if (i)
  33       __attribute__((fallthrough)); /* { dg-warning "not preceding" } */
  34     __attribute__((fallthrough));
  35   case 5:
  36    ;
  37    __attribute__((fallthrough));
  38   case 6:
  39     if (i) /* { dg-warning "statement may fall through" } */
  40       bar (6);
  41     else
  42       {
  43         __attribute__((fallthrough));
  44       }
  45   case 7:
  46     if (i > 1)
  47       {
  48         __attribute__((fallthrough));
  49       }
  50     else
  51       bar (7); /* { dg-warning "statement may fall through" } */
  52   default:
  53     --j;
  54   }
  55
  56   __attribute__((fallthrough)); /* { dg-error "invalid use" } */
  57 }