gcc/testsuite/gcc.dg/warn-addr-cmp.c

   1 /* { dg-do compile } */
   2 /* { dg-require-weak "" } */
   3 /* { dg-options "-Waddress" } */
   4 /* Warning when addr convert to bool always gives known result.
   5    Ada/Pascal programmers sometimes write 0-param functions without
   6    (), and might as well warn on variables, too.  */
   7
   8 int func (void);
   9 extern int var;
  10 int weak_func (void) __attribute__ ((weak));
  11 extern int weak_var __attribute__ ((weak));
  12
  13 int
  14 test_func_cmp (void)
  15 {
  16   if (func)      /* { dg-warning "the address of 'func'" } */
  17     return 1;
  18   if (!func)     /* { dg-warning "the address of 'func'" } */
  19     return 1;
  20   if (&var)     /* { dg-warning "the address of 'var'" } */
  21     return 1;
  22   if (!&var)     /* { dg-warning "the address of 'var'" } */
  23     return 1;
  24   if (weak_func)
  25     return 1;
  26   if (!weak_func)
  27     return 1;
  28   if (&weak_var)
  29     return 1;
  30   if (!&weak_var)
  31     return 1;
  32   return 0;
  33 }
  34
  35 /* Test equality with 0 on the right hand side.  */
  36 int
  37 test_func_cmp_rhs_zero (void)
  38 {
  39   if (func == 0)     /* { dg-warning "the comparison will always evaluate as 'false'" } */
  40     return 1;
  41   if (func != 0)     /* { dg-warning "the comparison will always evaluate as 'true'" } */
  42     return 1;
  43   if (&var == 0)     /* { dg-warning "the comparison will always evaluate as 'false'" } */
  44     return 1;
  45   if (&var != 0)     /* { dg-warning "the comparison will always evaluate as 'true'" } */
  46     return 1;
  47   if (weak_func == 0)
  48     return 1;
  49   if (weak_func != 0)
  50     return 1;
  51   if (&weak_var == 0)
  52     return 1;
  53   if (&weak_var != 0)
  54     return 1;
  55   return 0;
  56 }
  57
  58 /* Test equality with 0 on the left hand side.  */
  59 int
  60 test_func_cmp_lhs_zero (void)
  61 {
  62   if (0 == func)     /* { dg-warning "the comparison will always evaluate as 'false'" } */
  63     return 1;
  64   if (0 != func)     /* { dg-warning "the comparison will always evaluate as 'true'" } */
  65     return 1;
  66   if (0 == &var)     /* { dg-warning "the comparison will always evaluate as 'false'" } */
  67     return 1;
  68   if (0 != &var)     /* { dg-warning "the comparison will always evaluate as 'true'" } */
  69     return 1;
  70   if (0 == weak_func)
  71     return 1;
  72   if (0 != weak_func)
  73     return 1;
  74   if (0 == &weak_var)
  75     return 1;
  76   if (0 != &weak_var)
  77     return 1;
  78   return 0;
  79 }