gcc/testsuite/c-c++-common/Wbool-compare-1.c

   1 /* PR c++/62153 */
   2 /* { dg-do compile } */
   3 /* { dg-options "-Wall" } */
   4
   5 #ifndef __cplusplus
   6 # define bool _Bool
   7 # define true 1
   8 # define false 0
   9 #endif
  10
  11 extern bool foo (void);
  12 bool r;
  13
  14 enum { E = 4 };
  15
  16 void
  17 fn1 (bool b)
  18 {
  19   r = b == 2; /* { dg-warning "with boolean expression is always false" } */
  20   r = b != 2; /* { dg-warning "with boolean expression is always true" } */
  21   r = b < 2; /* { dg-warning "with boolean expression is always true" } */
  22   r = b > 2; /* { dg-warning "with boolean expression is always false" } */
  23   r = b <= 2; /* { dg-warning "with boolean expression is always true" } */
  24   r = b >= 2; /* { dg-warning "with boolean expression is always false" } */
  25
  26   r = b == -1; /* { dg-warning "with boolean expression is always false" } */
  27   r = b != -1; /* { dg-warning "with boolean expression is always true" } */
  28   r = b < -1; /* { dg-warning "with boolean expression is always false" } */
  29   r = b > -1; /* { dg-warning "with boolean expression is always true" } */
  30   r = b <= -1; /* { dg-warning "with boolean expression is always false" } */
  31   r = b >= -1; /* { dg-warning "with boolean expression is always true" } */
  32
  33   r = foo () == 2; /* { dg-warning "with boolean expression is always false" } */
  34   r = foo () != 2; /* { dg-warning "with boolean expression is always true" } */
  35   r = foo () < 2; /* { dg-warning "with boolean expression is always true" } */
  36   r = foo () > 2; /* { dg-warning "with boolean expression is always false" } */
  37   r = foo () <= 2; /* { dg-warning "with boolean expression is always true" } */
  38   r = foo () >= 2; /* { dg-warning "with boolean expression is always false" } */
  39
  40   r = b == E; /* { dg-warning "with boolean expression is always false" } */
  41   r = b != E; /* { dg-warning "with boolean expression is always true" } */
  42   r = b < E; /* { dg-warning "with boolean expression is always true" } */
  43   r = b > E; /* { dg-warning "with boolean expression is always false" } */
  44   r = b <= E; /* { dg-warning "with boolean expression is always true" } */
  45   r = b >= E; /* { dg-warning "with boolean expression is always false" } */
  46
  47   /* Swap LHS and RHS.  */
  48   r = 2 == b; /* { dg-warning "with boolean expression is always false" } */
  49   r = 2 != b; /* { dg-warning "with boolean expression is always true" } */
  50   r = 2 < b; /* { dg-warning "with boolean expression is always false" } */
  51   r = 2 > b; /* { dg-warning "with boolean expression is always true" } */
  52   r = 2 <= b; /* { dg-warning "with boolean expression is always false" } */
  53   r = 2 >= b; /* { dg-warning "with boolean expression is always true" } */
  54
  55   r = -1 == b; /* { dg-warning "with boolean expression is always false" } */
  56   r = -1 != b; /* { dg-warning "with boolean expression is always true" } */
  57   r = -1 < b; /* { dg-warning "with boolean expression is always true" } */
  58   r = -1 > b; /* { dg-warning "with boolean expression is always false" } */
  59   r = -1 <= b; /* { dg-warning "with boolean expression is always true" } */
  60   r = -1 >= b; /* { dg-warning "with boolean expression is always false" } */
  61
  62   r = E == b; /* { dg-warning "with boolean expression is always false" } */
  63   r = E != b; /* { dg-warning "with boolean expression is always true" } */
  64   r = E < b; /* { dg-warning "with boolean expression is always false" } */
  65   r = E > b; /* { dg-warning "with boolean expression is always true" } */
  66   r = E <= b; /* { dg-warning "with boolean expression is always false" } */
  67   r = E >= b; /* { dg-warning "with boolean expression is always true" } */
  68
  69   /* These are of course fine.  */
  70   r = b == false;
  71   r = b != false;
  72   r = b == true;
  73   r = b != true;
  74
  75   r = b <= false;
  76   r = b > false;
  77   r = b < true;
  78   r = b >= true;
  79 }
  80
  81 void
  82 fn2 (int i1, int i2)
  83 {
  84   r = (i1 == i2) == 2; /* { dg-warning "with boolean expression is always false" } */
  85   r = (i1 == i2) != 2; /* { dg-warning "with boolean expression is always true" } */
  86   r = (i1 == i2) < 2; /* { dg-warning "with boolean expression is always true" } */
  87   r = (i1 == i2) > 2; /* { dg-warning "with boolean expression is always false" } */
  88   r = (i1 == i2) <= 2; /* { dg-warning "with boolean expression is always true" } */
  89   r = (i1 == i2) >= 2; /* { dg-warning "with boolean expression is always false" } */
  90
  91   r = (i1 == i2) == -1; /* { dg-warning "with boolean expression is always false" } */
  92   r = (i1 == i2) != -1; /* { dg-warning "with boolean expression is always true" } */
  93   r = (i1 == i2) < -1; /* { dg-warning "with boolean expression is always false" } */
  94   r = (i1 == i2) > -1; /* { dg-warning "with boolean expression is always true" } */
  95   r = (i1 == i2) <= -1; /* { dg-warning "with boolean expression is always false" } */
  96   r = (i1 == i2) >= -1; /* { dg-warning "with boolean expression is always true" } */
  97
  98   r = (i1 == i2) == E; /* { dg-warning "with boolean expression is always false" } */
  99   r = (i1 == i2) != E; /* { dg-warning "with boolean expression is always true" } */
 100   r = (i1 == i2) < E; /* { dg-warning "with boolean expression is always true" } */
 101   r = (i1 == i2) > E; /* { dg-warning "with boolean expression is always false" } */
 102   r = (i1 == i2) <= E; /* { dg-warning "with boolean expression is always true" } */
 103   r = (i1 == i2) >= E; /* { dg-warning "with boolean expression is always false" } */
 104 }
 105
 106 void
 107 fn3 (int n, bool b)
 108 {
 109   /* Don't warn here.  */
 110   r = b == n;
 111   r = b != n;
 112   r = b < n;
 113   r = b > n;
 114   r = b <= n;
 115   r = b >= n;
 116
 117   r = n == E;
 118   r = n != E;
 119   r = n < E;
 120   r = n > E;
 121   r = n <= E;
 122   r = n >= E;
 123 }