1  /* Test for diagnostics for constant overflow.  */
       2  /* Origin: Joseph Myers <joseph@codesourcery.com> */
       3  /* { dg-do compile } */
       4  /* { dg-options "-std=c99" } */
       5  
       6  #include <limits.h>
       7  
       8  enum e {
       9    E0 = INT_MAX,
      10    /* Unsigned overflow wraps around.  */
      11    E1 = UINT_MAX + 1,
      12    /* Overflow in an unevaluated part of an expression is OK (example
      13       in the standard).  */
      14    E2 = 2 || 1 / 0,
      15    E3 = 1 / 0, /* { dg-warning "10:division by zero" } */
      16    /* { dg-error "3:enumerator value for 'E3' is not an integer constant" "enum error" { target *-*-* } .-1 } */
      17    /* But as in DR#031, the 1/0 in an evaluated subexpression means the
      18       whole expression violates the constraints.  */
      19    E4 = 0 * (1 / 0), /* { dg-warning "15:division by zero" } */
      20    /* { dg-error "enumerator value for 'E4' is not an integer constant" "enum error" { target *-*-* } .-1 } */
      21    E5 = INT_MAX + 1, /* { dg-warning "16:integer overflow in expression" } */
      22    /* Again, overflow in evaluated subexpression.  */
      23    E6 = 0 * (INT_MAX + 1), /* { dg-warning "21:integer overflow in expression" } */
      24    /* A cast does not constitute overflow in conversion.  */
      25    E7 = (char) INT_MAX
      26  };
      27  
      28  struct s {
      29    int a;
      30    int : 0 * (1 / 0); /* { dg-warning "16:division by zero" } */
      31    /* { dg-error "not an integer constant" "22:integer constant" { target *-*-* } .-1 } */
      32    int : 0 * (INT_MAX + 1); /* { dg-warning "integer overflow in expression" } */
      33  };
      34  
      35  void
      36  f (void)
      37  {
      38    /* This expression is not required to be a constant expression, so
      39       it should just involve undefined behavior at runtime.  */
      40    int c = INT_MAX + 1; /* { dg-warning "19:integer overflow in expression" } */
      41  }
      42  
      43  /* But this expression does need to be constant.  */
      44  static int sc = INT_MAX + 1; /* { dg-warning "25:integer overflow in expression" } */
      45  
      46  /* The first two of these involve overflow, so are not null pointer
      47     constants.  The third has the overflow in an unevaluated
      48     subexpression, so is a null pointer constant.  */
      49  void *p = 0 * (INT_MAX + 1); /* { dg-warning "integer overflow in expression" } */
      50  /* { dg-warning "initialization of 'void \\*' from 'int' makes pointer from integer without a cast" "null" { target *-*-* } .-1 } */
      51  void *q = 0 * (1 / 0); /* { dg-warning "division by zero" } */
      52  /* { dg-error "initializer element is not constant" "constant" { target *-*-* } .-1 } */
      53  /* { dg-warning "initialization of 'void \\*' from 'int' makes pointer from integer without a cast" "null" { target *-*-* } .-2 } */
      54  void *r = (1 ? 0 : INT_MAX+1);
      55  
      56  void
      57  g (int i)
      58  {
      59    switch (i)
      60      {
      61      case 0 * (1/0): /* { dg-warning "division by zero" } */
      62        /* { dg-error "case label does not reduce to an integer constant" "constant" { target *-*-* } .-1 } */
      63        ;
      64      case 1 + 0 * (INT_MAX + 1): /* { dg-warning "integer overflow in expression" } */
      65        ;
      66      }
      67  }
      68  
      69  int
      70  h (void)
      71  {
      72    return INT_MAX + 1; /* { dg-warning "integer overflow in expression" } */
      73  }
      74  
      75  int
      76  h1 (void)
      77  {
      78    return INT_MAX + 1 - INT_MAX; /* { dg-warning "integer overflow in expression" } */
      79  }
      80  
      81  void fuc (unsigned char);
      82  void fsc (signed char);
      83  
      84  void
      85  h2 (void)
      86  {
      87    fsc (SCHAR_MAX + 1);
      88    fsc (SCHAR_MIN - 1); /* { dg-warning "overflow in conversion from .int. to .signed char. changes value " } */
      89    fsc (UCHAR_MAX);
      90    fsc (UCHAR_MAX + 1); /* { dg-warning "overflow in conversion from .int. to .signed char. changes value from " } */
      91    fuc (-1);
      92    fuc (UCHAR_MAX + 1); /* { dg-warning "unsigned conversion from .int. to .unsigned char. changes value " } */
      93    fuc (SCHAR_MIN);
      94    fuc (SCHAR_MIN - 1); /* { dg-warning "unsigned conversion from .int. to .unsigned char. changes value " } */
      95    fuc (-UCHAR_MAX); /* { dg-warning "unsigned conversion from .int. to .unsigned char. changes value " } */
      96  }
      97  
      98  void fui (unsigned int);
      99  void fsi (signed int);
     100  
     101  int si;
     102  unsigned ui;
     103  
     104  void
     105  h2i (int x)
     106  {
     107    /* For some reason, we only give certain warnings for implicit
     108       conversions among values of the same precision with -Wconversion,
     109       while we don't give others at all.  */
     110    fsi ((unsigned)INT_MAX + 1);
     111    si = (unsigned)INT_MAX + 1;
     112    si = x ? (unsigned)INT_MAX + 1 : 1;
     113    fsi ((unsigned)INT_MAX + 2);
     114    si = (unsigned)INT_MAX + 2;
     115    si = x ? (unsigned)INT_MAX + 2 : 1;
     116    fsi (UINT_MAX);
     117    si = UINT_MAX;
     118    fui (-1);
     119    ui = -1;
     120    ui = x ? -1 : 1U;
     121    fui (INT_MIN);
     122    ui = INT_MIN;
     123    ui = x ? INT_MIN : 1U;
     124  }