gcc/testsuite/gcc.dg/overflow-warn-3.c

   1 /* Test for diagnostics for constant overflow.  Test with -pedantic.  */
   2 /* Origin: Joseph Myers <joseph@codesourcery.com> */
   3 /* { dg-do compile } */
   4 /* { dg-options "-std=c99 -pedantic" } */
   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 "warning: division by zero" } */
  16   /* { dg-error "error: enumerator value for 'E3' is not an integer constant" "enum error" { target *-*-* } 15 } */
  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 "warning: division by zero" } */
  20   /* { dg-error "error: enumerator value for 'E4' is not an integer constant" "enum error" { xfail *-*-* } 19 } */
  21   E5 = INT_MAX + 1, /* { dg-warning "warning: integer overflow in expression" } */
  22   /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 21 } */
  23   /* Again, overflow in evaluated subexpression.  */
  24   E6 = 0 * (INT_MAX + 1), /* { dg-warning "warning: integer overflow in expression" } */
  25   /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 24 } */
  26   /* A cast does not constitute overflow in conversion.  */
  27   E7 = (char) INT_MAX
  28 };
  29
  30 struct s {
  31   int a;
  32   int : 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
  33   int : 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
  34   /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 33 } */
  35 };
  36
  37 void
  38 f (void)
  39 {
  40   /* This expression is not required to be a constant expression, so
  41      it should just involve undefined behavior at runtime.  */
  42   int c = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
  43   /* { dg-bogus "warning: overflow in constant expression" "constant" { xfail *-*-* } 42 } */
  44 }
  45
  46 /* But this expression does need to be constant.  */
  47 static int sc = INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
  48 /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 47 } */
  49
  50 /* The first two of these involve overflow, so are not null pointer
  51    constants.  The third has the overflow in an unevaluated
  52    subexpression, so is a null pointer constant.  */
  53 void *p = 0 * (INT_MAX + 1); /* { dg-warning "warning: integer overflow in expression" } */
  54 /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 53 } */
  55 /* { dg-warning "warning: initialization makes pointer from integer without a cast" "null" { target *-*-* } 53 } */
  56 void *q = 0 * (1 / 0); /* { dg-warning "warning: division by zero" } */
  57 /* { dg-warning "warning: initialization makes pointer from integer without a cast" "null" { xfail *-*-* } 56 } */
  58 void *r = (1 ? 0 : INT_MAX+1);
  59
  60 void
  61 g (int i)
  62 {
  63   switch (i)
  64     {
  65     case 0 * (1/0): /* { dg-warning "warning: division by zero" } */
  66       ;
  67     case 1 + 0 * (INT_MAX + 1): /* { dg-warning "warning: integer overflow in expression" } */
  68       /* { dg-warning "warning: overflow in constant expression" "constant" { target *-*-* } 67 } */
  69       ;
  70     }
  71 }
  72
  73 int
  74 h (void)
  75 {
  76   return INT_MAX + 1; /* { dg-warning "warning: integer overflow in expression" } */
  77 }
  78
  79 int
  80 h1 (void)
  81 {
  82   return INT_MAX + 1 - INT_MAX; /* { dg-warning "warning: integer overflow in expression" } */
  83 }
  84
  85 void fuc (unsigned char);
  86 void fsc (signed char);
  87
  88 void
  89 h2 (void)
  90 {
  91   fsc (SCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
  92   fsc (SCHAR_MIN - 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
  93   fsc (UCHAR_MAX); /* { dg-warning "warning: overflow in implicit constant conversion" } */
  94   fsc (UCHAR_MAX + 1); /* { dg-warning "warning: overflow in implicit constant conversion" } */
  95   fuc (-1);
  96   fuc (UCHAR_MAX + 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
  97   fuc (SCHAR_MIN);
  98   fuc (SCHAR_MIN - 1); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
  99   fuc (-UCHAR_MAX); /* { dg-warning "warning: large integer implicitly truncated to unsigned type" } */
 100 }
 101
 102 void fui (unsigned int);
 103 void fsi (signed int);
 104
 105 int si;
 106 unsigned ui;
 107
 108 void
 109 h2i (int x)
 110 {
 111   /* For some reason, we only give certain warnings for implicit
 112      conversions among values of the same precision with -Wconversion,
 113      while we don't give others at all.  */
 114   fsi ((unsigned)INT_MAX + 1);
 115   si = (unsigned)INT_MAX + 1;
 116   si = x ? (unsigned)INT_MAX + 1 : 1;
 117   fsi ((unsigned)INT_MAX + 2);
 118   si = (unsigned)INT_MAX + 2;
 119   si = x ? (unsigned)INT_MAX + 2 : 1;
 120   fsi (UINT_MAX);
 121   si = UINT_MAX;
 122   fui (-1);
 123   ui = -1;
 124   ui = x ? -1 : 1U;
 125   fui (INT_MIN);
 126   ui = INT_MIN;
 127   ui = x ? INT_MIN : 1U;
 128 }