1 /* Test for diagnostics for constant overflow. Test with -pedantic-errors. */
2 /* Origin: Joseph Myers <joseph@codesourcery.com> */
3 /* { dg-do compile } */
4 /* { dg-options "-std=c99 -pedantic-errors" } */
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 "division by zero" } */
16 /* { dg-error "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 "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 "integer overflow in expression" } */
22 /* { dg-error "overflow in constant expression" "constant" { target *-*-* } .-1 } */
23 /* Again, overflow in evaluated subexpression. */
24 E6 = 0 * (INT_MAX + 1), /* { dg-warning "integer overflow in expression of type .int. results in .-\[0-9\]+." } */
25 /* { dg-error "overflow in constant expression" "constant" { target *-*-* } .-1 } */
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 "division by zero" } */
33 /* { dg-error "not an integer constant" "integer constant" { target *-*-* } .-1 } */
34 int : 0 * (INT_MAX + 1); /* { dg-warning "integer overflow in expression" } */
35 /* { dg-error "overflow in constant expression" "constant" { target *-*-* } .-1 } */
36 };
37
38 void
39 f (void)
40 {
41 /* This expression is not required to be a constant expression, so
42 it should just involve undefined behavior at runtime. */
43 int c = INT_MAX + 1; /* { dg-warning "integer overflow in expression" } */
44
45 }
46
47 /* But this expression does need to be constant. */
48 static int sc = INT_MAX + 1; /* { dg-warning "integer overflow in expression" } */
49 /* { dg-error "overflow in constant expression" "constant" { target *-*-* } .-1 } */
50
51 /* The first two of these involve overflow, so are not null pointer
52 constants. The third has the overflow in an unevaluated
53 subexpression, so is a null pointer constant. */
54 void *p = 0 * (INT_MAX + 1); /* { dg-warning "integer overflow in expression" } */
55 /* { dg-error "overflow in constant expression" "constant" { target *-*-* } .-1 } */
56 /* { dg-error "initialization of 'void \\*' from 'int' makes pointer from integer without a cast" "null" { target *-*-* } .-2 } */
57 void *q = 0 * (1 / 0); /* { dg-warning "division by zero" } */
58 /* { dg-error "initializer element is not constant" "constant" { target *-*-* } .-1 } */
59 /* { dg-error "initialization of 'void \\*' from 'int' makes pointer from integer without a cast" "null" { target *-*-* } .-2 } */
60 void *r = (1 ? 0 : INT_MAX+1);
61
62 void
63 g (int i)
64 {
65 switch (i)
66 {
67 case 0 * (1/0): /* { dg-warning "division by zero" } */
68 /* { dg-error "case label does not reduce to an integer constant" "constant" { target *-*-* } .-1 } */
69 ;
70 case 1 + 0 * (INT_MAX + 1): /* { dg-warning "integer overflow in expression" } */
71 /* { dg-error "overflow in constant expression" "constant" { target *-*-* } .-1 } */
72 ;
73 }
74 }
75
76 int
77 h (void)
78 {
79 return INT_MAX + 1; /* { dg-warning "integer overflow in expression" } */
80 }
81
82 int
83 h1 (void)
84 {
85 return INT_MAX + 1 - INT_MAX; /* { dg-warning "integer overflow in expression" } */
86 }
87
88 void fuc (unsigned char);
89 void fsc (signed char);
90
91 void
92 h2 (void)
93 {
94 fsc (SCHAR_MAX + 1); /* { dg-warning "overflow in conversion from .int. to .signed char. changes value" } */
95 fsc (SCHAR_MIN - 1); /* { dg-warning "overflow in conversion" } */
96 fsc (UCHAR_MAX); /* { dg-warning "overflow in conversion" } */
97 fsc (UCHAR_MAX + 1); /* { dg-warning "overflow in conversion" } */
98 fuc (-1);
99 fuc (UCHAR_MAX + 1); /* { dg-warning "unsigned conversion from .int. to .unsigned char. changes value" } */
100 fuc (SCHAR_MIN);
101 fuc (SCHAR_MIN - 1); /* { dg-warning "unsigned conversion" } */
102 fuc (-UCHAR_MAX); /* { dg-warning "unsigned conversion" } */
103 }
104
105 void fui (unsigned int);
106 void fsi (signed int);
107
108 int si;
109 unsigned ui;
110
111 void
112 h2i (int x)
113 {
114 /* For some reason, we only give certain warnings for implicit
115 conversions among values of the same precision with -Wconversion,
116 while we don't give others at all. */
117 fsi ((unsigned)INT_MAX + 1);
118 si = (unsigned)INT_MAX + 1;
119 si = x ? (unsigned)INT_MAX + 1 : 1;
120 fsi ((unsigned)INT_MAX + 2);
121 si = (unsigned)INT_MAX + 2;
122 si = x ? (unsigned)INT_MAX + 2 : 1;
123 fsi (UINT_MAX);
124 si = UINT_MAX;
125 fui (-1);
126 ui = -1;
127 ui = x ? -1 : 1U;
128 fui (INT_MIN);
129 ui = INT_MIN;
130 ui = x ? INT_MIN : 1U;
131 }