1 /* $NetBSD: msg_324.c,v 1.10 2024/01/28 08:17:27 rillig Exp $ */
2 # 3 "msg_324.c"
3
4 // Test for message: suggest cast from '%s' to '%s' on op '%s' to avoid overflow [324]
5
6 /*
7 * This warning applies to binary operators if the result of the operator
8 * is converted to a type that is bigger than the operands' result type
9 * after the usual arithmetic promotions.
10 *
11 * In such a case, the operator's result would be truncated to the operator's
12 * result type (invoking undefined behavior for signed integers), and that
13 * truncated value would then be converted. At that point, a few bits may
14 * have been lost.
15 */
16
17 /* lint1-flags: -g -S -w -P -X 351 */
18
19 void
example(char c,int i,unsigned u)20 example(char c, int i, unsigned u)
21 {
22 long long ll;
23 unsigned long long ull;
24
25 /* expect+2: warning: suggest cast from 'int' to 'long long' on op '+' to avoid overflow [324] */
26 /* expect+1: warning: 'll' set but not used in function 'example' [191] */
27 ll = c + i;
28 /* expect+1: warning: suggest cast from 'int' to 'long long' on op '-' to avoid overflow [324] */
29 ll = i - c;
30 /* expect+2: warning: suggest cast from 'unsigned int' to 'unsigned long long' on op '*' to avoid overflow [324] */
31 /* expect+1: warning: 'ull' set but not used in function 'example' [191] */
32 ull = c * u;
33 /* expect+1: warning: suggest cast from 'unsigned int' to 'unsigned long long' on op '+' to avoid overflow [324] */
34 ull = u + c;
35 /* expect+1: warning: suggest cast from 'unsigned int' to 'unsigned long long' on op '-' to avoid overflow [324] */
36 ull = i - u;
37 /* expect+1: warning: suggest cast from 'unsigned int' to 'unsigned long long' on op '*' to avoid overflow [324] */
38 ull = u * i;
39 /* expect+1: warning: suggest cast from 'int' to 'long long' on op '<<' to avoid overflow [324] */
40 ll = i << c;
41
42 /*
43 * The operators SHR, DIV and MOD cannot produce an overflow,
44 * therefore no warning is necessary for them.
45 */
46 ll = i >> c;
47 ull = u / c;
48 ull = u % c;
49
50 /*
51 * Assigning the result of an increment or decrement operator to a
52 * differently-sized type is no unusual that there is no need to warn
53 * about it. It's also more unlikely that there is an actual loss
54 * since this only happens for a single value of the old type, unlike
55 * "ull = u * u", which has many more possibilities for overflowing.
56 */
57 ull = u++;
58 ull = ++u;
59 ull = u--;
60 ull = --u;
61 }
62