1 // RUN: %clang_cc1 -std=c11 -fsyntax-only -verify -Wunused-value -Wunused-label %s
2 // RUN: %clang_cc1 -std=c11 -fsyntax-only -verify -Wunused %s
3 // RUN: %clang_cc1 -std=c11 -fsyntax-only -verify -Wall %s
4
5 int i = 0;
6 int j = 0;
7
8 void foo();
9
10 // PR4806
pr4806()11 void pr4806() {
12 1,foo(); // expected-warning {{expression result unused}}
13
14 // other
15 foo();
16 i; // expected-warning {{expression result unused}}
17
18 i,foo(); // expected-warning {{expression result unused}}
19 foo(),i; // expected-warning {{expression result unused}}
20
21 i,j,foo(); // expected-warning {{expression result unused}} expected-warning {{expression result unused}}
22 i,foo(),j; // expected-warning {{expression result unused}} expected-warning {{expression result unused}}
23 foo(),i,j; // expected-warning {{expression result unused}} expected-warning {{expression result unused}}
24
25 i++;
26
27 i++,foo();
28 foo(),i++;
29
30 i++,j,foo(); // expected-warning {{expression result unused}}
31 i++,foo(),j; // expected-warning {{expression result unused}}
32 foo(),i++,j; // expected-warning {{expression result unused}}
33
34 i,j++,foo(); // expected-warning {{expression result unused}}
35 i,foo(),j++; // expected-warning {{expression result unused}}
36 foo(),i,j++; // expected-warning {{expression result unused}}
37
38 i++,j++,foo();
39 i++,foo(),j++;
40 foo(),i++,j++;
41
42 {};
43 ({});
44 ({}),foo();
45 foo(),({});
46
47 (int)1U; // expected-warning {{expression result unused}}
48 (void)1U;
49
50 // pointer to volatile has side effect (thus no warning)
51 int* pi = &i;
52 volatile int* pj = &j;
53 *pi; // expected-warning {{expression result unused}}
54 *pj;
55
56 foo_label: // expected-warning {{unused label}}
57 i; // expected-warning {{expression result unused}}
58 }
59
60 // Don't warn about unused '||', '&&' expressions that contain assignments.
61 int test_logical_foo1();
62 int test_logical_foo2();
63 int test_logical_foo3();
test_logical_bar()64 int test_logical_bar() {
65 int x = 0;
66 (x = test_logical_foo1()) || // no-warning
67 (x = test_logical_foo2()) || // no-warning
68 (x = test_logical_foo3()); // no-warning
69
70 x || test_logical_foo1(); // no-warning
71
72 return x;
73 }
74
75 // PR8282
conditional_for_control_flow(int cond,int x,int y)76 void conditional_for_control_flow(int cond, int x, int y)
77 {
78 cond? y++ : x; // no-warning
79 cond? y : ++x; // no-warning
80 cond? (x |= y) : ++x; // no-warning
81 cond? y : x; // expected-warning {{expression result unused}}
82 }
83
84 struct s0 { int f0; };
85
86 void f0(int a);
f1(struct s0 * a)87 void f1(struct s0 *a) {
88 // rdar://8139785
89 f0((int)(a->f0 + 1, 10)); // expected-warning {{expression result unused}}
90 }
91
92 void blah(int a);
93 #define GenTest(x) _Generic(x, default : blah)(x)
94
unevaluated_operands(void)95 void unevaluated_operands(void) {
96 int val = 0;
97
98 (void)sizeof(++val); // expected-warning {{expression with side effects has no effect in an unevaluated context}}
99 (void)_Generic(val++, default : 0); // expected-warning {{expression with side effects has no effect in an unevaluated context}}
100 (void)_Alignof(val++); // expected-warning {{expression with side effects has no effect in an unevaluated context}} expected-warning {{'_Alignof' applied to an expression is a GNU extension}}
101
102 // VLAs can have side effects so long as it's part of the type and not
103 // an expression.
104 (void)sizeof(int[++val]); // Ok
105 (void)_Alignof(int[++val]); // Ok
106
107 // Side effects as part of macro expansion are ok.
108 GenTest(val++);
109 }
110