1// RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -Wno-unused %s
2
3int f(int, int);
4
5typedef struct A {
6  int x, y;
7} A;
8
9void test() {
10  int a;
11  int xs[10];
12  a + ++a; // expected-warning {{unsequenced modification and access to 'a'}}
13  a = ++a; // expected-warning {{multiple unsequenced modifications to 'a'}}
14  a + a++; // expected-warning {{unsequenced modification and access to 'a'}}
15  a = a++; // expected-warning {{multiple unsequenced modifications to 'a'}}
16  (a++, a++); // ok
17  ++a + ++a; // expected-warning {{multiple unsequenced modifications}}
18  a++ + a++; // expected-warning {{multiple unsequenced modifications}}
19  a = xs[++a]; // expected-warning {{multiple unsequenced modifications}}
20  a = xs[a++]; // expected-warning {{multiple unsequenced modifications}}
21  a = (++a, ++a); // expected-warning {{multiple unsequenced modifications}}
22  a = (a++, ++a); // expected-warning {{multiple unsequenced modifications}}
23  a = (a++, a++); // expected-warning {{multiple unsequenced modifications}}
24  f(a, a); // ok
25  f(a = 0, a); // expected-warning {{unsequenced modification and access}}
26  f(a, a += 0); // expected-warning {{unsequenced modification and access}}
27  f(a = 0, a = 0); // expected-warning {{multiple unsequenced modifications}}
28  a = f(++a, 0); // ok
29  a = f(a++, 0); // ok
30  a = f(++a, a++); // expected-warning {{multiple unsequenced modifications}}
31
32  ++a + f(++a, 0); // expected-warning {{multiple unsequenced modifications}}
33  f(++a, 0) + ++a; // expected-warning {{multiple unsequenced modifications}}
34  a++ + f(a++, 0); // expected-warning {{multiple unsequenced modifications}}
35  f(a++, 0) + a++; // expected-warning {{multiple unsequenced modifications}}
36
37  a = ++a; // expected-warning {{multiple unsequenced modifications}}
38  a += ++a; // expected-warning {{unsequenced modification and access}}
39
40  A agg1 = { a++, a++ }; // expected-warning {{multiple unsequenced modifications}}
41  A agg2 = { a++ + a, a++ }; // expected-warning {{unsequenced modification and access}}
42
43  (xs[2] && (a = 0)) + a; // ok
44  (0 && (a = 0)) + a; // ok
45  (1 && (a = 0)) + a; // expected-warning {{unsequenced modification and access}}
46
47  (xs[3] || (a = 0)) + a; // ok
48  (0 || (a = 0)) + a; // expected-warning {{unsequenced modification and access}}
49  (1 || (a = 0)) + a; // ok
50
51  (xs[4] ? a : ++a) + a; // ok
52  (0 ? a : ++a) + a; // expected-warning {{unsequenced modification and access}}
53  (1 ? a : ++a) + a; // ok
54  (xs[5] ? ++a : ++a) + a; // FIXME: warn here
55
56  (++a, xs[6] ? ++a : 0) + a; // expected-warning {{unsequenced modification and access}}
57
58  // Here, the read of the fourth 'a' might happen before or after the write to
59  // the second 'a'.
60  a += (a++, a) + a; // expected-warning {{unsequenced modification and access}}
61
62  int *p = xs;
63  a = *(a++, p); // ok
64  a = a++ && a; // ok
65
66  A *q = &agg1;
67  (q = &agg2)->y = q->x; // expected-warning {{unsequenced modification and access to 'q'}}
68
69  // This has undefined behavior if a == 0; otherwise, the side-effect of the
70  // increment is sequenced before the value computation of 'f(a, a)', which is
71  // sequenced before the value computation of the '&&', which is sequenced
72  // before the assignment. We treat the sequencing in '&&' as being
73  // unconditional.
74  a = a++ && f(a, a);
75
76  // This has undefined behavior if a != 0. FIXME: We should diagnose this.
77  (a && a++) + a;
78
79  (xs[7] && ++a) * (!xs[7] && ++a); // ok
80
81  xs[0] = (a = 1, a); // ok
82
83  xs[8] ? ++a + a++ : 0; // expected-warning {{multiple unsequenced modifications}}
84  xs[8] ? 0 : ++a + a++; // expected-warning {{multiple unsequenced modifications}}
85  xs[8] ? ++a : a++; // ok
86
87  xs[8] && (++a + a++); // expected-warning {{multiple unsequenced modifications}}
88  xs[8] || (++a + a++); // expected-warning {{multiple unsequenced modifications}}
89
90  (__builtin_classify_type(++a) ? 1 : 0) + ++a; // ok
91  (__builtin_constant_p(++a) ? 1 : 0) + ++a; // ok
92  (__builtin_expect(++a, 0) ? 1 : 0) + ++a; // expected-warning {{multiple unsequenced modifications}}
93  _Generic(++a, default: 0) + ++a; // ok
94  sizeof(++a) + ++a; // ok
95  _Alignof(++a) + ++a; // expected-warning {{extension}}
96}
97