1// RUN: %clang_cc1 -fsyntax-only -verify %s -Wno-unreachable-code
2
3int foo(int X, int Y);
4
5double sqrt(double X);  // implicitly const because of no -fmath-errno!
6
7void bar(volatile int *VP, int *P, int A,
8         _Complex double C, volatile _Complex double VC) {
9
10  VP < P;              // expected-warning {{relational comparison result unused}}
11  (void)A;
12  (void)foo(1,2);      // no warning.
13
14  A < foo(1, 2);       // expected-warning {{relational comparison result unused}}
15
16  foo(1,2)+foo(4,3);   // expected-warning {{expression result unused}}
17
18
19  *P;                  // expected-warning {{expression result unused}}
20  *VP;                 // no warning.
21  P[4];                // expected-warning {{expression result unused}}
22  VP[4];               // no warning.
23
24  __real__ C;          // expected-warning {{expression result unused}}
25  __real__ VC;
26
27  // We know this can't change errno because of no -fmath-errno.
28  sqrt(A);  // expected-warning {{ignoring return value of function declared with const attribute}}
29}
30
31extern void t1();
32extern void t2();
33void t3(int c) {
34  c ? t1() : t2();
35}
36
37// This shouldn't warn: the expr at the end of the stmtexpr really is used.
38int stmt_expr(int x, int y) {
39  return ({int _a = x, _b = y; _a > _b ? _a : _b; });
40}
41
42void nowarn(unsigned char* a, unsigned char* b)
43{
44  unsigned char c = 1;
45  *a |= c, *b += c;
46
47
48  // PR4633
49  int y, x;
50  ((void)0), y = x;
51}
52
53void t4(int a) {
54  int b = 0;
55
56  if (a)
57    b < 1; // expected-warning{{relational comparison result unused}}
58  else
59    b < 2; // expected-warning{{relational comparison result unused}}
60
61  while (1)
62    b < 3; // expected-warning{{relational comparison result unused}}
63
64  do
65    b < 4; // expected-warning{{relational comparison result unused}}
66  while (1);
67
68  for (;;)
69    b < 5; // expected-warning{{relational comparison result unused}}
70
71  for (b < 1;;) {} // expected-warning{{relational comparison result unused}}
72  for (;b < 1;) {}
73  for (;;b < 1) {} // expected-warning{{relational comparison result unused}}
74}
75
76// rdar://7186119
77int t5f(void) __attribute__((warn_unused_result));
78void t5() {
79  t5f();   // expected-warning {{ignoring return value of function declared with warn_unused_result}}
80}
81
82
83int fn1() __attribute__ ((warn_unused_result));
84int fn2() __attribute__ ((pure));
85int fn3() __attribute__ ((__const));
86// rdar://6587766
87int t6() {
88  if (fn1() < 0 || fn2(2,1) < 0 || fn3(2) < 0)  // no warnings
89    return -1;
90
91  fn1();  // expected-warning {{ignoring return value of function declared with warn_unused_result attribute}}
92  fn2(92, 21);  // expected-warning {{ignoring return value of function declared with pure attribute}}
93  fn3(42);  // expected-warning {{ignoring return value of function declared with const attribute}}
94  __builtin_abs(0); // expected-warning {{ignoring return value of function declared with const attribute}}
95  (void)0, fn1();  // expected-warning {{ignoring return value of function declared with warn_unused_result attribute}}
96  return 0;
97}
98
99int t7 __attribute__ ((warn_unused_result)); // expected-warning {{'warn_unused_result' attribute only applies to functions}}
100
101// PR4010
102int (*fn4)(void) __attribute__ ((warn_unused_result));
103void t8() {
104  fn4(); // expected-warning {{ignoring return value of function declared with warn_unused_result attribute}}
105}
106
107void t9() __attribute__((warn_unused_result)); // expected-warning {{attribute 'warn_unused_result' cannot be applied to functions without return value}}
108
109// rdar://7410924
110void *some_function(void);
111void t10() {
112  (void*) some_function(); //expected-warning {{expression result unused; should this cast be to 'void'?}}
113}
114
115void f(int i, ...) {
116    __builtin_va_list ap;
117
118    __builtin_va_start(ap, i);
119    __builtin_va_arg(ap, int);
120    __builtin_va_end(ap);
121}
122
123// PR8371
124int fn5() __attribute__ ((__const));
125
126// Don't warn for unused expressions in macro bodies; however, do warn for
127// unused expressions in macro arguments. Macros below are reduced from code
128// found in the wild.
129#define NOP(a) (a)
130#define M1(a, b) (long)foo((a), (b))
131#define M2 (long)0;
132#define M3(a) (t3(a), fn2())
133#define M4(a, b) (foo((a), (b)) ? 0 : t3(a), 1)
134#define M5(a, b) (foo((a), (b)), 1)
135#define M6() fn1()
136#define M7() fn2()
137void t11(int i, int j) {
138  M1(i, j);  // no warning
139  NOP((long)foo(i, j)); // expected-warning {{expression result unused}}
140  M2;  // no warning
141  NOP((long)0); // expected-warning {{expression result unused}}
142  M3(i); // no warning
143  NOP((t3(i), fn2())); // expected-warning {{ignoring return value}}
144  M4(i, j); // no warning
145  NOP((foo(i, j) ? 0 : t3(i), 1)); // expected-warning {{expression result unused}}
146  M5(i, j); // no warning
147  NOP((foo(i, j), 1)); // expected-warning {{expression result unused}}
148  M6(); // expected-warning {{ignoring return value}}
149  M7(); // no warning
150}
151#undef NOP
152#undef M1
153#undef M2
154#undef M3
155#undef M4
156#undef M5
157#undef M6
158#undef M7
159
160#define UNREFERENCED_PARAMETER(x) (x)
161
162void unused_parm(int a) {
163  // Don't warn if the warning is introduced by a macro that's spelled
164  // UNREFERENCED_PARAMETER, as that's a commonly used macro in Windows headers.
165  UNREFERENCED_PARAMETER(a);
166}
167