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1 // Force x86-64 because some of our heuristics are actually based
2 // on integer sizes.
3 
4 // RUN: %clang_cc1 -triple x86_64-apple-darwin -fsyntax-only -verify -std=c++11 %s
5 
6 namespace RuntimeBehavior {
7   // Avoid emitting tautological compare warnings when the code already has
8   // compile time checks on variable sizes.
9 
10   const int kintmax = 2147483647;
test0(short x)11   void test0(short x) {
12     if (sizeof(x) < sizeof(int) || x < kintmax) {}
13 
14     if (x < kintmax) {}
15     // expected-warning@-1{{comparison of constant 2147483647 with expression of type 'short' is always true}}
16   }
17 
test1(short x)18   void test1(short x) {
19     if (x < kintmax) {}
20     // expected-warning@-1{{comparison of constant 2147483647 with expression of type 'short' is always true}}
21 
22     if (sizeof(x) < sizeof(int))
23       return;
24 
25     if (x < kintmax) {}
26   }
27 }
28 
29 namespace ArrayCompare {
30   #define GetValue(ptr)  ((ptr != 0) ? ptr[0] : 0)
31   extern int a[] __attribute__((weak));
32   int b[] = {8,13,21};
33   struct {
34     int x[10];
35   } c;
36   const char str[] = "text";
ignore()37   void ignore() {
38     if (a == 0) {}
39     if (a != 0) {}
40     (void)GetValue(b);
41   }
test()42   void test() {
43     if (b == 0) {}
44     // expected-warning@-1{{comparison of array 'b' equal to a null pointer is always false}}
45     if (b != 0) {}
46     // expected-warning@-1{{comparison of array 'b' not equal to a null pointer is always true}}
47     if (0 == b) {}
48     // expected-warning@-1{{comparison of array 'b' equal to a null pointer is always false}}
49     if (0 != b) {}
50     // expected-warning@-1{{comparison of array 'b' not equal to a null pointer is always true}}
51     if (c.x == 0) {}
52     // expected-warning@-1{{comparison of array 'c.x' equal to a null pointer is always false}}
53     if (c.x != 0) {}
54     // expected-warning@-1{{comparison of array 'c.x' not equal to a null pointer is always true}}
55     if (str == 0) {}
56     // expected-warning@-1{{comparison of array 'str' equal to a null pointer is always false}}
57     if (str != 0) {}
58     // expected-warning@-1{{comparison of array 'str' not equal to a null pointer is always true}}
59   }
60 }
61 
62 namespace FunctionCompare {
63   #define CallFunction(f) ((f != 0) ? f() : 0)
64   extern void a()  __attribute__((weak));
65   void fun1();
66   int fun2();
67   int* fun3();
68   int* fun4(int);
69   class S {
70   public:
71     static int foo();
72   };
ignore()73   void ignore() {
74     if (a == 0) {}
75     if (0 != a) {}
76     (void)CallFunction(fun2);
77   }
test()78   void test() {
79     if (fun1 == 0) {}
80     // expected-warning@-1{{comparison of function 'fun1' equal to a null pointer is always false}}
81     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
82     if (fun2 == 0) {}
83     // expected-warning@-1{{comparison of function 'fun2' equal to a null pointer is always false}}
84     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
85     // expected-note@-3{{suffix with parentheses to turn this into a function call}}
86     if (fun3 == 0) {}
87     // expected-warning@-1{{comparison of function 'fun3' equal to a null pointer is always false}}
88     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
89     // expected-note@-3{{suffix with parentheses to turn this into a function call}}
90     if (fun4 == 0) {}
91     // expected-warning@-1{{comparison of function 'fun4' equal to a null pointer is always false}}
92     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
93     if (nullptr != fun1) {}
94     // expected-warning@-1{{comparison of function 'fun1' not equal to a null pointer is always true}}
95     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
96     if (nullptr != fun2) {}
97     // expected-warning@-1{{comparison of function 'fun2' not equal to a null pointer is always true}}
98     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
99     if (nullptr != fun3) {}
100     // expected-warning@-1{{comparison of function 'fun3' not equal to a null pointer is always true}}
101     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
102     // expected-note@-3{{suffix with parentheses to turn this into a function call}}
103     if (nullptr != fun4) {}
104     // expected-warning@-1{{comparison of function 'fun4' not equal to a null pointer is always true}}
105     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
106     if (S::foo == 0) {}
107     // expected-warning@-1{{comparison of function 'S::foo' equal to a null pointer is always false}}
108     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
109     // expected-note@-3{{suffix with parentheses to turn this into a function call}}
110   }
111 }
112 
113 namespace PointerCompare {
114   extern int a __attribute__((weak));
115   int b;
116   static int c;
117   class S {
118   public:
119     static int a;
120     int b;
121   };
ignored()122   void ignored() {
123     if (&a == 0) {}
124   }
test()125   void test() {
126     S s;
127     if (&b == 0) {}
128     // expected-warning@-1{{comparison of address of 'b' equal to a null pointer is always false}}
129     if (&c == 0) {}
130     // expected-warning@-1{{comparison of address of 'c' equal to a null pointer is always false}}
131     if (&s.a == 0) {}
132     // expected-warning@-1{{comparison of address of 's.a' equal to a null pointer is always false}}
133     if (&s.b == 0) {}
134     // expected-warning@-1{{comparison of address of 's.b' equal to a null pointer is always false}}
135     if (&S::a == 0) {}
136     // expected-warning@-1{{comparison of address of 'S::a' equal to a null pointer is always false}}
137   }
138 }
139 
140 namespace macros {
141   #define assert(x) if (x) {}
142   int array[5];
143   void fun();
144   int x;
145 
test()146   void test() {
147     assert(array == 0);
148     // expected-warning@-1{{comparison of array 'array' equal to a null pointer is always false}}
149     assert(array != 0);
150     // expected-warning@-1{{comparison of array 'array' not equal to a null pointer is always true}}
151     assert(array == 0 && "expecting null pointer");
152     // expected-warning@-1{{comparison of array 'array' equal to a null pointer is always false}}
153     assert(array != 0 && "expecting non-null pointer");
154     // expected-warning@-1{{comparison of array 'array' not equal to a null pointer is always true}}
155 
156     assert(fun == 0);
157     // expected-warning@-1{{comparison of function 'fun' equal to a null pointer is always false}}
158     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
159     assert(fun != 0);
160     // expected-warning@-1{{comparison of function 'fun' not equal to a null pointer is always true}}
161     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
162     assert(fun == 0 && "expecting null pointer");
163     // expected-warning@-1{{comparison of function 'fun' equal to a null pointer is always false}}
164     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
165     assert(fun != 0 && "expecting non-null pointer");
166     // expected-warning@-1{{comparison of function 'fun' not equal to a null pointer is always true}}
167     // expected-note@-2{{prefix with the address-of operator to silence this warning}}
168 
169     assert(&x == 0);
170     // expected-warning@-1{{comparison of address of 'x' equal to a null pointer is always false}}
171     assert(&x != 0);
172     // expected-warning@-1{{comparison of address of 'x' not equal to a null pointer is always true}}
173     assert(&x == 0 && "expecting null pointer");
174     // expected-warning@-1{{comparison of address of 'x' equal to a null pointer is always false}}
175     assert(&x != 0 && "expecting non-null pointer");
176     // expected-warning@-1{{comparison of address of 'x' not equal to a null pointer is always true}}
177   }
178 }
179