1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
|
// RUN: %clang_cc1 -fsyntax-only -verify %s
int foo(int x) {
return x == x; // expected-warning {{self-comparison always evaluates to true}}
}
int foo2(int x) {
return (x) != (((x))); // expected-warning {{self-comparison always evaluates to false}}
}
void foo3(short s, short t) {
if (s == s) {} // expected-warning {{self-comparison always evaluates to true}}
if (s == t) {} // no-warning
}
void foo4(void* v, void* w) {
if (v == v) {} // expected-warning {{self-comparison always evaluates to true}}
if (v == w) {} // no-warning
}
int qux(int x) {
return x < x; // expected-warning {{self-comparison}}
}
int qux2(int x) {
return x > x; // expected-warning {{self-comparison}}
}
int bar(float x) {
return x == x; // no-warning
}
int bar2(float x) {
return x != x; // no-warning
}
#define IS_THE_ANSWER(x) (x == 42)
int macro_comparison() {
return IS_THE_ANSWER(42);
}
// Don't complain in unevaluated contexts.
int compare_sizeof(int x) {
return sizeof(x == x); // no-warning
}
int array_comparisons() {
int array1[2];
int array2[2];
//
// compare same array
//
return array1 == array1; // expected-warning{{self-comparison always evaluates to true}}
return array1 != array1; // expected-warning{{self-comparison always evaluates to false}}
return array1 < array1; // expected-warning{{self-comparison always evaluates to false}}
return array1 <= array1; // expected-warning{{self-comparison always evaluates to true}}
return array1 > array1; // expected-warning{{self-comparison always evaluates to false}}
return array1 >= array1; // expected-warning{{self-comparison always evaluates to true}}
//
// compare differrent arrays
//
return array1 == array2; // expected-warning{{array comparison always evaluates to false}}
return array1 != array2; // expected-warning{{array comparison always evaluates to true}}
//
// we don't know what these are going to be
//
return array1 < array2; // expected-warning{{array comparison always evaluates to a constant}}
return array1 <= array2; // expected-warning{{array comparison always evaluates to a constant}}
return array1 > array2; // expected-warning{{array comparison always evaluates to a constant}}
return array1 >= array2; // expected-warning{{array comparison always evaluates to a constant}}
}
// Don't issue a warning when either the left or right side of the comparison
// results from a macro expansion. <rdar://problem/8435950>
#define R8435950_A i
#define R8435950_B i
int R8435950(int i) {
if (R8435950_A == R8435950_B) // no-warning
return 0;
return 1;
}
|
