1 // RUN: %clang_cc1 -fsyntax-only -verify %s
2
foo(int x)3 int foo(int x) {
4 return x == x; // expected-warning {{self-comparison always evaluates to true}}
5 }
6
foo2(int x)7 int foo2(int x) {
8 return (x) != (((x))); // expected-warning {{self-comparison always evaluates to false}}
9 }
10
foo3(short s,short t)11 void foo3(short s, short t) {
12 if (s == s) {} // expected-warning {{self-comparison always evaluates to true}}
13 if (s == t) {} // no-warning
14 }
15
foo4(void * v,void * w)16 void foo4(void* v, void* w) {
17 if (v == v) {} // expected-warning {{self-comparison always evaluates to true}}
18 if (v == w) {} // no-warning
19 }
20
qux(int x)21 int qux(int x) {
22 return x < x; // expected-warning {{self-comparison}}
23 }
24
qux2(int x)25 int qux2(int x) {
26 return x > x; // expected-warning {{self-comparison}}
27 }
28
bar(float x)29 int bar(float x) {
30 return x == x; // no-warning
31 }
32
bar2(float x)33 int bar2(float x) {
34 return x != x; // no-warning
35 }
36
37 #define IS_THE_ANSWER(x) (x == 42)
38
macro_comparison()39 int macro_comparison() {
40 return IS_THE_ANSWER(42);
41 }
42
43 // Don't complain in unevaluated contexts.
compare_sizeof(int x)44 int compare_sizeof(int x) {
45 return sizeof(x == x); // no-warning
46 }
47
array_comparisons()48 int array_comparisons() {
49 int array1[2];
50 int array2[2];
51
52 //
53 // compare same array
54 //
55 return array1 == array1; // expected-warning{{self-comparison always evaluates to true}}
56 return array1 != array1; // expected-warning{{self-comparison always evaluates to false}}
57 return array1 < array1; // expected-warning{{self-comparison always evaluates to false}}
58 return array1 <= array1; // expected-warning{{self-comparison always evaluates to true}}
59 return array1 > array1; // expected-warning{{self-comparison always evaluates to false}}
60 return array1 >= array1; // expected-warning{{self-comparison always evaluates to true}}
61
62 //
63 // compare different arrays
64 //
65 return array1 == array2; // expected-warning{{array comparison always evaluates to false}}
66 return array1 != array2; // expected-warning{{array comparison always evaluates to true}}
67
68 //
69 // we don't know what these are going to be
70 //
71 return array1 < array2; // expected-warning{{array comparison always evaluates to a constant}}
72 return array1 <= array2; // expected-warning{{array comparison always evaluates to a constant}}
73 return array1 > array2; // expected-warning{{array comparison always evaluates to a constant}}
74 return array1 >= array2; // expected-warning{{array comparison always evaluates to a constant}}
75
76 }
77
78 // Don't issue a warning when either the left or right side of the comparison
79 // results from a macro expansion. <rdar://problem/8435950>
80 #define R8435950_A i
81 #define R8435950_B i
82
R8435950(int i)83 int R8435950(int i) {
84 if (R8435950_A == R8435950_B) // no-warning
85 return 0;
86 return 1;
87 }
88
89 __attribute__((weak)) int weak_1[3];
90 __attribute__((weak)) int weak_2[3];
compare_weak()91 _Bool compare_weak() {
92 return weak_1 == weak_2;
93 }
94