1 // RUN: %clang_cc1 -fsyntax-only -verify %s 2 3 int foo(int x) { 4 return x == x; // expected-warning {{self-comparison always evaluates to true}} 5 } 6 7 int foo2(int x) { 8 return (x) != (((x))); // expected-warning {{self-comparison always evaluates to false}} 9 } 10 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 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 21 int qux(int x) { 22 return x < x; // expected-warning {{self-comparison}} 23 } 24 25 int qux2(int x) { 26 return x > x; // expected-warning {{self-comparison}} 27 } 28 29 int bar(float x) { 30 return x == x; // no-warning 31 } 32 33 int bar2(float x) { 34 return x != x; // no-warning 35 } 36 37 #define IS_THE_ANSWER(x) (x == 42) 38 39 int macro_comparison() { 40 return IS_THE_ANSWER(42); 41 } 42 43 // Don't complain in unevaluated contexts. 44 int compare_sizeof(int x) { 45 return sizeof(x == x); // no-warning 46 } 47 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 differrent 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 83 int R8435950(int i) { 84 if (R8435950_A == R8435950_B) // no-warning 85 return 0; 86 return 1; 87 } 88 89
