94 lines · c
1// RUN: %clang_cc1 -fsyntax-only -verify %s2 3int foo(int x) {4 return x == x; // expected-warning {{self-comparison always evaluates to true}}5}6 7int foo2(int x) {8 return (x) != (((x))); // expected-warning {{self-comparison always evaluates to false}}9}10 11void foo3(short s, short t) { 12 if (s == s) {} // expected-warning {{self-comparison always evaluates to true}}13 if (s == t) {} // no-warning14}15 16void foo4(void* v, void* w) {17 if (v == v) {} // expected-warning {{self-comparison always evaluates to true}}18 if (v == w) {} // no-warning19}20 21int qux(int x) {22 return x < x; // expected-warning {{self-comparison}}23}24 25int qux2(int x) {26 return x > x; // expected-warning {{self-comparison}}27}28 29int bar(float x) {30 return x == x; // no-warning31}32 33int bar2(float x) {34 return x != x; // no-warning35}36 37#define IS_THE_ANSWER(x) (x == 42)38 39int macro_comparison(void) {40 return IS_THE_ANSWER(42);41}42 43// Don't complain in unevaluated contexts.44int compare_sizeof(int x) {45 return sizeof(x == x); // no-warning46}47 48int array_comparisons(void) {49 int array1[2];50 int array2[2];51 52 //53 // compare same array54 //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 arrays64 //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 be70 //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 comparison79// results from a macro expansion.80#define R8435950_A i 81#define R8435950_B i 82 83int R8435950(int i) {84 if (R8435950_A == R8435950_B) // no-warning85 return 0;86 return 1;87}88 89__attribute__((weak)) int weak_1[3];90__attribute__((weak)) int weak_2[3];91_Bool compare_weak(void) {92 return weak_1 == weak_2;93}94