clang/test/Sema/warn-unused-but-set-variables.c

   1 // RUN: %clang_cc1 -fblocks -fsyntax-only -Wunused-but-set-variable -verify %s
   2
   3 struct S {
   4   int i;
   5 };
   6
   7 int f0(void) {
   8   int y; // expected-warning{{variable 'y' set but not used}}
   9   y = 0;
  10
  11   int z __attribute__((unused));
  12   z = 0;
  13
  14   struct S s; // expected-warning{{variable 's' set but not used}}
  15   struct S t;
  16   s = t;
  17
  18   // Don't warn for an extern variable.
  19   extern int w;
  20   w = 0;
  21
  22   // Following gcc, this should not warn.
  23   int a;
  24   w = (a = 0);
  25
  26   int j = 0; // expected-warning{{variable 'j' set but not used}}
  27   for (int i = 0; i < 1000; i++)
  28     j += 1;
  29
  30   // Following gcc, warn for a volatile variable.
  31   volatile int b; // expected-warning{{variable 'b' set but not used}}
  32   b = 0;
  33
  34   // volatile variable k is used, no warning.
  35   volatile int k = 0;
  36   for (int i = 0; i < 1000; i++)
  37     k += 1;
  38
  39   // typedef of volatile type, no warning.
  40   typedef volatile int volint;
  41   volint l = 0;
  42   l += 1;
  43
  44   int x;
  45   x = 0;
  46   return x;
  47 }
  48
  49 void f1(void) {
  50   (void)^() {
  51     int y; // expected-warning{{variable 'y' set but not used}}
  52     y = 0;
  53
  54     int x;
  55     x = 0;
  56     return x;
  57   };
  58 }
  59
  60 void f2 (void) {
  61   // Don't warn, even if it's only used in a non-ODR context.
  62   int x;
  63   x = 0;
  64   (void) sizeof(x);
  65 }
  66
  67 void for_cleanup(int *x) {
  68   *x = 0;
  69 }
  70
  71 void f3(void) {
  72   // Don't warn if the __cleanup__ attribute is used.
  73   __attribute__((__cleanup__(for_cleanup))) int x;
  74   x = 5;
  75 }
  76
  77 void f4(void) {
  78   int x1 = 0; // expected-warning{{variable 'x1' set but not used}}
  79   x1++;
  80   int x2 = 0; // expected-warning{{variable 'x2' set but not used}}
  81   x2--;
  82   int x3 = 0; // expected-warning{{variable 'x3' set but not used}}
  83   ++x3;
  84   int x4 = 0; // expected-warning{{variable 'x4' set but not used}}
  85   --x4;
  86
  87   static int counter = 0; // expected-warning{{variable 'counter' set but not used}}
  88   counter += 1;
  89
  90   volatile int v1 = 0;
  91   ++v1;
  92   typedef volatile int volint;
  93   volint v2 = 0;
  94   v2++;
  95 }