gcc/testsuite/gcc.dg/Wstring-compare.c

   1 /* PR tree-optimization/90879 - fold zero-equality of strcmp between
   2    a longer string and a smaller array
   3    { dg-do compile }
   4    { dg-options "-O2 -Wall -Wextra -ftrack-macro-expansion=0" } */
   5
   6 #include "strlenopt.h"
   7
   8 #define T(a, b) sink (0 == strcmp (a, b), a, b)
   9
  10 void sink (int, ...);
  11
  12 struct S { char a4[4], c; };
  13
  14 extern char a4[4];
  15 extern char a5[5];
  16 extern char b4[4];
  17
  18 /* Verify that comparison of string literals with arrays with unknown
  19    content but size that prevents them from comparing equal is diagnosed.  */
  20
  21 void strcmp_array_lit (void)
  22 {
  23   if (strcmp (a4, "1234"))  // { dg-warning "'strcmp' of a string of length 4 and an array of size 4 evaluates to nonzero" }
  24                             // { dg-bogus "in this expression" "unwanted note" { target *-*-* } .-1 }
  25     sink (0, a4);
  26
  27   int cmp;
  28   cmp = strcmp (a4, "1234");  // { dg-warning "'strcmp' of a string of length 4 and an array of size 4 evaluates to nonzero" }
  29   if (cmp)                  // { dg-message "in this expression" }
  30     sink (0, a4);
  31
  32   T (a4, "4321");           // { dg-warning "'strcmp' of a string of length 4 and an array of size 4 evaluates to nonzero " }
  33   T (a4, "12345");          // { dg-warning "length 5 and an array of size 4 " }
  34   T (a4, "123456");         // { dg-warning "length 6 and an array of size 4 " }
  35   T ("1234", a4);           // { dg-warning "length 4 and an array of size 4 " }
  36   T ("12345", a4);          // { dg-warning "length 5 and an array of size 4 " }
  37   T ("123456", a4);         // { dg-warning "length 6 and an array of size 4 " }
  38 }
  39
  40
  41 void strcmp_array_pstr (void)
  42 {
  43   const char *s4 = "1234";
  44
  45   {
  46     if (strcmp (a4, s4))    // { dg-warning "'strcmp' of a string of length 4 and an array of size 4 evaluates to nonzero" }
  47                             // { dg-bogus "in this expression" "unwanted note" { target *-*-* } .-1 }
  48       sink (1, a4);
  49     else
  50       sink (0, a4);
  51   }
  52
  53   {
  54     int c;
  55     c = strcmp (a4, s4);    // { dg-warning "'strcmp' of a string of length 4 and an array of size 4 evaluates to nonzero" }
  56     if (c)                  // { dg-message "in this expression" }
  57       sink (1, a4);
  58     else
  59       sink (0, a4);
  60   }
  61
  62   const char *t4 = "4321";
  63   const char *s5 = "12345";
  64   const char *s6 = "123456";
  65
  66   T (a4, t4);               // { dg-warning "'strcmp' of a string of length 4 and an array of size 4 evaluates to nonzero " }
  67   T (a4, s5);               // { dg-warning "length 5 and an array of size 4 " }
  68   T (a4, s6);               // { dg-warning "length 6 and an array of size 4 " }
  69   T (s4, a4);               // { dg-warning "length 4 and an array of size 4 " }
  70   T (s5, a4);               // { dg-warning "length 5 and an array of size 4 " }
  71   T (s6, a4);               // { dg-warning "length 6 and an array of size 4 " }
  72 }
  73
  74
  75 void strcmp_array_cond_pstr (int i)
  76 {
  77   const char *s4 = i ? "1234" : "4321";
  78   T (a4, s4);               // { dg-warning "'strcmp' of a string of length 4 and an array of size 4 evaluates to nonzero " }
  79   T (a5, s4);
  80 }
  81
  82 void strcmp_array_copy (void)
  83 {
  84   char s[8];
  85
  86   {
  87     strcpy (s, "1234");
  88     if (strcmp (a4, s))     // { dg-warning "'strcmp' of a string of length 4 and an array of size 4 evaluates to nonzero" }
  89                             // { dg-bogus "in this expression" "unwanted note" { target *-*-* } .-1 }
  90       sink (1, a4);
  91     else
  92       sink (0, a4);
  93   }
  94
  95   {
  96     strcpy (s, "1234");
  97
  98     int c;
  99     c = strcmp (a4, s);     // { dg-warning "'strcmp' of a string of length 4 and an array of size 4 evaluates to nonzero" }
 100     if (c)                  // { dg-message "in this expression" }
 101       sink (1, a4);
 102     else
 103       sink (0, a4);
 104   }
 105
 106   strcpy (s, "4321");
 107   T (a4, s);                // { dg-warning "'strcmp' of a string of length 4 and an array of size 4 evaluates to nonzero " }
 108   strcpy (s, "12345");
 109   T (a4, s);                // { dg-warning "length 5 and an array of size 4 " }
 110   strcpy (s, "123456");
 111   T (a4, s);                // { dg-warning "length 6 and an array of size 4 " }
 112   strcpy (s, "4321");
 113   T (s, a4);                // { dg-warning "length 4 and an array of size 4 " }
 114   strcpy (s, "54321");
 115   T (s, a4);                // { dg-warning "length 5 and an array of size 4 " }
 116   strcpy (s, "654321");
 117   T (s, a4);                // { dg-warning "length 6 and an array of size 4 " }
 118 }
 119
 120
 121 void strcmp_member_array_lit (const struct S *p)
 122 {
 123   // Not handled due to the fix for PR 92756.
 124   T (p->a4, "1234");        // { dg-warning "length 4 and an array of size 4 " "pr92765" { xfail *-*-* } }
 125 }
 126
 127
 128 #undef T
 129 #define T(a, b, n) sink (0 == strncmp (a, b, n), a, b)
 130
 131 void strncmp_array_lit (void)
 132 {
 133   if (strncmp (a4, "12345", 5))   // { dg-warning "'strncmp' of a string of length 5, an array of size 4 and bound of 5 evaluates to nonzero" }
 134                                   // { dg-bogus "in this expression" "unwanted note" { target *-*-* } .-1 }
 135     sink (0, a4);
 136
 137   int cmp;
 138   cmp = strncmp (a4, "54321", 5);   // { dg-warning "'strncmp' of a string of length 5, an array of size 4 and bound of 5 evaluates to nonzero" }
 139   if (cmp)                          // { dg-message "in this expression" }
 140     sink (0, a4);
 141
 142   // Verify no warning when the bound is the same as the array size.
 143   T (a4, "4321", 4);
 144   T (a4, "654321", 4);
 145
 146   T (a4, "12345", 5);       // { dg-warning "length 5, an array of size 4 and bound of 5 " }
 147   T (a4, "123456", 6);      // { dg-warning "length 6, an array of size 4 and bound of 6" }
 148
 149   T ("1234", a4, 4);
 150   T ("12345", a4, 4);
 151
 152   T ("12345", a4, 5);       // { dg-warning "length 5, an array of size 4 and bound of 5 " }
 153   T ("123456", a4, 6);      // { dg-warning "length 6, an array of size 4 and bound of 6 " }
 154 }
 155
 156
 157 void strncmp_strarray_copy (void)
 158 {
 159   {
 160     char a[] = "1234";
 161     char b[6];
 162     strcpy (b, "12345");
 163     if (strncmp (a, b, 5))  // { dg-warning "'strncmp' of strings of length 4 and 5 and bound of 5 evaluates to nonzero" }
 164                             // { dg-bogus "in this expression" "unwanted note" { target *-*-* } .-1 }
 165       sink (0, a, b);
 166   }
 167
 168   {
 169     char a[] = "4321";
 170     char b[6];
 171     strcpy (b, "54321");
 172     int cmp;
 173     cmp = strncmp (a, b, 5);  // { dg-warning "'strncmp' of strings of length 4 and 5 and bound of 5 evaluates to nonzero" }
 174     if (cmp)                  // { dg-message "in this expression" }
 175       sink (0, a, b);
 176   }
 177
 178   strcpy (a4, "abc");
 179   T (a4, "54321", 5);       // { dg-warning "'strncmp' of strings of length 3 and 5 and bound of 5 evaluates to nonzero " }
 180 }
 181
 182