gcc/testsuite/gcc.dg/strlenopt-69.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 -Wno-string-compare -fdump-tree-optimized -ftrack-macro-expansion=0" } */
   5
   6 #include "strlenopt.h"
   7
   8 #define A(expr)                                                 \
   9   ((expr)                                                       \
  10    ? (void)0                                                    \
  11    : (__builtin_printf ("assertion failed on line %i: %s\n",    \
  12                         __LINE__, #expr),                       \
  13       __builtin_abort ()))
  14
  15 void clobber (void*, ...);
  16
  17 struct S { char a4[4], c; };
  18
  19 extern char a4[4];
  20 extern char b4[4];
  21
  22 /* Verify that comparison of string literals with arrays with unknown
  23    content but size that prevents them from comparing equal is folded
  24    to a constant.  */
  25
  26 void test_array_lit (void)
  27 {
  28   A (strcmp (a4, "1234")); clobber (a4);
  29   A (strcmp (a4, "12345")); clobber (a4);
  30   A (strcmp (a4, "123456")); clobber (a4);
  31   A (strcmp ("1234", a4)); clobber (a4);
  32   A (strcmp ("12345", a4)); clobber (a4);
  33   A (strcmp ("123456", a4)); clobber (a4);
  34 }
  35
  36 void test_memarray_lit (struct S *p)
  37 {
  38   A (strcmp (p->a4, "1234"));
  39   A (strcmp (p->a4, "12345"));
  40   A (strcmp (p->a4, "123456"));
  41
  42   A (strcmp ("1234", p->a4));
  43   A (strcmp ("12345", p->a4));
  44   A (strcmp ("123456", p->a4));
  45 }
  46
  47 /* Verify that the equality of empty strings is folded.  */
  48
  49 void test_empty_string (void)
  50 {
  51   A (0 == strcmp ("", ""));
  52
  53   *a4 = '\0';
  54   A (0 == strcmp (a4, ""));
  55   A (0 == strcmp ("", a4));
  56   A (0 == strcmp (a4, a4));
  57
  58   char s[8] = "";
  59   A (0 == strcmp (a4, s));
  60
  61   a4[1] = '\0';
  62   b4[1] = '\0';
  63   A (0 == strcmp (a4 + 1, b4 + 1));
  64
  65   a4[2] = '\0';
  66   b4[2] = '\0';
  67   A (0 == strcmp (&a4[2], &b4[2]));
  68
  69   clobber (a4, b4);
  70
  71   memset (a4, 0, sizeof a4);
  72   memset (b4, 0, sizeof b4);
  73   A (0 == strcmp (a4, b4));
  74 }
  75
  76 /* Verify that comparison of dynamically created strings with unknown
  77    arrays is folded.  */
  78
  79 void test_array_copy (void)
  80 {
  81   char s[8];
  82   strcpy (s, "1234");
  83   A (strcmp (a4, s));
  84
  85   strcpy (s, "12345");
  86   A (strlen (s) == 5);
  87   A (strcmp (a4, s)); clobber (a4);
  88
  89   strcpy (s, "123456");
  90   A (strcmp (a4, s)); clobber (a4);
  91
  92   strcpy (s, "1234");
  93   A (strcmp (s, a4)); clobber (a4);
  94
  95   strcpy (s, "12345");
  96   A (strcmp (s, a4)); clobber (a4);
  97
  98   strcpy (s, "123456");
  99   A (strcmp (s, a4)); clobber (a4);
 100 }
 101
 102
 103 void test_array_bounded (void)
 104 {
 105   A (strncmp (a4, "12345", 5)); clobber (a4);
 106   A (strncmp ("54321", a4, 5)); clobber (a4);
 107
 108   A (strncmp (a4, "123456", 5)); clobber (a4);
 109   A (strncmp ("654321", a4, 5)); clobber (a4);
 110 }
 111
 112 void test_array_copy_bounded (void)
 113 {
 114   char s[8];
 115   strcpy (s, "12345");
 116   A (strncmp (a4, s, 5)); clobber (a4);
 117   strcpy (s, "54321");
 118   A (strncmp (s, a4, 5)); clobber (a4);
 119
 120   strcpy (s, "123456");
 121   A (strncmp (a4, s, 5)); clobber (a4);
 122   strcpy (s, "654321");
 123   A (strncmp (s, a4, 5)); clobber (a4);
 124 }
 125
 126 /* { dg-final { scan-tree-dump-not "abort|strcmp|strncmp" "optimized" } } */