gcc/testsuite/gcc.dg/strlenopt-66.c

   1 /* PRE tree-optimization/90626 - fold strcmp(a, b) == 0 to zero when
   2    one string length is exact and the other is unequal
   3    { dg-do run }
   4    { dg-options "-O2 -Wall" } */
   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
  16 __attribute__ ((noclone, noinline, noipa)) void
  17 clobber (void *p, int x, size_t n)
  18 {
  19   for (volatile unsigned char *q = p; n--; )
  20     *q = x;
  21 }
  22
  23 __attribute__ ((noclone, noinline, noipa)) void
  24 test_strcmp (void)
  25 {
  26   char a[8], b[8];
  27   strcpy (a, "1235");
  28   strcpy (b, "1234");
  29
  30   A (strcmp (a, b));
  31
  32   clobber (a, 0, sizeof a);
  33   clobber (b, 0, sizeof b);
  34   clobber (b + 4, '5', 1);
  35
  36   memcpy (a, "1234", 4);
  37   memcpy (b, "1234", 4);
  38
  39   A (0 > strcmp (a, b));
  40   A (0 < strcmp (b, a));
  41 }
  42
  43 __attribute__ ((noclone, noinline, noipa)) void
  44 test_strncmp (void)
  45 {
  46   char a[8], b[8];
  47   strcpy (a, "1235");
  48   strcpy (b, "1234");
  49
  50   A (0 == strncmp (a, b, 1));
  51   A (0 == strncmp (a, b, 2));
  52   A (0 == strncmp (a, b, 3));
  53   A (0 <  strncmp (a, b, 4));
  54   A (0 >  strncmp (b, a, 4));
  55
  56   clobber (a, 0, sizeof a);
  57   clobber (b, 0, sizeof b);
  58   clobber (b + 4, '5', 1);
  59
  60   memcpy (a, "1234", 4);
  61   memcpy (b, "1234", 4);
  62
  63   A (0 == strncmp (a, b, 4));
  64   A (0 >  strncmp (a, b, 5));
  65   A (0 <  strncmp (b, a, 5));
  66 }
  67
  68
  69 __attribute__ ((noclone, noinline, noipa)) void
  70 test_strncmp_a4_cond_s5_s2_2 (const char *s, int i)
  71 {
  72   char a4[4];
  73   strcpy (a4, s);
  74   A (0 == strncmp (a4, i ? "12345" : "12", 2));
  75 }
  76
  77
  78 __attribute__ ((noclone, noinline, noipa)) void
  79 test_strncmp_a4_cond_a5_s2_5 (const char *s, const char *t, int i)
  80 {
  81   char a4[4], a5[5];
  82   strcpy (a4, s);
  83   strcpy (a5, t);
  84   A (0 == strncmp (a4, i ? a5 : "12", 5));
  85 }
  86
  87 __attribute__ ((noclone, noinline, noipa)) void
  88 test_strncmp_a4_cond_a5_a3_n (const char *s1, const char *s2, const char *s3,
  89                               int i, unsigned n)
  90 {
  91   char a3[3], a4[4], a5[5];
  92   strcpy (a3, s1);
  93   strcpy (a4, s2);
  94   strcpy (a5, s3);
  95   A (0 == strncmp (a4, i ? a5 : a3, n));
  96 }
  97
  98
  99 int main (void)
 100 {
 101   test_strcmp ();
 102   test_strncmp ();
 103   test_strncmp_a4_cond_s5_s2_2 ("12", 0);
 104   test_strncmp_a4_cond_a5_s2_5 ("12", "1234", 0);
 105
 106   test_strncmp_a4_cond_a5_a3_n ("12", "1", "1",    0, 1);
 107   test_strncmp_a4_cond_a5_a3_n ("",   "1", "1234", 1, 1);
 108
 109   test_strncmp_a4_cond_a5_a3_n ("12", "12", "1",    0, 2);
 110   test_strncmp_a4_cond_a5_a3_n ("",   "12", "1234", 1, 2);
 111
 112   test_strncmp_a4_cond_a5_a3_n ("12", "123", "1",    0, 2);
 113   test_strncmp_a4_cond_a5_a3_n ("",   "123", "1234", 1, 3);
 114 }