1  /* Verify that strncmp equalities aren't eliminated when the trailing array
       2     type referenced by a member pointer is smaller than the string in cases
       3     when the pointer pointed to by the enclosing object references an object
       4     sufficiently large to store a string of equal length.
       5    { dg-do compile }
       6    { dg-options "-O2 -Wall -Wextra -Wno-stringop-overread -fdump-tree-optimized" } */
       7  
       8  void init (void*);
       9  
      10  struct A1 { char i, a[1]; };
      11  
      12  void f1_arr (void)
      13  {
      14    char a[9];
      15    init (a);
      16  
      17    struct A1 *p = (struct A1*)a;
      18  
      19    if (__builtin_strncmp (p->a, "01234567", 8) == 0)
      20      {
      21        extern void array_test (void);
      22        array_test ();
      23      }
      24  }
      25  
      26  void f1_ptr (void)
      27  {
      28    void *p;
      29    init (&p);
      30  
      31    struct A1 *q = (struct A1*)p;
      32  
      33    if (__builtin_strncmp (q->a, "0123456789", 10) == 0)
      34      {
      35        extern void pointer_test (void);
      36        pointer_test ();
      37      }
      38  }
      39  
      40  void f1_struct (void)
      41  {
      42    struct { char a[9]; } b;
      43    init (&b);
      44  
      45    struct A1 *p = (struct A1*)&b;
      46  
      47    if (__builtin_strncmp (p->a, "01234567", 8) == 0)
      48      {
      49        extern void struct_test (void);
      50        struct_test ();
      51      }
      52  }
      53  
      54  void f1_memptr (void)
      55  {
      56    struct { void *p; } b;
      57    init (&b);
      58  
      59    struct A1 *p = (struct A1*)b.p;
      60  
      61    if (__builtin_strncmp (p->a, "0123456789", 10) == 0)
      62      {
      63        extern void memptr_test (void);
      64        memptr_test ();
      65      }
      66  }
      67  
      68  
      69  struct A2 { char i, a[2]; };
      70  
      71  void f2_arr (void)
      72  {
      73    char a[8];
      74    init (a);
      75  
      76    struct A2 *p = (struct A2*)a;
      77  
      78    if (__builtin_strncmp (p->a, "0123456", 7) == 0)
      79      {
      80        extern void array_test (void);
      81        array_test ();
      82      }
      83  }
      84  
      85  void f2_ptr (void)
      86  {
      87    void *p;
      88    init (&p);
      89  
      90    struct A2 *q = (struct A2*)p;
      91  
      92    if (__builtin_strncmp (q->a, "0123456789", 10) == 0)
      93      {
      94        extern void pointer_test (void);
      95        pointer_test ();
      96      }
      97  }
      98  
      99  void f2_struct (void)
     100  {
     101    struct { char a[8]; } b;
     102    init (&b);
     103  
     104    struct A2 *p = (struct A2*)&b;
     105  
     106    if (__builtin_strncmp (p->a, "0123456", 7) == 0)
     107      {
     108        extern void struct_test (void);
     109        struct_test ();
     110      }
     111  }
     112  
     113  void f2_memptr (void)
     114  {
     115    struct { void *p; } b;
     116    init (&b);
     117  
     118    struct A2 *p = (struct A2*)b.p;
     119  
     120    if (__builtin_strncmp (p->a, "0123456789", 10) == 0)
     121      {
     122        extern void memptr_test (void);
     123        memptr_test ();
     124      }
     125  }
     126  
     127  /* { dg-final { scan-tree-dump-times "array_test" 2 "optimized" } }
     128     { dg-final { scan-tree-dump-times "pointer_test" 2 "optimized" } }
     129     { dg-final { scan-tree-dump-times "struct_test" 2 "optimized" } }
     130     { dg-final { scan-tree-dump-times "memptr_test" 2 "optimized" } } */