1  /* PR tree-optimization/83821 - local aggregate initialization defeats
       2     strlen optimization
       3     Verify that a strlen() call is not eliminated for a pointer to a region
       4     of memory allocated by calloc() if a byte is written into the region
       5     that isn't known to be nul.
       6     { dg-do compile }
       7     { dg-options "-O2 -fdump-tree-optimized" } */
       8  
       9  unsigned n0, n1;
      10  
      11  void*
      12  keep_strlen_calloc_store_cst_memset (int i, unsigned a, unsigned b)
      13  {
      14    char *p = __builtin_calloc (a, 1);
      15  
      16    p[i] = 'x';
      17  
      18    __builtin_memset (p, 0, b);
      19  
      20    n0 = __builtin_strlen (p);
      21  
      22    return p;
      23  }
      24  
      25  void*
      26  keep_strlen_calloc_store_var_memset (int i, int x, unsigned a, unsigned b)
      27  {
      28    char *p = __builtin_calloc (a, 1);
      29  
      30    p[i] = x;
      31  
      32    __builtin_memset (p, 0, b);
      33  
      34    n0 = __builtin_strlen (p);
      35  
      36    return p;
      37  }
      38  
      39  void*
      40  keep_strlen_calloc_store_memset_2 (int i, int x, unsigned a, unsigned b, unsigned c)
      41  {
      42    char *p = __builtin_calloc (a, 1);
      43  
      44    p[i] = x;
      45    __builtin_memset (p, 0, b);
      46  
      47    n0 = __builtin_strlen (p);
      48  
      49    p[3] = x;
      50    __builtin_memset (p, 0, c);
      51  
      52    n1 = __builtin_strlen (p);
      53  
      54    return p;
      55  }
      56  
      57  /* { dg-final { scan-tree-dump-times "__builtin_strlen" 4 "optimized" } } */