1  /* PR tree-optimization/83821 - local aggregate initialization defeats
       2     strlen optimization
       3     Verify that with DSE disabled, a memset() call to zero out a subregion
       4     of memory allocated by calloc() is not eliminated after a non-zero byte
       5     is written into it using memset() in between the two calls.
       6     { dg-do compile }
       7     { dg-options "-O2 -fno-tree-dse -fdump-tree-optimized" } */
       8  
       9  char* keep_memset_calls (void)
      10  {
      11    char *p = __builtin_calloc (12, 1);
      12  
      13    __builtin_memset (p + 5, 1, 2);   /* dead store (not eliminated) */
      14  
      15    __builtin_memset (p, 0, 12);      /* must not be eliminated */
      16  
      17    return p;
      18  }
      19  
      20  /* { dg-final { scan-tree-dump-not "malloc" "optimized" } }
      21     { dg-final { scan-tree-dump-times "_calloc \\\(" 1 "optimized" } }
      22     { dg-final { scan-tree-dump-times "_memset \\\(" 2 "optimized" } } */