1  /* { dg-do run } */
       2  /* { dg-require-effective-target clz } */
       3  /* { dg-options "-O2 -fdump-tree-optimized" } */
       4  
       5  #define PREC (__CHAR_BIT__ * __SIZEOF_INT__)
       6  
       7  int
       8  __attribute__ ((noinline, noclone))
       9  foo (unsigned int b) {
      10      int c = 0;
      11  
      12      while (b) {
      13  	b >>= 1;
      14  	c++;
      15      }
      16  
      17      return c;
      18  }
      19  
      20  int main()
      21  {
      22    if (foo(0) != 0)
      23      __builtin_abort ();
      24    if (foo(5) != 3)
      25      __builtin_abort ();
      26    if (foo(1 << (PREC - 1)) != PREC)
      27      __builtin_abort ();
      28    return 0;
      29  }
      30  
      31  /* { dg-final { scan-tree-dump-times "__builtin_clz|\\.CLZ" 1 "optimized" } } */