gcc/testsuite/gcc.dg/tree-ssa/clz-int.c

   1 /* { dg-do run } */
   2 /* { dg-require-effective-target clzl } */
   3 /* { dg-options "-O2 -fno-tree-ch -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     if (b == 0)
  13       return PREC;
  14
  15     while (!(b & (1 << (PREC - 1)))) {
  16         b <<= 1;
  17         c++;
  18     }
  19
  20     return c;
  21 }
  22
  23 int main()
  24 {
  25   if (foo(0) != PREC)
  26     __builtin_abort ();
  27   if (foo(1 << (PREC - 1)) != 0)
  28     __builtin_abort ();
  29   if (foo(35) != PREC - 6)
  30     __builtin_abort ();
  31   return 0;
  32 }
  33
  34 /* { dg-final { scan-tree-dump-times "__builtin_clz|\\.CLZ" 1 "optimized" } } */