1  /* { dg-do compile } */
       2  /* { dg-options "-O2 -ffinite-math-only -frounding-math -fdump-tree-optimized" } */
       3  double foo (double a)
       4  {
       5    return a - a;
       6  }
       7  
       8  /* { dg-final { scan-tree-dump " = a_\[0-9\]\\(D\\) - a_\[0-9\]\\(D\\);" "optimized" } } */