[Bug other/23469] Behaviour of built-in __signbitf(x) differs with optimization

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-08-18 
21:41 -------
This is not a bug as signbit just have to return a non zero value if it has the 
value passed has its sign 
bit set.
So defining it this way:
inline int mysignbit(float x) {
  union { float f; unsigned int i; } u;
  u.f = x;
  return u.i&0x80000000UL;
}

Is also legal.

The reason for the different is optimizing for size vs optimizing for speed.  
The definition you gave is 
faster but larger.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23469