[Bug c/47796] The code to write to a bit_field data strucuture will be removed unexpectedly with gcc 4.5.1 -O2 option

[qihua.dai at intel dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47796

qihua.dai at intel dot com changed:

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

--- Comment #5 from qihua.dai at intel dot com 2011-02-21 07:02:55 UTC ---
(In reply to comment #4)
> (In reply to comment #3)
> > If it's not a bug, why is there the different behavior for -O0 and -O2
> Because strict aliasing is not enabled at -O0, only at -O2 and above (-Os
> included).

Why no warning message for this volation using gcc 4.5.1 or gcc 4.4.0?
And why is there the different behavior for gcc 4.4.0 -O2 and gcc 4.5.1 -O2?
Why does gcc 4.4.0 -O2 have not this problem?