[Bug java/21855] array bounds checking elimination

["rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21855

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW
          Component|tree-optimization           |java

--- Comment #15 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-01-10 16:20:13 UTC ---
(In reply to comment #14)
> (In reply to comment #13)
> > We can't optimize this because System.out.println can change args[].
> 
> That's the whole point: System.out.println cannot change args[], which is a
> java array, and the length of a Java array is constant.  It is not an invalid
> test case.

I suppose

  public static void main(String[] args)

is passing args by value (but the implementation detail uses reference
passing for efficiency?).  In this case the Java frontend should do
like the C++ frontend and tell this to the middle-end by properly
marking args as 1) DECL_BY_REFERENCE, 2) use a TYPE_RESTRICT qualified
pointer for the reference.  Then we would optimize this case.

Java frontend issue.