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[Bug java/21855] array bounds checking elimination
- From: "rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 10 Jan 2012 16:20:13 +0000
- Subject: [Bug java/21855] array bounds checking elimination
- Auto-submitted: auto-generated
- References: <bug-21855-4@http.gcc.gnu.org/bugzilla/>
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.