http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21855
--- Comment #16 from Andrew Haley <aph at gcc dot gnu.org> 2012-01-10 16:26:51 UTC --- (In reply to comment #15) > (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?). args is indeed a reference to a Java array. The length field of a Java array is immutable. The elements of an array are not immutable. > 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. If we could mark the length field as immutable that would fix it. Is there any way to do that?
