Java GC descriptor vs. tree_int_cst on 64-bit platforms

[Joern Rennecke]

> Bingo.  I added
> 
>   TREE_TYPE (value) = type_for_mode (ptr_mode, MODE_INT);
> 
> Now it looks like I'm getting the whole descriptor (whereas the top bits
> were truncated before).  I'll run some tests and see what I get.

The 'unsignedp' argument of type_for_mode is an int.  MODE_INT happens to
have the right numerical value - i.e. 1 - right now, but you should not
rely on this to remain unchanged.

The correct expression is:

type_for_mode (ptr_mode, 1)