review (S) for 7032162: assert(flat != TypePtr::BOTTOM) failed: cannot alias-analyze an untyped ptr

[Tom Rodriguez]

http://cr.openjdk.java.net/~never/7032162

7032162: assert(flat != TypePtr::BOTTOM) failed: cannot alias-analyze an untyped ptr
Reviewed-by:

This appears to be an existing problem with OptimizeStringConcat where
missing control can allow some loads to be split up to where their
base is NULL which causes addresses that can't be analyzed.  The fix
is to use the appropriate control.  If it's truly unneeded it will be
optimized away.  The bug was exposed by the String not in perm changes
because we were no longer treating some constant strings as embeddable
constants.  This is fixed by handling them specially in push_constant.
Tested with failing test from report and full CTW with string opts.