> There is plenty of evidence to suggest that will indeed be the case, and the difference between LP64 and L64P32 ("x32") on x86-64 will make that even more clear than the current major performance _loss_ one experiences when going from a pure 32 bit to pure 64 bit JVM.
You should probably try to make sure you understand how the ABI works before trying to discuss it in details. It's ILP32, not L64P32 (i.e. "long" is also 32-bit).
As for the issue of compressed pointers in the JVM, it shows very well one thing: that you can easily solve the performance issue by making your code smarter, instead of breaking compatibility with what has be done up to now to make a new ABI.