Request for reviews (XS): 6807084: AutoBox elimination is broken with compressed oops

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/6807084/webrev.00

Fixed 6807084: AutoBox elimination is broken with compressed oops

Problem:
AutoBox elimination code looks for an Integer object load from
AutoBox cache array in ideal graph and expects LoadP nodes.
With compressed oops it gets DecodeN( LoadN ) instead of LoadP
and bails out.

Solution:
Add checks for DecodeN nodes into AutoBox elimination code.

Reviewed by:

Fix verified (y/n): y, generated code

Other testing:
JPRT, CTW (with -XX:+UseCompressedOops -XX:+AggressiveOpts)