Request for review(XXS): 6984056: C1: incorrect code for integer constant addition on x64

[Igor Veresov]

C1 generates incorrect code for addition of a constant to an int. 
Instead of emitting a 32bit arithmetic operation it does 64bit. That 
causes usage of the upper bits instead of overflowing, which causes 
incorrect results.

Tested with the failing nightly test.

Webrev: http://cr.openjdk.java.net/~iveresov/6984056/webrev.00/


Thanks,
igor