[9] RFR(S): 8066312: Add new Node* Node::find_user(int opc) method

[Zoltán Majó]

Hi,


please review the following small patch.

Bug: https://bugs.openjdk.java.net/browse/JDK-8066312

Problem: There are some locations in the source code that search for 
users of a node of a particular type.

Solution: To simplify the code, this patch adds a new method, 
Node::find_user(int opc) that can be used for searching. This patch also 
updates some comments in the source code.

Webrev: http://cr.openjdk.java.net/~zmajo/8066312/webrev.00/

Testing: JPRT

Thank you and best regards,


Zoltan