RFR(M): 8220376: C2: Int >0 not recognized as !=0 for div by 0 check

[Patric Hedlin]

Dear all,

I would like to ask for help to review the following change/update:

Issue:  https://bugs.openjdk.java.net/browse/JDK-8220376
Webrev: http://cr.openjdk.java.net/~phedlin/tr8220376/

8220376: C2: Int >0 not recognized as !=0 for div by 0 check

     Adding a simple subsumption test to IfNode::Ideal to enable a local
     short-circuit for (obviously) redundant if-nodes.

Testing: hs-tier1-4, hs-precheckin-comp


Best regards,
Patric