hg: hsx/hotspot-comp/hotspot: 7179138: Incorrect result with String concatenation optimization

[vladimir.kozlov at oracle.com]

Changeset: 751bd303aa45
Author:    kvn
Date:      2012-06-26 09:06 -0700
URL:       http://hg.openjdk.java.net/hsx/hotspot-comp/hotspot/rev/751bd303aa45

7179138: Incorrect result with String concatenation optimization
Summary: check for and skip diamond shaped NULL check code for the result of toString()
Reviewed-by: twisti, roland

! src/share/vm/opto/stringopts.cpp
+ test/compiler/7179138/Test7179138_1.java
+ test/compiler/7179138/Test7179138_2.java