# HG changeset patch
# User Bernhard Urban <bernhard.urban@jku.at>
# Date 1375370608 -7200
# Node ID 3736fb3dcc56d96b1ad51db4e5c96eb5ad46f53a
# Parent  92fc1db20ad95ccb1d7ee91a7b63b4c867560f97
checkcastnode: fix comment and scope in unittest

diff -r 92fc1db20ad9 -r 3736fb3dcc56 graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/EliminateNestedCheckCastsTest.java
--- a/graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/EliminateNestedCheckCastsTest.java	Thu Aug 01 16:40:59 2013 +0200
+++ b/graal/com.oracle.graal.compiler.test/src/com/oracle/graal/compiler/test/EliminateNestedCheckCastsTest.java	Thu Aug 01 17:23:28 2013 +0200
@@ -106,11 +106,11 @@
     }
 
     private StructuredGraph compileSnippet(final String snippet, final int checkcasts, final int afterCanon) {
-        return Debug.scope(snippet, new Callable<StructuredGraph>() {
+        final StructuredGraph graph = parse(snippet);
+        return Debug.scope("NestedCheckCastsTest", graph, new Callable<StructuredGraph>() {
 
             @Override
             public StructuredGraph call() throws Exception {
-                StructuredGraph graph = parse(snippet);
                 Debug.dump(graph, "After parsing: " + snippet);
                 Assert.assertEquals(checkcasts, graph.getNodes().filter(CheckCastNode.class).count());
                 new CanonicalizerPhase.Instance(runtime(), new Assumptions(false), true).apply(graph);
diff -r 92fc1db20ad9 -r 3736fb3dcc56 graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/CheckCastNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/CheckCastNode.java	Thu Aug 01 16:40:59 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/CheckCastNode.java	Thu Aug 01 17:23:28 2013 +0200
@@ -146,7 +146,8 @@
             return object();
         }
 
-        // remove checkcast if next node is a more specific checkcast
+        // if the previous node is also a checkcast, with a less precise and compatible type,
+        // replace both with one checkcast checking the more specific type.
         if (predecessor() instanceof CheckCastNode) {
             CheckCastNode ccn = (CheckCastNode) predecessor();
             if (ccn != null && ccn.type != null && ccn == object && ccn.forStoreCheck == forStoreCheck && ccn.type.isAssignableFrom(type)) {