# HG changeset patch
# User Lukas Stadler <lukas.stadler@jku.at>
# Date 1357901084 -3600
# Node ID c1a5c3bc56565ee47b09288e9c17766f9370c694
# Parent  4e25ceefee4c2ef9fdae300001c039e0960c9006
more accurate inferStamp for UnsafeCastNode and CheckCastNode

diff -r 4e25ceefee4c -r c1a5c3bc5656 graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/UnsafeCastNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/UnsafeCastNode.java	Fri Jan 11 11:44:11 2013 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/UnsafeCastNode.java	Fri Jan 11 11:44:44 2013 +0100
@@ -50,6 +50,19 @@
     }
 
     @Override
+    public boolean inferStamp() {
+        if (kind() != Kind.Object || object().kind() != Kind.Object) {
+            return false;
+        }
+        if (object().objectStamp().alwaysNull() && objectStamp().nonNull()) {
+            // a null value flowing into a nonNull UnsafeCastNode should be guarded by a type/isNull guard, but the
+            // compiler might see this situation before the branch is deleted
+            return false;
+        }
+        return updateStamp(stamp().join(object().stamp()));
+    }
+
+    @Override
     public ValueNode canonical(CanonicalizerTool tool) {
         if (kind() != object.kind()) {
             return this;
diff -r 4e25ceefee4c -r c1a5c3bc5656 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	Fri Jan 11 11:44:11 2013 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/CheckCastNode.java	Fri Jan 11 11:44:44 2013 +0100
@@ -59,11 +59,10 @@
 
     @Override
     public boolean inferStamp() {
-        if (object().stamp().nonNull() && !stamp().nonNull()) {
-            setStamp(StampFactory.declaredNonNull(type));
-            return true;
+        if (object().objectStamp().alwaysNull() && objectStamp().nonNull()) {
+            return false;
         }
-        return super.inferStamp();
+        return updateStamp(stamp().join(object().stamp()));
     }
 
     @Override