# HG changeset patch
# User Thomas Wuerthinger <thomas.wuerthinger@oracle.com>
# Date 1369224889 -7200
# Node ID 6c1f7b853d356606006543dcdaa99fcd850b9931
# Parent  ecd5cd2806e8af704f2c98515ad28110b205103f
Generalize the code for detecting invalid stamps in join operations.

diff -r ecd5cd2806e8 -r 6c1f7b853d35 graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/PiNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/PiNode.java	Wed May 22 14:07:57 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/PiNode.java	Wed May 22 14:14:49 2013 +0200
@@ -61,12 +61,6 @@
 
     @Override
     public boolean inferStamp() {
-        if (stamp() instanceof ObjectStamp && object().objectStamp().alwaysNull() && objectStamp().nonNull()) {
-            // a null value flowing into a nonNull PiNode 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()));
     }
 
diff -r ecd5cd2806e8 -r 6c1f7b853d35 graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/ValueNode.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/ValueNode.java	Wed May 22 14:07:57 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/ValueNode.java	Wed May 22 14:14:49 2013 +0200
@@ -60,7 +60,7 @@
      * @return true if the stamp has changed, false otherwise.
      */
     protected final boolean updateStamp(Stamp newStamp) {
-        if (newStamp.equals(stamp)) {
+        if (newStamp == null || newStamp.equals(stamp)) {
             return false;
         } else {
             stamp = newStamp;
diff -r ecd5cd2806e8 -r 6c1f7b853d35 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	Wed May 22 14:07:57 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/UnsafeCastNode.java	Wed May 22 14:14:49 2013 +0200
@@ -52,12 +52,6 @@
         if (stamp() == StampFactory.forNodeIntrinsic()) {
             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()));
     }
 
diff -r ecd5cd2806e8 -r 6c1f7b853d35 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	Wed May 22 14:07:57 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/CheckCastNode.java	Wed May 22 14:14:49 2013 +0200
@@ -69,9 +69,6 @@
 
     @Override
     public boolean inferStamp() {
-        if (object().objectStamp().alwaysNull() && objectStamp().nonNull()) {
-            return false;
-        }
         return updateStamp(stamp().join(object().stamp()));
     }
 
diff -r ecd5cd2806e8 -r 6c1f7b853d35 graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/type/ObjectStamp.java
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/type/ObjectStamp.java	Wed May 22 14:07:57 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/type/ObjectStamp.java	Wed May 22 14:14:49 2013 +0200
@@ -22,6 +22,8 @@
  */
 package com.oracle.graal.nodes.type;
 
+import java.lang.reflect.*;
+
 import com.oracle.graal.api.meta.*;
 
 public class ObjectStamp extends Stamp {
@@ -33,14 +35,29 @@
 
     public ObjectStamp(ResolvedJavaType type, boolean exactType, boolean nonNull, boolean alwaysNull) {
         super(Kind.Object);
-        assert !exactType || type != null;
-        assert !(nonNull && alwaysNull);
+        assert isValid(type, exactType, nonNull, alwaysNull);
         this.type = type;
         this.exactType = exactType;
         this.nonNull = nonNull;
         this.alwaysNull = alwaysNull;
     }
 
+    public static boolean isValid(ResolvedJavaType type, boolean exactType, boolean nonNull, boolean alwaysNull) {
+        if (exactType && type == null) {
+            return false;
+        }
+
+        if (exactType && Modifier.isAbstract(type.getModifiers()) && !type.isArray()) {
+            return false;
+        }
+
+        if (nonNull && alwaysNull) {
+            return false;
+        }
+
+        return true;
+    }
+
     @Override
     public ResolvedJavaType javaType(MetaAccessProvider metaAccess) {
         if (type != null) {
@@ -152,12 +169,19 @@
                 joinType = type;
             }
         }
+
         if (joinType == type && joinExactType == exactType && joinNonNull == nonNull && joinAlwaysNull == alwaysNull) {
             return this;
         } else if (joinType == other.type && joinExactType == other.exactType && joinNonNull == other.nonNull && joinAlwaysNull == other.alwaysNull) {
             return other;
         } else {
-            return new ObjectStamp(joinType, joinExactType, joinNonNull, joinAlwaysNull);
+            if (isValid(joinType, joinExactType, joinNonNull, joinAlwaysNull)) {
+                return new ObjectStamp(joinType, joinExactType, joinNonNull, joinAlwaysNull);
+            } else {
+                // This situation can happen in case the compiler wants to join two contradicting
+                // stamps.
+                return null;
+            }
         }
     }
 
diff -r ecd5cd2806e8 -r 6c1f7b853d35 graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/InliningPhase.java
--- a/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/InliningPhase.java	Wed May 22 14:07:57 2013 +0200
+++ b/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/InliningPhase.java	Wed May 22 14:14:49 2013 +0200
@@ -255,7 +255,7 @@
                         callerHasMoreInformationAboutArguments = true;
                     } else {
                         Stamp joinedStamp = localNode.stamp().join(arg.stamp());
-                        if (!joinedStamp.equals(localNode.stamp())) {
+                        if (joinedStamp != null && !joinedStamp.equals(localNode.stamp())) {
                             localNode.setStamp(joinedStamp);
                             callerHasMoreInformationAboutArguments = true;
                         }