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changeset 10492:34444b095a51

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Read nodes with attached barrier (G1) can not float
author Christos Kotselidis <christos.kotselidis@oracle.com>
date Fri, 21 Jun 2013 11:34:17 +0200
parents e98e021d1e7e
children a46c3180faed
files graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/FloatableAccessNode.java graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/FloatingReadPhase.java
diffstat 2 files changed, 11 insertions(+), 1 deletions(-) [+]
line wrap: on
line diff
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/FloatableAccessNode.java	Fri Jun 21 11:08:10 2013 +0200
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/FloatableAccessNode.java	Fri Jun 21 11:34:17 2013 +0200
@@ -22,6 +22,7 @@
  */
 package com.oracle.graal.nodes.extended;
 
+import com.oracle.graal.api.meta.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.type.*;
 
@@ -43,4 +44,13 @@
     }
 
     public abstract FloatingAccessNode asFloatingNode(ValueNode lastLocationAccess);
+
+    /**
+     * AccessNodes can float only if their location identities are not ANY_LOCATION. Furthermore, in
+     * case G1 is enabled any access (read) to the java.lang.ref.Reference.referent field which has
+     * an attached write barrier with pre-semantics can not also float.
+     */
+    public boolean canFloat() {
+        return location().getLocationIdentity() != LocationIdentity.ANY_LOCATION && getWriteBarrierType() == WriteBarrierType.NONE;
+    }
 }
--- a/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/FloatingReadPhase.java	Fri Jun 21 11:08:10 2013 +0200
+++ b/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/FloatingReadPhase.java	Fri Jun 21 11:34:17 2013 +0200
@@ -175,7 +175,7 @@
             StructuredGraph graph = accessNode.graph();
             assert accessNode.getNullCheck() == false;
             LocationIdentity locationIdentity = accessNode.location().getLocationIdentity();
-            if (locationIdentity != ANY_LOCATION) {
+            if (accessNode.canFloat()) {
                 ValueNode lastLocationAccess = state.getLastLocationAccess(locationIdentity);
                 FloatingAccessNode floatingNode = accessNode.asFloatingNode(lastLocationAccess);
                 floatingNode.setNullCheck(accessNode.getNullCheck());