--- old/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.word/src/org/graalvm/compiler/word/WordOperationPlugin.java	2019-05-16 21:17:53.504269460 +0200
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.word/src/org/graalvm/compiler/word/WordOperationPlugin.java	2019-05-16 21:17:53.092266797 +0200
@@ -447,7 +447,7 @@
 
     protected ValueNode readOp(GraphBuilderContext b, JavaKind readKind, AddressNode address, LocationIdentity location, Opcode op) {
         assert op == Opcode.READ_POINTER || op == Opcode.READ_OBJECT || op == Opcode.READ_BARRIERED;
-        final BarrierType barrier = (op == Opcode.READ_BARRIERED ? BarrierType.PRECISE : BarrierType.NONE);
+        final BarrierType barrier = (op == Opcode.READ_BARRIERED ? BarrierType.UNKNOWN : BarrierType.NONE);
         final boolean compressible = (op == Opcode.READ_OBJECT || op == Opcode.READ_BARRIERED);
 
         return readOp(b, readKind, address, location, barrier, compressible);
@@ -465,7 +465,7 @@
 
     protected void writeOp(GraphBuilderContext b, JavaKind writeKind, AddressNode address, LocationIdentity location, ValueNode value, Opcode op) {
         assert op == Opcode.WRITE_POINTER || op == Opcode.WRITE_OBJECT || op == Opcode.WRITE_BARRIERED || op == Opcode.INITIALIZE;
-        final BarrierType barrier = (op == Opcode.WRITE_BARRIERED ? BarrierType.PRECISE : BarrierType.NONE);
+        final BarrierType barrier = (op == Opcode.WRITE_BARRIERED ? BarrierType.UNKNOWN : BarrierType.NONE);
         final boolean compressible = (op == Opcode.WRITE_OBJECT || op == Opcode.WRITE_BARRIERED);
         assert op != Opcode.INITIALIZE || location.isInit() : "must use init location for initializing";
         b.add(new JavaWriteNode(writeKind, address, location, value, barrier, compressible));