--- a/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core/src/org/graalvm/compiler/core/phases/LowTier.java	Thu Oct 31 14:23:06 2019 -0700
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core/src/org/graalvm/compiler/core/phases/LowTier.java	Thu Oct 31 16:54:16 2019 -0700
@@ -24,7 +24,7 @@
 
 package org.graalvm.compiler.core.phases;
 
-import static org.graalvm.compiler.core.common.GraalOptions.ImmutableCode;
+import static org.graalvm.compiler.core.common.GraalOptions.LateMembars;
 import static org.graalvm.compiler.phases.common.DeadCodeEliminationPhase.Optionality.Required;
 
 import org.graalvm.compiler.core.common.GraalOptions;
@@ -33,11 +33,11 @@
 import org.graalvm.compiler.options.OptionKey;
 import org.graalvm.compiler.options.OptionType;
 import org.graalvm.compiler.options.OptionValues;
-import org.graalvm.compiler.phases.PhaseSuite;
 import org.graalvm.compiler.phases.common.CanonicalizerPhase;
 import org.graalvm.compiler.phases.common.DeadCodeEliminationPhase;
 import org.graalvm.compiler.phases.common.ExpandLogicPhase;
 import org.graalvm.compiler.phases.common.FixReadsPhase;
+import org.graalvm.compiler.phases.common.InsertMembarsPhase;
 import org.graalvm.compiler.phases.common.LoweringPhase;
 import org.graalvm.compiler.phases.common.ProfileCompiledMethodsPhase;
 import org.graalvm.compiler.phases.common.PropagateDeoptimizeProbabilityPhase;
@@ -46,7 +46,7 @@
 import org.graalvm.compiler.phases.schedule.SchedulePhase.SchedulingStrategy;
 import org.graalvm.compiler.phases.tiers.LowTierContext;
 
-public class LowTier extends PhaseSuite<LowTierContext> {
+public class LowTier extends BaseTier<LowTierContext> {
 
     static class Options {
 
@@ -58,13 +58,8 @@
     }
 
     public LowTier(OptionValues options) {
-        CanonicalizerPhase canonicalizer = new CanonicalizerPhase();
-        CanonicalizerPhase canonicalizerWithoutGVN = new CanonicalizerPhase();
-        canonicalizerWithoutGVN.disableGVN();
-        if (ImmutableCode.getValue(options)) {
-            canonicalizer.disableReadCanonicalization();
-            canonicalizerWithoutGVN.disableReadCanonicalization();
-        }
+        CanonicalizerPhase canonicalizer = createCanonicalizerPhase(options);
+        CanonicalizerPhase canonicalizerWithoutGVN = canonicalizer.copyWithoutGVN();
 
         if (Options.ProfileCompiledMethods.getValue(options)) {
             appendPhase(new ProfileCompiledMethodsPhase());
@@ -85,6 +80,9 @@
 
         appendPhase(new PropagateDeoptimizeProbabilityPhase());
 
+        if (LateMembars.getValue(options)) {
+            appendPhase(new InsertMembarsPhase());
+        }
         appendPhase(new SchedulePhase(SchedulePhase.SchedulingStrategy.LATEST_OUT_OF_LOOPS));
     }
 }