--- /dev/null	2017-01-22 10:16:57.869617664 -0800
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.lir/src/org/graalvm/compiler/lir/alloc/trace/TraceBuilderPhase.java	2017-02-15 17:05:34.256865944 -0800
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package org.graalvm.compiler.lir.alloc.trace;
+
+import static org.graalvm.compiler.lir.alloc.trace.TraceUtil.isTrivialTrace;
+
+import java.util.List;
+
+import org.graalvm.compiler.core.common.alloc.BiDirectionalTraceBuilder;
+import org.graalvm.compiler.core.common.alloc.SingleBlockTraceBuilder;
+import org.graalvm.compiler.core.common.alloc.Trace;
+import org.graalvm.compiler.core.common.alloc.TraceBuilderResult;
+import org.graalvm.compiler.core.common.alloc.TraceBuilderResult.TrivialTracePredicate;
+import org.graalvm.compiler.core.common.alloc.TraceStatisticsPrinter;
+import org.graalvm.compiler.core.common.alloc.UniDirectionalTraceBuilder;
+import org.graalvm.compiler.core.common.cfg.AbstractBlockBase;
+import org.graalvm.compiler.debug.Debug;
+import org.graalvm.compiler.debug.GraalError;
+import org.graalvm.compiler.lir.LIR;
+import org.graalvm.compiler.lir.gen.LIRGenerationResult;
+import org.graalvm.compiler.lir.phases.AllocationPhase;
+import org.graalvm.compiler.options.EnumOptionValue;
+import org.graalvm.compiler.options.Option;
+import org.graalvm.compiler.options.OptionType;
+import org.graalvm.compiler.options.OptionValue;
+
+import jdk.vm.ci.code.TargetDescription;
+
+public class TraceBuilderPhase extends AllocationPhase {
+
+    public enum TraceBuilder {
+        UniDirectional,
+        BiDirectional,
+        SingleBlock
+    }
+
+    public static class Options {
+        // @formatter:off
+        @Option(help = "Trace building algorithm.", type = OptionType.Debug)
+        public static final EnumOptionValue<TraceBuilder> TraceBuilding = new EnumOptionValue<>(TraceBuilder.UniDirectional);
+        @Option(help = "Schedule trivial traces as early as possible.", type = OptionType.Debug)
+        public static final OptionValue<Boolean> TraceRAScheduleTrivialTracesEarly = new OptionValue<>(true);
+        // @formatter:on
+    }
+
+    private static final int TRACE_LOG_LEVEL = 1;
+    public static final int TRACE_DUMP_LEVEL = 3;
+
+    @Override
+    protected void run(TargetDescription target, LIRGenerationResult lirGenRes, AllocationContext context) {
+        AbstractBlockBase<?>[] linearScanOrder = lirGenRes.getLIR().linearScanOrder();
+        AbstractBlockBase<?> startBlock = linearScanOrder[0];
+        LIR lir = lirGenRes.getLIR();
+        assert startBlock.equals(lir.getControlFlowGraph().getStartBlock());
+
+        final TraceBuilderResult traceBuilderResult = getTraceBuilderResult(lir, startBlock, linearScanOrder);
+
+        if (Debug.isLogEnabled(TRACE_LOG_LEVEL)) {
+            List<Trace> traces = traceBuilderResult.getTraces();
+            for (int i = 0; i < traces.size(); i++) {
+                Trace trace = traces.get(i);
+                Debug.log(TRACE_LOG_LEVEL, "Trace %5d: %s%s", i, trace, isTrivialTrace(lirGenRes.getLIR(), trace) ? " (trivial)" : "");
+            }
+        }
+        TraceStatisticsPrinter.printTraceStatistics(traceBuilderResult, lirGenRes.getCompilationUnitName());
+        Debug.dump(TRACE_DUMP_LEVEL, traceBuilderResult, "After TraceBuilding");
+        context.contextAdd(traceBuilderResult);
+    }
+
+    private static TraceBuilderResult getTraceBuilderResult(LIR lir, AbstractBlockBase<?> startBlock, AbstractBlockBase<?>[] linearScanOrder) {
+        TraceBuilderResult.TrivialTracePredicate pred = getTrivialTracePredicate(lir);
+
+        TraceBuilder selectedTraceBuilder = Options.TraceBuilding.getValue();
+        Debug.log(TRACE_LOG_LEVEL, "Building Traces using %s", selectedTraceBuilder);
+        switch (Options.TraceBuilding.getValue()) {
+            case SingleBlock:
+                return SingleBlockTraceBuilder.computeTraces(startBlock, linearScanOrder, pred);
+            case BiDirectional:
+                return BiDirectionalTraceBuilder.computeTraces(startBlock, linearScanOrder, pred);
+            case UniDirectional:
+                return UniDirectionalTraceBuilder.computeTraces(startBlock, linearScanOrder, pred);
+        }
+        throw GraalError.shouldNotReachHere("Unknown trace building algorithm: " + Options.TraceBuilding.getValue());
+    }
+
+    public static TraceBuilderResult.TrivialTracePredicate getTrivialTracePredicate(LIR lir) {
+        if (!Options.TraceRAScheduleTrivialTracesEarly.getValue()) {
+            return null;
+        }
+        return new TrivialTracePredicate() {
+            @Override
+            public boolean isTrivialTrace(Trace trace) {
+                return TraceUtil.isTrivialTrace(lir, trace);
+            }
+        };
+    }
+}