--- a/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/GraalCompiler.java	Wed Jan 27 10:08:22 2016 +0100
+++ b/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/GraalCompiler.java	Wed Feb 03 11:03:55 2016 +0100
@@ -23,9 +23,7 @@
 package com.oracle.graal.compiler;
 
 import static com.oracle.graal.compiler.GraalCompilerOptions.EmitLIRRepeatCount;
-import static com.oracle.graal.compiler.common.GraalOptions.RegisterPressure;
 import static com.oracle.graal.compiler.common.GraalOptions.UseGraalInstrumentation;
-import static com.oracle.graal.compiler.common.alloc.RegisterAllocationConfig.ALL_REGISTERS;
 import static com.oracle.graal.phases.common.DeadCodeEliminationPhase.Optionality.Optional;
 
 import java.util.List;
@@ -52,8 +50,8 @@
 import com.oracle.graal.debug.DebugCloseable;
 import com.oracle.graal.debug.DebugMetric;
 import com.oracle.graal.debug.DebugTimer;
+import com.oracle.graal.lir.BailoutAndRestartBackendException;
 import com.oracle.graal.lir.LIR;
-import com.oracle.graal.lir.alloc.lsra.OutOfRegistersException;
 import com.oracle.graal.lir.asm.CompilationResultBuilder;
 import com.oracle.graal.lir.asm.CompilationResultBuilderFactory;
 import com.oracle.graal.lir.framemap.FrameMap;
@@ -68,7 +66,6 @@
 import com.oracle.graal.nodes.StructuredGraph.ScheduleResult;
 import com.oracle.graal.nodes.cfg.Block;
 import com.oracle.graal.nodes.spi.NodeLIRBuilderTool;
-import com.oracle.graal.options.OptionValue;
 import com.oracle.graal.options.OptionValue.OverrideScope;
 import com.oracle.graal.phases.OptimisticOptimizations;
 import com.oracle.graal.phases.PhaseSuite;
@@ -241,15 +238,16 @@
     public static LIRGenerationResult emitLIR(Backend backend, StructuredGraph graph, Object stub, RegisterConfig registerConfig, LIRSuites lirSuites) {
         try {
             return emitLIR0(backend, graph, stub, registerConfig, lirSuites);
-        } catch (OutOfRegistersException e) {
-            if (RegisterPressure.getValue() != null && !RegisterPressure.getValue().equals(ALL_REGISTERS)) {
-                try (OverrideScope s = OptionValue.override(RegisterPressure, ALL_REGISTERS)) {
-                    // retry with default register set
-                    return emitLIR0(backend, graph, stub, registerConfig, lirSuites);
+        } catch (BailoutAndRestartBackendException e) {
+            if (BailoutAndRestartBackendException.Options.LIRUnlockBackendRestart.getValue() && e.shouldRestart()) {
+                try (OverrideScope scope = e.getOverrideScope()) {
+                    LIRSuites lirSuites0 = e.updateLIRSuites(lirSuites);
+                    if (lirSuites0 != null) {
+                        return emitLIR0(backend, graph, stub, registerConfig, lirSuites0);
+                    }
                 }
-            } else {
-                throw e;
             }
+            throw e;
         }
     }
 

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.lir/src/com/oracle/graal/lir/BailoutAndRestartBackendException.java	Wed Feb 03 11:03:55 2016 +0100
@@ -0,0 +1,78 @@
+/*
+ * 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 com.oracle.graal.lir;
+
+import jdk.vm.ci.code.BailoutException;
+
+import com.oracle.graal.lir.phases.LIRSuites;
+import com.oracle.graal.options.Option;
+import com.oracle.graal.options.OptionType;
+import com.oracle.graal.options.OptionValue;
+import com.oracle.graal.options.OptionValue.OverrideScope;
+import com.oracle.graal.options.StableOptionValue;
+
+/**
+ * Restarts the {@link LIR low-level} compilation with a modified configuration.
+ * {@link BailoutAndRestartBackendException.Options#LIRUnlockBackendRestart LIRUnlockBackendRestart}
+ * needs to be enabled. Use only for debugging purposes only.
+ */
+public abstract class BailoutAndRestartBackendException extends BailoutException {
+
+    public static class Options {
+        // @formatter:off
+        @Option(help = "Unlock backend restart feature.", type = OptionType.Debug)
+        public static final StableOptionValue<Boolean> LIRUnlockBackendRestart = new StableOptionValue<>(false);
+        // @formatter:on
+    }
+
+    private static final long serialVersionUID = 792969002851591180L;
+
+    public BailoutAndRestartBackendException(String msg) {
+        super(msg);
+    }
+
+    public BailoutAndRestartBackendException(Throwable cause, String msg) {
+        super(cause, msg);
+    }
+
+    public BailoutAndRestartBackendException(boolean permanent, String msg) {
+        super(permanent, msg);
+    }
+
+    /** Returns {@code true} if the low-level compilation should be restarted. */
+    public abstract boolean shouldRestart();
+
+    /**
+     * Returns an {@link OverrideScope} to change {@link OptionValue OptionValues} or {@code null}
+     * if no changes are required.
+     */
+    public abstract OverrideScope getOverrideScope();
+
+    /**
+     * Updates the {@link LIRSuites} used by the low-level compiler. Note that {@link LIRSuites} are
+     * usually shared, so a modified input parameter will affect other compilations. In case only
+     * the current compilation should be altered, create a copy using {@link LIRSuites#copy()}.
+     */
+    public abstract LIRSuites updateLIRSuites(LIRSuites lirSuites);
+
+}

--- a/graal/com.oracle.graal.lir/src/com/oracle/graal/lir/alloc/lsra/OutOfRegistersException.java	Wed Jan 27 10:08:22 2016 +0100
+++ b/graal/com.oracle.graal.lir/src/com/oracle/graal/lir/alloc/lsra/OutOfRegistersException.java	Wed Feb 03 11:03:55 2016 +0100
@@ -22,9 +22,15 @@
  */
 package com.oracle.graal.lir.alloc.lsra;
 
-import jdk.vm.ci.code.BailoutException;
+import static com.oracle.graal.compiler.common.GraalOptions.RegisterPressure;
+import static com.oracle.graal.compiler.common.alloc.RegisterAllocationConfig.ALL_REGISTERS;
 
-public class OutOfRegistersException extends BailoutException {
+import com.oracle.graal.lir.BailoutAndRestartBackendException;
+import com.oracle.graal.lir.phases.LIRSuites;
+import com.oracle.graal.options.OptionValue;
+import com.oracle.graal.options.OptionValue.OverrideScope;
+
+public class OutOfRegistersException extends BailoutAndRestartBackendException {
 
     private static final long serialVersionUID = -3479786650143432195L;
 
@@ -63,4 +69,19 @@
     public String getDescription() {
         return description;
     }
+
+    @Override
+    public boolean shouldRestart() {
+        return RegisterPressure.getValue() != null && !RegisterPressure.getValue().equals(ALL_REGISTERS);
+    }
+
+    @Override
+    public OverrideScope getOverrideScope() {
+        return OptionValue.override(RegisterPressure, ALL_REGISTERS);
+    }
+
+    @Override
+    public LIRSuites updateLIRSuites(LIRSuites lirSuites) {
+        return lirSuites;
+    }
 }