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changeset 8300:6a9a467e2e8b

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Merge
author Gilles Duboscq <duboscq@ssw.jku.at>
date Fri, 15 Mar 2013 17:26:52 +0100
parents 1774e72a60b3 (current diff) 22cab6e509a3 (diff)
children a1558c08d990
files graal/com.oracle.graal.compiler.amd64/src/com/oracle/graal/compiler/amd64/AMD64DeoptimizationStub.java graal/com.oracle.graal.compiler.ptx/src/com/oracle/graal/compiler/ptx/PTXDeoptimizationStub.java graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/GraalCompiler.java graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/gen/LIRGenerator.java graal/com.oracle.graal.lir.amd64/src/com/oracle/graal/lir/amd64/AMD64Code.java graal/com.oracle.graal.lir.ptx/src/com/oracle/graal/lir/ptx/PTXCode.java graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/spi/LIRGeneratorTool.java
diffstat 23 files changed, 170 insertions(+), 444 deletions(-) [+]
line wrap: on
line diff
--- a/graal/com.oracle.graal.compiler.amd64/src/com/oracle/graal/compiler/amd64/AMD64DeoptimizationStub.java	Fri Mar 15 16:57:43 2013 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,61 +0,0 @@
-/*
- * Copyright (c) 2011, 2012, 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.compiler.amd64;
-
-import com.oracle.graal.api.code.*;
-import com.oracle.graal.api.code.RuntimeCallTarget.*;
-import com.oracle.graal.api.meta.*;
-import com.oracle.graal.asm.*;
-import com.oracle.graal.asm.amd64.*;
-import com.oracle.graal.lir.*;
-import com.oracle.graal.lir.amd64.*;
-import com.oracle.graal.lir.asm.*;
-
-public class AMD64DeoptimizationStub extends AMD64Code {
-
-    public static final Descriptor DEOPTIMIZE = new Descriptor("deoptimize", true, void.class);
-
-    public final Label label = new Label();
-    public final LIRFrameState info;
-    public final DeoptimizationAction action;
-    public final DeoptimizationReason reason;
-
-    public AMD64DeoptimizationStub(DeoptimizationAction action, DeoptimizationReason reason, LIRFrameState info) {
-        this.action = action;
-        this.reason = reason;
-        this.info = info;
-    }
-
-    @Override
-    public void emitCode(TargetMethodAssembler tasm, AMD64MacroAssembler masm) {
-        Register scratch = tasm.frameMap.registerConfig.getScratchRegister();
-        masm.bind(label);
-        masm.movl(scratch, tasm.runtime.encodeDeoptActionAndReason(action, reason));
-        AMD64Call.directCall(tasm, masm, tasm.runtime.lookupRuntimeCall(DEOPTIMIZE), info);
-    }
-
-    @Override
-    public String description() {
-        return "deopt stub[reason=" + reason + ", action=" + action + "]";
-    }
-}
--- a/graal/com.oracle.graal.compiler.amd64/src/com/oracle/graal/compiler/amd64/AMD64LIRGenerator.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.compiler.amd64/src/com/oracle/graal/compiler/amd64/AMD64LIRGenerator.java	Fri Mar 15 17:26:52 2013 +0100
@@ -67,7 +67,6 @@
 import com.oracle.graal.lir.amd64.AMD64Move.MembarOp;
 import com.oracle.graal.lir.amd64.AMD64Move.MoveFromRegOp;
 import com.oracle.graal.lir.amd64.AMD64Move.MoveToRegOp;
-import com.oracle.graal.lir.amd64.AMD64Move.NullCheckOp;
 import com.oracle.graal.lir.amd64.AMD64Move.StackLeaOp;
 import com.oracle.graal.lir.amd64.AMD64Move.StoreConstantOp;
 import com.oracle.graal.lir.amd64.AMD64Move.StoreOp;
@@ -255,23 +254,23 @@
     }
 
     @Override
-    public void emitJump(LabelRef label, LIRFrameState info) {
-        append(new JumpOp(label, info));
+    public void emitJump(LabelRef label) {
+        append(new JumpOp(label));
     }
 
     @Override
-    public void emitCompareBranch(Value left, Value right, Condition cond, boolean unorderedIsTrue, LabelRef label, LIRFrameState info) {
+    public void emitCompareBranch(Value left, Value right, Condition cond, boolean unorderedIsTrue, LabelRef label) {
         boolean mirrored = emitCompare(left, right);
         Condition finalCondition = mirrored ? cond.mirror() : cond;
         switch (left.getKind().getStackKind()) {
             case Int:
             case Long:
             case Object:
-                append(new BranchOp(finalCondition, label, info));
+                append(new BranchOp(finalCondition, label));
                 break;
             case Float:
             case Double:
-                append(new FloatBranchOp(finalCondition, unorderedIsTrue, label, info));
+                append(new FloatBranchOp(finalCondition, unorderedIsTrue, label));
                 break;
             default:
                 throw GraalInternalError.shouldNotReachHere("" + left.getKind());
@@ -279,14 +278,14 @@
     }
 
     @Override
-    public void emitOverflowCheckBranch(LabelRef destination, LIRFrameState info, boolean negated) {
-        append(new BranchOp(negated ? ConditionFlag.NoOverflow : ConditionFlag.Overflow, destination, info));
+    public void emitOverflowCheckBranch(LabelRef destination, boolean negated) {
+        append(new BranchOp(negated ? ConditionFlag.NoOverflow : ConditionFlag.Overflow, destination));
     }
 
     @Override
-    public void emitIntegerTestBranch(Value left, Value right, boolean negated, LabelRef label, LIRFrameState info) {
+    public void emitIntegerTestBranch(Value left, Value right, boolean negated, LabelRef label) {
         emitIntegerTest(left, right);
-        append(new BranchOp(negated ? Condition.NE : Condition.EQ, label, info));
+        append(new BranchOp(negated ? Condition.NE : Condition.EQ, label));
     }
 
     @Override
@@ -773,13 +772,6 @@
     }
 
     @Override
-    public void emitDeoptimizeOnOverflow(DeoptimizationAction action, DeoptimizationReason reason) {
-        LIRFrameState info = state(reason);
-        LabelRef stubEntry = createDeoptStub(action, reason, info);
-        append(new BranchOp(ConditionFlag.Overflow, stubEntry, info));
-    }
-
-    @Override
     public void emitMembar(int barriers) {
         int necessaryBarriers = target.arch.requiredBarriers(barriers);
         if (target.isMP && necessaryBarriers != 0) {
@@ -899,29 +891,6 @@
     }
 
     @Override
-    protected LabelRef createDeoptStub(DeoptimizationAction action, DeoptimizationReason reason, LIRFrameState info) {
-        assert info.topFrame.getBCI() >= 0 : "invalid bci for deopt framestate";
-        AMD64DeoptimizationStub stub = new AMD64DeoptimizationStub(action, reason, info);
-        lir.stubs.add(stub);
-        return LabelRef.forLabel(stub.label);
-    }
-
-    @Override
-    public void emitGuardCheck(LogicNode comp, DeoptimizationReason deoptReason, DeoptimizationAction action, boolean negated) {
-        if (comp instanceof IsNullNode && negated) {
-            emitNullCheckGuard(((IsNullNode) comp).object());
-        } else {
-            super.emitGuardCheck(comp, deoptReason, action, negated);
-        }
-    }
-
-    private void emitNullCheckGuard(ValueNode object) {
-        Variable value = load(operand(object));
-        LIRFrameState info = state();
-        append(new NullCheckOp(value, info));
-    }
-
-    @Override
     public void visitCompareAndSwap(CompareAndSwapNode node) {
         Kind kind = node.newValue().kind();
         assert kind == node.expected().kind();
--- a/graal/com.oracle.graal.compiler.ptx/src/com/oracle/graal/compiler/ptx/PTXDeoptimizationStub.java	Fri Mar 15 16:57:43 2013 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,59 +0,0 @@
-/*
- * Copyright (c) 2013, 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.compiler.ptx;
-
-import com.oracle.graal.api.code.*;
-import com.oracle.graal.api.code.RuntimeCallTarget.*;
-import com.oracle.graal.api.meta.*;
-import com.oracle.graal.asm.*;
-import com.oracle.graal.asm.ptx.*;
-import com.oracle.graal.lir.*;
-import com.oracle.graal.lir.ptx.*;
-import com.oracle.graal.lir.asm.*;
-
-public class PTXDeoptimizationStub extends PTXCode {
-
-    public static final Descriptor DEOPTIMIZE = new Descriptor("deoptimize", true, void.class);
-    public static final Descriptor SET_DEOPT_INFO = new Descriptor("setDeoptInfo", true, void.class, Object.class);
-
-    public final Label label = new Label();
-    public final LIRFrameState info;
-    public final DeoptimizationAction action;
-    public final DeoptimizationReason reason;
-
-    public PTXDeoptimizationStub(DeoptimizationAction action, DeoptimizationReason reason, LIRFrameState info) {
-        this.action = action;
-        this.reason = reason;
-        this.info = info;
-    }
-
-    @Override
-    public void emitCode(TargetMethodAssembler tasm, PTXAssembler masm) {
-        masm.exit();
-    }
-
-    @Override
-    public String description() {
-        return "deopt stub[reason=" + reason + ", action=" + action + "]";
-    }
-}
--- a/graal/com.oracle.graal.compiler.ptx/src/com/oracle/graal/compiler/ptx/PTXLIRGenerator.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.compiler.ptx/src/com/oracle/graal/compiler/ptx/PTXLIRGenerator.java	Fri Mar 15 17:26:52 2013 +0100
@@ -179,20 +179,20 @@
     }
 
     @Override
-    public void emitJump(LabelRef label, LIRFrameState info) {
-        append(new JumpOp(label, info));
+    public void emitJump(LabelRef label) {
+        append(new JumpOp(label));
     }
 
     @Override
-    public void emitCompareBranch(Value left, Value right, Condition cond, boolean unorderedIsTrue, LabelRef label, LIRFrameState info) {
+    public void emitCompareBranch(Value left, Value right, Condition cond, boolean unorderedIsTrue, LabelRef label) {
         switch (left.getKind().getStackKind()) {
             case Int:
                 append(new CompareOp(ICMP, cond, left, right));
-                append(new BranchOp(cond, label, info));
+                append(new BranchOp(cond, label));
                 break;
             case Object:
                 append(new CompareOp(ACMP, cond, left, right));
-                append(new BranchOp(cond, label, info));
+                append(new BranchOp(cond, label));
                 break;
             default:
                 throw GraalInternalError.shouldNotReachHere("" + left.getKind());
@@ -200,12 +200,12 @@
     }
 
     @Override
-    public void emitOverflowCheckBranch(LabelRef label, LIRFrameState info, boolean negated) {
+    public void emitOverflowCheckBranch(LabelRef label, boolean negated) {
         throw new InternalError("NYI");
     }
 
     @Override
-    public void emitIntegerTestBranch(Value left, Value right, boolean negated, LabelRef label, LIRFrameState info) {
+    public void emitIntegerTestBranch(Value left, Value right, boolean negated, LabelRef label) {
         throw new InternalError("NYI");
     }
 
@@ -349,11 +349,6 @@
     }
 
     @Override
-    public void emitDeoptimizeOnOverflow(DeoptimizationAction action, DeoptimizationReason reason) {
-        throw new InternalError("NYI");
-    }
-
-    @Override
     public void emitDeoptimize(DeoptimizationAction action, DeoptimizationReason reason) {
         append(new ReturnOp(Value.ILLEGAL));
     }
@@ -453,14 +448,6 @@
     }
 
     @Override
-    protected LabelRef createDeoptStub(DeoptimizationAction action, DeoptimizationReason reason, LIRFrameState info) {
-        assert info.topFrame.getBCI() >= 0 : "invalid bci for deopt framestate";
-        PTXDeoptimizationStub stub = new PTXDeoptimizationStub(action, reason, info);
-        lir.stubs.add(stub);
-        return LabelRef.forLabel(stub.label);
-    }
-
-    @Override
     public void visitCompareAndSwap(CompareAndSwapNode node) {
         throw new InternalError("NYI");
     }
--- a/graal/com.oracle.graal.compiler.sparc/src/com/oracle/graal/compiler/sparc/SPARCLIRGenerator.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.compiler.sparc/src/com/oracle/graal/compiler/sparc/SPARCLIRGenerator.java	Fri Mar 15 17:26:52 2013 +0100
@@ -62,7 +62,7 @@
     }
 
     @Override
-    public void emitJump(LabelRef label, LIRFrameState info) {
+    public void emitJump(LabelRef label) {
         @SuppressWarnings("unused")
         SPARCLIRInstruction instruction = null;
         // SPARC: Auto-generated method stub
@@ -70,19 +70,19 @@
     }
 
     @Override
-    public void emitCompareBranch(Value left, Value right, Condition cond, boolean unorderedIsTrue, LabelRef label, LIRFrameState info) {
+    public void emitCompareBranch(Value left, Value right, Condition cond, boolean unorderedIsTrue, LabelRef label) {
         // SPARC: Auto-generated method stub
 
     }
 
     @Override
-    public void emitOverflowCheckBranch(LabelRef label, LIRFrameState info, boolean negated) {
+    public void emitOverflowCheckBranch(LabelRef label, boolean negated) {
         // SPARC: Auto-generated method stub
 
     }
 
     @Override
-    public void emitIntegerTestBranch(Value left, Value right, boolean negated, LabelRef label, LIRFrameState info) {
+    public void emitIntegerTestBranch(Value left, Value right, boolean negated, LabelRef label) {
         // SPARC: Auto-generated method stub
 
     }
@@ -118,12 +118,6 @@
     }
 
     @Override
-    protected LabelRef createDeoptStub(DeoptimizationAction action, DeoptimizationReason reason, LIRFrameState info) {
-        // SPARC: Auto-generated method stub
-        return null;
-    }
-
-    @Override
     protected void emitSequentialSwitch(Constant[] keyConstants, LabelRef[] keyTargets, LabelRef defaultTarget, Value key) {
         // SPARC: Auto-generated method stub
 
@@ -340,12 +334,6 @@
     }
 
     @Override
-    public void emitDeoptimizeOnOverflow(DeoptimizationAction action, DeoptimizationReason reason) {
-        // SPARC: Auto-generated method stub
-
-    }
-
-    @Override
     public void emitDeoptimize(DeoptimizationAction action, DeoptimizationReason reason) {
         // SPARC: Auto-generated method stub
 
--- a/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/GraalCompiler.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/GraalCompiler.java	Fri Mar 15 17:26:52 2013 +0100
@@ -204,7 +204,7 @@
 
         plan.runPhases(PhasePosition.LOW_LEVEL, graph);
 
-        new GuardLoweringPhase().apply(graph);
+        new GuardLoweringPhase(target).apply(graph);
 
         // Add safepoints to loops
         new SafepointInsertionPhase().apply(graph);
--- a/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/gen/LIRGenerator.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.compiler/src/com/oracle/graal/compiler/gen/LIRGenerator.java	Fri Mar 15 17:26:52 2013 +0100
@@ -350,27 +350,6 @@
         List<ScheduledNode> nodes = lir.nodesFor(block);
         for (int i = 0; i < nodes.size(); i++) {
             Node instr = nodes.get(i);
-
-            if (GraalOptions.OptImplicitNullChecks) {
-                Node nextInstr = null;
-                if (i < nodes.size() - 1) {
-                    nextInstr = nodes.get(i + 1);
-                }
-
-                if (instr instanceof GuardNode) {
-                    GuardNode guardNode = (GuardNode) instr;
-                    if (guardNode.condition() instanceof IsNullNode && guardNode.negated()) {
-                        IsNullNode isNullNode = (IsNullNode) guardNode.condition();
-                        if (nextInstr instanceof Access) {
-                            Access access = (Access) nextInstr;
-                            if (isNullNode.object() == access.object() && canBeNullCheck(access.location())) {
-                                access.setNullCheck(true);
-                                continue;
-                            }
-                        }
-                    }
-                }
-            }
             if (GraalOptions.TraceLIRGeneratorLevel >= 3) {
                 TTY.println("LIRGen for " + instr);
             }
@@ -411,7 +390,7 @@
             NodeClassIterable successors = block.getEndNode().successors();
             assert successors.isNotEmpty() : "should have at least one successor : " + block.getEndNode();
 
-            emitJump(getLIRBlock((FixedNode) successors.first()), null);
+            emitJump(getLIRBlock((FixedNode) successors.first()));
         }
 
         if (GraalOptions.TraceLIRGeneratorLevel >= 1) {
@@ -470,10 +449,6 @@
         ((LIRLowerable) node).generate(this);
     }
 
-    private boolean canBeNullCheck(LocationNode location) {
-        return !(location instanceof IndexedLocationNode) && location.displacement() < this.target().implicitNullCheckLimit;
-    }
-
     protected CallingConvention createCallingConvention() {
         return frameMap.registerConfig.getCallingConvention(JavaCallee, method.getSignature().getReturnType(null), MetaUtil.signatureToTypes(method), target, false);
     }
@@ -572,7 +547,7 @@
         }
         resolver.dispose();
 
-        append(new JumpOp(getLIRBlock(merge), null));
+        append(new JumpOp(getLIRBlock(merge)));
     }
 
     private Value operandForPhi(PhiNode phi) {
@@ -590,89 +565,46 @@
 
     @Override
     public void emitIf(IfNode x) {
-        emitBranch(x.condition(), getLIRBlock(x.trueSuccessor()), getLIRBlock(x.falseSuccessor()), null);
+        emitBranch(x.condition(), getLIRBlock(x.trueSuccessor()), getLIRBlock(x.falseSuccessor()));
     }
 
-    @Override
-    public void emitGuardCheck(LogicNode comp, DeoptimizationReason deoptReason, DeoptimizationAction action, boolean negated) {
-        if (comp instanceof LogicConstantNode && ((LogicConstantNode) comp).getValue() != negated) {
-            // True constant, nothing to emit.
-            // False constants are handled within emitBranch.
-        } else {
-            // Fall back to a normal branch.
-            LIRFrameState info = state(deoptReason);
-            LabelRef stubEntry = createDeoptStub(action, deoptReason, info);
-            if (negated) {
-                emitBranch(comp, stubEntry, null, info);
-            } else {
-                emitBranch(comp, null, stubEntry, info);
-            }
-        }
-    }
-
-    public void emitBranch(LogicNode node, LabelRef trueSuccessor, LabelRef falseSuccessor, LIRFrameState info) {
+    public void emitBranch(LogicNode node, LabelRef trueSuccessor, LabelRef falseSuccessor) {
         if (node instanceof IsNullNode) {
-            emitNullCheckBranch((IsNullNode) node, trueSuccessor, falseSuccessor, info);
+            emitNullCheckBranch((IsNullNode) node, trueSuccessor, falseSuccessor);
         } else if (node instanceof CompareNode) {
-            emitCompareBranch((CompareNode) node, trueSuccessor, falseSuccessor, info);
+            emitCompareBranch((CompareNode) node, trueSuccessor, falseSuccessor);
         } else if (node instanceof LogicConstantNode) {
-            emitConstantBranch(((LogicConstantNode) node).getValue(), trueSuccessor, falseSuccessor, info);
+            emitConstantBranch(((LogicConstantNode) node).getValue(), trueSuccessor, falseSuccessor);
         } else if (node instanceof IntegerTestNode) {
-            emitIntegerTestBranch((IntegerTestNode) node, trueSuccessor, falseSuccessor, info);
+            emitIntegerTestBranch((IntegerTestNode) node, trueSuccessor, falseSuccessor);
         } else {
             throw GraalInternalError.unimplemented(node.toString());
         }
     }
 
-    private void emitNullCheckBranch(IsNullNode node, LabelRef trueSuccessor, LabelRef falseSuccessor, LIRFrameState info) {
-        if (falseSuccessor != null) {
-            emitCompareBranch(operand(node.object()), Constant.NULL_OBJECT, Condition.NE, false, falseSuccessor, info);
-            if (trueSuccessor != null) {
-                emitJump(trueSuccessor, null);
-            }
-        } else {
-            emitCompareBranch(operand(node.object()), Constant.NULL_OBJECT, Condition.EQ, false, trueSuccessor, info);
-        }
+    private void emitNullCheckBranch(IsNullNode node, LabelRef trueSuccessor, LabelRef falseSuccessor) {
+        emitCompareBranch(operand(node.object()), Constant.NULL_OBJECT, Condition.NE, false, falseSuccessor);
+        emitJump(trueSuccessor);
     }
 
-    public void emitCompareBranch(CompareNode compare, LabelRef trueSuccessorBlock, LabelRef falseSuccessorBlock, LIRFrameState info) {
-        if (falseSuccessorBlock != null) {
-            emitCompareBranch(operand(compare.x()), operand(compare.y()), compare.condition().negate(), !compare.unorderedIsTrue(), falseSuccessorBlock, info);
-            if (trueSuccessorBlock != null) {
-                emitJump(trueSuccessorBlock, null);
-            }
-        } else {
-            emitCompareBranch(operand(compare.x()), operand(compare.y()), compare.condition(), compare.unorderedIsTrue(), trueSuccessorBlock, info);
-        }
+    public void emitCompareBranch(CompareNode compare, LabelRef trueSuccessorBlock, LabelRef falseSuccessorBlock) {
+        emitCompareBranch(operand(compare.x()), operand(compare.y()), compare.condition().negate(), !compare.unorderedIsTrue(), falseSuccessorBlock);
+        emitJump(trueSuccessorBlock);
     }
 
-    public void emitOverflowCheckBranch(LabelRef noOverflowBlock, LabelRef overflowBlock, LIRFrameState info) {
-        if (overflowBlock != null) {
-            emitOverflowCheckBranch(overflowBlock, info, false);
-            if (noOverflowBlock != null) {
-                emitJump(noOverflowBlock, null);
-            }
-        } else {
-            emitOverflowCheckBranch(noOverflowBlock, info, true);
-        }
+    public void emitOverflowCheckBranch(LabelRef noOverflowBlock, LabelRef overflowBlock) {
+        emitOverflowCheckBranch(overflowBlock, false);
+        emitJump(noOverflowBlock);
     }
 
-    public void emitIntegerTestBranch(IntegerTestNode test, LabelRef trueSuccessorBlock, LabelRef falseSuccessorBlock, LIRFrameState info) {
-        if (falseSuccessorBlock != null) {
-            emitIntegerTestBranch(operand(test.x()), operand(test.y()), true, falseSuccessorBlock, info);
-            if (trueSuccessorBlock != null) {
-                emitJump(trueSuccessorBlock, null);
-            }
-        } else {
-            emitIntegerTestBranch(operand(test.x()), operand(test.y()), false, trueSuccessorBlock, info);
-        }
+    public void emitIntegerTestBranch(IntegerTestNode test, LabelRef trueSuccessorBlock, LabelRef falseSuccessorBlock) {
+        emitIntegerTestBranch(operand(test.x()), operand(test.y()), true, falseSuccessorBlock);
+        emitJump(trueSuccessorBlock);
     }
 
-    public void emitConstantBranch(boolean value, LabelRef trueSuccessorBlock, LabelRef falseSuccessorBlock, LIRFrameState info) {
+    public void emitConstantBranch(boolean value, LabelRef trueSuccessorBlock, LabelRef falseSuccessorBlock) {
         LabelRef block = value ? trueSuccessorBlock : falseSuccessorBlock;
-        if (block != null) {
-            emitJump(block, info);
-        }
+        emitJump(block);
     }
 
     @Override
@@ -699,13 +631,13 @@
         }
     }
 
-    public abstract void emitJump(LabelRef label, LIRFrameState info);
+    public abstract void emitJump(LabelRef label);
 
-    public abstract void emitCompareBranch(Value left, Value right, Condition cond, boolean unorderedIsTrue, LabelRef label, LIRFrameState info);
+    public abstract void emitCompareBranch(Value left, Value right, Condition cond, boolean unorderedIsTrue, LabelRef label);
 
-    public abstract void emitOverflowCheckBranch(LabelRef label, LIRFrameState info, boolean negated);
+    public abstract void emitOverflowCheckBranch(LabelRef label, boolean negated);
 
-    public abstract void emitIntegerTestBranch(Value left, Value right, boolean negated, LabelRef label, LIRFrameState info);
+    public abstract void emitIntegerTestBranch(Value left, Value right, boolean negated, LabelRef label);
 
     public abstract Variable emitConditionalMove(Value leftVal, Value right, Condition cond, boolean unorderedIsTrue, Value trueValue, Value falseValue);
 
@@ -777,8 +709,6 @@
         return result;
     }
 
-    protected abstract LabelRef createDeoptStub(DeoptimizationAction action, DeoptimizationReason reason, LIRFrameState info);
-
     @Override
     public Variable emitCall(RuntimeCallTarget callTarget, CallingConvention cc, boolean canTrap, Value... args) {
         LIRFrameState info = canTrap ? state() : null;
@@ -847,7 +777,7 @@
     public void emitSwitch(SwitchNode x) {
         int keyCount = x.keyCount();
         if (keyCount == 0) {
-            emitJump(getLIRBlock(x.defaultSuccessor()), null);
+            emitJump(getLIRBlock(x.defaultSuccessor()));
         } else {
             Variable value = load(operand(x.value()));
             LabelRef defaultTarget = x.defaultSuccessor() == null ? null : getLIRBlock(x.defaultSuccessor());
@@ -859,7 +789,7 @@
                 long valueRange = x.keyAt(keyCount - 1).asLong() - x.keyAt(0).asLong() + 1;
                 int switchRangeCount = switchRangeCount(x);
                 if (switchRangeCount == 0) {
-                    emitJump(getLIRBlock(x.defaultSuccessor()), null);
+                    emitJump(getLIRBlock(x.defaultSuccessor()));
                 } else if (switchRangeCount >= GraalOptions.MinimumJumpTableSize && keyCount / (double) valueRange >= GraalOptions.MinTableSwitchDensity) {
                     int minValue = x.keyAt(0).asInt();
                     assert valueRange < Integer.MAX_VALUE;
--- a/graal/com.oracle.graal.lir.amd64/src/com/oracle/graal/lir/amd64/AMD64Code.java	Fri Mar 15 16:57:43 2013 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,40 +0,0 @@
-/*
- * Copyright (c) 2012, 2012, 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.amd64;
-
-import com.oracle.graal.asm.amd64.*;
-import com.oracle.graal.lir.*;
-import com.oracle.graal.lir.asm.*;
-
-/**
- * Convenience class to provide AMD64MacroAssembler for the {@link #emitCode} method.
- */
-public abstract class AMD64Code implements LIR.Code {
-
-    @Override
-    public final void emitCode(TargetMethodAssembler tasm) {
-        emitCode(tasm, (AMD64MacroAssembler) tasm.asm);
-    }
-
-    public abstract void emitCode(TargetMethodAssembler tasm, AMD64MacroAssembler masm);
-}
--- a/graal/com.oracle.graal.lir.amd64/src/com/oracle/graal/lir/amd64/AMD64ControlFlow.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.lir.amd64/src/com/oracle/graal/lir/amd64/AMD64ControlFlow.java	Fri Mar 15 17:26:52 2013 +0100
@@ -63,16 +63,14 @@
     public static class BranchOp extends AMD64LIRInstruction implements StandardOp.BranchOp {
         protected ConditionFlag condition;
         protected LabelRef destination;
-        @State protected LIRFrameState state;
 
-        public BranchOp(Condition condition, LabelRef destination, LIRFrameState info) {
-            this(intCond(condition), destination, info);
+        public BranchOp(Condition condition, LabelRef destination) {
+            this(intCond(condition), destination);
         }
 
-        public BranchOp(ConditionFlag condition, LabelRef destination, LIRFrameState state) {
+        public BranchOp(ConditionFlag condition, LabelRef destination) {
             this.condition = condition;
             this.destination = destination;
-            this.state = state;
         }
 
         @Override
@@ -96,8 +94,8 @@
     public static class FloatBranchOp extends BranchOp {
         protected boolean unorderedIsTrue;
 
-        public FloatBranchOp(Condition condition, boolean unorderedIsTrue, LabelRef destination, LIRFrameState info) {
-            super(floatCond(condition), destination, info);
+        public FloatBranchOp(Condition condition, boolean unorderedIsTrue, LabelRef destination) {
+            super(floatCond(condition), destination);
             this.unorderedIsTrue = unorderedIsTrue;
         }
 
--- a/graal/com.oracle.graal.lir.ptx/src/com/oracle/graal/lir/ptx/PTXCode.java	Fri Mar 15 16:57:43 2013 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,40 +0,0 @@
-/*
- * Copyright (c) 2013, 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.ptx;
-
-import com.oracle.graal.asm.ptx.*;
-import com.oracle.graal.lir.*;
-import com.oracle.graal.lir.asm.*;
-
-/**
- * Convenience class to provide PTXAssembler for the {@link #emitCode} method.
- */
-public abstract class PTXCode implements LIR.Code {
-
-    @Override
-    public final void emitCode(TargetMethodAssembler tasm) {
-        emitCode(tasm, (PTXAssembler) tasm.asm);
-    }
-
-    public abstract void emitCode(TargetMethodAssembler tasm, PTXAssembler masm);
-}
--- a/graal/com.oracle.graal.lir.ptx/src/com/oracle/graal/lir/ptx/PTXControlFlow.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.lir.ptx/src/com/oracle/graal/lir/ptx/PTXControlFlow.java	Fri Mar 15 17:26:52 2013 +0100
@@ -54,12 +54,10 @@
 
         protected Condition condition;
         protected LabelRef destination;
-        @State protected LIRFrameState state;
 
-        public BranchOp(Condition condition, LabelRef destination, LIRFrameState state) {
+        public BranchOp(Condition condition, LabelRef destination) {
             this.condition = condition;
             this.destination = destination;
-            this.state = state;
         }
 
         @Override
--- a/graal/com.oracle.graal.lir/src/com/oracle/graal/lir/LIR.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.lir/src/com/oracle/graal/lir/LIR.java	Fri Mar 15 17:26:52 2013 +0100
@@ -56,12 +56,6 @@
      */
     private final List<Block> codeEmittingOrder;
 
-    /**
-     * Various out-of-line stubs to be emitted near the end of the method after all other LIR code
-     * has been emitted.
-     */
-    public final List<Code> stubs;
-
     private int numVariables;
 
     public SpillMoveFactory spillMoveFactory;
@@ -78,19 +72,6 @@
     private final SpeculationLog speculationLog;
 
     /**
-     * An opaque chunk of machine code.
-     */
-    public interface Code {
-
-        void emitCode(TargetMethodAssembler tasm);
-
-        /**
-         * A description of this code stub useful for commenting the code in a disassembly.
-         */
-        String description();
-    }
-
-    /**
      * Creates a new LIR instance for the specified compilation.
      */
     public LIR(ControlFlowGraph cfg, BlockMap<List<ScheduledNode>> blockToNodesMap, List<Block> linearScanOrder, List<Block> codeEmittingOrder, SpeculationLog speculationLog) {
@@ -99,8 +80,6 @@
         this.codeEmittingOrder = codeEmittingOrder;
         this.linearScanOrder = linearScanOrder;
         this.lirInstructions = new BlockMap<>(cfg);
-
-        stubs = new ArrayList<>();
         this.speculationLog = speculationLog;
     }
 
@@ -167,11 +146,6 @@
         for (Block b : codeEmittingOrder()) {
             emitBlock(tasm, b);
         }
-
-        // generate code stubs
-        for (Code c : stubs) {
-            emitCodeStub(tasm, c);
-        }
     }
 
     private void emitBlock(TargetMethodAssembler tasm, Block block) {
@@ -202,13 +176,6 @@
         }
     }
 
-    private static void emitCodeStub(TargetMethodAssembler tasm, Code code) {
-        if (Debug.isDumpEnabled()) {
-            tasm.blockComment(String.format("code stub: %s", code.description()));
-        }
-        code.emitCode(tasm);
-    }
-
     public void setHasArgInCallerFrame() {
         hasArgInCallerFrame = true;
     }
--- a/graal/com.oracle.graal.lir/src/com/oracle/graal/lir/StandardOp.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.lir/src/com/oracle/graal/lir/StandardOp.java	Fri Mar 15 17:26:52 2013 +0100
@@ -80,11 +80,9 @@
     public static class JumpOp extends LIRInstruction {
 
         private final LabelRef destination;
-        @State protected LIRFrameState state;
 
-        public JumpOp(LabelRef destination, LIRFrameState state) {
+        public JumpOp(LabelRef destination) {
             this.destination = destination;
-            this.state = state;
         }
 
         @Override
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/FixedGuardNode.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/FixedGuardNode.java	Fri Mar 15 17:26:52 2013 +0100
@@ -29,7 +29,7 @@
 import com.oracle.graal.nodes.type.*;
 
 @NodeInfo(nameTemplate = "FixedGuard(!={p#negated}) {p#reason/s}")
-public final class FixedGuardNode extends FixedWithNextNode implements Simplifiable, Lowerable, LIRLowerable, Node.IterableNodeType, Negatable {
+public final class FixedGuardNode extends FixedWithNextNode implements Simplifiable, Lowerable, Node.IterableNodeType, Negatable {
 
     @Input private LogicNode condition;
     private final DeoptimizationReason reason;
@@ -79,11 +79,6 @@
     }
 
     @Override
-    public void generate(LIRGeneratorTool gen) {
-        gen.emitGuardCheck(condition, reason, action, negated);
-    }
-
-    @Override
     public void simplify(SimplifierTool tool) {
         if (condition instanceof LogicConstantNode) {
             LogicConstantNode c = (LogicConstantNode) condition;
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/FixedNode.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/FixedNode.java	Fri Mar 15 17:26:52 2013 +0100
@@ -22,6 +22,8 @@
  */
 package com.oracle.graal.nodes;
 
+import java.util.*;
+
 import com.oracle.graal.nodes.type.*;
 
 public abstract class FixedNode extends ValueNode {
@@ -32,6 +34,10 @@
         super(stamp);
     }
 
+    public FixedNode(Stamp stamp, List<ValueNode> dependencies) {
+        super(stamp, dependencies);
+    }
+
     public FixedNode(Stamp stamp, ValueNode... dependencies) {
         super(stamp, dependencies);
     }
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/FixedWithNextNode.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/FixedWithNextNode.java	Fri Mar 15 17:26:52 2013 +0100
@@ -22,6 +22,8 @@
  */
 package com.oracle.graal.nodes;
 
+import java.util.*;
+
 import com.oracle.graal.nodes.type.*;
 
 /**
@@ -43,6 +45,10 @@
         super(stamp);
     }
 
+    public FixedWithNextNode(Stamp stamp, List<ValueNode> dependencies) {
+        super(stamp, dependencies);
+    }
+
     public FixedWithNextNode(Stamp stamp, ValueNode... dependencies) {
         super(stamp, dependencies);
     }
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/GuardNode.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/GuardNode.java	Fri Mar 15 17:26:52 2013 +0100
@@ -42,7 +42,7 @@
  * control flow would have reached the guarded node (without taking exceptions into account).
  */
 @NodeInfo(nameTemplate = "Guard(!={p#negated}) {p#reason/s}")
-public final class GuardNode extends FloatingNode implements Canonicalizable, LIRLowerable, Node.IterableNodeType, Negatable {
+public final class GuardNode extends FloatingNode implements Canonicalizable, Node.IterableNodeType, Negatable {
 
     @Input private LogicNode condition;
     private final DeoptimizationReason reason;
@@ -91,11 +91,6 @@
     }
 
     @Override
-    public void generate(LIRGeneratorTool gen) {
-        gen.emitGuardCheck(condition(), reason(), action(), negated());
-    }
-
-    @Override
     public ValueNode canonical(CanonicalizerTool tool) {
         if (condition() instanceof LogicConstantNode) {
             LogicConstantNode c = (LogicConstantNode) condition();
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/ValueNode.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/ValueNode.java	Fri Mar 15 17:26:52 2013 +0100
@@ -28,7 +28,6 @@
 import com.oracle.graal.graph.*;
 import com.oracle.graal.graph.iterators.*;
 import com.oracle.graal.nodes.type.*;
-import com.oracle.graal.nodes.type.GenericStamp.*;
 import com.oracle.graal.nodes.util.*;
 
 /**
@@ -174,9 +173,6 @@
 
     @Override
     public boolean verify() {
-        for (ValueNode v : dependencies().nonNull()) {
-            assertTrue(!(v.stamp() instanceof GenericStamp) || ((GenericStamp) v.stamp()).type() == GenericStampType.Dependency, "cannot depend on node with stamp %s", v.stamp());
-        }
         assertTrue(kind() != null, "Should have a valid kind");
         assertTrue(kind() == kind().getStackKind(), "Should have a stack kind : %s", kind());
         return super.verify();
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/AccessNode.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/AccessNode.java	Fri Mar 15 17:26:52 2013 +0100
@@ -22,6 +22,8 @@
  */
 package com.oracle.graal.nodes.extended;
 
+import java.util.*;
+
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
 import com.oracle.graal.nodes.type.*;
@@ -58,6 +60,12 @@
         this.location = location;
     }
 
+    public AccessNode(ValueNode object, ValueNode location, Stamp stamp, List<ValueNode> dependencies) {
+        super(stamp, dependencies);
+        this.object = object;
+        this.location = location;
+    }
+
     public AccessNode(ValueNode object, ValueNode location, Stamp stamp, ValueNode... dependencies) {
         super(stamp, dependencies);
         this.object = object;
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ReadNode.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ReadNode.java	Fri Mar 15 17:26:52 2013 +0100
@@ -22,6 +22,8 @@
  */
 package com.oracle.graal.nodes.extended;
 
+import java.util.*;
+
 import com.oracle.graal.api.meta.*;
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
@@ -37,6 +39,10 @@
         super(object, location, stamp);
     }
 
+    public ReadNode(ValueNode object, ValueNode location, Stamp stamp, List<ValueNode> dependencies) {
+        super(object, location, stamp, dependencies);
+    }
+
     private ReadNode(ValueNode object, int displacement, Object locationIdentity, Kind kind) {
         super(object, object.graph().add(new LocationNode(locationIdentity, kind, displacement)), StampFactory.forKind(kind));
     }
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ValueAnchorNode.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/extended/ValueAnchorNode.java	Fri Mar 15 17:26:52 2013 +0100
@@ -64,7 +64,7 @@
                 return previousAnchor;
             }
         }
-        for (Node node : dependencies().nonNull().and(isNotA(BeginNode.class))) {
+        for (Node node : dependencies().nonNull().and(isNotA(FixedNode.class))) {
             if (node instanceof ConstantNode) {
                 continue;
             }
--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/spi/LIRGeneratorTool.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/spi/LIRGeneratorTool.java	Fri Mar 15 17:26:52 2013 +0100
@@ -97,8 +97,6 @@
 
     public abstract void emitMembar(int barriers);
 
-    public abstract void emitDeoptimizeOnOverflow(DeoptimizationAction action, DeoptimizationReason reason);
-
     public abstract void emitDeoptimize(DeoptimizationAction action, DeoptimizationReason reason);
 
     public abstract Value emitCall(RuntimeCallTarget callTarget, CallingConvention cc, boolean canTrap, Value... args);
@@ -107,8 +105,6 @@
 
     public abstract void emitConditional(ConditionalNode i);
 
-    public abstract void emitGuardCheck(LogicNode comp, DeoptimizationReason deoptReason, DeoptimizationAction deoptAction, boolean negated);
-
     public abstract void emitSwitch(SwitchNode i);
 
     public abstract void emitInvoke(Invoke i);
--- a/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/GuardLoweringPhase.java	Fri Mar 15 16:57:43 2013 +0100
+++ b/graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/GuardLoweringPhase.java	Fri Mar 15 17:26:52 2013 +0100
@@ -23,30 +23,47 @@
 package com.oracle.graal.phases.common;
 
 import java.util.*;
+import java.util.Map.Entry;
 
+import com.oracle.graal.api.code.*;
 import com.oracle.graal.graph.*;
 import com.oracle.graal.nodes.*;
+import com.oracle.graal.nodes.calc.*;
 import com.oracle.graal.nodes.cfg.*;
+import com.oracle.graal.nodes.extended.*;
+import com.oracle.graal.nodes.util.*;
 import com.oracle.graal.phases.*;
 import com.oracle.graal.phases.schedule.*;
 
 public class GuardLoweringPhase extends Phase {
 
+    private TargetDescription target;
+
+    public GuardLoweringPhase(TargetDescription target) {
+        this.target = target;
+    }
+
     @Override
     protected void run(StructuredGraph graph) {
         SchedulePhase schedule = new SchedulePhase();
         schedule.apply(graph);
 
         for (Block block : schedule.getCFG().getBlocks()) {
-            processBlock(block, schedule, graph);
+            processBlock(block, schedule, graph, target);
         }
     }
 
-    private static void processBlock(Block block, SchedulePhase schedule, StructuredGraph graph) {
+    private static void processBlock(Block block, SchedulePhase schedule, StructuredGraph graph, TargetDescription target) {
         List<ScheduledNode> nodes = schedule.nodesFor(block);
+        if (GraalOptions.OptImplicitNullChecks && target.implicitNullCheckLimit > 0) {
+            useImplicitNullChecks(block.getBeginNode(), nodes, graph, target);
+        }
         FixedWithNextNode lastFixed = block.getBeginNode();
         BeginNode lastFastPath = null;
         for (Node node : nodes) {
+            if (!node.isAlive()) {
+                continue;
+            }
             if (lastFastPath != null && node instanceof FixedNode) {
                 lastFastPath.setNext((FixedNode) node);
                 lastFastPath = null;
@@ -81,4 +98,70 @@
             }
         }
     }
+
+    private static void useImplicitNullChecks(BeginNode begin, List<ScheduledNode> nodes, StructuredGraph graph, TargetDescription target) {
+        ListIterator<ScheduledNode> iterator = nodes.listIterator();
+        IdentityHashMap<ValueNode, GuardNode> nullGuarded = new IdentityHashMap<>();
+        FixedWithNextNode lastFixed = begin;
+        FixedWithNextNode reconnect = null;
+        while (iterator.hasNext()) {
+            Node node = iterator.next();
+
+            if (reconnect != null && node instanceof FixedNode) {
+                reconnect.setNext((FixedNode) node);
+                reconnect = null;
+            }
+            if (node instanceof FixedWithNextNode) {
+                lastFixed = (FixedWithNextNode) node;
+            }
+
+            if (node instanceof GuardNode) {
+                GuardNode guard = (GuardNode) node;
+                if (guard.negated() && guard.condition() instanceof IsNullNode) {
+                    ValueNode obj = ((IsNullNode) guard.condition()).object();
+                    nullGuarded.put(obj, guard);
+                }
+            } else if (node instanceof Access) {
+                Access access = (Access) node;
+                GuardNode guard = nullGuarded.get(access.object());
+                if (guard != null && isImplicitNullCheck(access.location(), target)) {
+                    NodeInputList<ValueNode> dependencies = ((ValueNode) access).dependencies();
+                    dependencies.remove(guard);
+                    if (access instanceof FloatingReadNode) {
+                        ReadNode read = graph.add(new ReadNode(access.object(), access.location(), ((FloatingReadNode) access).stamp(), dependencies));
+                        node.replaceAndDelete(read);
+                        access = read;
+                        lastFixed.setNext(read);
+                        lastFixed = read;
+                        reconnect = read;
+                        iterator.set(read);
+                    }
+                    assert access instanceof AccessNode;
+                    access.setNullCheck(true);
+                    LogicNode condition = guard.condition();
+                    guard.replaceAndDelete(access.node());
+                    if (condition.usages().isEmpty()) {
+                        GraphUtil.killWithUnusedFloatingInputs(condition);
+                    }
+                    nullGuarded.remove(access.object());
+                }
+            }
+            if (node instanceof StateSplit && ((StateSplit) node).stateAfter() != null) {
+                nullGuarded.clear();
+            } else {
+                Iterator<Entry<ValueNode, GuardNode>> it = nullGuarded.entrySet().iterator();
+                while (it.hasNext()) {
+                    Entry<ValueNode, GuardNode> entry = it.next();
+                    GuardNode guard = entry.getValue();
+                    if (guard.usages().contains(node)) {
+                        it.remove();
+                    }
+                }
+            }
+        }
+    }
+
+    private static boolean isImplicitNullCheck(LocationNode location, TargetDescription target) {
+        return !(location instanceof IndexedLocationNode) && location.displacement() < target.implicitNullCheckLimit;
+    }
 }