Replace LinkedList by IntrusiveList to avoid allocations on JIT (#931)

* Replace LinkedList by IntrusiveList to avoid allocations on JIT

* Fix wrong replacements

ARMeilleure/CodeGen/Optimizations/Optimizer.cs

@@ -16,17 +16,17 @@ namespace ARMeilleure.CodeGen.Optimizations
             {
                 modified = false;
 
-                foreach (BasicBlock block in cfg.Blocks)
+                for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
                 {
-                    LinkedListNode<Node> node = block.Operations.First;
+                    Node node = block.Operations.First;
 
                     while (node != null)
                     {
-                        LinkedListNode<Node> nextNode = node.Next;
+                        Node nextNode = node.ListNext;
 
-                        bool isUnused = IsUnused(node.Value);
+                        bool isUnused = IsUnused(node);
 
-                        if (!(node.Value is Operation operation) || isUnused)
+                        if (!(node is Operation operation) || isUnused)
                         {
                             if (isUnused)
                             {
@@ -80,13 +80,11 @@ namespace ARMeilleure.CodeGen.Optimizations
             }
         }
 
-        private static void RemoveNode(BasicBlock block, LinkedListNode<Node> llNode)
+        private static void RemoveNode(BasicBlock block, Node node)
         {
             // Remove a node from the nodes list, and also remove itself
             // from all the use lists on the operands that this node uses.
-            block.Operations.Remove(llNode);
+            block.Operations.Remove(node);
-
-            Node node = llNode.Value;
 
             for (int index = 0; index < node.SourcesCount; index++)
             {

ARMeilleure/CodeGen/RegisterAllocators/HybridAllocator.cs

@@ -95,7 +95,7 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
 
                 bool hasCall = false;
 
-                foreach (Node node in block.Operations)
+                for (Node node = block.Operations.First; node != null; node = node.ListNext)
                 {
                     if (node is Operation operation && operation.Instruction == Instruction.Call)
                     {
@@ -176,10 +176,8 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
                 intLocalFreeRegisters &= ~(intSpillTempRegisters | intCallerSavedRegisters);
                 vecLocalFreeRegisters &= ~(vecSpillTempRegisters | vecCallerSavedRegisters);
 
-                for (LinkedListNode<Node> llNode = block.Operations.First; llNode != null; llNode = llNode.Next)
+                for (Node node = block.Operations.First; node != null; node = node.ListNext)
                 {
-                    Node node = llNode.Value;
-
                     int intLocalUse = 0;
                     int vecLocalUse = 0;
 
@@ -232,7 +230,7 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
 
                             Operation fillOp = new Operation(Instruction.Fill, temp, Const(info.SpillOffset));
 
-                            block.Operations.AddBefore(llNode, fillOp);
+                            block.Operations.AddBefore(node, fillOp);
                         }
                     }
 
@@ -306,7 +304,9 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
 
                             Operation spillOp = new Operation(Instruction.Spill, null, Const(info.SpillOffset), temp);
 
-                            llNode = block.Operations.AddAfter(llNode, spillOp);
+                            block.Operations.AddAfter(node, spillOp);
+
+                            node = spillOp;
                         }
                     }
 

ARMeilleure/CodeGen/RegisterAllocators/LinearScanAllocator.cs

@@ -28,7 +28,7 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
 
         private LiveInterval[] _parentIntervals;
 
-        private List<LinkedListNode<Node>> _operationNodes;
+        private List<(IntrusiveList<Node>, Node)> _operationNodes;
 
         private int _operationsCount;
 
@@ -583,15 +583,19 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
 
                 int splitPosition = kv.Key;
 
-                LinkedListNode<Node> node = GetOperationNode(splitPosition);
+                (IntrusiveList<Node> nodes, Node node) = GetOperationNode(splitPosition);
 
                 Operation[] sequence = copyResolver.Sequence();
 
-                node = node.List.AddBefore(node, sequence[0]);
+                nodes.AddBefore(node, sequence[0]);
+
+                node = sequence[0];
 
                 for (int index = 1; index < sequence.Length; index++)
                 {
-                    node = node.List.AddAfter(node, sequence[index]);
+                    nodes.AddAfter(node, sequence[index]);
+
+                    node = sequence[index];
                 }
             }
         }
@@ -605,10 +609,8 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
                 return block.Index >= blocksCount;
             }
 
-            for (LinkedListNode<BasicBlock> node = cfg.Blocks.First; node != null; node = node.Next)
+            for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
             {
-                BasicBlock block = node.Value;
-
                 if (IsSplitEdgeBlock(block))
                 {
                     continue;
@@ -666,13 +668,17 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
                     }
                     else if (successor.Predecessors.Count == 1)
                     {
-                        LinkedListNode<Node> prependNode = successor.Operations.AddFirst(sequence[0]);
+                        successor.Operations.AddFirst(sequence[0]);
+
+                        Node prependNode = sequence[0];
 
                         for (int index = 1; index < sequence.Length; index++)
                         {
                             Operation operation = sequence[index];
 
-                            prependNode = successor.Operations.AddAfter(prependNode, operation);
+                            successor.Operations.AddAfter(prependNode, operation);
+
+                            prependNode = operation;
                         }
                     }
                     else
@@ -695,7 +701,7 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
 
             foreach (int usePosition in current.UsePositions())
             {
-                Node operation = GetOperationNode(usePosition).Value;
+                (_, Node operation) = GetOperationNode(usePosition);
 
                 for (int index = 0; index < operation.SourcesCount; index++)
                 {
@@ -729,14 +735,14 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
                 interval.Local.Type);
         }
 
-        private LinkedListNode<Node> GetOperationNode(int position)
+        private (IntrusiveList<Node>, Node) GetOperationNode(int position)
         {
             return _operationNodes[position / InstructionGap];
         }
 
         private void NumberLocals(ControlFlowGraph cfg)
         {
-            _operationNodes = new List<LinkedListNode<Node>>();
+            _operationNodes = new List<(IntrusiveList<Node>, Node)>();
 
             _intervals = new List<LiveInterval>();
 
@@ -754,13 +760,11 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
             {
                 BasicBlock block = cfg.PostOrderBlocks[index];
 
-                for (LinkedListNode<Node> node = block.Operations.First; node != null; node = node.Next)
+                for (Node node = block.Operations.First; node != null; node = node.ListNext)
                 {
-                    _operationNodes.Add(node);
+                    _operationNodes.Add((block.Operations, node));
 
-                    Node operation = node.Value;
+                    foreach (Operand dest in Destinations(node))
-
-                    foreach (Operand dest in Destinations(operation))
                     {
                         if (dest.Kind == OperandKind.LocalVariable && visited.Add(dest))
                         {
@@ -776,7 +780,7 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
                 if (block.Operations.Count == 0)
                 {
                     // Pretend we have a dummy instruction on the empty block.
-                    _operationNodes.Add(null);
+                    _operationNodes.Add((null, null));
 
                     _operationsCount += InstructionGap;
                 }
@@ -795,12 +799,12 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
             BitMap[] blkLiveKill = new BitMap[cfg.Blocks.Count];
 
             // Compute local live sets.
-            foreach (BasicBlock block in cfg.Blocks)
+            for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
             {
                 BitMap liveGen  = new BitMap(mapSize);
                 BitMap liveKill = new BitMap(mapSize);
 
-                foreach (Node node in block.Operations)
+                for (Node node = block.Operations.First; node != null; node = node.ListNext)
                 {
                     foreach (Operand source in Sources(node))
                     {
@@ -979,13 +983,13 @@ namespace ARMeilleure.CodeGen.RegisterAllocators
 
         private static IEnumerable<Node> BottomOperations(BasicBlock block)
         {
-            LinkedListNode<Node> node = block.Operations.Last;
+            Node node = block.Operations.Last;
 
-            while (node != null && !(node.Value is PhiNode))
+            while (node != null && !(node is PhiNode))
             {
-                yield return node.Value;
+                yield return node;
 
-                node = node.Previous;
+                node = node.ListPrevious;
             }
         }
 

ARMeilleure/CodeGen/X86/CodeGenerator.cs

@@ -157,11 +157,11 @@ namespace ARMeilleure.CodeGen.X86
 
                 UnwindInfo unwindInfo = WritePrologue(context);
 
-                foreach (BasicBlock block in cfg.Blocks)
+                for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
                 {
                     context.EnterBlock(block);
 
-                    foreach (Node node in block.Operations)
+                    for (Node node = block.Operations.First; node != null; node = node.ListNext)
                     {
                         if (node is Operation operation)
                         {

ARMeilleure/CodeGen/X86/PreAllocator.cs

@@ -8,8 +8,6 @@ using static ARMeilleure.IntermediateRepresentation.OperandHelper;
 
 namespace ARMeilleure.CodeGen.X86
 {
-    using LLNode = LinkedListNode<Node>;
-
     static class PreAllocator
     {
         public static void RunPass(CompilerContext cctx, StackAllocator stackAlloc, out int maxCallArgs)
@@ -20,24 +18,24 @@ namespace ARMeilleure.CodeGen.X86
 
             Operand[] preservedArgs = new Operand[CallingConvention.GetArgumentsOnRegsCount()];
 
-            foreach (BasicBlock block in cctx.Cfg.Blocks)
+            for (BasicBlock block = cctx.Cfg.Blocks.First; block != null; block = block.ListNext)
             {
-                LLNode nextNode;
+                Node nextNode;
 
-                for (LLNode node = block.Operations.First; node != null; node = nextNode)
+                for (Node node = block.Operations.First; node != null; node = nextNode)
                 {
-                    nextNode = node.Next;
+                    nextNode = node.ListNext;
 
-                    if (!(node.Value is Operation operation))
+                    if (!(node is Operation operation))
                     {
                         continue;
                     }
 
-                    HandleConstantCopy(node, operation);
+                    HandleConstantCopy(block.Operations, node, operation);
 
-                    HandleSameDestSrc1Copy(node, operation);
+                    HandleSameDestSrc1Copy(block.Operations, node, operation);
 
-                    HandleFixedRegisterCopy(node, operation);
+                    HandleFixedRegisterCopy(block.Operations, node, operation);
 
                     switch (operation.Instruction)
                     {
@@ -62,51 +60,51 @@ namespace ARMeilleure.CodeGen.X86
                             // being called, as mandated by the ABI.
                             if (callConv == CallConvName.Windows)
                             {
-                                node = HandleCallWindowsAbi(stackAlloc, node, operation);
+                                node = HandleCallWindowsAbi(block.Operations, stackAlloc, node, operation);
                             }
                             else /* if (callConv == CallConvName.SystemV) */
                             {
-                                node = HandleCallSystemVAbi(node, operation);
+                                node = HandleCallSystemVAbi(block.Operations, node, operation);
                             }
                             break;
 
                         case Instruction.ConvertToFPUI:
-                            HandleConvertToFPUI(node, operation);
+                            HandleConvertToFPUI(block.Operations, node, operation);
                             break;
 
                         case Instruction.LoadArgument:
                             if (callConv == CallConvName.Windows)
                             {
-                                HandleLoadArgumentWindowsAbi(cctx, node, preservedArgs, operation);
+                                HandleLoadArgumentWindowsAbi(cctx, block.Operations, node, preservedArgs, operation);
                             }
                             else /* if (callConv == CallConvName.SystemV) */
                             {
-                                HandleLoadArgumentSystemVAbi(cctx, node, preservedArgs, operation);
+                                HandleLoadArgumentSystemVAbi(cctx, block.Operations, node, preservedArgs, operation);
                             }
                             break;
 
                         case Instruction.Negate:
                             if (!operation.GetSource(0).Type.IsInteger())
                             {
-                                node = HandleNegate(node, operation);
+                                node = HandleNegate(block.Operations, node, operation);
                             }
                             break;
 
                         case Instruction.Return:
                             if (callConv == CallConvName.Windows)
                             {
-                                HandleReturnWindowsAbi(cctx, node, preservedArgs, operation);
+                                HandleReturnWindowsAbi(cctx, block.Operations, node, preservedArgs, operation);
                             }
                             else /* if (callConv == CallConvName.SystemV) */
                             {
-                                HandleReturnSystemVAbi(node, operation);
+                                HandleReturnSystemVAbi(block.Operations, node, operation);
                             }
                             break;
 
                         case Instruction.VectorInsert8:
                             if (!HardwareCapabilities.SupportsSse41)
                             {
-                                node = HandleVectorInsert8(node, operation);
+                                node = HandleVectorInsert8(block.Operations, node, operation);
                             }
                             break;
                     }
@@ -114,7 +112,7 @@ namespace ARMeilleure.CodeGen.X86
             }
         }
 
-        private static void HandleConstantCopy(LLNode node, Operation operation)
+        private static void HandleConstantCopy(IntrusiveList<Node> nodes, Node node, Operation operation)
         {
             if (operation.SourcesCount == 0 || IsIntrinsic(operation.Instruction))
             {
@@ -135,7 +133,7 @@ namespace ARMeilleure.CodeGen.X86
                     // - Insert a copy with the constant value (as integer) to a GPR.
                     // - Insert a copy from the GPR to a XMM register.
                     // - Replace the constant use with the XMM register.
-                    src1 = AddXmmCopy(node, src1);
+                    src1 = AddXmmCopy(nodes, node, src1);
 
                     operation.SetSource(0, src1);
                 }
@@ -164,7 +162,7 @@ namespace ARMeilleure.CodeGen.X86
 
                     if (src1.Kind == OperandKind.Constant)
                     {
-                        src1 = AddCopy(node, src1);
+                        src1 = AddCopy(nodes, node, src1);
 
                         operation.SetSource(0, src1);
                     }
@@ -182,25 +180,23 @@ namespace ARMeilleure.CodeGen.X86
             {
                 if (!src2.Type.IsInteger())
                 {
-                    src2 = AddXmmCopy(node, src2);
+                    src2 = AddXmmCopy(nodes, node, src2);
 
                     operation.SetSource(1, src2);
                 }
                 else if (!HasConstSrc2(inst) || IsLongConst(src2))
                 {
-                    src2 = AddCopy(node, src2);
+                    src2 = AddCopy(nodes, node, src2);
 
                     operation.SetSource(1, src2);
                 }
             }
         }
 
-        private static LLNode HandleFixedRegisterCopy(LLNode node, Operation operation)
+        private static Node HandleFixedRegisterCopy(IntrusiveList<Node> nodes, Node node, Operation operation)
         {
             Operand dest = operation.Destination;
 
-            LinkedList<Node> nodes = node.List;
-
             switch (operation.Instruction)
             {
                 case Instruction.CompareAndSwap128:
@@ -359,7 +355,7 @@ namespace ARMeilleure.CodeGen.X86
             return node;
         }
 
-        private static LLNode HandleSameDestSrc1Copy(LLNode node, Operation operation)
+        private static Node HandleSameDestSrc1Copy(IntrusiveList<Node> nodes, Node node, Operation operation)
         {
             if (operation.Destination == null || operation.SourcesCount == 0)
             {
@@ -371,8 +367,6 @@ namespace ARMeilleure.CodeGen.X86
             Operand dest = operation.Destination;
             Operand src1 = operation.GetSource(0);
 
-            LinkedList<Node> nodes = node.List;
-
             // The multiply instruction (that maps to IMUL) is somewhat special, it has
             // a three operand form where the second source is a immediate value.
             bool threeOperandForm = inst == Instruction.Multiply && operation.GetSource(1).Kind == OperandKind.Constant;
@@ -441,7 +435,7 @@ namespace ARMeilleure.CodeGen.X86
             return node;
         }
 
-        private static LLNode HandleConvertToFPUI(LLNode node, Operation operation)
+        private static Node HandleConvertToFPUI(IntrusiveList<Node> nodes, Node node, Operation operation)
         {
             // Unsigned integer to FP conversions are not supported on X86.
             // We need to turn them into signed integer to FP conversions, and
@@ -451,9 +445,7 @@ namespace ARMeilleure.CodeGen.X86
 
             Debug.Assert(source.Type.IsInteger(), $"Invalid source type \"{source.Type}\".");
 
-            LinkedList<Node> nodes = node.List;
+            Node currentNode = node;
-
-            LLNode currentNode = node;
 
             if (source.Type == OperandType.I32)
             {
@@ -494,12 +486,12 @@ namespace ARMeilleure.CodeGen.X86
                 node = nodes.AddAfter(node, new Operation(Instruction.Add, dest, dest, lsbF));
             }
 
-            Delete(currentNode, operation);
+            Delete(nodes, currentNode, operation);
 
             return node;
         }
 
-        private static LLNode HandleNegate(LLNode node, Operation operation)
+        private static Node HandleNegate(IntrusiveList<Node> nodes, Node node, Operation operation)
         {
             // There's no SSE FP negate instruction, so we need to transform that into
             // a XOR of the value to be negated with a mask with the highest bit set.
@@ -510,9 +502,7 @@ namespace ARMeilleure.CodeGen.X86
             Debug.Assert(dest.Type == OperandType.FP32 ||
                          dest.Type == OperandType.FP64, $"Invalid destination type \"{dest.Type}\".");
 
-            LinkedList<Node> nodes = node.List;
+            Node currentNode = node;
-
-            LLNode currentNode = node;
 
             Operand res = Local(dest.Type);
 
@@ -531,12 +521,12 @@ namespace ARMeilleure.CodeGen.X86
 
             node = nodes.AddAfter(node, new Operation(Instruction.Copy, dest, res));
 
-            Delete(currentNode, operation);
+            Delete(nodes, currentNode, operation);
 
             return node;
         }
 
-        private static LLNode HandleVectorInsert8(LLNode node, Operation operation)
+        private static Node HandleVectorInsert8(IntrusiveList<Node> nodes, Node node, Operation operation)
         {
             // Handle vector insertion, when SSE 4.1 is not supported.
             Operand dest = operation.Destination;
@@ -550,9 +540,7 @@ namespace ARMeilleure.CodeGen.X86
 
             Debug.Assert(index < 16);
 
-            LinkedList<Node> nodes = node.List;
+            Node currentNode = node;
-
-            LLNode currentNode = node;
 
             Operand temp1 = Local(OperandType.I32);
             Operand temp2 = Local(OperandType.I32);
@@ -580,17 +568,15 @@ namespace ARMeilleure.CodeGen.X86
 
             node = nodes.AddAfter(node, vinsOp);
 
-            Delete(currentNode, operation);
+            Delete(nodes, currentNode, operation);
 
             return node;
         }
 
-        private static LLNode HandleCallWindowsAbi(StackAllocator stackAlloc, LLNode node, Operation operation)
+        private static Node HandleCallWindowsAbi(IntrusiveList<Node> nodes, StackAllocator stackAlloc, Node node, Operation operation)
         {
             Operand dest = operation.Destination;
 
-            LinkedList<Node> nodes = node.List;
-
             // Handle struct arguments.
             int retArgs = 0;
 
@@ -661,7 +647,7 @@ namespace ARMeilleure.CodeGen.X86
 
                     Operation storeOp = new Operation(Instruction.Store, null, stackAddr, source);
 
-                    HandleConstantCopy(nodes.AddBefore(node, storeOp), storeOp);
+                    HandleConstantCopy(nodes, nodes.AddBefore(node, storeOp), storeOp);
 
                     operation.SetSource(index, stackAddr);
                 }
@@ -687,7 +673,7 @@ namespace ARMeilleure.CodeGen.X86
 
                 Operation copyOp = new Operation(Instruction.Copy, argReg, source);
 
-                HandleConstantCopy(nodes.AddBefore(node, copyOp), copyOp);
+                HandleConstantCopy(nodes, nodes.AddBefore(node, copyOp), copyOp);
 
                 sources[1 + retArgs + index] = argReg;
             }
@@ -702,7 +688,7 @@ namespace ARMeilleure.CodeGen.X86
 
                 Operation spillOp = new Operation(Instruction.SpillArg, null, offset, source);
 
-                HandleConstantCopy(nodes.AddBefore(node, spillOp), spillOp);
+                HandleConstantCopy(nodes, nodes.AddBefore(node, spillOp), spillOp);
             }
 
             if (dest != null)
@@ -738,15 +724,14 @@ namespace ARMeilleure.CodeGen.X86
             return node;
         }
 
-        private static LLNode HandleCallSystemVAbi(LLNode node, Operation operation)
+        private static Node HandleCallSystemVAbi(IntrusiveList<Node> nodes, Node node, Operation operation)
         {
             Operand dest = operation.Destination;
 
-            LinkedList<Node> nodes = node.List;
+            List<Operand> sources = new List<Operand>
-
+            {
-            List<Operand> sources = new List<Operand>();
+                operation.GetSource(0)
-
+            };
-            sources.Add(operation.GetSource(0));
 
             int argsCount = operation.SourcesCount - 1;
 
@@ -797,7 +782,7 @@ namespace ARMeilleure.CodeGen.X86
 
                     Operation copyOp = new Operation(Instruction.Copy, argReg, source);
 
-                    HandleConstantCopy(nodes.AddBefore(node, copyOp), copyOp);
+                    HandleConstantCopy(nodes, nodes.AddBefore(node, copyOp), copyOp);
 
                     sources.Add(argReg);
                 }
@@ -807,7 +792,7 @@ namespace ARMeilleure.CodeGen.X86
 
                     Operation spillOp = new Operation(Instruction.SpillArg, null, offset, source);
 
-                    HandleConstantCopy(nodes.AddBefore(node, spillOp), spillOp);
+                    HandleConstantCopy(nodes, nodes.AddBefore(node, spillOp), spillOp);
 
                     stackOffset += source.Type.GetSizeInBytes();
                 }
@@ -846,7 +831,8 @@ namespace ARMeilleure.CodeGen.X86
 
         private static void HandleLoadArgumentWindowsAbi(
             CompilerContext cctx,
-            LLNode node,
+            IntrusiveList<Node> nodes,
+            Node node,
             Operand[] preservedArgs,
             Operation operation)
         {
@@ -896,9 +882,9 @@ namespace ARMeilleure.CodeGen.X86
                     ? Instruction.Load
                     : Instruction.Copy, dest, preservedArgs[index]);
 
-                node.List.AddBefore(node, argCopyOp);
+                nodes.AddBefore(node, argCopyOp);
 
-                Delete(node, operation);
+                Delete(nodes, node, operation);
             }
             else
             {
@@ -908,7 +894,8 @@ namespace ARMeilleure.CodeGen.X86
 
         private static void HandleLoadArgumentSystemVAbi(
             CompilerContext cctx,
-            LLNode node,
+            IntrusiveList<Node> nodes,
+            Node node,
             Operand[] preservedArgs,
             Operation operation)
         {
@@ -994,9 +981,9 @@ namespace ARMeilleure.CodeGen.X86
 
                 Operation argCopyOp = new Operation(Instruction.Copy, dest, preservedArgs[index]);
 
-                node.List.AddBefore(node, argCopyOp);
+                nodes.AddBefore(node, argCopyOp);
 
-                Delete(node, operation);
+                Delete(nodes, node, operation);
             }
             else
             {
@@ -1006,7 +993,8 @@ namespace ARMeilleure.CodeGen.X86
 
         private static void HandleReturnWindowsAbi(
             CompilerContext cctx,
-            LLNode node,
+            IntrusiveList<Node> nodes,
+            Node node,
             Operand[] preservedArgs,
             Operation operation)
         {
@@ -1049,19 +1037,19 @@ namespace ARMeilleure.CodeGen.X86
             {
                 Operation retStoreOp = new Operation(Instruction.Store, null, retReg, source);
 
-                node.List.AddBefore(node, retStoreOp);
+                nodes.AddBefore(node, retStoreOp);
             }
             else
             {
                 Operation retCopyOp = new Operation(Instruction.Copy, retReg, source);
 
-                node.List.AddBefore(node, retCopyOp);
+                nodes.AddBefore(node, retCopyOp);
             }
 
             operation.SetSources(new Operand[0]);
         }
 
-        private static void HandleReturnSystemVAbi(LLNode node, Operation operation)
+        private static void HandleReturnSystemVAbi(IntrusiveList<Node> nodes, Node node, Operation operation)
         {
             if (operation.SourcesCount == 0)
             {
@@ -1075,8 +1063,8 @@ namespace ARMeilleure.CodeGen.X86
                 Operand retLReg = Gpr(CallingConvention.GetIntReturnRegister(),     OperandType.I64);
                 Operand retHReg = Gpr(CallingConvention.GetIntReturnRegisterHigh(), OperandType.I64);
 
-                node.List.AddBefore(node, new Operation(Instruction.VectorExtract, retLReg, source, Const(0)));
+                nodes.AddBefore(node, new Operation(Instruction.VectorExtract, retLReg, source, Const(0)));
-                node.List.AddBefore(node, new Operation(Instruction.VectorExtract, retHReg, source, Const(1)));
+                nodes.AddBefore(node, new Operation(Instruction.VectorExtract, retHReg, source, Const(1)));
             }
             else
             {
@@ -1086,30 +1074,30 @@ namespace ARMeilleure.CodeGen.X86
 
                 Operation retCopyOp = new Operation(Instruction.Copy, retReg, source);
 
-                node.List.AddBefore(node, retCopyOp);
+                nodes.AddBefore(node, retCopyOp);
             }
         }
 
-        private static Operand AddXmmCopy(LLNode node, Operand source)
+        private static Operand AddXmmCopy(IntrusiveList<Node> nodes, Node node, Operand source)
         {
             Operand temp = Local(source.Type);
 
-            Operand intConst = AddCopy(node, GetIntConst(source));
+            Operand intConst = AddCopy(nodes, node, GetIntConst(source));
 
             Operation copyOp = new Operation(Instruction.VectorCreateScalar, temp, intConst);
 
-            node.List.AddBefore(node, copyOp);
+            nodes.AddBefore(node, copyOp);
 
             return temp;
         }
 
-        private static Operand AddCopy(LLNode node, Operand source)
+        private static Operand AddCopy(IntrusiveList<Node> nodes, Node node, Operand source)
         {
             Operand temp = Local(source.Type);
 
             Operation copyOp = new Operation(Instruction.Copy, temp, source);
 
-            node.List.AddBefore(node, copyOp);
+            nodes.AddBefore(node, copyOp);
 
             return temp;
         }
@@ -1142,7 +1130,7 @@ namespace ARMeilleure.CodeGen.X86
             return value == (int)value;
         }
 
-        private static void Delete(LLNode node, Operation operation)
+        private static void Delete(IntrusiveList<Node> nodes, Node node, Operation operation)
         {
             operation.Destination = null;
 
@@ -1151,7 +1139,7 @@ namespace ARMeilleure.CodeGen.X86
                 operation.SetSource(index, null);
             }
 
-            node.List.Remove(node);
+            nodes.Remove(node);
         }
 
         private static Operand Gpr(X86Register register, OperandType type)

ARMeilleure/Diagnostics/IRDumper.cs

@@ -35,7 +35,7 @@ namespace ARMeilleure.Diagnostics
 
             IncreaseIndentation();
 
-            foreach (BasicBlock block in cfg.Blocks)
+            for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
             {
                 string blockName = GetBlockName(block);
 
@@ -55,7 +55,7 @@ namespace ARMeilleure.Diagnostics
 
                 IncreaseIndentation();
 
-                foreach (Node node in block.Operations)
+                for (Node node = block.Operations.First; node != null; node = node.ListNext)
                 {
                     string[] sources = new string[node.SourcesCount];
 

ARMeilleure/IntermediateRepresentation/BasicBlock.cs

@@ -2,13 +2,14 @@ using System.Collections.Generic;
 
 namespace ARMeilleure.IntermediateRepresentation
 {
-    class BasicBlock
+    class BasicBlock : IIntrusiveListNode<BasicBlock>
     {
         public int Index { get; set; }
 
-        public LinkedListNode<BasicBlock> Node { get; set; }
+        public BasicBlock ListPrevious { get; set; }
+        public BasicBlock ListNext { get; set; }
 
-        public LinkedList<Node> Operations { get; }
+        public IntrusiveList<Node> Operations { get; }
 
         private BasicBlock _next;
         private BasicBlock _branch;
@@ -33,7 +34,7 @@ namespace ARMeilleure.IntermediateRepresentation
 
         public BasicBlock()
         {
-            Operations = new LinkedList<Node>();
+            Operations = new IntrusiveList<Node>();
 
             Predecessors = new List<BasicBlock>();
 
@@ -77,7 +78,7 @@ namespace ARMeilleure.IntermediateRepresentation
 
         public Node GetLastOp()
         {
-            return Operations.Last?.Value;
+            return Operations.Last;
         }
     }
 }

ARMeilleure/IntermediateRepresentation/IIntrusiveListNode.cs

@@ -0,0 +1,8 @@
+namespace ARMeilleure.IntermediateRepresentation
+{
+    interface IIntrusiveListNode<T> where T : class
+    {
+        T ListPrevious { get; set; }
+        T ListNext { get; set; }
+    }
+}

ARMeilleure/IntermediateRepresentation/IntrusiveList.cs

@@ -0,0 +1,178 @@
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+
+namespace ARMeilleure.IntermediateRepresentation
+{
+    /// <summary>
+    /// Represents a efficient linked list that stores the pointer on the object directly and does not allocate.
+    /// </summary>
+    /// <typeparam name="T">Type of the list items</typeparam>
+    class IntrusiveList<T> where T : class, IIntrusiveListNode<T>
+    {
+        /// <summary>
+        /// First item of the list, or null if empty.
+        /// </summary>
+        public T First { get; private set; }
+
+        /// <summary>
+        /// Last item of the list, or null if empty.
+        /// </summary>
+        public T Last { get; private set; }
+
+        /// <summary>
+        /// Total number of items on the list.
+        /// </summary>
+        public int Count { get; private set; }
+
+        /// <summary>
+        /// Adds a item as the first item of the list.
+        /// </summary>
+        /// <param name="newNode">Item to be added</param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void AddFirst(T newNode)
+        {
+            if (First != null)
+            {
+                AddBefore(First, newNode);
+            }
+            else
+            {
+                Debug.Assert(newNode.ListPrevious == null);
+                Debug.Assert(newNode.ListNext == null);
+                Debug.Assert(Last == null);
+
+                First = newNode;
+                Last = newNode;
+
+                Debug.Assert(Count == 0);
+
+                Count = 1;
+            }
+        }
+
+        /// <summary>
+        /// Adds a item as the last item of the list.
+        /// </summary>
+        /// <param name="newNode">Item to be added</param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void AddLast(T newNode)
+        {
+            if (Last != null)
+            {
+                AddAfter(Last, newNode);
+            }
+            else
+            {
+                Debug.Assert(newNode.ListPrevious == null);
+                Debug.Assert(newNode.ListNext == null);
+                Debug.Assert(First == null);
+
+                First = newNode;
+                Last = newNode;
+
+                Debug.Assert(Count == 0);
+
+                Count = 1;
+            }
+        }
+
+        /// <summary>
+        /// Adds a item before a existing item on the list.
+        /// </summary>
+        /// <param name="node">Item on the list that will succeed the new item</param>
+        /// <param name="newNode">Item to be added</param>
+        /// <returns>New item</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public T AddBefore(T node, T newNode)
+        {
+            Debug.Assert(newNode.ListPrevious == null);
+            Debug.Assert(newNode.ListNext == null);
+
+            newNode.ListPrevious = node.ListPrevious;
+            newNode.ListNext = node;
+
+            node.ListPrevious = newNode;
+
+            if (newNode.ListPrevious != null)
+            {
+                newNode.ListPrevious.ListNext = newNode;
+            }
+
+            if (First == node)
+            {
+                First = newNode;
+            }
+
+            Count++;
+
+            return newNode;
+        }
+
+        /// <summary>
+        /// Adds a item after a existing item on the list.
+        /// </summary>
+        /// <param name="node">Item on the list that will preceed the new item</param>
+        /// <param name="newNode">Item to be added</param>
+        /// <returns>New item</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public T AddAfter(T node, T newNode)
+        {
+            Debug.Assert(newNode.ListPrevious == null);
+            Debug.Assert(newNode.ListNext == null);
+
+            newNode.ListPrevious = node;
+            newNode.ListNext = node.ListNext;
+
+            node.ListNext = newNode;
+
+            if (newNode.ListNext != null)
+            {
+                newNode.ListNext.ListPrevious = newNode;
+            }
+
+            if (Last == node)
+            {
+                Last = newNode;
+            }
+
+            Count++;
+
+            return newNode;
+        }
+
+        /// <summary>
+        /// Removes a item from the list.
+        /// </summary>
+        /// <param name="node">The item to be removed</param>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public void Remove(T node)
+        {
+            if (node.ListPrevious != null)
+            {
+                node.ListPrevious.ListNext = node.ListNext;
+            }
+            else
+            {
+                Debug.Assert(First == node);
+
+                First = node.ListNext;
+            }
+
+            if (node.ListNext != null)
+            {
+                node.ListNext.ListPrevious = node.ListPrevious;
+            }
+            else
+            {
+                Debug.Assert(Last == node);
+
+                Last = node.ListPrevious;
+            }
+
+            node.ListPrevious = null;
+            node.ListNext = null;
+
+            Count--;
+        }
+    }
+}

ARMeilleure/IntermediateRepresentation/Node.cs

@@ -1,10 +1,12 @@
 using System;
-using System.Collections.Generic;
 
 namespace ARMeilleure.IntermediateRepresentation
 {
-    class Node
+    class Node : IIntrusiveListNode<Node>
     {
+        public Node ListPrevious { get; set; }
+        public Node ListNext { get; set; }
+
         public Operand Destination
         {
             get
@@ -27,9 +29,6 @@ namespace ARMeilleure.IntermediateRepresentation
         private Operand[] _destinations;
         private Operand[] _sources;
 
-        private LinkedListNode<Node>[] _asgUseNodes;
-        private LinkedListNode<Node>[] _srcUseNodes;
-
         public int DestinationsCount => _destinations.Length;
         public int SourcesCount      => _sources.Length;
 
@@ -38,8 +37,6 @@ namespace ARMeilleure.IntermediateRepresentation
             Destination = destination;
 
             _sources = new Operand[sourcesCount];
-
-            _srcUseNodes = new LinkedListNode<Node>[sourcesCount];
         }
 
         public Node(Operand[] destinations, int sourcesCount)
@@ -47,8 +44,6 @@ namespace ARMeilleure.IntermediateRepresentation
             SetDestinations(destinations ?? throw new ArgumentNullException(nameof(destinations)));
 
             _sources = new Operand[sourcesCount];
-
-            _srcUseNodes = new LinkedListNode<Node>[sourcesCount];
         }
 
         public Operand GetDestination(int index)
@@ -67,12 +62,12 @@ namespace ARMeilleure.IntermediateRepresentation
 
             if (oldOp != null && oldOp.Kind == OperandKind.LocalVariable)
             {
-                oldOp.Assignments.Remove(_asgUseNodes[index]);
+                oldOp.Assignments.Remove(this);
             }
 
             if (destination != null && destination.Kind == OperandKind.LocalVariable)
             {
-                _asgUseNodes[index] = destination.Assignments.AddLast(this);
+                destination.Assignments.Add(this);
             }
 
             _destinations[index] = destination;
@@ -84,12 +79,12 @@ namespace ARMeilleure.IntermediateRepresentation
 
             if (oldOp != null && oldOp.Kind == OperandKind.LocalVariable)
             {
-                oldOp.Uses.Remove(_srcUseNodes[index]);
+                oldOp.Uses.Remove(this);
             }
 
             if (source != null && source.Kind == OperandKind.LocalVariable)
             {
-                _srcUseNodes[index] = source.Uses.AddLast(this);
+                source.Uses.Add(this);
             }
 
             _sources[index] = source;
@@ -105,7 +100,7 @@ namespace ARMeilleure.IntermediateRepresentation
 
                     if (oldOp != null && oldOp.Kind == OperandKind.LocalVariable)
                     {
-                        oldOp.Assignments.Remove(_asgUseNodes[index]);
+                        oldOp.Assignments.Remove(this);
                     }
                 }
 
@@ -116,8 +111,6 @@ namespace ARMeilleure.IntermediateRepresentation
                 _destinations = new Operand[destinations.Length];
             }
 
-            _asgUseNodes = new LinkedListNode<Node>[destinations.Length];
-
             for (int index = 0; index < destinations.Length; index++)
             {
                 Operand newOp = destinations[index];
@@ -126,7 +119,7 @@ namespace ARMeilleure.IntermediateRepresentation
 
                 if (newOp.Kind == OperandKind.LocalVariable)
                 {
-                    _asgUseNodes[index] = newOp.Assignments.AddLast(this);
+                    newOp.Assignments.Add(this);
                 }
             }
         }
@@ -139,14 +132,12 @@ namespace ARMeilleure.IntermediateRepresentation
 
                 if (oldOp != null && oldOp.Kind == OperandKind.LocalVariable)
                 {
-                    oldOp.Uses.Remove(_srcUseNodes[index]);
+                    oldOp.Uses.Remove(this);
                 }
             }
 
             _sources = new Operand[sources.Length];
 
-            _srcUseNodes = new LinkedListNode<Node>[sources.Length];
-
             for (int index = 0; index < sources.Length; index++)
             {
                 Operand newOp = sources[index];
@@ -155,7 +146,7 @@ namespace ARMeilleure.IntermediateRepresentation
 
                 if (newOp.Kind == OperandKind.LocalVariable)
                 {
-                    _srcUseNodes[index] = newOp.Uses.AddLast(this);
+                    newOp.Uses.Add(this);
                 }
             }
         }

ARMeilleure/IntermediateRepresentation/Operand.cs

@@ -11,13 +11,13 @@ namespace ARMeilleure.IntermediateRepresentation
 
         public ulong Value { get; private set; }
 
-        public LinkedList<Node> Assignments { get; }
+        public List<Node> Assignments { get; }
-        public LinkedList<Node> Uses        { get; }
+        public List<Node> Uses        { get; }
 
         private Operand()
         {
-            Assignments = new LinkedList<Node>();
+            Assignments = new List<Node>();
-            Uses        = new LinkedList<Node>();
+            Uses        = new List<Node>();
         }
 
         public Operand(OperandKind kind, OperandType type = OperandType.None) : this()

ARMeilleure/Translation/ControlFlowGraph.cs

@@ -9,13 +9,13 @@ namespace ARMeilleure.Translation
     {
         public BasicBlock Entry { get; }
 
-        public LinkedList<BasicBlock> Blocks { get; }
+        public IntrusiveList<BasicBlock> Blocks { get; }
 
         public BasicBlock[] PostOrderBlocks { get; }
 
         public int[] PostOrderMap { get; }
 
-        public ControlFlowGraph(BasicBlock entry, LinkedList<BasicBlock> blocks)
+        public ControlFlowGraph(BasicBlock entry, IntrusiveList<BasicBlock> blocks)
         {
             Entry  = entry;
             Blocks = blocks;
@@ -57,7 +57,7 @@ namespace ARMeilleure.Translation
             }
         }
 
-        private void RemoveUnreachableBlocks(LinkedList<BasicBlock> blocks)
+        private void RemoveUnreachableBlocks(IntrusiveList<BasicBlock> blocks)
         {
             HashSet<BasicBlock> visited = new HashSet<BasicBlock>();
 
@@ -87,25 +87,23 @@ namespace ARMeilleure.Translation
                 // Remove unreachable blocks and renumber.
                 int index = 0;
 
-                for (LinkedListNode<BasicBlock> node = blocks.First; node != null;)
+                for (BasicBlock block = blocks.First; block != null;)
                 {
-                    LinkedListNode<BasicBlock> nextNode = node.Next;
+                    BasicBlock nextBlock = block.ListNext;
-
-                    BasicBlock block = node.Value;
 
                     if (!visited.Contains(block))
                     {
-                        block.Next   = null;
+                        block.Next = null;
                         block.Branch = null;
 
-                        blocks.Remove(node);
+                        blocks.Remove(block);
                     }
                     else
                     {
                         block.Index = index++;
                     }
 
-                    node = nextNode;
+                    block = nextBlock;
                 }
             }
         }
@@ -130,7 +128,7 @@ namespace ARMeilleure.Translation
             }
 
             // Insert the new block on the list of blocks.
-            BasicBlock succPrev = successor.Node.Previous?.Value;
+            BasicBlock succPrev = successor.ListPrevious;
 
             if (succPrev != null && succPrev != predecessor && succPrev.Next == successor)
             {
@@ -145,12 +143,12 @@ namespace ARMeilleure.Translation
 
                 splitBlock2.Operations.AddLast(new Operation(Instruction.Branch, null));
 
-                Blocks.AddBefore(successor.Node, splitBlock2);
+                Blocks.AddBefore(successor, splitBlock2);
             }
 
             splitBlock.Next = successor;
 
-            Blocks.AddBefore(successor.Node, splitBlock);
+            Blocks.AddBefore(successor, splitBlock);
 
             return splitBlock;
         }

ARMeilleure/Translation/Dominance.cs

@@ -71,7 +71,7 @@ namespace ARMeilleure.Translation
 
         public static void FindDominanceFrontiers(ControlFlowGraph cfg)
         {
-            foreach (BasicBlock block in cfg.Blocks)
+            for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
             {
                 if (block.Predecessors.Count < 2)
                 {

ARMeilleure/Translation/EmitterContext.cs

@@ -12,7 +12,7 @@ namespace ARMeilleure.Translation
     {
         private Dictionary<Operand, BasicBlock> _irLabels;
 
-        private LinkedList<BasicBlock> _irBlocks;
+        private IntrusiveList<BasicBlock> _irBlocks;
 
         private BasicBlock _irBlock;
 
@@ -22,7 +22,7 @@ namespace ARMeilleure.Translation
         {
             _irLabels = new Dictionary<Operand, BasicBlock>();
 
-            _irBlocks = new LinkedList<BasicBlock>();
+            _irBlocks = new IntrusiveList<BasicBlock>();
 
             _needsNewBlock = true;
         }
@@ -508,7 +508,8 @@ namespace ARMeilleure.Translation
             if (_irLabels.TryGetValue(label, out BasicBlock nextBlock))
             {
                 nextBlock.Index = _irBlocks.Count;
-                nextBlock.Node  = _irBlocks.AddLast(nextBlock);
+
+                _irBlocks.AddLast(nextBlock);
 
                 NextBlock(nextBlock);
             }
@@ -524,7 +525,7 @@ namespace ARMeilleure.Translation
         {
             BasicBlock block = new BasicBlock(_irBlocks.Count);
 
-            block.Node = _irBlocks.AddLast(block);
+            _irBlocks.AddLast(block);
 
             NextBlock(block);
         }
@@ -556,7 +557,7 @@ namespace ARMeilleure.Translation
 
         public ControlFlowGraph GetControlFlowGraph()
         {
-            return new ControlFlowGraph(_irBlocks.First.Value, _irBlocks);
+            return new ControlFlowGraph(_irBlocks.First, _irBlocks);
         }
     }
 }

ARMeilleure/Translation/RegisterToLocal.cs

@@ -25,9 +25,9 @@ namespace ARMeilleure.Translation
                 return local;
             }
 
-            foreach (BasicBlock block in cfg.Blocks)
+            for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
             {
-                foreach (Node node in block.Operations)
+                for (Node node = block.Operations.First; node != null; node = node.ListNext)
                 {
                     Operand dest = node.Destination;
 

ARMeilleure/Translation/RegisterUsage.cs

@@ -74,9 +74,9 @@ namespace ARMeilleure.Translation
             RegisterMask[] localInputs  = new RegisterMask[cfg.Blocks.Count];
             RegisterMask[] localOutputs = new RegisterMask[cfg.Blocks.Count];
 
-            foreach (BasicBlock block in cfg.Blocks)
+            for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
             {
-                foreach (Node node in block.Operations)
+                for (Node node = block.Operations.First; node != null; node = node.ListNext)
                 {
                     Operation operation = node as Operation;
 
@@ -192,13 +192,13 @@ namespace ARMeilleure.Translation
             while (modified);
 
             // Insert load and store context instructions where needed.
-            foreach (BasicBlock block in cfg.Blocks)
+            for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
             {
                 bool hasContextLoad = HasContextLoad(block);
 
                 if (hasContextLoad)
                 {
-                    block.Operations.RemoveFirst();
+                    block.Operations.Remove(block.Operations.First);
                 }
 
                 // The only block without any predecessor should be the entry block.
@@ -213,7 +213,7 @@ namespace ARMeilleure.Translation
 
                 if (hasContextStore)
                 {
-                    block.Operations.RemoveLast();
+                    block.Operations.Remove(block.Operations.Last);
                 }
 
                 if (EndsWithReturn(block) || hasContextStore)
@@ -226,7 +226,7 @@ namespace ARMeilleure.Translation
 
         private static bool HasContextLoad(BasicBlock block)
         {
-            return StartsWith(block, Instruction.LoadFromContext) && block.Operations.First.Value.SourcesCount == 0;
+            return StartsWith(block, Instruction.LoadFromContext) && block.Operations.First.SourcesCount == 0;
         }
 
         private static bool HasContextStore(BasicBlock block)
@@ -241,7 +241,7 @@ namespace ARMeilleure.Translation
                 return false;
             }
 
-            return block.Operations.First.Value is Operation operation && operation.Instruction == inst;
+            return block.Operations.First is Operation operation && operation.Instruction == inst;
         }
 
         private static bool EndsWith(BasicBlock block, Instruction inst)
@@ -251,7 +251,7 @@ namespace ARMeilleure.Translation
                 return false;
             }
 
-            return block.Operations.Last.Value is Operation operation && operation.Instruction == inst;
+            return block.Operations.Last is Operation operation && operation.Instruction == inst;
         }
 
         private static RegisterMask GetMask(Register register)

ARMeilleure/Translation/SsaConstruction.cs

@@ -47,7 +47,7 @@ namespace ARMeilleure.Translation
         {
             DefMap[] globalDefs = new DefMap[cfg.Blocks.Count];
 
-            foreach (BasicBlock block in cfg.Blocks)
+            for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
             {
                 globalDefs[block.Index] = new DefMap();
             }
@@ -55,11 +55,11 @@ namespace ARMeilleure.Translation
             Queue<BasicBlock> dfPhiBlocks = new Queue<BasicBlock>();
 
             // First pass, get all defs and locals uses.
-            foreach (BasicBlock block in cfg.Blocks)
+            for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
             {
                 Operand[] localDefs = new Operand[RegisterConsts.TotalCount];
 
-                LinkedListNode<Node> node = block.Operations.First;
+                Node node = block.Operations.First;
 
                 Operand RenameLocal(Operand operand)
                 {
@@ -75,7 +75,7 @@ namespace ARMeilleure.Translation
 
                 while (node != null)
                 {
-                    if (node.Value is Operation operation)
+                    if (node is Operation operation)
                     {
                         for (int index = 0; index < operation.SourcesCount; index++)
                         {
@@ -94,7 +94,7 @@ namespace ARMeilleure.Translation
                         }
                     }
 
-                    node = node.Next;
+                    node = node.ListNext;
                 }
 
                 for (int index = 0; index < RegisterConsts.TotalCount; index++)
@@ -126,11 +126,11 @@ namespace ARMeilleure.Translation
             }
 
             // Second pass, rename variables with definitions on different blocks.
-            foreach (BasicBlock block in cfg.Blocks)
+            for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
             {
                 Operand[] localDefs = new Operand[RegisterConsts.TotalCount];
 
-                LinkedListNode<Node> node = block.Operations.First;
+                Node node = block.Operations.First;
 
                 Operand RenameGlobal(Operand operand)
                 {
@@ -155,7 +155,7 @@ namespace ARMeilleure.Translation
 
                 while (node != null)
                 {
-                    if (node.Value is Operation operation)
+                    if (node is Operation operation)
                     {
                         for (int index = 0; index < operation.SourcesCount; index++)
                         {
@@ -163,7 +163,7 @@ namespace ARMeilleure.Translation
                         }
                     }
 
-                    node = node.Next;
+                    node = node.ListNext;
                 }
             }
         }
@@ -238,17 +238,17 @@ namespace ARMeilleure.Translation
 
         private static void AddPhi(BasicBlock block, PhiNode phi)
         {
-            LinkedListNode<Node> node = block.Operations.First;
+            Node node = block.Operations.First;
 
             if (node != null)
             {
-                while (node.Next?.Value is PhiNode)
+                while (node.ListNext is PhiNode)
                 {
-                    node = node.Next;
+                    node = node.ListNext;
                 }
             }
 
-            if (node?.Value is PhiNode)
+            if (node is PhiNode)
             {
                 block.Operations.AddAfter(node, phi);
             }

ARMeilleure/Translation/SsaDeconstruction.cs

@@ -9,13 +9,13 @@ namespace ARMeilleure.Translation
     {
         public static void Deconstruct(ControlFlowGraph cfg)
         {
-            foreach (BasicBlock block in cfg.Blocks)
+            for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
             {
-                LinkedListNode<Node> node = block.Operations.First;
+                Node node = block.Operations.First;
 
-                while (node?.Value is PhiNode phi)
+                while (node is PhiNode phi)
                 {
-                    LinkedListNode<Node> nextNode = node.Next;
+                    Node nextNode = node.ListNext;
 
                     Operand local = Local(phi.Destination.Type);