1 files changed, 940 insertions, 0 deletions
diff --git a/ARMeilleure/CodeGen/Arm64/PreAllocator.cs b/ARMeilleure/CodeGen/Arm64/PreAllocator.cs
new file mode 100644
index 00000000..a7f07394
--- /dev/null
+++ b/ARMeilleure/CodeGen/Arm64/PreAllocator.cs
@@ -0,0 +1,940 @@
+using ARMeilleure.CodeGen.RegisterAllocators;
+using ARMeilleure.IntermediateRepresentation;
+using ARMeilleure.Translation;
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using static ARMeilleure.IntermediateRepresentation.Operand.Factory;
+using static ARMeilleure.IntermediateRepresentation.Operation.Factory;
+
+namespace ARMeilleure.CodeGen.Arm64
+{
+    class PreAllocator
+    {
+        private class ConstantDict
+        {
+            private readonly Dictionary<(ulong, OperandType), Operand> _constants;
+
+            public ConstantDict()
+            {
+                _constants = new Dictionary<(ulong, OperandType), Operand>();
+            }
+
+            public void Add(ulong value, OperandType type, Operand local)
+            {
+                _constants.Add((value, type), local);
+            }
+
+            public bool TryGetValue(ulong value, OperandType type, out Operand local)
+            {
+                return _constants.TryGetValue((value, type), out local);
+            }
+        }
+
+        public static void RunPass(CompilerContext cctx, StackAllocator stackAlloc, out int maxCallArgs)
+        {
+            maxCallArgs = -1;
+
+            Span<Operation> buffer = default;
+
+            Operand[] preservedArgs = new Operand[CallingConvention.GetArgumentsOnRegsCount()];
+
+            for (BasicBlock block = cctx.Cfg.Blocks.First; block != null; block = block.ListNext)
+            {
+                ConstantDict constants = new ConstantDict();
+
+                Operation nextNode;
+
+                for (Operation node = block.Operations.First; node != default; node = nextNode)
+                {
+                    nextNode = node.ListNext;
+
+                    if (node.Instruction == Instruction.Phi)
+                    {
+                        continue;
+                    }
+
+                    HandleConstantRegCopy(constants, block.Operations, node);
+                    HandleDestructiveRegCopy(block.Operations, node);
+
+                    switch (node.Instruction)
+                    {
+                        case Instruction.Call:
+                            // Get the maximum number of arguments used on a call.
+                            // On windows, when a struct is returned from the call,
+                            // we also need to pass the pointer where the struct
+                            // should be written on the first argument.
+                            int argsCount = node.SourcesCount - 1;
+
+                            if (node.Destination != default && node.Destination.Type == OperandType.V128)
+                            {
+                                argsCount++;
+                            }
+
+                            if (maxCallArgs < argsCount)
+                            {
+                                maxCallArgs = argsCount;
+                            }
+
+                            // Copy values to registers expected by the function
+                            // being called, as mandated by the ABI.
+                            HandleCall(constants, block.Operations, node);
+                            break;
+                        case Instruction.CompareAndSwap:
+                        case Instruction.CompareAndSwap16:
+                        case Instruction.CompareAndSwap8:
+                            nextNode = HandleCompareAndSwap(block.Operations, node);
+                            break;
+                        case Instruction.LoadArgument:
+                            nextNode = HandleLoadArgument(cctx, ref buffer, block.Operations, preservedArgs, node);
+                            break;
+                        case Instruction.Return:
+                            HandleReturn(block.Operations, node);
+                            break;
+                        case Instruction.Tailcall:
+                            HandleTailcall(constants, block.Operations, stackAlloc, node, node);
+                            break;
+                    }
+                }
+            }
+        }
+
+        private static void HandleConstantRegCopy(ConstantDict constants, IntrusiveList<Operation> nodes, Operation node)
+        {
+            if (node.SourcesCount == 0 || IsIntrinsicWithConst(node))
+            {
+                return;
+            }
+
+            Instruction inst = node.Instruction;
+
+            Operand src1 = node.GetSource(0);
+            Operand src2;
+
+            if (src1.Kind == OperandKind.Constant)
+            {
+                if (!src1.Type.IsInteger())
+                {
+                    // Handle non-integer types (FP32, FP64 and V128).
+                    // For instructions without an immediate operand, we do the following:
+                    // - 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 = AddFloatConstantCopy(constants, nodes, node, src1);
+
+                    node.SetSource(0, src1);
+                }
+                else if (!HasConstSrc1(node, src1.Value))
+                {
+                    // Handle integer types.
+                    // Most ALU instructions accepts a 32-bits immediate on the second operand.
+                    // We need to ensure the following:
+                    // - If the constant is on operand 1, we need to move it.
+                    // -- But first, we try to swap operand 1 and 2 if the instruction is commutative.
+                    // -- Doing so may allow us to encode the constant as operand 2 and avoid a copy.
+                    // - If the constant is on operand 2, we check if the instruction supports it,
+                    // if not, we also add a copy. 64-bits constants are usually not supported.
+                    if (IsCommutative(node))
+                    {
+                        src2 = node.GetSource(1);
+
+                        Operand temp = src1;
+
+                        src1 = src2;
+                        src2 = temp;
+
+                        node.SetSource(0, src1);
+                        node.SetSource(1, src2);
+                    }
+
+                    if (src1.Kind == OperandKind.Constant)
+                    {
+                        src1 = AddIntConstantCopy(constants, nodes, node, src1);
+
+                        node.SetSource(0, src1);
+                    }
+                }
+            }
+
+            if (node.SourcesCount < 2)
+            {
+                return;
+            }
+
+            src2 = node.GetSource(1);
+
+            if (src2.Kind == OperandKind.Constant)
+            {
+                if (!src2.Type.IsInteger())
+                {
+                    src2 = AddFloatConstantCopy(constants, nodes, node, src2);
+
+                    node.SetSource(1, src2);
+                }
+                else if (!HasConstSrc2(inst, src2))
+                {
+                    src2 = AddIntConstantCopy(constants, nodes, node, src2);
+
+                    node.SetSource(1, src2);
+                }
+            }
+
+            if (node.SourcesCount < 3 ||
+                node.Instruction == Instruction.BranchIf ||
+                node.Instruction == Instruction.Compare ||
+                node.Instruction == Instruction.VectorInsert ||
+                node.Instruction == Instruction.VectorInsert16 ||
+                node.Instruction == Instruction.VectorInsert8)
+            {
+                return;
+            }
+
+            for (int srcIndex = 2; srcIndex < node.SourcesCount; srcIndex++)
+            {
+                Operand src = node.GetSource(srcIndex);
+
+                if (src.Kind == OperandKind.Constant)
+                {
+                    if (!src.Type.IsInteger())
+                    {
+                        src = AddFloatConstantCopy(constants, nodes, node, src);
+
+                        node.SetSource(srcIndex, src);
+                    }
+                    else
+                    {
+                        src = AddIntConstantCopy(constants, nodes, node, src);
+
+                        node.SetSource(srcIndex, src);
+                    }
+                }
+            }
+        }
+
+        private static void HandleDestructiveRegCopy(IntrusiveList<Operation> nodes, Operation node)
+        {
+            if (node.Destination == default || node.SourcesCount == 0)
+            {
+                return;
+            }
+
+            Operand dest = node.Destination;
+            Operand src1 = node.GetSource(0);
+
+            if (IsSameOperandDestSrc1(node) && src1.Kind == OperandKind.LocalVariable)
+            {
+                bool useNewLocal = false;
+
+                for (int srcIndex = 1; srcIndex < node.SourcesCount; srcIndex++)
+                {
+                    if (node.GetSource(srcIndex) == dest)
+                    {
+                        useNewLocal = true;
+
+                        break;
+                    }
+                }
+
+                if (useNewLocal)
+                {
+                    // Dest is being used as some source already, we need to use a new
+                    // local to store the temporary value, otherwise the value on dest
+                    // local would be overwritten.
+                    Operand temp = Local(dest.Type);
+
+                    nodes.AddBefore(node, Operation(Instruction.Copy, temp, src1));
+
+                    node.SetSource(0, temp);
+
+                    nodes.AddAfter(node, Operation(Instruction.Copy, dest, temp));
+
+                    node.Destination = temp;
+                }
+                else
+                {
+                    nodes.AddBefore(node, Operation(Instruction.Copy, dest, src1));
+
+                    node.SetSource(0, dest);
+                }
+            }
+        }
+
+        private static void HandleCall(ConstantDict constants, IntrusiveList<Operation> nodes, Operation node)
+        {
+            Operation operation = node;
+
+            Operand dest = operation.Destination;
+
+            List<Operand> sources = new List<Operand>
+            {
+                operation.GetSource(0)
+            };
+
+            int argsCount = operation.SourcesCount - 1;
+
+            int intMax = CallingConvention.GetArgumentsOnRegsCount();
+            int vecMax = CallingConvention.GetArgumentsOnRegsCount();
+
+            int intCount = 0;
+            int vecCount = 0;
+
+            int stackOffset = 0;
+
+            for (int index = 0; index < argsCount; index++)
+            {
+                Operand source = operation.GetSource(index + 1);
+
+                bool passOnReg;
+
+                if (source.Type.IsInteger())
+                {
+                    passOnReg = intCount < intMax;
+                }
+                else if (source.Type == OperandType.V128)
+                {
+                    passOnReg = intCount + 1 < intMax;
+                }
+                else
+                {
+                    passOnReg = vecCount < vecMax;
+                }
+
+                if (source.Type == OperandType.V128 && passOnReg)
+                {
+                    // V128 is a struct, we pass each half on a GPR if possible.
+                    Operand argReg  = Gpr(CallingConvention.GetIntArgumentRegister(intCount++), OperandType.I64);
+                    Operand argReg2 = Gpr(CallingConvention.GetIntArgumentRegister(intCount++), OperandType.I64);
+
+                    nodes.AddBefore(node, Operation(Instruction.VectorExtract, argReg,  source, Const(0)));
+                    nodes.AddBefore(node, Operation(Instruction.VectorExtract, argReg2, source, Const(1)));
+
+                    continue;
+                }
+
+                if (passOnReg)
+                {
+                    Operand argReg = source.Type.IsInteger()
+                        ? Gpr(CallingConvention.GetIntArgumentRegister(intCount++), source.Type)
+                        : Xmm(CallingConvention.GetVecArgumentRegister(vecCount++), source.Type);
+
+                    Operation copyOp = Operation(Instruction.Copy, argReg, source);
+
+                    HandleConstantRegCopy(constants, nodes, nodes.AddBefore(node, copyOp));
+
+                    sources.Add(argReg);
+                }
+                else
+                {
+                    Operand offset = Const(stackOffset);
+
+                    Operation spillOp = Operation(Instruction.SpillArg, default, offset, source);
+
+                    HandleConstantRegCopy(constants, nodes, nodes.AddBefore(node, spillOp));
+
+                    stackOffset += source.Type.GetSizeInBytes();
+                }
+            }
+
+            if (dest != default)
+            {
+                if (dest.Type == OperandType.V128)
+                {
+                    Operand retLReg = Gpr(CallingConvention.GetIntReturnRegister(),     OperandType.I64);
+                    Operand retHReg = Gpr(CallingConvention.GetIntReturnRegisterHigh(), OperandType.I64);
+
+                    node = nodes.AddAfter(node, Operation(Instruction.VectorCreateScalar, dest, retLReg));
+                    nodes.AddAfter(node, Operation(Instruction.VectorInsert, dest, dest, retHReg, Const(1)));
+
+                    operation.Destination = default;
+                }
+                else
+                {
+                    Operand retReg = dest.Type.IsInteger()
+                        ? Gpr(CallingConvention.GetIntReturnRegister(), dest.Type)
+                        : Xmm(CallingConvention.GetVecReturnRegister(), dest.Type);
+
+                    Operation copyOp = Operation(Instruction.Copy, dest, retReg);
+
+                    nodes.AddAfter(node, copyOp);
+
+                    operation.Destination = retReg;
+                }
+            }
+
+            operation.SetSources(sources.ToArray());
+        }
+
+        private static void HandleTailcall(
+            ConstantDict constants,
+            IntrusiveList<Operation> nodes,
+            StackAllocator stackAlloc,
+            Operation node,
+            Operation operation)
+        {
+            List<Operand> sources = new List<Operand>
+            {
+                operation.GetSource(0)
+            };
+
+            int argsCount = operation.SourcesCount - 1;
+
+            int intMax = CallingConvention.GetArgumentsOnRegsCount();
+            int vecMax = CallingConvention.GetArgumentsOnRegsCount();
+
+            int intCount = 0;
+            int vecCount = 0;
+
+            // Handle arguments passed on registers.
+            for (int index = 0; index < argsCount; index++)
+            {
+                Operand source = operation.GetSource(1 + index);
+
+                bool passOnReg;
+
+                if (source.Type.IsInteger())
+                {
+                    passOnReg = intCount + 1 < intMax;
+                }
+                else
+                {
+                    passOnReg = vecCount < vecMax;
+                }
+
+                if (source.Type == OperandType.V128 && passOnReg)
+                {
+                    // V128 is a struct, we pass each half on a GPR if possible.
+                    Operand argReg  = Gpr(CallingConvention.GetIntArgumentRegister(intCount++), OperandType.I64);
+                    Operand argReg2 = Gpr(CallingConvention.GetIntArgumentRegister(intCount++), OperandType.I64);
+
+                    nodes.AddBefore(node, Operation(Instruction.VectorExtract, argReg, source, Const(0)));
+                    nodes.AddBefore(node, Operation(Instruction.VectorExtract, argReg2, source, Const(1)));
+
+                    continue;
+                }
+
+                if (passOnReg)
+                {
+                    Operand argReg = source.Type.IsInteger()
+                        ? Gpr(CallingConvention.GetIntArgumentRegister(intCount++), source.Type)
+                        : Xmm(CallingConvention.GetVecArgumentRegister(vecCount++), source.Type);
+
+                    Operation copyOp = Operation(Instruction.Copy, argReg, source);
+
+                    HandleConstantRegCopy(constants, nodes, nodes.AddBefore(node, copyOp));
+
+                    sources.Add(argReg);
+                }
+                else
+                {
+                    throw new NotImplementedException("Spilling is not currently supported for tail calls. (too many arguments)");
+                }
+            }
+
+            // The target address must be on the return registers, since we
+            // don't return anything and it is guaranteed to not be a
+            // callee saved register (which would be trashed on the epilogue).
+            Operand tcAddress = Gpr(CodeGenCommon.TcAddressRegister, OperandType.I64);
+
+            Operation addrCopyOp = Operation(Instruction.Copy, tcAddress, operation.GetSource(0));
+
+            nodes.AddBefore(node, addrCopyOp);
+
+            sources[0] = tcAddress;
+
+            operation.SetSources(sources.ToArray());
+        }
+
+        private static Operation HandleCompareAndSwap(IntrusiveList<Operation> nodes, Operation node)
+        {
+            Operand expected = node.GetSource(1);
+
+            if (expected.Type == OperandType.V128)
+            {
+                Operand dest = node.Destination;
+                Operand expectedLow = Local(OperandType.I64);
+                Operand expectedHigh = Local(OperandType.I64);
+                Operand desiredLow = Local(OperandType.I64);
+                Operand desiredHigh = Local(OperandType.I64);
+                Operand actualLow = Local(OperandType.I64);
+                Operand actualHigh = Local(OperandType.I64);
+
+                Operand address = node.GetSource(0);
+                Operand desired = node.GetSource(2);
+
+                void SplitOperand(Operand source, Operand low, Operand high)
+                {
+                    nodes.AddBefore(node, Operation(Instruction.VectorExtract, low, source, Const(0)));
+                    nodes.AddBefore(node, Operation(Instruction.VectorExtract, high, source, Const(1)));
+                }
+
+                SplitOperand(expected, expectedLow, expectedHigh);
+                SplitOperand(desired, desiredLow, desiredHigh);
+
+                Operation operation = node;
+
+                // Update the sources and destinations with split 64-bit halfs of the whole 128-bit values.
+                // We also need a additional registers that will be used to store temporary information.
+                operation.SetDestinations(new[] { actualLow, actualHigh, Local(OperandType.I64), Local(OperandType.I64) });
+                operation.SetSources(new[] { address, expectedLow, expectedHigh, desiredLow, desiredHigh });
+
+                // Add some dummy uses of the input operands, as the CAS operation will be a loop,
+                // so they can't be used as destination operand.
+                for (int i = 0; i < operation.SourcesCount; i++)
+                {
+                    Operand src = operation.GetSource(i);
+                    node = nodes.AddAfter(node, Operation(Instruction.Copy, src, src));
+                }
+
+                // Assemble the vector with the 64-bit values at the given memory location.
+                node = nodes.AddAfter(node, Operation(Instruction.VectorCreateScalar, dest, actualLow));
+                node = nodes.AddAfter(node, Operation(Instruction.VectorInsert, dest, dest, actualHigh, Const(1)));
+            }
+            else
+            {
+                // We need a additional register where the store result will be written to.
+                node.SetDestinations(new[] { node.Destination, Local(OperandType.I32) });
+
+                // Add some dummy uses of the input operands, as the CAS operation will be a loop,
+                // so they can't be used as destination operand.
+                Operation operation = node;
+
+                for (int i = 0; i < operation.SourcesCount; i++)
+                {
+                    Operand src = operation.GetSource(i);
+                    node = nodes.AddAfter(node, Operation(Instruction.Copy, src, src));
+                }
+            }
+
+            return node.ListNext;
+        }
+
+        private static void HandleReturn(IntrusiveList<Operation> nodes, Operation node)
+        {
+            if (node.SourcesCount == 0)
+            {
+                return;
+            }
+
+            Operand source = node.GetSource(0);
+
+            if (source.Type == OperandType.V128)
+            {
+                Operand retLReg = Gpr(CallingConvention.GetIntReturnRegister(),     OperandType.I64);
+                Operand retHReg = Gpr(CallingConvention.GetIntReturnRegisterHigh(), OperandType.I64);
+
+                nodes.AddBefore(node, Operation(Instruction.VectorExtract, retLReg, source, Const(0)));
+                nodes.AddBefore(node, Operation(Instruction.VectorExtract, retHReg, source, Const(1)));
+            }
+            else
+            {
+                Operand retReg = source.Type.IsInteger()
+                    ? Gpr(CallingConvention.GetIntReturnRegister(), source.Type)
+                    : Xmm(CallingConvention.GetVecReturnRegister(), source.Type);
+
+                Operation retCopyOp = Operation(Instruction.Copy, retReg, source);
+
+                nodes.AddBefore(node, retCopyOp);
+            }
+        }
+
+        private static Operation HandleLoadArgument(
+            CompilerContext cctx,
+            ref Span<Operation> buffer,
+            IntrusiveList<Operation> nodes,
+            Operand[] preservedArgs,
+            Operation node)
+        {
+            Operand source = node.GetSource(0);
+
+            Debug.Assert(source.Kind == OperandKind.Constant, "Non-constant LoadArgument source kind.");
+
+            int index = source.AsInt32();
+
+            int intCount = 0;
+            int vecCount = 0;
+
+            for (int cIndex = 0; cIndex < index; cIndex++)
+            {
+                OperandType argType = cctx.FuncArgTypes[cIndex];
+
+                if (argType.IsInteger())
+                {
+                    intCount++;
+                }
+                else if (argType == OperandType.V128)
+                {
+                    intCount += 2;
+                }
+                else
+                {
+                    vecCount++;
+                }
+            }
+
+            bool passOnReg;
+
+            if (source.Type.IsInteger())
+            {
+                passOnReg = intCount < CallingConvention.GetArgumentsOnRegsCount();
+            }
+            else if (source.Type == OperandType.V128)
+            {
+                passOnReg = intCount + 1 < CallingConvention.GetArgumentsOnRegsCount();
+            }
+            else
+            {
+                passOnReg = vecCount < CallingConvention.GetArgumentsOnRegsCount();
+            }
+
+            if (passOnReg)
+            {
+                Operand dest = node.Destination;
+
+                if (preservedArgs[index] == default)
+                {
+                    if (dest.Type == OperandType.V128)
+                    {
+                        // V128 is a struct, we pass each half on a GPR if possible.
+                        Operand pArg = Local(OperandType.V128);
+
+                        Operand argLReg = Gpr(CallingConvention.GetIntArgumentRegister(intCount), OperandType.I64);
+                        Operand argHReg = Gpr(CallingConvention.GetIntArgumentRegister(intCount + 1), OperandType.I64);
+
+                        Operation copyL = Operation(Instruction.VectorCreateScalar, pArg, argLReg);
+                        Operation copyH = Operation(Instruction.VectorInsert, pArg, pArg, argHReg, Const(1));
+
+                        cctx.Cfg.Entry.Operations.AddFirst(copyH);
+                        cctx.Cfg.Entry.Operations.AddFirst(copyL);
+
+                        preservedArgs[index] = pArg;
+                    }
+                    else
+                    {
+                        Operand pArg = Local(dest.Type);
+
+                        Operand argReg = dest.Type.IsInteger()
+                            ? Gpr(CallingConvention.GetIntArgumentRegister(intCount), dest.Type)
+                            : Xmm(CallingConvention.GetVecArgumentRegister(vecCount), dest.Type);
+
+                        Operation copyOp = Operation(Instruction.Copy, pArg, argReg);
+
+                        cctx.Cfg.Entry.Operations.AddFirst(copyOp);
+
+                        preservedArgs[index] = pArg;
+                    }
+                }
+
+                Operation nextNode;
+
+                if (dest.AssignmentsCount == 1)
+                {
+                    // Let's propagate the argument if we can to avoid copies.
+                    Propagate(ref buffer, dest, preservedArgs[index]);
+                    nextNode = node.ListNext;
+                }
+                else
+                {
+                    Operation argCopyOp = Operation(Instruction.Copy, dest, preservedArgs[index]);
+                    nextNode = nodes.AddBefore(node, argCopyOp);
+                }
+
+                Delete(nodes, node);
+                return nextNode;
+            }
+            else
+            {
+                // TODO: Pass on stack.
+                return node;
+            }
+        }
+
+        private static void Propagate(ref Span<Operation> buffer, Operand dest, Operand value)
+        {
+            ReadOnlySpan<Operation> uses = dest.GetUses(ref buffer);
+
+            foreach (Operation use in uses)
+            {
+                for (int srcIndex = 0; srcIndex < use.SourcesCount; srcIndex++)
+                {
+                    Operand useSrc = use.GetSource(srcIndex);
+
+                    if (useSrc == dest)
+                    {
+                        use.SetSource(srcIndex, value);
+                    }
+                    else if (useSrc.Kind == OperandKind.Memory)
+                    {
+                        MemoryOperand memoryOp = useSrc.GetMemory();
+
+                        Operand baseAddr = memoryOp.BaseAddress;
+                        Operand index = memoryOp.Index;
+                        bool changed = false;
+
+                        if (baseAddr == dest)
+                        {
+                            baseAddr = value;
+                            changed = true;
+                        }
+
+                        if (index == dest)
+                        {
+                            index = value;
+                            changed = true;
+                        }
+
+                        if (changed)
+                        {
+                            use.SetSource(srcIndex, MemoryOp(
+                                useSrc.Type,
+                                baseAddr,
+                                index,
+                                memoryOp.Scale,
+                                memoryOp.Displacement));
+                        }
+                    }
+                }
+            }
+        }
+
+        private static Operand AddFloatConstantCopy(
+            ConstantDict constants,
+            IntrusiveList<Operation> nodes,
+            Operation node,
+            Operand source)
+        {
+            Operand temp = Local(source.Type);
+
+            Operand intConst = AddIntConstantCopy(constants, nodes, node, GetIntConst(source));
+
+            Operation copyOp = Operation(Instruction.VectorCreateScalar, temp, intConst);
+
+            nodes.AddBefore(node, copyOp);
+
+            return temp;
+        }
+
+        private static Operand AddIntConstantCopy(
+            ConstantDict constants,
+            IntrusiveList<Operation> nodes,
+            Operation node,
+            Operand source)
+        {
+            if (constants.TryGetValue(source.Value, source.Type, out Operand temp))
+            {
+                return temp;
+            }
+
+            temp = Local(source.Type);
+
+            Operation copyOp = Operation(Instruction.Copy, temp, source);
+
+            nodes.AddBefore(node, copyOp);
+
+            constants.Add(source.Value, source.Type, temp);
+
+            return temp;
+        }
+
+        private static Operand GetIntConst(Operand value)
+        {
+            if (value.Type == OperandType.FP32)
+            {
+                return Const(value.AsInt32());
+            }
+            else if (value.Type == OperandType.FP64)
+            {
+                return Const(value.AsInt64());
+            }
+
+            return value;
+        }
+
+        private static void Delete(IntrusiveList<Operation> nodes, Operation node)
+        {
+            node.Destination = default;
+
+            for (int index = 0; index < node.SourcesCount; index++)
+            {
+                node.SetSource(index, default);
+            }
+
+            nodes.Remove(node);
+        }
+
+        private static Operand Gpr(int register, OperandType type)
+        {
+            return Register(register, RegisterType.Integer, type);
+        }
+
+        private static Operand Xmm(int register, OperandType type)
+        {
+            return Register(register, RegisterType.Vector, type);
+        }
+
+        private static bool IsSameOperandDestSrc1(Operation operation)
+        {
+            switch (operation.Instruction)
+            {
+                case Instruction.Extended:
+                    return IsSameOperandDestSrc1(operation.Intrinsic);
+                case Instruction.VectorInsert:
+                case Instruction.VectorInsert16:
+                case Instruction.VectorInsert8:
+                    return true;
+            }
+
+            return false;
+        }
+
+        private static bool IsSameOperandDestSrc1(Intrinsic intrinsic)
+        {
+            IntrinsicInfo info = IntrinsicTable.GetInfo(intrinsic & ~(Intrinsic.Arm64VTypeMask | Intrinsic.Arm64VSizeMask));
+
+            return info.Type == IntrinsicType.ScalarBinaryRd ||
+                   info.Type == IntrinsicType.ScalarTernaryFPRdByElem ||
+                   info.Type == IntrinsicType.ScalarTernaryShlRd ||
+                   info.Type == IntrinsicType.ScalarTernaryShrRd ||
+                   info.Type == IntrinsicType.VectorBinaryRd ||
+                   info.Type == IntrinsicType.VectorInsertByElem ||
+                   info.Type == IntrinsicType.VectorTernaryRd ||
+                   info.Type == IntrinsicType.VectorTernaryRdBitwise ||
+                   info.Type == IntrinsicType.VectorTernaryFPRdByElem ||
+                   info.Type == IntrinsicType.VectorTernaryRdByElem ||
+                   info.Type == IntrinsicType.VectorTernaryShlRd ||
+                   info.Type == IntrinsicType.VectorTernaryShrRd;
+        }
+
+        private static bool HasConstSrc1(Operation node, ulong value)
+        {
+            switch (node.Instruction)
+            {
+                case Instruction.Add:
+                case Instruction.BranchIf:
+                case Instruction.Compare:
+                case Instruction.Subtract:
+                    // The immediate encoding of those instructions does not allow Rn to be
+                    // XZR (it will be SP instead), so we can't allow a Rn constant in this case.
+                    return value == 0 && NotConstOrConst0(node.GetSource(1));
+                case Instruction.BitwiseAnd:
+                case Instruction.BitwiseExclusiveOr:
+                case Instruction.BitwiseNot:
+                case Instruction.BitwiseOr:
+                case Instruction.ByteSwap:
+                case Instruction.CountLeadingZeros:
+                case Instruction.Multiply:
+                case Instruction.Negate:
+                case Instruction.RotateRight:
+                case Instruction.ShiftLeft:
+                case Instruction.ShiftRightSI:
+                case Instruction.ShiftRightUI:
+                    return value == 0;
+                case Instruction.Copy:
+                case Instruction.LoadArgument:
+                case Instruction.Spill:
+                case Instruction.SpillArg:
+                    return true;
+                case Instruction.Extended:
+                    return value == 0;
+            }
+
+            return false;
+        }
+
+        private static bool NotConstOrConst0(Operand operand)
+        {
+            return operand.Kind != OperandKind.Constant || operand.Value == 0;
+        }
+
+        private static bool HasConstSrc2(Instruction inst, Operand operand)
+        {
+            ulong value = operand.Value;
+
+            switch (inst)
+            {
+                case Instruction.Add:
+                case Instruction.BranchIf:
+                case Instruction.Compare:
+                case Instruction.Subtract:
+                    return ConstFitsOnUImm12Sh(value);
+                case Instruction.BitwiseAnd:
+                case Instruction.BitwiseExclusiveOr:
+                case Instruction.BitwiseOr:
+                    return value == 0 || CodeGenCommon.TryEncodeBitMask(operand, out _, out _, out _);
+                case Instruction.Multiply:
+                case Instruction.Store:
+                case Instruction.Store16:
+                case Instruction.Store8:
+                    return value == 0;
+                case Instruction.RotateRight:
+                case Instruction.ShiftLeft:
+                case Instruction.ShiftRightSI:
+                case Instruction.ShiftRightUI:
+                case Instruction.VectorExtract:
+                case Instruction.VectorExtract16:
+                case Instruction.VectorExtract8:
+                    return true;
+                case Instruction.Extended:
+                    // TODO: Check if actual intrinsic is supposed to have consts here?
+                    // Right now we only hit this case for fixed-point int <-> FP conversion instructions.
+                    return true;
+            }
+
+            return false;
+        }
+
+        private static bool IsCommutative(Operation operation)
+        {
+            switch (operation.Instruction)
+            {
+                case Instruction.Add:
+                case Instruction.BitwiseAnd:
+                case Instruction.BitwiseExclusiveOr:
+                case Instruction.BitwiseOr:
+                case Instruction.Multiply:
+                    return true;
+
+                case Instruction.BranchIf:
+                case Instruction.Compare:
+                    {
+                        Operand comp = operation.GetSource(2);
+
+                        Debug.Assert(comp.Kind == OperandKind.Constant);
+
+                        var compType = (Comparison)comp.AsInt32();
+
+                        return compType == Comparison.Equal || compType == Comparison.NotEqual;
+                    }
+            }
+
+            return false;
+        }
+
+        private static bool ConstFitsOnUImm12Sh(ulong value)
+        {
+            return (value & ~0xfffUL) == 0 || (value & ~0xfff000UL) == 0;
+        }
+
+        private static bool IsIntrinsicWithConst(Operation operation)
+        {
+            bool isIntrinsic = IsIntrinsic(operation.Instruction);
+
+            if (isIntrinsic)
+            {
+                Intrinsic intrinsic = operation.Intrinsic;
+                IntrinsicInfo info = IntrinsicTable.GetInfo(intrinsic & ~(Intrinsic.Arm64VTypeMask | Intrinsic.Arm64VSizeMask));
+
+                // Those have integer inputs that don't support consts.
+                return info.Type != IntrinsicType.ScalarFPConvGpr &&
+                       info.Type != IntrinsicType.ScalarFPConvFixedGpr &&
+                       info.Type != IntrinsicType.SetRegister;
+            }
+
+            return false;
+        }
+
+        private static bool IsIntrinsic(Instruction inst)
+        {
+            return inst == Instruction.Extended;
+        }
+    }
+}