New shader translator implementation (#654)

* Start implementing a new shader translator

* Fix shift instructions and a typo

* Small refactoring on StructuredProgram, move RemovePhis method to a separate class

* Initial geometry shader support

* Implement TLD4

* Fix -- There's no negation on FMUL32I

* Add constant folding and algebraic simplification optimizations, nits

* Some leftovers from constant folding

* Avoid cast for constant assignments

* Add a branch elimination pass, and misc small fixes

* Remove redundant branches, add expression propagation and other improvements on the code

* Small leftovers -- add missing break and continue, remove unused properties, other improvements

* Add null check to handle empty block cases on block visitor

* Add HADD2 and HMUL2 half float shader instructions

* Optimize pack/unpack sequences, some fixes related to half float instructions

* Add TXQ, TLD, TLDS and TLD4S shader texture instructions, and some support for bindless textures, some refactoring on codegen

* Fix copy paste mistake that caused RZ to be ignored on the AST instruction

* Add workaround for conditional exit, and fix half float instruction with constant buffer

* Add missing 0.0 source for TLDS.LZ variants

* Simplify the switch for TLDS.LZ

* Texture instructions related fixes

* Implement the HFMA instruction, and some misc. fixes

* Enable constant folding on UnpackHalf2x16 instructions

* Refactor HFMA to use OpCode* for opcode decoding rather than on the helper methods

* Remove the old shader translator

* Remove ShaderDeclInfo and other unused things

* Add dual vertex shader support

* Add ShaderConfig, used to pass shader type and maximum cbuffer size

* Move and rename some instruction enums

* Move texture instructions into a separate file

* Move operand GetExpression and locals management to OperandManager

* Optimize opcode decoding using a simple list and binary search

* Add missing condition for do-while on goto elimination

* Misc. fixes on texture instructions

* Simplify TLDS switch

* Address PR feedback, and a nit

5 files changed, 753 insertions, 0 deletions

diff --git a/Ryujinx.Graphics/Shader/Translation/Optimizations/BranchElimination.cs b/Ryujinx.Graphics/Shader/Translation/Optimizations/BranchElimination.cs
new file mode 100644
index 00000000..2b0f1905
--- /dev/null
+++ b/Ryujinx.Graphics/Shader/Translation/Optimizations/BranchElimination.cs
@@ -0,0 +1,64 @@
+using Ryujinx.Graphics.Shader.IntermediateRepresentation;
+using System;
+
+namespace Ryujinx.Graphics.Shader.Translation.Optimizations
+{
+    static class BranchElimination
+    {
+        public static bool Eliminate(BasicBlock block)
+        {
+            if (block.HasBranch && IsRedundantBranch((Operation)block.GetLastOp(), Next(block)))
+            {
+                block.Branch = null;
+
+                return true;
+            }
+
+            return false;
+        }
+
+        private static bool IsRedundantBranch(Operation current, BasicBlock nextBlock)
+        {
+            //Here we check that:
+            //- The current block ends with a branch.
+            //- The next block only contains a branch.
+            //- The branch on the next block is unconditional.
+            //- Both branches are jumping to the same location.
+            //In this case, the branch on the current block can be removed,
+            //as the next block is going to jump to the same place anyway.
+            if (nextBlock == null)
+            {
+                return false;
+            }
+
+            if (!(nextBlock.Operations.First?.Value is Operation next))
+            {
+                return false;
+            }
+
+            if (next.Inst != Instruction.Branch)
+            {
+                return false;
+            }
+
+            return current.Dest == next.Dest;
+        }
+
+        private static BasicBlock Next(BasicBlock block)
+        {
+            block = block.Next;
+
+            while (block != null && block.Operations.Count == 0)
+            {
+                if (block.HasBranch)
+                {
+                    throw new InvalidOperationException("Found a bogus empty block that \"ends with a branch\".");
+                }
+
+                block = block.Next;
+            }
+
+            return block;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Ryujinx.Graphics/Shader/Translation/Optimizations/ConstantFolding.cs b/Ryujinx.Graphics/Shader/Translation/Optimizations/ConstantFolding.cs
new file mode 100644
index 00000000..a2e05ef1
--- /dev/null
+++ b/Ryujinx.Graphics/Shader/Translation/Optimizations/ConstantFolding.cs
@@ -0,0 +1,323 @@
+using Ryujinx.Graphics.Shader.Decoders;
+using Ryujinx.Graphics.Shader.IntermediateRepresentation;
+using System;
+
+using static Ryujinx.Graphics.Shader.IntermediateRepresentation.OperandHelper;
+
+namespace Ryujinx.Graphics.Shader.Translation.Optimizations
+{
+    static class ConstantFolding
+    {
+        public static void Fold(Operation operation)
+        {
+            if (!AreAllSourcesConstant(operation))
+            {
+                return;
+            }
+
+            switch (operation.Inst)
+            {
+                case Instruction.Add:
+                    EvaluateBinary(operation, (x, y) => x + y);
+                    break;
+
+                case Instruction.BitwiseAnd:
+                    EvaluateBinary(operation, (x, y) => x & y);
+                    break;
+
+                case Instruction.BitwiseExclusiveOr:
+                    EvaluateBinary(operation, (x, y) => x ^ y);
+                    break;
+
+                case Instruction.BitwiseNot:
+                    EvaluateUnary(operation, (x) => ~x);
+                    break;
+
+                case Instruction.BitwiseOr:
+                    EvaluateBinary(operation, (x, y) => x | y);
+                    break;
+
+                case Instruction.BitfieldExtractS32:
+                    BitfieldExtractS32(operation);
+                    break;
+
+                case Instruction.BitfieldExtractU32:
+                    BitfieldExtractU32(operation);
+                    break;
+
+                case Instruction.Clamp:
+                    EvaluateTernary(operation, (x, y, z) => Math.Clamp(x, y, z));
+                    break;
+
+                case Instruction.ClampU32:
+                    EvaluateTernary(operation, (x, y, z) => (int)Math.Clamp((uint)x, (uint)y, (uint)z));
+                    break;
+
+                case Instruction.CompareEqual:
+                    EvaluateBinary(operation, (x, y) => x == y);
+                    break;
+
+                case Instruction.CompareGreater:
+                    EvaluateBinary(operation, (x, y) => x > y);
+                    break;
+
+                case Instruction.CompareGreaterOrEqual:
+                    EvaluateBinary(operation, (x, y) => x >= y);
+                    break;
+
+                case Instruction.CompareGreaterOrEqualU32:
+                    EvaluateBinary(operation, (x, y) => (uint)x >= (uint)y);
+                    break;
+
+                case Instruction.CompareGreaterU32:
+                    EvaluateBinary(operation, (x, y) => (uint)x > (uint)y);
+                    break;
+
+                case Instruction.CompareLess:
+                    EvaluateBinary(operation, (x, y) => x < y);
+                    break;
+
+                case Instruction.CompareLessOrEqual:
+                    EvaluateBinary(operation, (x, y) => x <= y);
+                    break;
+
+                case Instruction.CompareLessOrEqualU32:
+                    EvaluateBinary(operation, (x, y) => (uint)x <= (uint)y);
+                    break;
+
+                case Instruction.CompareLessU32:
+                    EvaluateBinary(operation, (x, y) => (uint)x < (uint)y);
+                    break;
+
+                case Instruction.CompareNotEqual:
+                    EvaluateBinary(operation, (x, y) => x != y);
+                    break;
+
+                case Instruction.Divide:
+                    EvaluateBinary(operation, (x, y) => y != 0 ? x / y : 0);
+                    break;
+
+                case Instruction.FP | Instruction.Add:
+                    EvaluateFPBinary(operation, (x, y) => x + y);
+                    break;
+
+                case Instruction.FP | Instruction.Clamp:
+                    EvaluateFPTernary(operation, (x, y, z) => Math.Clamp(x, y, z));
+                    break;
+
+                case Instruction.FP | Instruction.CompareEqual:
+                    EvaluateFPBinary(operation, (x, y) => x == y);
+                    break;
+
+                case Instruction.FP | Instruction.CompareGreater:
+                    EvaluateFPBinary(operation, (x, y) => x > y);
+                    break;
+
+                case Instruction.FP | Instruction.CompareGreaterOrEqual:
+                    EvaluateFPBinary(operation, (x, y) => x >= y);
+                    break;
+
+                case Instruction.FP | Instruction.CompareLess:
+                    EvaluateFPBinary(operation, (x, y) => x < y);
+                    break;
+
+                case Instruction.FP | Instruction.CompareLessOrEqual:
+                    EvaluateFPBinary(operation, (x, y) => x <= y);
+                    break;
+
+                case Instruction.FP | Instruction.CompareNotEqual:
+                    EvaluateFPBinary(operation, (x, y) => x != y);
+                    break;
+
+                case Instruction.FP | Instruction.Divide:
+                    EvaluateFPBinary(operation, (x, y) => x / y);
+                    break;
+
+                case Instruction.FP | Instruction.Multiply:
+                    EvaluateFPBinary(operation, (x, y) => x * y);
+                    break;
+
+                case Instruction.FP | Instruction.Negate:
+                    EvaluateFPUnary(operation, (x) => -x);
+                    break;
+
+                case Instruction.FP | Instruction.Subtract:
+                    EvaluateFPBinary(operation, (x, y) => x - y);
+                    break;
+
+                case Instruction.IsNan:
+                    EvaluateFPUnary(operation, (x) => float.IsNaN(x));
+                    break;
+
+                case Instruction.Maximum:
+                    EvaluateBinary(operation, (x, y) => Math.Max(x, y));
+                    break;
+
+                case Instruction.MaximumU32:
+                    EvaluateBinary(operation, (x, y) => (int)Math.Max((uint)x, (uint)y));
+                    break;
+
+                case Instruction.Minimum:
+                    EvaluateBinary(operation, (x, y) => Math.Min(x, y));
+                    break;
+
+                case Instruction.MinimumU32:
+                    EvaluateBinary(operation, (x, y) => (int)Math.Min((uint)x, (uint)y));
+                    break;
+
+                case Instruction.Multiply:
+                    EvaluateBinary(operation, (x, y) => x * y);
+                    break;
+
+                case Instruction.Negate:
+                    EvaluateUnary(operation, (x) => -x);
+                    break;
+
+                case Instruction.ShiftLeft:
+                    EvaluateBinary(operation, (x, y) => x << y);
+                    break;
+
+                case Instruction.ShiftRightS32:
+                    EvaluateBinary(operation, (x, y) => x >> y);
+                    break;
+
+                case Instruction.ShiftRightU32:
+                    EvaluateBinary(operation, (x, y) => (int)((uint)x >> y));
+                    break;
+
+                case Instruction.Subtract:
+                    EvaluateBinary(operation, (x, y) => x - y);
+                    break;
+
+                case Instruction.UnpackHalf2x16:
+                    UnpackHalf2x16(operation);
+                    break;
+            }
+        }
+
+        private static bool AreAllSourcesConstant(Operation operation)
+        {
+            for (int index = 0; index < operation.SourcesCount; index++)
+            {
+                if (operation.GetSource(index).Type != OperandType.Constant)
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        private static void BitfieldExtractS32(Operation operation)
+        {
+            int value = GetBitfieldExtractValue(operation);
+
+            int shift = 32 - operation.GetSource(2).Value;
+
+            value = (value << shift) >> shift;
+
+            operation.TurnIntoCopy(Const(value));
+        }
+
+        private static void BitfieldExtractU32(Operation operation)
+        {
+            operation.TurnIntoCopy(Const(GetBitfieldExtractValue(operation)));
+        }
+
+        private static int GetBitfieldExtractValue(Operation operation)
+        {
+            int value  = operation.GetSource(0).Value;
+            int lsb    = operation.GetSource(1).Value;
+            int length = operation.GetSource(2).Value;
+
+            return value.Extract(lsb, length);
+        }
+
+        private static void UnpackHalf2x16(Operation operation)
+        {
+            int value = operation.GetSource(0).Value;
+
+            value = (value >> operation.ComponentIndex * 16) & 0xffff;
+
+            operation.TurnIntoCopy(ConstF(HalfConversion.HalfToSingle(value)));
+        }
+
+        private static void FPNegate(Operation operation)
+        {
+            float value = operation.GetSource(0).AsFloat();
+
+            operation.TurnIntoCopy(ConstF(-value));
+        }
+
+        private static void EvaluateUnary(Operation operation, Func<int, int> op)
+        {
+            int x = operation.GetSource(0).Value;
+
+            operation.TurnIntoCopy(Const(op(x)));
+        }
+
+        private static void EvaluateFPUnary(Operation operation, Func<float, float> op)
+        {
+            float x = operation.GetSource(0).AsFloat();
+
+            operation.TurnIntoCopy(ConstF(op(x)));
+        }
+
+        private static void EvaluateFPUnary(Operation operation, Func<float, bool> op)
+        {
+            float x = operation.GetSource(0).AsFloat();
+
+            operation.TurnIntoCopy(Const(op(x) ? IrConsts.True : IrConsts.False));
+        }
+
+        private static void EvaluateBinary(Operation operation, Func<int, int, int> op)
+        {
+            int x = operation.GetSource(0).Value;
+            int y = operation.GetSource(1).Value;
+
+            operation.TurnIntoCopy(Const(op(x, y)));
+        }
+
+        private static void EvaluateBinary(Operation operation, Func<int, int, bool> op)
+        {
+            int x = operation.GetSource(0).Value;
+            int y = operation.GetSource(1).Value;
+
+            operation.TurnIntoCopy(Const(op(x, y) ? IrConsts.True : IrConsts.False));
+        }
+
+        private static void EvaluateFPBinary(Operation operation, Func<float, float, float> op)
+        {
+            float x = operation.GetSource(0).AsFloat();
+            float y = operation.GetSource(1).AsFloat();
+
+            operation.TurnIntoCopy(ConstF(op(x, y)));
+        }
+
+        private static void EvaluateFPBinary(Operation operation, Func<float, float, bool> op)
+        {
+            float x = operation.GetSource(0).AsFloat();
+            float y = operation.GetSource(1).AsFloat();
+
+            operation.TurnIntoCopy(Const(op(x, y) ? IrConsts.True : IrConsts.False));
+        }
+
+        private static void EvaluateTernary(Operation operation, Func<int, int, int, int> op)
+        {
+            int x = operation.GetSource(0).Value;
+            int y = operation.GetSource(1).Value;
+            int z = operation.GetSource(2).Value;
+
+            operation.TurnIntoCopy(Const(op(x, y, z)));
+        }
+
+        private static void EvaluateFPTernary(Operation operation, Func<float, float, float, float> op)
+        {
+            float x = operation.GetSource(0).AsFloat();
+            float y = operation.GetSource(1).AsFloat();
+            float z = operation.GetSource(2).AsFloat();
+
+            operation.TurnIntoCopy(ConstF(op(x, y, z)));
+        }
+    }
+}
\ No newline at end of file
diff --git a/Ryujinx.Graphics/Shader/Translation/Optimizations/HalfConversion.cs b/Ryujinx.Graphics/Shader/Translation/Optimizations/HalfConversion.cs
new file mode 100644
index 00000000..9ef35abc
--- /dev/null
+++ b/Ryujinx.Graphics/Shader/Translation/Optimizations/HalfConversion.cs
@@ -0,0 +1,47 @@
+using System;
+
+namespace Ryujinx.Graphics.Shader.Translation.Optimizations
+{
+    static class HalfConversion
+    {
+        public static float HalfToSingle(int value)
+        {
+            int mantissa = (value >> 0)  & 0x3ff;
+            int exponent = (value >> 10) & 0x1f;
+            int sign     = (value >> 15) & 0x1;
+
+            if (exponent == 0x1f)
+            {
+                //NaN or Infinity.
+                mantissa <<= 13;
+                exponent   = 0xff;
+            }
+            else if (exponent != 0 || mantissa != 0 )
+            {
+                if (exponent == 0)
+                {
+                    //Denormal.
+                    int e = -1;
+                    int m = mantissa;
+
+                    do
+                    {
+                        e++;
+                        m <<= 1;
+                    }
+                    while ((m & 0x400) == 0);
+
+                    mantissa = m & 0x3ff;
+                    exponent = e;
+                }
+
+                mantissa <<= 13;
+                exponent   = 127 - 15 + exponent;
+            }
+
+            int output = (sign << 31) | (exponent << 23) | mantissa;
+
+            return BitConverter.Int32BitsToSingle(output);
+        }
+    }
+}
\ No newline at end of file
diff --git a/Ryujinx.Graphics/Shader/Translation/Optimizations/Optimizer.cs b/Ryujinx.Graphics/Shader/Translation/Optimizations/Optimizer.cs
new file mode 100644
index 00000000..88118e3a
--- /dev/null
+++ b/Ryujinx.Graphics/Shader/Translation/Optimizations/Optimizer.cs
@@ -0,0 +1,172 @@
+using Ryujinx.Graphics.Shader.IntermediateRepresentation;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Ryujinx.Graphics.Shader.Translation.Optimizations
+{
+    static class Optimizer
+    {
+        public static void Optimize(BasicBlock[] blocks)
+        {
+            bool modified;
+
+            do
+            {
+                modified = false;
+
+                for (int blkIndex = 0; blkIndex < blocks.Length; blkIndex++)
+                {
+                    BasicBlock block = blocks[blkIndex];
+
+                    LinkedListNode<INode> node = block.Operations.First;
+
+                    while (node != null)
+                    {
+                        LinkedListNode<INode> nextNode = node.Next;
+
+                        bool isUnused = IsUnused(node.Value);
+
+                        if (!(node.Value is Operation operation) || isUnused)
+                        {
+                            if (isUnused)
+                            {
+                                RemoveNode(block, node);
+
+                                modified = true;
+                            }
+
+                            node = nextNode;
+
+                            continue;
+                        }
+
+                        ConstantFolding.Fold(operation);
+
+                        Simplification.Simplify(operation);
+
+                        if (DestIsLocalVar(operation))
+                        {
+                            if (operation.Inst == Instruction.Copy)
+                            {
+                                PropagateCopy(operation);
+
+                                RemoveNode(block, node);
+
+                                modified = true;
+                            }
+                            else if (operation.Inst == Instruction.PackHalf2x16 && PropagatePack(operation))
+                            {
+                                if (operation.Dest.UseOps.Count == 0)
+                                {
+                                    RemoveNode(block, node);
+                                }
+
+                                modified = true;
+                            }
+                        }
+
+                        node = nextNode;
+                    }
+
+                    if (BranchElimination.Eliminate(block))
+                    {
+                        RemoveNode(block, block.Operations.Last);
+
+                        modified = true;
+                    }
+                }
+            }
+            while (modified);
+        }
+
+        private static void PropagateCopy(Operation copyOp)
+        {
+            //Propagate copy source operand to all uses of
+            //the destination operand.
+            Operand dest = copyOp.Dest;
+            Operand src  = copyOp.GetSource(0);
+
+            INode[] uses = dest.UseOps.ToArray();
+
+            foreach (INode useNode in uses)
+            {
+                for (int index = 0; index < useNode.SourcesCount; index++)
+                {
+                    if (useNode.GetSource(index) == dest)
+                    {
+                        useNode.SetSource(index, src);
+                    }
+                }
+            }
+        }
+
+        private static bool PropagatePack(Operation packOp)
+        {
+            //Propagate pack source operands to uses by unpack
+            //instruction. The source depends on the unpack instruction.
+            bool modified = false;
+
+            Operand dest = packOp.Dest;
+            Operand src0 = packOp.GetSource(0);
+            Operand src1 = packOp.GetSource(1);
+
+            INode[] uses = dest.UseOps.ToArray();
+
+            foreach (INode useNode in uses)
+            {
+                if (!(useNode is Operation operation) || operation.Inst != Instruction.UnpackHalf2x16)
+                {
+                    continue;
+                }
+
+                if (operation.GetSource(0) == dest)
+                {
+                    operation.TurnIntoCopy(operation.ComponentIndex == 1 ? src1 : src0);
+
+                    modified = true;
+                }
+            }
+
+            return modified;
+        }
+
+        private static void RemoveNode(BasicBlock block, LinkedListNode<INode> llNode)
+        {
+            //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);
+
+            Queue<INode> nodes = new Queue<INode>();
+
+            nodes.Enqueue(llNode.Value);
+
+            while (nodes.TryDequeue(out INode node))
+            {
+                for (int index = 0; index < node.SourcesCount; index++)
+                {
+                    Operand src = node.GetSource(index);
+
+                    if (src.Type != OperandType.LocalVariable)
+                    {
+                        continue;
+                    }
+
+                    if (src.UseOps.Remove(node) && src.UseOps.Count == 0)
+                    {
+                        nodes.Enqueue(src.AsgOp);
+                    }
+                }
+            }
+        }
+
+        private static bool IsUnused(INode node)
+        {
+            return DestIsLocalVar(node) && node.Dest.UseOps.Count == 0;
+        }
+
+        private static bool DestIsLocalVar(INode node)
+        {
+            return node.Dest != null && node.Dest.Type == OperandType.LocalVariable;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Ryujinx.Graphics/Shader/Translation/Optimizations/Simplification.cs b/Ryujinx.Graphics/Shader/Translation/Optimizations/Simplification.cs
new file mode 100644
index 00000000..56b1543f
--- /dev/null
+++ b/Ryujinx.Graphics/Shader/Translation/Optimizations/Simplification.cs
@@ -0,0 +1,147 @@
+using Ryujinx.Graphics.Shader.IntermediateRepresentation;
+
+using static Ryujinx.Graphics.Shader.IntermediateRepresentation.OperandHelper;
+
+namespace Ryujinx.Graphics.Shader.Translation.Optimizations
+{
+    static class Simplification
+    {
+        private const int AllOnes = ~0;
+
+        public static void Simplify(Operation operation)
+        {
+            switch (operation.Inst)
+            {
+                case Instruction.Add:
+                case Instruction.BitwiseExclusiveOr:
+                    TryEliminateBinaryOpComutative(operation, 0);
+                    break;
+
+                case Instruction.BitwiseAnd:
+                    TryEliminateBitwiseAnd(operation);
+                    break;
+
+                case Instruction.BitwiseOr:
+                    TryEliminateBitwiseOr(operation);
+                    break;
+
+                case Instruction.ConditionalSelect:
+                    TryEliminateConditionalSelect(operation);
+                    break;
+
+                case Instruction.Divide:
+                    TryEliminateBinaryOpY(operation, 1);
+                    break;
+
+                case Instruction.Multiply:
+                    TryEliminateBinaryOpComutative(operation, 1);
+                    break;
+
+                case Instruction.ShiftLeft:
+                case Instruction.ShiftRightS32:
+                case Instruction.ShiftRightU32:
+                case Instruction.Subtract:
+                    TryEliminateBinaryOpY(operation, 0);
+                    break;
+            }
+        }
+
+        private static void TryEliminateBitwiseAnd(Operation operation)
+        {
+            //Try to recognize and optimize those 3 patterns (in order):
+            //x & 0xFFFFFFFF == x,          0xFFFFFFFF & y == y,
+            //x & 0x00000000 == 0x00000000, 0x00000000 & y == 0x00000000
+            Operand x = operation.GetSource(0);
+            Operand y = operation.GetSource(1);
+
+            if (IsConstEqual(x, AllOnes))
+            {
+                operation.TurnIntoCopy(y);
+            }
+            else if (IsConstEqual(y, AllOnes))
+            {
+                operation.TurnIntoCopy(x);
+            }
+            else if (IsConstEqual(x, 0) || IsConstEqual(y, 0))
+            {
+                operation.TurnIntoCopy(Const(0));
+            }
+        }
+
+        private static void TryEliminateBitwiseOr(Operation operation)
+        {
+            //Try to recognize and optimize those 3 patterns (in order):
+            //x | 0x00000000 == x,          0x00000000 | y == y,
+            //x | 0xFFFFFFFF == 0xFFFFFFFF, 0xFFFFFFFF | y == 0xFFFFFFFF
+            Operand x = operation.GetSource(0);
+            Operand y = operation.GetSource(1);
+
+            if (IsConstEqual(x, 0))
+            {
+                operation.TurnIntoCopy(y);
+            }
+            else if (IsConstEqual(y, 0))
+            {
+                operation.TurnIntoCopy(x);
+            }
+            else if (IsConstEqual(x, AllOnes) || IsConstEqual(y, AllOnes))
+            {
+                operation.TurnIntoCopy(Const(AllOnes));
+            }
+        }
+
+        private static void TryEliminateBinaryOpY(Operation operation, int comparand)
+        {
+            Operand x = operation.GetSource(0);
+            Operand y = operation.GetSource(1);
+
+            if (IsConstEqual(y, comparand))
+            {
+                operation.TurnIntoCopy(x);
+            }
+        }
+
+        private static void TryEliminateBinaryOpComutative(Operation operation, int comparand)
+        {
+            Operand x = operation.GetSource(0);
+            Operand y = operation.GetSource(1);
+
+            if (IsConstEqual(x, comparand))
+            {
+                operation.TurnIntoCopy(y);
+            }
+            else if (IsConstEqual(y, comparand))
+            {
+                operation.TurnIntoCopy(x);
+            }
+        }
+
+        private static void TryEliminateConditionalSelect(Operation operation)
+        {
+            Operand cond = operation.GetSource(0);
+
+            if (cond.Type != OperandType.Constant)
+            {
+                return;
+            }
+
+            //The condition is constant, we can turn it into a copy, and select
+            //the source based on the condition value.
+            int srcIndex = cond.Value != 0 ? 1 : 2;
+
+            Operand source = operation.GetSource(srcIndex);
+
+            operation.TurnIntoCopy(source);
+        }
+
+        private static bool IsConstEqual(Operand operand, int comparand)
+        {
+            if (operand.Type != OperandType.Constant)
+            {
+                return false;
+            }
+
+            return operand.Value == comparand;
+        }
+    }
+}
\ No newline at end of file