Initial work

Ryujinx.Graphics.Shader/StructuredIr/PhiFunctions.cs

@@ -0,0 +1,74 @@
+using Ryujinx.Graphics.Shader.IntermediateRepresentation;
+using System.Collections.Generic;
+
+namespace Ryujinx.Graphics.Shader.StructuredIr
+{
+    static class PhiFunctions
+    {
+        public static void Remove(BasicBlock[] blocks)
+        {
+            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;
+
+                    if (!(node.Value is PhiNode phi))
+                    {
+                        node = nextNode;
+
+                        continue;
+                    }
+
+                    for (int index = 0; index < phi.SourcesCount; index++)
+                    {
+                        Operand src = phi.GetSource(index);
+
+                        BasicBlock srcBlock = phi.GetBlock(index);
+
+                        Operation copyOp = new Operation(Instruction.Copy, phi.Dest, src);
+
+                        AddBeforeBranch(srcBlock, copyOp);
+                    }
+
+                    block.Operations.Remove(node);
+
+                    node = nextNode;
+                }
+            }
+        }
+
+        private static void AddBeforeBranch(BasicBlock block, INode node)
+        {
+            INode lastOp = block.GetLastOp();
+
+            if (lastOp is Operation operation && IsControlFlowInst(operation.Inst))
+            {
+                block.Operations.AddBefore(block.Operations.Last, node);
+            }
+            else
+            {
+                block.Operations.AddLast(node);
+            }
+        }
+
+        private static bool IsControlFlowInst(Instruction inst)
+        {
+            switch (inst)
+            {
+                case Instruction.Branch:
+                case Instruction.BranchIfFalse:
+                case Instruction.BranchIfTrue:
+                case Instruction.Discard:
+                case Instruction.Return:
+                    return true;
+            }
+
+            return false;
+        }
+    }
+}