Implement soft float64 conversion on shaders when host has no support (#5159)

* Implement soft float64 conversion on shaders when host has no support

* Shader cache version bump

* Fix rebase error

src/Ryujinx.Graphics.Shader/Translation/Optimizations/DoubleToFloat.cs

@@ -0,0 +1,70 @@
+using Ryujinx.Graphics.Shader.IntermediateRepresentation;
+using System.Collections.Generic;
+
+using static Ryujinx.Graphics.Shader.IntermediateRepresentation.OperandHelper;
+
+namespace Ryujinx.Graphics.Shader.Translation.Optimizations
+{
+    static class DoubleToFloat
+    {
+        public static void RunPass(HelperFunctionManager hfm, BasicBlock block)
+        {
+            for (LinkedListNode<INode> node = block.Operations.First; node != null; node = node.Next)
+            {
+                if (node.Value is not Operation operation)
+                {
+                    continue;
+                }
+
+                node = InsertSoftFloat64(hfm, node);
+            }
+        }
+
+        private static LinkedListNode<INode> InsertSoftFloat64(HelperFunctionManager hfm, LinkedListNode<INode> node)
+        {
+            Operation operation = (Operation)node.Value;
+
+            if (operation.Inst == Instruction.PackDouble2x32)
+            {
+                int functionId = hfm.GetOrCreateFunctionId(HelperFunctionName.ConvertDoubleToFloat);
+
+                Operand[] callArgs = new Operand[] { Const(functionId), operation.GetSource(0), operation.GetSource(1) };
+
+                Operand floatValue = operation.Dest;
+
+                operation.Dest = null;
+
+                LinkedListNode<INode> newNode = node.List.AddBefore(node, new Operation(Instruction.Call, 0, floatValue, callArgs));
+
+                Utils.DeleteNode(node, operation);
+
+                return newNode;
+            }
+            else if (operation.Inst == Instruction.UnpackDouble2x32)
+            {
+                int functionId = hfm.GetOrCreateFunctionId(HelperFunctionName.ConvertFloatToDouble);
+
+                // TODO: Allow UnpackDouble2x32 to produce two outputs and get rid of "operation.Index".
+
+                Operand resultLow = operation.Index == 0 ? operation.Dest : Local();
+                Operand resultHigh = operation.Index == 1 ? operation.Dest : Local();
+
+                operation.Dest = null;
+
+                Operand[] callArgs = new Operand[] { Const(functionId), operation.GetSource(0), resultLow, resultHigh };
+
+                LinkedListNode<INode> newNode = node.List.AddBefore(node, new Operation(Instruction.Call, 0, (Operand)null, callArgs));
+
+                Utils.DeleteNode(node, operation);
+
+                return newNode;
+            }
+            else
+            {
+                operation.TurnDoubleIntoFloat();
+
+                return node;
+            }
+        }
+    }
+}