Added setting to prevent Ldvirtftn argument remove for better DCE optimisation.

Author: iskiselev

ICSharpCode.Decompiler/DecompilerSettings.cs

@@ -333,6 +333,21 @@ public CSharpFormattingOptions CSharpFormattingOptions {
 				}
 			}
 		}
+
+		bool skipLdvirtftnArgumentRemove = false;
+
+		public bool SkipLdvirtftnArgumentRemove
+		{
+			get { return skipLdvirtftnArgumentRemove; }
+			set
+            {
+				if (skipLdvirtftnArgumentRemove != value)
+				{
+					skipLdvirtftnArgumentRemove = value;
+					OnPropertyChanged("SkipLdvirtftnArgumentRemove");
+				}
+			}
+		}
 
 		public event PropertyChangedEventHandler PropertyChanged;
 

ICSharpCode.Decompiler/ILAst/ILAstOptimizer.cs

@@ -445,7 +445,8 @@ void IntroducePropertyAccessInstructions(ILExpression expr, ILExpression parentE
 				if (expr.Arguments[0].Match(ILCode.Ldloc, out target)
 				    && expr.Arguments[1].Code == ILCode.Ldvirtftn
 				    && expr.Arguments[1].Arguments.Count == 1
-				    && expr.Arguments[1].Arguments[0].MatchLdloc(target))
+				    && expr.Arguments[1].Arguments[0].MatchLdloc(target)
+				    && context.Settings.SkipLdvirtftnArgumentRemove)
 				{
 					// Remove the 'target' argument from the ldvirtftn instruction.
 					// It's not needed in the translation to C#, and needs to be eliminated so that the target expression