Helpers ILCode.IsConditionalControlFlow() and ILCode.IsUnconditionalControlFlow()

ICSharpCode.Decompiler/ILAst/GotoRemoval.cs

@@ -65,8 +65,9 @@ namespace ICSharpCode.Decompiler.ILAst
 					
 					int count = ilCase.Body.Count;
 					if (count >= 2) {
-						if (!ilCase.Body[count - 2].CanFallThough() &&
-						    ilCase.Body[count - 1].Match(ILCode.LoopOrSwitchBreak)) {
+						if (ilCase.Body[count - 2].IsUnconditionalControlFlow() &&
+						    ilCase.Body[count - 1].Match(ILCode.LoopOrSwitchBreak)) 
+						{
 							ilCase.Body.RemoveAt(count - 1);
 						}
 					}

ICSharpCode.Decompiler/ILAst/ILAstBuilder.cs

@@ -309,7 +309,7 @@ namespace ICSharpCode.Decompiler.ILAst
 				
 				// Find all successors
 				List<ByteCode> branchTargets = new List<ByteCode>();
-				if (byteCode.Code.CanFallThough()) {
+				if (!byteCode.Code.IsUnconditionalControlFlow()) {
 					branchTargets.Add(byteCode.Next);
 				}
 				if (byteCode.Operand is Instruction[]) {

ICSharpCode.Decompiler/ILAst/ILAstOptimizer.cs

@@ -309,15 +309,16 @@ namespace ICSharpCode.Decompiler.ILAst
 					
 					// Start a new basic block if necessary
 					if (currNode is ILLabel ||
-					    lastNode is ILTryCatchBlock ||
 					    currNode is ILTryCatchBlock ||
-					    (lastNode is ILExpression && ((ILExpression)lastNode).IsBranch()))
+					    lastNode is ILTryCatchBlock ||
+					    lastNode.IsConditionalControlFlow() ||
+					    lastNode.IsUnconditionalControlFlow())
 					{
 						// Try to reuse the label
 						ILLabel label = currNode is ILLabel ? ((ILLabel)currNode) : new ILLabel() { Name = "Block_" + (nextLabelIndex++) };
 						
 						// Terminate the last block
-						if (lastNode.CanFallThough()) {
+						if (!lastNode.IsUnconditionalControlFlow()) {
 							// Explicit branch from one block to other
 							basicBlock.FallthoughGoto = new ILExpression(ILCode.Br, label);
 						} else if (lastNode.Match(ILCode.Br)) {
@@ -432,8 +433,8 @@ namespace ICSharpCode.Decompiler.ILAst
 				for (int i = 0; i < block.Body.Count; i++) {
 					ILCondition cond = block.Body[i] as ILCondition;
 					if (cond != null) {
-						bool trueExits = cond.TrueBlock.Body.Count > 0 && !cond.TrueBlock.Body.Last().CanFallThough();
-						bool falseExits = cond.FalseBlock.Body.Count > 0 && !cond.FalseBlock.Body.Last().CanFallThough();
+						bool trueExits = cond.TrueBlock.Body.LastOrDefault().IsUnconditionalControlFlow();
+						bool falseExits = cond.FalseBlock.Body.LastOrDefault().IsUnconditionalControlFlow();
 						
 						if (trueExits) {
 							// Move the false block after the condition
@@ -504,13 +505,16 @@ namespace ICSharpCode.Decompiler.ILAst
 			return modified;
 		}
 		
-		public static bool CanFallThough(this ILNode node)
+		public static bool IsConditionalControlFlow(this ILNode node)
 		{
 			ILExpression expr = node as ILExpression;
-			if (expr != null) {
-				return expr.Code.CanFallThough();
-			}
-			return true;
+			return expr != null && expr.Code.IsConditionalControlFlow();
+		}
+		
+		public static bool IsUnconditionalControlFlow(this ILNode node)
+		{
+			ILExpression expr = node as ILExpression;
+			return expr != null && expr.Code.IsUnconditionalControlFlow();
 		}
 		
 		/// <summary>

ICSharpCode.Decompiler/ILAst/ILCodes.cs

@@ -280,7 +280,41 @@ namespace ICSharpCode.Decompiler.ILAst
 			return code.ToString().ToLowerInvariant().TrimStart('_').Replace('_','.');
 		}
 		
-		public static bool CanFallThough(this ILCode code)
+		public static bool IsConditionalControlFlow(this ILCode code)
+		{
+			switch(code) {
+				case ILCode.__Brfalse_S:
+				case ILCode.__Brtrue_S:
+				case ILCode.__Beq_S:
+				case ILCode.__Bge_S:
+				case ILCode.__Bgt_S:
+				case ILCode.__Ble_S:
+				case ILCode.__Blt_S:
+				case ILCode.__Bne_Un_S:
+				case ILCode.__Bge_Un_S:
+				case ILCode.__Bgt_Un_S:
+				case ILCode.__Ble_Un_S:
+				case ILCode.__Blt_Un_S:
+				case ILCode.__Brfalse:
+				case ILCode.Brtrue:
+				case ILCode.__Beq:
+				case ILCode.__Bge:
+				case ILCode.__Bgt:
+				case ILCode.__Ble:
+				case ILCode.__Blt:
+				case ILCode.__Bne_Un:
+				case ILCode.__Bge_Un:
+				case ILCode.__Bgt_Un:
+				case ILCode.__Ble_Un:
+				case ILCode.__Blt_Un:
+				case ILCode.Switch:
+					return true;
+				default:
+					return false;
+			}
+		}
+		
+		public static bool IsUnconditionalControlFlow(this ILCode code)
 		{
 			switch(code) {
 				case ILCode.Br:
@@ -295,9 +329,9 @@ namespace ICSharpCode.Decompiler.ILAst
 				case ILCode.LoopContinue:
 				case ILCode.LoopOrSwitchBreak:
 				case ILCode.YieldBreak:
-					return false;
-				default:
 					return true;
+				default:
+					return false;
 			}
 		}