Fix #2398: TranslateCondition: truncate condition value if necessary

ICSharpCode.Decompiler.Tests/TestCases/Correctness/Comparisons.cs

@@ -44,6 +44,10 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Correctness
 			TestUShort(0);
 			TestUShort(ushort.MaxValue);
 
+			Console.WriteLine("Issue2398:");
+			Issue2398(0x100000000);
+
+			Console.WriteLine("OverloadedOperators:");
 			Console.WriteLine(IsNotNull(new OverloadedOperators()));
 			Console.WriteLine(IsNull(new OverloadedOperators()));
 			Console.WriteLine(NullIs(new OverloadedOperators()));
@@ -88,6 +92,12 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Correctness
 			Console.WriteLine("uint: {0} == Id(-1) = {1}", i, i == Id(-1));
 		}
 
+		static void Issue2398(long value)
+		{
+			if ((int)value != 0)
+				Console.WriteLine("TRUE");
+		}
+
 		static bool IsNull(OverloadedOperators oo)
 		{
 			return (object)oo == null;

ICSharpCode.Decompiler.Tests/TestCases/Pretty/TypeAnalysisTests.cs

@@ -306,5 +306,15 @@ namespace ICSharpCode.Decompiler.Tests.TestCases.Pretty
 		{
 			return (string)(object)a;
 		}
+
+		public static bool CompareLast32Bits(long a, long b)
+		{
+			return (int)a == (int)b;
+		}
+
+		public static bool Last32BitsAreZero(long a)
+		{
+			return (int)a == 0;
+		}
 	}
 }

ICSharpCode.Decompiler/CSharp/ExpressionBuilder.cs

@@ -198,7 +198,12 @@ namespace ICSharpCode.Decompiler.CSharp
 
 		public TranslatedExpression TranslateCondition(ILInstruction condition, bool negate = false)
 		{
+			Debug.Assert(condition.ResultType == StackType.I4);
 			var expr = Translate(condition, compilation.FindType(KnownTypeCode.Boolean));
+			if (expr.Type.GetStackType().GetSize() > 4)
+			{
+				expr = expr.ConvertTo(FindType(StackType.I4, expr.Type.GetSign()), this);
+			}
 			return expr.ConvertToBoolean(this, negate);
 		}
 
@@ -3618,6 +3623,10 @@ namespace ICSharpCode.Decompiler.CSharp
 			// We can only correctly translate it to C# if the rhs is of type boolean:
 			if (op != BinaryOperatorType.Any && (rhs.Type.IsKnownType(KnownTypeCode.Boolean) || IfInstruction.IsInConditionSlot(inst)))
 			{
+				if (rhs.Type.GetStackType().GetSize() > 4)
+				{
+					rhs = rhs.ConvertTo(FindType(StackType.I4, rhs.Type.GetSign()), this);
+				}
 				rhs = rhs.ConvertToBoolean(this);
 				return new BinaryOperatorExpression(condition, op, rhs)
 					.WithILInstruction(inst)