Fixed disassembling and decompiling negative zeroes.

ICSharpCode.Decompiler/Disassembler/DisassemblerHelpers.cs

@@ -359,6 +359,10 @@ namespace ICSharpCode.Decompiler.Disassembler
 			} else if (operand is float) {
 				float val = (float)operand;
 				if (val == 0) {
+					if (1 / val == float.NegativeInfinity) {
+						// negative zero is a special case
+						writer.Write('-');
+					}
 					writer.Write("0.0");
 				} else if (float.IsInfinity(val) || float.IsNaN(val)) {
 					byte[] data = BitConverter.GetBytes(val);
@@ -375,6 +379,10 @@ namespace ICSharpCode.Decompiler.Disassembler
 			} else if (operand is double) {
 				double val = (double)operand;
 				if (val == 0) {
+					if (1 / val == double.NegativeInfinity) {
+						// negative zero is a special case
+						writer.Write('-');
+					}
 					writer.Write("0.0");
 				} else if (double.IsInfinity(val) || double.IsNaN(val)) {
 					byte[] data = BitConverter.GetBytes(val);

ICSharpCode.Decompiler/Tests/DoubleConstants.cs

@@ -0,0 +1,28 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+
+public class DoubleConstants
+{
+	public const double Zero = 0.0;
+	public const double MinusZero = -0.0;
+	public const double NaN = double.NaN;
+	public const double PositiveInfinity = double.PositiveInfinity;
+	public const double NegativeInfinity = double.NegativeInfinity;
+}

ICSharpCode.Decompiler/Tests/ICSharpCode.Decompiler.Tests.csproj

@@ -67,6 +67,7 @@
     <Compile Include="CallOverloadedMethod.cs" />
     <Compile Include="CheckedUnchecked.cs" />
     <Compile Include="ControlFlow.cs" />
+    <Compile Include="DoubleConstants.cs" />
     <Compile Include="ExpressionTrees.cs" />
     <None Include="IL\SequenceOfNestedIfs.Output.cs" />
     <Compile Include="IL\ILTests.cs" />

ICSharpCode.Decompiler/Tests/TestRunner.cs

@@ -88,6 +88,12 @@ namespace ICSharpCode.Decompiler.Tests
 			TestFile(@"..\..\Tests\ControlFlow.cs", optimize: false, useDebug: true);
 		}
 		
+		[Test]
+		public void DoubleConstants()
+		{
+			TestFile(@"..\..\Tests\DoubleConstants.cs");
+		}
+		
 		[Test]
 		public void IncrementDecrement()
 		{

NRefactory/ICSharpCode.NRefactory.CSharp/OutputVisitor/CSharpOutputVisitor.cs

@@ -1057,6 +1057,12 @@ namespace ICSharpCode.NRefactory.CSharp
 					}
 					return;
 				}
+				if (f == 0 && 1 / f == double.NegativeInfinity) {
+					// negative zero is a special case
+					// (again, not a primitive expression, but it's better to handle
+					// the special case here than to do it in all code generators)
+					formatter.WriteToken("-");
+				}
 				formatter.WriteToken(f.ToString("R", NumberFormatInfo.InvariantInfo) + "f");
 				lastWritten = LastWritten.Other;
 			} else if (val is double) {
@@ -1075,6 +1081,12 @@ namespace ICSharpCode.NRefactory.CSharp
 					}
 					return;
 				}
+				if (f == 0 && 1 / f == double.NegativeInfinity) {
+					// negative zero is a special case
+					// (again, not a primitive expression, but it's better to handle
+					// the special case here than to do it in all code generators)
+					formatter.WriteToken("-");
+				}
 				string number = f.ToString("R", NumberFormatInfo.InvariantInfo);
 				if (number.IndexOf('.') < 0 && number.IndexOf('E') < 0) {
 					number += ".0";