Fixed some corner cases

ICSharpCode.Decompiler/ILAst/ILAstOptimizer.cs

@@ -839,7 +839,8 @@ namespace ICSharpCode.Decompiler.ILAst
 				}
 			}
 
-			adjustmentExpr = new ILExpression(divide ? ILCode.Div_Un : ILCode.Mul, null, adjustmentExpr, sizeOfExpression);
+			if (!(sizeOfExpression.Code == ILCode.Ldc_I4 && (int)sizeOfExpression.Operand == 1))
+				adjustmentExpr = new ILExpression(divide ? ILCode.Div_Un : ILCode.Mul, null, adjustmentExpr, sizeOfExpression);
 		}
 		
 		public static void ReplaceVariables(ILNode node, Func<ILVariable, ILVariable> variableMapping)

ICSharpCode.Decompiler/Tests/UnsafeCode.cs

@@ -143,6 +143,11 @@ public class UnsafeCode
 		return (long*)((byte*)p + 3);
 	}
 
+	public unsafe int PointerArithmetic5(void* p, byte* q, int i)
+	{
+		return (int)(q[i] + *(byte*)p);
+	}
+
 	public unsafe int PointerSubtraction(long* p, long* q)
 	{
 		return (int)((long)(p - q));