From 89083eaf48ca3cf1e151497803ff4fbcc013b135 Mon Sep 17 00:00:00 2001
From: Daniel Grunwald <daniel@danielgrunwald.de>
Date: Sat, 23 Aug 2025 15:50:54 +0200
Subject: [PATCH] Fix #3344: Add support for the `ckfinite` opcode.

---
 .../ICSharpCode.Decompiler.Tests.csproj       |  2 +
 .../ILPrettyTestRunner.cs                     |  6 +++
 .../TestCases/ILPretty/Issue3344CkFinite.cs   | 22 +++++++++
 .../TestCases/ILPretty/Issue3344CkFinite.il   | 48 +++++++++++++++++++
 .../CSharp/StatementBuilder.cs                | 27 +++++++++++
 5 files changed, 105 insertions(+)
 create mode 100644 ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue3344CkFinite.cs
 create mode 100644 ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue3344CkFinite.il

diff --git a/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj b/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
index 941e2d87c..c13352fec 100644
--- a/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
+++ b/ICSharpCode.Decompiler.Tests/ICSharpCode.Decompiler.Tests.csproj
@@ -100,6 +100,7 @@
     <None Include="TestCases\ILPretty\GuessAccessors.il" />
     <None Include="TestCases\ILPretty\Issue2260SwitchString.il" />
     <None Include="TestCases\ILPretty\Issue3442.il" />
+    <None Include="TestCases\ILPretty\Issue3344CkFinite.il" />
     <None Include="TestCases\ILPretty\Issue3466.il" />
     <None Include="testcases\ilpretty\Issue3504.il" />
     <None Include="testcases\ilpretty\Issue3524.il" />
@@ -142,6 +143,7 @@
     <Compile Include="ProjectDecompiler\TargetFrameworkTests.cs" />
     <Compile Include="ProjectDecompiler\WholeProjectDecompilerTests.cs" />
     <Compile Include="TestAssemblyResolver.cs" />
+    <Compile Include="TestCases\ILPretty\Issue3344CkFinite.cs" />
     <Compile Include="TestCases\ILPretty\Issue3421.cs" />
     <Compile Include="TestCases\ILPretty\Issue3442.cs" />
     <Compile Include="TestCases\ILPretty\Issue3466.cs" />
diff --git a/ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs b/ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs
index 2fc5bbc87..4bfbfb812 100644
--- a/ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs
+++ b/ICSharpCode.Decompiler.Tests/ILPrettyTestRunner.cs
@@ -207,6 +207,12 @@ namespace ICSharpCode.Decompiler.Tests
 			await Run();
 		}
 
+		[Test]
+		public async Task Issue3344CkFinite()
+		{
+			await Run();
+		}
+
 		[Test]
 		public async Task Issue3421()
 		{
diff --git a/ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue3344CkFinite.cs b/ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue3344CkFinite.cs
new file mode 100644
index 000000000..0f8e6287e
--- /dev/null
+++ b/ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue3344CkFinite.cs
@@ -0,0 +1,22 @@
+using System;
+
+namespace ICSharpCode.Decompiler.Tests.TestCases.ILPretty
+{
+	public class Issue3344
+	{
+		private static float GetFloat()
+		{
+			return 3.5f;
+		}
+
+		private static float CkFinite()
+		{
+			float num = GetFloat();
+			if (!float.IsFinite(num))
+			{
+				throw new ArithmeticException();
+			}
+			return num;
+		}
+	}
+}
\ No newline at end of file
diff --git a/ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue3344CkFinite.il b/ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue3344CkFinite.il
new file mode 100644
index 000000000..f5a0c84f9
--- /dev/null
+++ b/ICSharpCode.Decompiler.Tests/TestCases/ILPretty/Issue3344CkFinite.il
@@ -0,0 +1,48 @@
+.assembly extern System.Runtime
+{
+	.publickeytoken = (B7 7A 5C 56 19 34 E0 89 )                         // .z\V.4..
+	.ver 4:0:0:0
+}
+
+.assembly Issue3344
+{
+	.hash algorithm 0x00008004 // SHA1
+	.ver 0:0:0:0
+}
+
+.class public auto ansi beforefieldinit ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue3344
+	extends [System.Runtime]System.Object
+{
+    .method private hidebysig static 
+        float32 GetFloat () cil managed 
+    {
+        .maxstack 8
+
+        IL_0000: ldc.r4 3.5
+        IL_0005: ret
+    }
+
+    .method private hidebysig static 
+        float32 CkFinite () cil managed 
+    {
+        .maxstack 1
+        .locals init (
+            [0] float32
+        )
+
+        call float32 ICSharpCode.Decompiler.Tests.TestCases.ILPretty.Issue3344::GetFloat()
+        ckfinite
+        ret
+    }
+
+	.method public hidebysig specialname rtspecialname 
+		instance void .ctor () cil managed 
+	{
+		.maxstack 8
+
+		IL_0000: ldarg.0
+		IL_0001: call instance void [System.Runtime]System.Object::.ctor()
+		IL_0006: ret
+	}
+
+}
\ No newline at end of file
diff --git a/ICSharpCode.Decompiler/CSharp/StatementBuilder.cs b/ICSharpCode.Decompiler/CSharp/StatementBuilder.cs
index 3e8dba558..d3f1cc838 100644
--- a/ICSharpCode.Decompiler/CSharp/StatementBuilder.cs
+++ b/ICSharpCode.Decompiler/CSharp/StatementBuilder.cs
@@ -1542,5 +1542,32 @@ namespace ICSharpCode.Decompiler.CSharp
 			stmt.InsertChildAfter(null, new Comment(" IL cpblk instruction"), Roles.Comment);
 			return stmt.WithILInstruction(inst);
 		}
+
+		protected internal override TranslatedStatement VisitCkfinite(Ckfinite inst)
+		{
+			var isFiniteCall = new InvocationExpression {
+				Target = new MemberReferenceExpression {
+					Target = new TypeReferenceExpression(new Syntax.PrimitiveType("float")),
+					MemberName = "IsFinite"
+				},
+				Arguments = {
+					exprBuilder.Translate(inst.Argument)
+				}
+			};
+			var arithmeticException = typeSystem.FindType(typeof(ArithmeticException));
+			var arithmeticExceptionSyntax = new SimpleType("ArithmeticException");
+			arithmeticExceptionSyntax.AddAnnotation(new TypeResolveResult(arithmeticException));
+			return new IfElseStatement {
+				Condition = new UnaryOperatorExpression {
+					Operator = UnaryOperatorType.Not,
+					Expression = isFiniteCall
+				},
+				TrueStatement = new ThrowStatement(
+					new ObjectCreateExpression {
+						Type = arithmeticExceptionSyntax
+					}
+				),
+			}.WithILInstruction(inst);
+		}
 	}
 }