JIT: Reset compGenTreeID on failed Materialize to avoid leaking gen tree IDs

src/coreclr/jit/scev.cpp

@@ -1451,7 +1451,18 @@ GenTree* ScalarEvolutionContext::Materialize(Scev* scev)
 {
     ValueNumPair vnp;
     GenTree*     result;
-    return Materialize(scev, true, &result, &vnp) ? result : nullptr;
+
+    // Materializing IR may create nodes before failing partway through (e.g.
+    // when a subexpression cannot be materialized). Snapshot the gen tree ID so
+    // that we can roll it back and avoid leaking IDs for the orphaned nodes.
+    INDEBUG(unsigned prevGenTreeID = m_compiler->compGenTreeID);
+    if (Materialize(scev, true, &result, &vnp))
+    {
+        return result;
+    }
+
+    INDEBUG(m_compiler->compGenTreeID = prevGenTreeID);
+    return nullptr;
 }
 
 //------------------------------------------------------------------------

src/tests/JIT/Regression/JitBlue/Runtime_129527/Runtime_129527.cs

@@ -0,0 +1,69 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Runtime_129527;
+
+using System.Runtime.Intrinsics.Arm;
+using System.Threading.Tasks;
+using Xunit;
+
+public struct S1
+{
+    public long F3;
+}
+
+public interface IRuntime
+{
+    void WriteLine<T>(string site, T value);
+}
+
+public sealed class Runtime : IRuntime
+{
+    public void WriteLine<T>(string site, T value)
+    {
+    }
+}
+
+public static class Runtime_129527
+{
+    private static IRuntime s_rt = new Runtime();
+    private static bool[] s_8 = new bool[1];
+    private static long s_13;
+
+    [Fact]
+    public static int TestEntryPoint()
+    {
+        M0();
+        return s_13 == 0 ? 100 : 101;
+    }
+
+    private static void M0()
+    {
+        uint var9 = default;
+        S1[] var24 = new S1[1];
+        ulong var34 = default;
+        try
+        {
+            var9 = 1;
+            s_8[0] |= false;
+        }
+        catch
+        {
+        }
+
+        for (int lvar31 = -2147483646; lvar31 > -2147483648; lvar31--)
+        {
+            ulong vr0 = (ulong)(lvar31 - var9++);
+            short var33 = Crc32.Arm64.IsSupported ? (short)Crc32.Arm64.ComputeCrc32C(0, vr0) : (short)vr0;
+            s_13 = var24[0].F3;
+            M6().GetAwaiter().GetResult();
+            s_rt.WriteLine("c_122", var34);
+            s_rt.WriteLine("c_126", var33);
+        }
+    }
+
+    private static async Task M6()
+    {
+        await Task.Yield();
+    }
+}

src/tests/JIT/Regression/Regression_ro_2.csproj

@@ -102,6 +102,7 @@
     <Compile Include="JitBlue\Runtime_128801\Runtime_128801.cs" />
     <Compile Include="JitBlue\Runtime_129076\Runtime_129076.cs" />
     <Compile Include="JitBlue\Runtime_129176\Runtime_129176.cs" />
+    <Compile Include="JitBlue\Runtime_129527\Runtime_129527.cs" />
     <Compile Include="JitBlue\Runtime_10337\Runtime_10337.cs" />
   </ItemGroup>
   <Import Project="$(TestSourceDir)MergedTestRunner.targets" />