Normalize TYP_STRUCT to TYP_SIMD in impInlineUnboxNullable (#116372)

Author: EgorBo

src/coreclr/jit/importer.cpp

@@ -2934,18 +2934,22 @@ GenTree* Compiler::impInlineUnboxNullable(CORINFO_CLASS_HANDLE nullableCls, GenT
     //  result._hasValue = true;
     //  result._value = MethodTableLookup(obj);
     //
-    CORINFO_FIELD_HANDLE valueFldHnd = info.compCompHnd->getFieldInClass(nullableCls, 1);
-    CORINFO_CLASS_HANDLE valueStructCls;
-    var_types            valueType = JITtype2varType(info.compCompHnd->getFieldType(valueFldHnd, &valueStructCls));
+    CORINFO_FIELD_HANDLE valueFldHnd    = info.compCompHnd->getFieldInClass(nullableCls, 1);
+    CORINFO_CLASS_HANDLE valueStructCls = NO_CLASS_HANDLE;
+    ClassLayout*         layout         = nullptr;
+
+    CorInfoType corFldType = info.compCompHnd->getFieldType(valueFldHnd, &valueStructCls);
+    var_types   valueType  = TypeHandleToVarType(corFldType, valueStructCls, &layout);
+
     static_assert_no_msg(OFFSETOF__CORINFO_NullableOfT__hasValue == 0);
     unsigned hasValOffset = OFFSETOF__CORINFO_NullableOfT__hasValue;
     unsigned valueOffset  = info.compCompHnd->getFieldOffset(valueFldHnd);
 
     GenTree* boxedContentAddr =
         gtNewOperNode(GT_ADD, TYP_BYREF, gtCloneExpr(objClone), gtNewIconNode(TARGET_POINTER_SIZE, TYP_I_IMPL));
     // Load the boxed content from the object (op1):
-    GenTree* boxedContent = valueType == TYP_STRUCT ? gtNewBlkIndir(typGetObjLayout(valueStructCls), boxedContentAddr)
-                                                    : gtNewIndir(valueType, boxedContentAddr);
+    GenTree* boxedContent = gtNewLoadValueNode(valueType, layout, boxedContentAddr);
+
     // Now do two stores via a comma:
     GenTree* setHasValue = gtNewStoreLclFldNode(resultTmp, TYP_UBYTE, hasValOffset, gtNewIconNode(1));
     GenTree* setValue    = gtNewStoreLclFldNode(resultTmp, valueType, valueOffset, boxedContent);

src/tests/JIT/Regression/JitBlue/Runtime_116369/Runtime_116369.cs

@@ -0,0 +1,28 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Generated by Fuzzlyn v3.3 on 2025-06-06 10:21:46
+// Run on X64 Windows
+// Seed: 1256851873714619775-async,vectort,vector128,vector256,x86aes,x86avx,x86avx2,x86bmi1,x86bmi1x64,x86bmi2,x86bmi2x64,x86fma,x86lzcnt,x86lzcntx64,x86pclmulqdq,x86pclmulqdqv256,x86popcnt,x86popcntx64,x86sse,x86ssex64,x86sse2,x86sse2x64,x86sse3,x86sse41,x86sse41x64,x86sse42,x86sse42x64,x86ssse3,x86x86base
+// Reduced from 14.5 KiB to 0.3 KiB in 00:00:21
+// Hits JIT assert for Release:
+// Assertion failed 'layout->GetType() == TYP_STRUCT' in 'System.Threading.AsyncLocal`1[System.Nullable`1[System.Runtime.Intrinsics.Vector128`1[int]]]:get_Value():System.Nullable`1[System.Runtime.Intrinsics.Vector128`1[int]]:this' during 'Importation' (IL size 44; hash 0x78887c0d; FullOpts)
+//
+//     File: C:\dev\dotnet\runtime3\src\coreclr\jit\gentree.cpp Line: 8641
+//
+
+using System;
+using System.Threading;
+using System.Runtime.Intrinsics;
+using Xunit;
+
+public class Runtime_115815
+{
+    public static AsyncLocal<Vector128<int>?> s_asyncLocal7 = new AsyncLocal<Vector128<int>?>();
+
+    [Fact]
+    public static void TestEntryPoint()
+    {
+        Vector128<int> vr0 = s_asyncLocal7.Value ??= Vector128.Create<int>(0);
+    }
+}

src/tests/JIT/Regression/JitBlue/Runtime_116369/Runtime_116369.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+</Project>