JIT: Fall back to a canonical SIMD handle in gtGetStructHandleForSimdOrHW (#80240)

Author: jakobbotsch

src/coreclr/jit/compiler.h

@@ -8397,6 +8397,8 @@ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
     // Get the handle for a SIMD type.
     CORINFO_CLASS_HANDLE gtGetStructHandleForSIMD(var_types simdType, CorInfoType simdBaseJitType)
     {
+        assert(varTypeIsSIMD(simdType));
+
         if (m_simdHandleCache == nullptr)
         {
             // This may happen if the JIT generates SIMD node on its own, without importing them.
@@ -8463,6 +8465,8 @@ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
                                                       CorInfoType simdBaseJitType,
                                                       bool        isSimdAsHWIntrinsic = false)
     {
+        assert(varTypeIsSIMD(simdType));
+
         CORINFO_CLASS_HANDLE clsHnd = NO_CLASS_HANDLE;
 
         if (isSimdAsHWIntrinsic)
@@ -8474,6 +8478,14 @@ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
             clsHnd = gtGetStructHandleForHWSIMD(simdType, simdBaseJitType);
         }
 
+        // Currently there are cases where isSimdAsHWIntrinsic is passed
+        // incorrectly. Fall back to the canonical SIMD handle in that case.
+        // TODO-cleanup: We can probably just always use the canonical handle.
+        if (clsHnd == NO_CLASS_HANDLE)
+        {
+            clsHnd = gtGetCanonicalStructHandleForSIMD(simdType);
+        }
+
         return clsHnd;
     }
 #endif // FEATURE_HW_INTRINSICS

src/coreclr/jit/gentree.cpp

@@ -17598,8 +17598,12 @@ CORINFO_CLASS_HANDLE Compiler::gtGetStructHandleIfPresent(GenTree* tree)
 #endif // FEATURE_SIMD
 #ifdef FEATURE_HW_INTRINSICS
             case GT_HWINTRINSIC:
-                structHnd = gtGetStructHandleForSimdOrHW(tree->TypeGet(), tree->AsHWIntrinsic()->GetSimdBaseJitType(),
-                                                         tree->AsHWIntrinsic()->IsSimdAsHWIntrinsic());
+                if (varTypeIsSIMD(tree))
+                {
+                    structHnd =
+                        gtGetStructHandleForSimdOrHW(tree->TypeGet(), tree->AsHWIntrinsic()->GetSimdBaseJitType(),
+                                                     tree->AsHWIntrinsic()->IsSimdAsHWIntrinsic());
+                }
                 break;
 #endif
             default:

src/coreclr/jit/hwintrinsic.cpp

@@ -88,6 +88,8 @@ CorInfoType Compiler::getBaseJitTypeFromArgIfNeeded(NamedIntrinsic       intrins
 
 CORINFO_CLASS_HANDLE Compiler::gtGetStructHandleForHWSIMD(var_types simdType, CorInfoType simdBaseJitType)
 {
+    assert(varTypeIsSIMD(simdType));
+
     if (m_simdHandleCache == nullptr)
     {
         return NO_CLASS_HANDLE;

src/tests/JIT/Regression/JitBlue/Runtime_80239/Runtime_80239.cs

@@ -0,0 +1,21 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Numerics;
+using System.Runtime.CompilerServices;
+
+class Runtime_80239
+{
+    static int Main(string[] args)
+    {
+        Unsafe.SkipInit(out Vector3 test);
+        test.X = 500.0f;
+        Consume(test);
+        return 100;
+    }
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    private static void Consume(Vector3 test)
+    {
+    }
+}

src/tests/JIT/Regression/JitBlue/Runtime_80239/Runtime_80239.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+</Project>