Account for HWI stores in LIR side effects code (#65079)

* Add a test

* Account for HWI stores in LIR side effect code

Otherwise we risk missing stores to addressable locations.

* Add MEMORYBARRIER to fix the assert

Won't ever matter as memory barriers split statements.

src/coreclr/jit/sideeffects.cpp

@@ -164,10 +164,18 @@ AliasSet::NodeInfo::NodeInfo(Compiler* compiler, GenTree* node)
         isWrite = true;
         node    = node->gtGetOp1();
     }
-    else if (node->OperIsStore())
+    else if (node->OperIsStore() || node->OperIs(GT_MEMORYBARRIER))
     {
         isWrite = true;
     }
+#ifdef FEATURE_HW_INTRINSICS
+    else if (node->OperIsHWIntrinsic() && node->AsHWIntrinsic()->OperIsMemoryStore())
+    {
+        isWrite = true;
+    }
+#endif // FEATURE_HW_INTRINSICS
+
+    assert(isWrite || !node->OperRequiresAsgFlag());
 
     // `node` is the location being accessed. Determine whether or not it is a memory or local variable access, and if
     // it is the latter, get the number of the lclVar.

src/tests/JIT/HardwareIntrinsics/General/HwiOp/HwiSideEffects.cs

@@ -0,0 +1,37 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Runtime.Intrinsics.X86;
+using System.Runtime.CompilerServices;
+
+// Tests that side effects induced by the HWI nodes are correctly accounted for.
+
+unsafe class HwiSideEffects
+{
+    public static int Main()
+    {
+        if (ProblemWithInterferenceChecks(2) != 2)
+        {
+            return 101;
+        }
+
+        return 100;
+    }
+
+    [MethodImpl(MethodImplOptions.NoInlining)]
+    private static uint ProblemWithInterferenceChecks(uint a)
+    {
+        uint x;
+        if (Bmi2.IsSupported)
+        {
+            // Make sure we don't try to contain "a" under the "add" here.
+            x = a + Bmi2.MultiplyNoFlags(a, a, &a);
+        }
+        else
+        {
+            x = a;
+        }
+
+        return x;
+    }
+}

src/tests/JIT/HardwareIntrinsics/General/HwiOp/HwiSideEffects.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <DebugType>None</DebugType>
+    <Optimize>True</Optimize>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+</Project>