Fix a bug with disappeared cast to byte in numeric binary expressions

Lowering::IndirsAreEquivalent doesn't check if the 2 indirections have the same type and because of that a RMW style instruction is generated instead of the expected

movzx    rax, byte  ptr [7FFA61024742h]
xor      eax, 33
mov      word  ptr [7FFA61024742h], ax

This behavior was fixed by adding an additional check to IndirsAreEquivalent (implementation of the mikedn's approach: dotnet/coreclr#1329 (comment)).

Fix dotnet/coreclr#1323.


Commit migrated from dotnet/coreclr@3bfbb9b

src/coreclr/src/jit/lower.cpp

@@ -3408,6 +3408,11 @@ bool Lowering::IndirsAreEquivalent(GenTreePtr candidate, GenTreePtr storeInd)
     if (pTreeA->OperGet() != pTreeB->OperGet())
         return false;
 
+    assert(genActualType(candidate->gtType) == genActualType(storeInd->gtType));
+
+    if (genTypeSize(candidate->gtType) != genTypeSize(storeInd->gtType))
+        return false;
+
     oper = pTreeA->OperGet();
     switch (oper)
     {

src/coreclr/tests/src/JIT/Regression/JitBlue/GitHub_1323/GitHub_1323.cs

@@ -0,0 +1,26 @@
+// Copyright (c) Andrey Akinshin. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+
+class Program
+{
+    static ushort SkillLevel;
+
+    static int Main(string[] args)
+    {
+        SkillLevel = 0x2121;
+        SkillLevel = (ushort)((byte)SkillLevel ^ 0x21);
+        if (SkillLevel != 0)
+        {
+            Console.WriteLine("Fail");
+            return -1;
+        }
+        else
+        {
+            Console.WriteLine("Pass");
+            return 100;
+        }
+    }
+}

src/coreclr/tests/src/JIT/Regression/JitBlue/GitHub_1323/GitHub_1323.csproj

@@ -0,0 +1,50 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <AssemblyName>$(MSBuildProjectName)</AssemblyName>
+    <SchemaVersion>2.0</SchemaVersion>
+    <ProjectGuid>{D8F6B7C2-EF97-4590-8800-98F37028CE83}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <FileAlignment>512</FileAlignment>
+    <ProjectTypeGuids>{786C830F-07A1-408B-BD7F-6EE04809D6DB};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
+    <ReferencePath>$(ProgramFiles)\Common Files\microsoft shared\VSTT\11.0\UITestExtensionPackages</ReferencePath>
+    <SolutionDir Condition="$(SolutionDir) == '' Or $(SolutionDir) == '*Undefined*'">..\..\</SolutionDir>
+
+    <NuGetPackageImportStamp>7a9bfb7d</NuGetPackageImportStamp>
+  </PropertyGroup>
+  <!-- Default configurations to help VS understand the configurations -->
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+  </PropertyGroup>
+  <ItemGroup>
+    <CodeAnalysisDependentAssemblyPaths Condition=" '$(VS100COMNTOOLS)' != '' " Include="$(VS100COMNTOOLS)..\IDE\PrivateAssemblies">
+      <Visible>False</Visible>
+    </CodeAnalysisDependentAssemblyPaths>
+  </ItemGroup>
+  <PropertyGroup>
+    <DebugType></DebugType>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="$(JitPackagesConfigFileDirectory)minimal\project.json" />
+    <None Include="app.config" />
+  </ItemGroup>
+  <ItemGroup>
+    <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
+  </ItemGroup>
+  <PropertyGroup>
+    <ProjectJson>$(JitPackagesConfigFileDirectory)minimal\project.json</ProjectJson>
+    <ProjectLockJson>$(JitPackagesConfigFileDirectory)minimal\project.lock.json</ProjectLockJson>
+  </PropertyGroup>
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
+  <PropertyGroup Condition=" '$(MsBuildProjectDirOverride)' != '' ">
+  </PropertyGroup> 
+</Project>

src/coreclr/tests/src/JIT/Regression/JitBlue/GitHub_1323/app.config

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <runtime>
+    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
+      <dependentAssembly>
+        <assemblyIdentity name="System.Runtime" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.20.0" newVersion="4.0.20.0" />
+      </dependentAssembly>
+      <dependentAssembly>
+        <assemblyIdentity name="System.Text.Encoding" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.10.0" newVersion="4.0.10.0" />
+      </dependentAssembly>
+      <dependentAssembly>
+        <assemblyIdentity name="System.Threading.Tasks" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.10.0" newVersion="4.0.10.0" />
+      </dependentAssembly>
+      <dependentAssembly>
+        <assemblyIdentity name="System.IO" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.10.0" newVersion="4.0.10.0" />
+      </dependentAssembly>
+      <dependentAssembly>
+        <assemblyIdentity name="System.Reflection" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="0.0.0.0-4.0.10.0" newVersion="4.0.10.0" />
+      </dependentAssembly>
+    </assemblyBinding>
+  </runtime>
+</configuration>