fix checkLclVarSemantics (#14053)

* extract CheckLclVarSemantics from CheckLIR.

* add a test that shows the silent bad execution.

* fix the checker.

* add the test to the exclude list.

* rename consumed to used

3 files changed, 168 insertions, 0 deletions

diff --git a/tests/issues.targets b/tests/issues.targets
index fce3f8aee7..af769509cd 100644
--- a/tests/issues.targets
+++ b/tests/issues.targets
@@ -184,6 +184,9 @@
         <ExcludeList Include="$(XunitTestBinBase)\Loader\classloader\TypeGeneratorTests\TypeGeneratorTest683\Generated683\*">
             <Issue>6707</Issue>
         </ExcludeList>
+        <ExcludeList Include="$(XunitTestBinBase)\JIT\Regression\JitBlue\GitHub_13910\GitHub_13910\GitHub_13910.cmd">
+            <Issue>13910</Issue>
+        </ExcludeList>
     </ItemGroup>
 
     <!-- The following are x86 failures -->
diff --git a/tests/src/JIT/Regression/JitBlue/GitHub_13910/GitHub_13910.cs b/tests/src/JIT/Regression/JitBlue/GitHub_13910/GitHub_13910.cs
new file mode 100644
index 0000000000..d1805d1fa0
--- /dev/null
+++ b/tests/src/JIT/Regression/JitBlue/GitHub_13910/GitHub_13910.cs
@@ -0,0 +1,120 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+using System;
+using System.Runtime.InteropServices;
+
+// Represents a problem with contained nodes chains, that contain lclVar reads, that were moved through lclVar stores.
+// Notice that the project file sets complus_JitStressModeNames.
+
+[StructLayout(LayoutKind.Explicit)]
+internal class AA
+{
+
+    [FieldOffset(8)]
+    public QQ q;
+
+
+    public static AA[] a_init = new AA[101];
+
+    public static AA[] a_zero = new AA[101];
+
+
+    public AA(int qq)
+    {
+
+        this.q = new QQ(qq);
+    }
+
+
+    public static void reset()
+    {
+        AA.a_init[100] = new AA(1);
+        AA.a_zero[100] = new AA(2);
+    }
+}
+
+internal class QQ
+{
+    public int val;
+
+    public QQ(int vv)
+    {
+        this.val = vv;
+    }
+
+    public int ret_code()
+    {
+        return 100;
+    }
+}
+
+internal class TestApp
+{
+
+    private static int test_2_2(int num)
+    {
+        int result;
+        if (AA.a_init[num].q != AA.a_zero[num].q) 
+        // Access field with contained IND instruction.
+        // EQ marks its operands as contained too. 
+        // AA.a_init[num].q and AA.a_zero[num].q are allocated to the same lclVar.
+        // So we calculate AA.a_init[num].q and store as tmp0, use this temp to do nullCheck.
+        // Then store AA.a_zero[num].q as tmp0, destroy the old value and try to do EQ thinking that 
+        // tmp0 is AA.a_init[num].q.
+        // It needs stress (complus_JitStressModeNames=STRESS_NULL_OBJECT_CHECK, STRESS_MAKE_CSE)
+        // to force the compiler to do implicit null checks and store values as local variables.
+// Bad IL example, t53 is set as contained, t143 is set as contained, it means they will be calculated as part of their parent t9.
+// But at that moment V02, that is read in t143 is already modified by [000056].
+// N035 (  1,  1) [000035] ------------       t35 =    LCL_VAR   ref    V02 tmp0         u:3 eax (last use) REG eax <l:$149, c:$182>
+//                                                 /--*  t35    ref
+// N037 (???,???) [000143] -c----------      t143 = *  LEA(b+12) byref  REG NA
+//                                                  /--*  t143   byref
+// N039 (  4,  4) [000054] Rc---O------       t54 = *  IND       ref    REG NA <l:$155, c:$184> // This contained flag is invalid because 
+//                                                                                              // the value will be read after the store 000056.
+// *********************************************************************************************
+//                                                  /--*  t117   ref
+// N073 ( 18, 22) [000056] DA-XG-------             *  STORE_LCL_VAR ref    V02 tmp0         d:4 eax REG eax // the store that corrupts t54 value.
+// N075 (  1,  1) [000057] ------------       t57 =    LCL_VAR   ref    V02 tmp0         u:4 eax REG eax <l:$160, c:$187>
+//                                                  /--*  t57    ref
+// N077 (  2,  2) [000058] ---X---N----             *  NULLCHECK byte   REG NA <l:$166, c:$165>
+// N079 (  1,  1) [000060] ------------       t60 =    LCL_VAR   ref    V02 tmp0         u:4 eax REG eax <l:$160, c:$187>
+//                                                  /--*  t60    ref
+// N081 (???,???) [000146] -c----------      t146 = *  LEA(b+12) byref  REG NA
+//                                                  /--*  t146   byref
+// N083 (  4,  4) [000079] R----O------       t79 = *  IND       ref    REG ecx <l:$16b, c:$189>
+//                                                  /--*  t79    ref
+// N085 (  4,  4) [000121] DA---O------             *  STORE_LCL_VAR ref    V07 cse1          ecx REG ecx
+// N087 (  1,  1) [000122] ------------      t122 =    LCL_VAR   ref    V07 cse1          ecx REG ecx <l:$16b, c:$189>
+//                                                  /--*  t54    ref // reads V02.
+//                                                  +--*  t122   ref
+// N089 ( 48, 56) [000009] J--XGO-N----        t9 = *  EQ        int    REG NA <l:$1c5, c:$1c4>
+        {
+            result = 100;
+        }
+        else
+        {
+            result = AA.a_zero[num].q.val;
+        }
+        return result;
+    }
+
+    private static int Main()
+    {
+        AA.reset();
+        int result;
+
+        int r = TestApp.test_2_2(100);
+        if (r != 100)
+        {
+            Console.WriteLine("Failed.");
+            result = 101;
+        }
+        else
+        {
+            Console.WriteLine("Passed.");
+            result = 100;
+        }
+        return result;
+    }
+}
diff --git a/tests/src/JIT/Regression/JitBlue/GitHub_13910/GitHub_13910.csproj b/tests/src/JIT/Regression/JitBlue/GitHub_13910/GitHub_13910.csproj
new file mode 100644
index 0000000000..8cb39e1055
--- /dev/null
+++ b/tests/src/JIT/Regression/JitBlue/GitHub_13910/GitHub_13910.csproj
@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$([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>{E2C84853-0100-4C5D-88C0-355F70483779}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <ProjectTypeGuids>{786C830F-07A1-408B-BD7F-6EE04809D6DB};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
+    <SolutionDir Condition="$(SolutionDir) == '' Or $(SolutionDir) == '*Undefined*'">..\..\</SolutionDir>
+  </PropertyGroup>
+  <!-- Default configurations to help VS understand the configurations -->
+  <PropertyGroup Condition=" '$(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>
+    <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
+  </ItemGroup>
+  <PropertyGroup>
+   <!-- Set JitStreess variables, Linux requires them to be properly capitalized. -->
+    <CLRTestBatchPreCommands><![CDATA[
+$(CLRTestBatchPreCommands)
+set COMPlus_JitStressModeNames=STRESS_NULL_OBJECT_CHECK, STRESS_MAKE_CSE
+]]></CLRTestBatchPreCommands>
+    <BashCLRTestPreCommands><![CDATA[
+$(BashCLRTestPreCommands)
+export COMPlus_JitStressModeNames=STRESS_NULL_OBJECT_CHECK, STRESS_MAKE_CSE
+]]></BashCLRTestPreCommands>
+  </PropertyGroup>
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
+  <PropertyGroup Condition=" '$(MsBuildProjectDirOverride)' != '' "></PropertyGroup>
+</Project>
\ No newline at end of file