From fb33095254c63e8bcb89dd4e15269de309c6ed5c Mon Sep 17 00:00:00 2001
From: Sergey Andreenko <seandree@microsoft.com>
Date: Mon, 31 Oct 2016 12:31:10 -0700
Subject: [PATCH] Correct pattern check

sequense
localVariable = cast.int(call.small_type());
return localVaribale
is correct tail call pattern.
---
 src/jit/morph.cpp                                  | 34 ++++++++++---
 .../GitHub_CoreRT_2073/GitHub_CoreRT_2073.il       | 55 ++++++++++++++++++++++
 .../GitHub_CoreRT_2073/GitHub_CoreRT_2073.ilproj   | 38 +++++++++++++++
 3 files changed, 121 insertions(+), 6 deletions(-)
 create mode 100644 tests/src/JIT/Regression/JitBlue/GitHub_CoreRT_2073/GitHub_CoreRT_2073.il
 create mode 100644 tests/src/JIT/Regression/JitBlue/GitHub_CoreRT_2073/GitHub_CoreRT_2073.ilproj

diff --git a/src/jit/morph.cpp b/src/jit/morph.cpp
index 58c6952..c9b4862 100644
--- a/src/jit/morph.cpp
+++ b/src/jit/morph.cpp
@@ -7737,12 +7737,34 @@ GenTreePtr Compiler::fgMorphCall(GenTreeCall* call)
 #ifdef DEBUG
         // Tail call needs to be in one of the following IR forms
         //    Either a call stmt or
-        //    GT_RETURN(GT_CALL(..)) or
-        //    var = call
-        noway_assert((stmtExpr->gtOper == GT_CALL && stmtExpr == call) ||
-                     (stmtExpr->gtOper == GT_RETURN &&
-                      (stmtExpr->gtOp.gtOp1 == call || stmtExpr->gtOp.gtOp1->gtOp.gtOp1 == call)) ||
-                     (stmtExpr->gtOper == GT_ASG && stmtExpr->gtOp.gtOp2 == call));
+        //    GT_RETURN(GT_CALL(..)) or GT_RETURN(GT_CAST(GT_CALL(..)))
+        //    var = GT_CALL(..) or var = (GT_CAST(GT_CALL(..)))
+        genTreeOps stmtOper = stmtExpr->gtOper;
+        if (stmtOper == GT_CALL)
+        {
+            noway_assert(stmtExpr == call);
+        }
+        else
+        {
+            noway_assert(stmtOper == GT_RETURN || stmtOper == GT_ASG);
+            GenTreePtr treeWithCall;
+            if (stmtOper == GT_RETURN)
+            {
+                treeWithCall = stmtExpr->gtGetOp1();
+            }
+            else
+            {
+                treeWithCall = stmtExpr->gtGetOp2();
+            }
+            if (treeWithCall->gtOper == GT_CAST)
+            {
+                noway_assert(treeWithCall->gtGetOp1() == call && !treeWithCall->gtOverflow());
+            }
+            else
+            {
+                noway_assert(treeWithCall == call);
+            }
+        }
 #endif
 
         // For void calls, we would have created a GT_CALL in the stmt list.
diff --git a/tests/src/JIT/Regression/JitBlue/GitHub_CoreRT_2073/GitHub_CoreRT_2073.il b/tests/src/JIT/Regression/JitBlue/GitHub_CoreRT_2073/GitHub_CoreRT_2073.il
new file mode 100644
index 0000000..28adbc4
--- /dev/null
+++ b/tests/src/JIT/Regression/JitBlue/GitHub_CoreRT_2073/GitHub_CoreRT_2073.il
@@ -0,0 +1,55 @@
+// 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.
+
+// Test for a issue when tail call with small return type 
+// doesn't pass tail call pattern assert.
+// In addition there is "call->branch on return->return" tail call pattern check.
+
+
+.assembly extern mscorlib {}
+
+.assembly GitHub_CoreRT_2073.exe {}
+
+.class public Test
+{
+
+.method private hidebysig static bool  tailAsgReturn(int32 deep) cil managed
+{
+    // Code size       24 (0x18)
+    .maxstack  20
+    IL_0000:  ldarg.0
+    IL_0001:  ldc.i4.s   -100
+    IL_0003:  bgt.s      IL_0007
+    IL_0005:  ldc.i4.1
+    IL_0006:  ret
+    IL_0007:  ldarg.0
+    IL_0008:  ldc.i4.0
+    IL_0009:  bgt.s      IL_000f
+
+    IL_000a:  ldarg.0
+    IL_000b:  ldc.i4.1
+    IL_000c:  sub
+    IL_000d:  call       bool Test::tailAsgReturn(int32)
+    IL_000e:  br IL_0017
+    IL_000f:  ldarg.0
+    IL_0010:  ldc.i4.2
+    IL_0011:  sub
+    IL_0012:  call       bool Test::tailAsgReturn(int32)
+    IL_0017:  ret
+} // end of method Test::tailAsgReturn
+
+.method public hidebysig static int32  Main(string[] args) cil managed
+{
+  .entrypoint
+  // Code size       14 (0xe)
+  .maxstack  8
+  IL_0000:  ldc.i4.s   100
+  IL_0002:  call       bool Test::tailAsgReturn(int32)
+  IL_0007:  brtrue.s   IL_000b
+  IL_0009:  ldc.i4.m1
+  IL_000a:  ret
+  IL_000b:  ldc.i4.s   100
+  IL_000d:  ret
+} // end of method Test::Main
+}
diff --git a/tests/src/JIT/Regression/JitBlue/GitHub_CoreRT_2073/GitHub_CoreRT_2073.ilproj b/tests/src/JIT/Regression/JitBlue/GitHub_CoreRT_2073/GitHub_CoreRT_2073.ilproj
new file mode 100644
index 0000000..fe8a3d3
--- /dev/null
+++ b/tests/src/JIT/Regression/JitBlue/GitHub_CoreRT_2073/GitHub_CoreRT_2073.ilproj
@@ -0,0 +1,38 @@
+<?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>$(MSBuildProjectName)</AssemblyName>
+    <SchemaVersion>2.0</SchemaVersion>
+    <ProjectGuid>{95DFC527-4DC1-495E-97D7-E94EE1F7140D}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <FileAlignment>512</FileAlignment>
+    <ProjectTypeGuids>{786C830F-07A1-408B-BD7F-6EE04809D6DB};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
+    <ReferencePath>$(ProgramFiles)\Common Files\microsoft shared\VSTT	.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="$(VS100COMNTOOLS)..\IDE\PrivateAssemblies">
+      <Visible>False</Visible>
+    </CodeAnalysisDependentAssemblyPaths>
+  </ItemGroup>
+  <PropertyGroup>
+    <DebugType>None</DebugType>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="GitHub_CoreRT_2073.il" />
+  </ItemGroup>
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
+  <PropertyGroup Condition=" '$(MsBuildProjectDirOverride)' != '' ">
+  </PropertyGroup> 
+</Project>
-- 
2.7.4