Preserve value numbers when discarding a cast.

This is a fix for an assert during CSE. After processing a CSE definition
the tree got morphed. During morphing a cast was discarded by narrowing
the operand of the cast. The value number of the operand was cleared. Later,
when processing a use of the CSE, the code was attempting to process the side effects
in the tree of the use and was encountering a node with no value number resulting
in an assert. The fix is to transfer the value number from the cast node to the narrowed
operand.

diff --git a/src/jit/compiler.h b/src/jit/compiler.h
index 66509fc..2773287 100644 (file)
--- a/src/jit/compiler.h
+++ b/src/jit/compiler.h
@@ -5520,6 +5520,7 @@ protected:
     bool                optNarrowTree   (GenTreePtr     tree,
                                          var_types      srct,
                                          var_types      dstt,
+                                         ValueNumPair   vnpNarrow,
                                          bool           doit);
 
     /**************************************************************************

diff --git a/src/jit/gentree.h b/src/jit/gentree.h
index cc68956..adc34c2 100644 (file)
--- a/src/jit/gentree.h
+++ b/src/jit/gentree.h
@@ -640,6 +640,10 @@ public:
             return gtVNPair.SetConservative(vn);
         }
     }
+    void                SetVNs(ValueNumPair vnp)
+    {
+        gtVNPair = vnp;
+    }
     void                ClearVN()
     {
         gtVNPair = ValueNumPair();          // Initializes both elements to "NoVN".

diff --git a/src/jit/morph.cpp b/src/jit/morph.cpp
index ba1e0da..f078afe 100644 (file)
--- a/src/jit/morph.cpp
+++ b/src/jit/morph.cpp
@@ -710,9 +710,9 @@ OPTIMIZECAST:
                 if  (!tree->gtOverflow()                  &&
                      !gtIsActiveCSE_Candidate(oper)       &&
                      (opts.compFlags & CLFLG_TREETRANS)   &&
-                     optNarrowTree(oper, srcType, dstType, false))
+                     optNarrowTree(oper, srcType, dstType, tree->gtVNPair, false))
                 {
-                    optNarrowTree(oper, srcType, dstType,  true);
+                    optNarrowTree(oper, srcType, dstType,  tree->gtVNPair, true);
                     
                     /* If oper is changed into a cast to TYP_INT, or to a GT_NOP, we may need to discard it */
                     if (oper->gtOper == GT_CAST && oper->CastToType() == genActualType(oper->CastFromType()))

diff --git a/src/jit/optimizer.cpp b/src/jit/optimizer.cpp
index 104b5ff..3f6a8f6 100644 (file)
--- a/src/jit/optimizer.cpp
+++ b/src/jit/optimizer.cpp
@@ -4726,6 +4726,7 @@ Compiler::callInterf    Compiler::optCallInterf(GenTreePtr call)
 bool                Compiler::optNarrowTree(GenTreePtr     tree,
                                             var_types      srct,
                                             var_types      dstt,
+                                            ValueNumPair   vnpNarrow,
                                             bool           doit)
 {
     genTreeOps      oper;
@@ -4755,6 +4756,8 @@ bool                Compiler::optNarrowTree(GenTreePtr     tree,
         return  false;
     }
 
+    ValueNumPair NoVNPair = ValueNumPair();
+
     if  (kind & GTK_LEAF)
     {
         switch (oper)
@@ -4868,16 +4871,16 @@ bool                Compiler::optNarrowTree(GenTreePtr     tree,
 
             // Is op2 a small constant than can be narrowed into dstt?
             // if so the result of the GT_AND will also fit into 'dstt' and can be narrowed
-            if ((op2->gtOper == GT_CNS_INT)  &&  optNarrowTree(op2, srct, dstt, false))
+            if ((op2->gtOper == GT_CNS_INT)  &&  optNarrowTree(op2, srct, dstt, NoVNPair, false))
             {               
                 // We will change the type of the tree and narrow op2
                 //
                 if  (doit)
                 {
                     tree->gtType = genActualType(dstt);
-                    tree->ClearVN();
+                    tree->SetVNs(vnpNarrow);
 
-                    optNarrowTree(op2, srct, dstt, true);
+                    optNarrowTree(op2, srct, dstt, NoVNPair, true);
                     // We may also need to cast away the upper bits of op1
                     if (srcSize == 8) 
                     {
@@ -4912,8 +4915,8 @@ COMMON_BINOP:
 
             if (gtIsActiveCSE_Candidate(op1)          ||
                 gtIsActiveCSE_Candidate(op2)          ||
-                !optNarrowTree(op1, srct, dstt, doit) ||
-                !optNarrowTree(op2, srct, dstt, doit)   )
+                !optNarrowTree(op1, srct, dstt, NoVNPair, doit) ||
+                !optNarrowTree(op2, srct, dstt, NoVNPair, doit)   )
             {
                 noway_assert(doit == false);
                 return  false;
@@ -4927,7 +4930,7 @@ COMMON_BINOP:
                     tree->gtFlags &= ~GTF_MUL_64RSLT;
 
                 tree->gtType = genActualType(dstt);
-                tree->ClearVN();
+                tree->SetVNs(vnpNarrow);
             }
 
             return true;
@@ -4940,7 +4943,7 @@ NARROW_IND:
             if  (doit && (dstSize <= genTypeSize(tree->gtType)))
             {
                 tree->gtType = genSignedType(dstt);
-                tree->ClearVN();
+                tree->SetVNs(vnpNarrow);
 
                 /* Make sure we don't mess up the variable type */
                 if  ((oper == GT_LCL_VAR) || (oper == GT_LCL_FLD))
@@ -5003,7 +5006,7 @@ NARROW_IND:
                             // The result type of a GT_CAST is never a small type.
                             // Use genActualType to widen dstt when it is a small types.
                             tree->gtType = genActualType(dstt);
-                            tree->ClearVN();
+                            tree->SetVNs(vnpNarrow);
                         }
                     }
 
@@ -5014,14 +5017,14 @@ NARROW_IND:
 
         case GT_COMMA:
             if (!gtIsActiveCSE_Candidate(op2)  &&
-                optNarrowTree(op2, srct, dstt, doit))
+                optNarrowTree(op2, srct, dstt, vnpNarrow, doit))
             {               
                 /* Simply change the type of the tree */
 
                 if  (doit)
                 {
                     tree->gtType = genActualType(dstt);
-                    tree->ClearVN();
+                    tree->SetVNs(vnpNarrow);
                 }
                 return true;
             }

diff --git a/tests/src/JIT/Regression/JitBlue/devdiv_180411/app.config b/tests/src/JIT/Regression/JitBlue/devdiv_180411/app.config
new file mode 100644 (file)
index 0000000..8077c95
--- /dev/null
+++ b/tests/src/JIT/Regression/JitBlue/devdiv_180411/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>
\ No newline at end of file

diff --git a/tests/src/JIT/Regression/JitBlue/devdiv_180411/devdiv_180411.il b/tests/src/JIT/Regression/JitBlue/devdiv_180411/devdiv_180411.il
new file mode 100644 (file)
index 0000000..b3f7894
--- /dev/null
+++ b/tests/src/JIT/Regression/JitBlue/devdiv_180411/devdiv_180411.il
@@ -0,0 +1,34 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+.assembly extern legacy library mscorlib {}
+
+.assembly devdiv_180411
+{
+}
+.class _simple {
+
+.method static int32 main(class System.String[]) {
+.entrypoint
+.maxstack      100
+call       int64 [devdiv_180411]_simple::test()
+conv.i4
+ldc.i4 100
+add     
+ret  
+}
+
+.method static int64 test() {
+.maxstack      100
+.locals init (int32 local_0x1)
+
+ldloc.s      0
+neg         
+conv.ovf.u8 
+conv.i4     
+neg         
+conv.u8
+ret  
+}
+
+}
\ No newline at end of file

diff --git a/tests/src/JIT/Regression/JitBlue/devdiv_180411/devdiv_180411.ilproj b/tests/src/JIT/Regression/JitBlue/devdiv_180411/devdiv_180411.ilproj
new file mode 100644 (file)
index 0000000..5486f03
--- /dev/null
+++ b/tests/src/JIT/Regression/JitBlue/devdiv_180411/devdiv_180411.ilproj
@@ -0,0 +1,44 @@
+<?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\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="$(VS100COMNTOOLS)..\IDE\PrivateAssemblies">
+      <Visible>False</Visible>
+    </CodeAnalysisDependentAssemblyPaths>
+  </ItemGroup>
+  <PropertyGroup>
+    <DebugType>None</DebugType>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="devdiv_180411.il" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="app.config" />
+  </ItemGroup>
+  <ItemGroup>
+    <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
+  </ItemGroup>
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
+  <PropertyGroup Condition=" '$(MsBuildProjectDirOverride)' != '' ">
+  </PropertyGroup> 
+</Project>
\ No newline at end of file