[RyuJit] Fix DCE in liveness. (#16845)

* add repro

* fix

2 files changed, 189 insertions, 0 deletions

diff --git a/tests/src/JIT/Regression/JitBlue/DevDiv_578214/DevDiv_578214.il b/tests/src/JIT/Regression/JitBlue/DevDiv_578214/DevDiv_578214.il
new file mode 100644
index 0000000000..325fa74ae6
--- /dev/null
+++ b/tests/src/JIT/Regression/JitBlue/DevDiv_578214/DevDiv_578214.il
@@ -0,0 +1,166 @@
+//  Microsoft (R) .NET Framework IL Disassembler.  Version 4.7.3108.0
+//  Copyright (c) Microsoft Corporation.  All rights reserved.
+
+// This test originally hit an error in dead code elimination phase that overwrote flag that trigers next iteration if the current iteration has deleted something (fgStmtRemoved)
+// from true to false during the iteration.
+
+// Metadata version: v4.0.30319
+.assembly extern System.Runtime { auto }
+.assembly DevDiv_578214 {}
+
+.class private auto ansi beforefieldinit DevDiv_578214.Program
+       extends [System.Runtime]System.Object
+{
+.method static int16 ILGEN_METHOD(unsigned int16, float32, native unsigned int, unsigned int16, unsigned int8, int16, unsigned int32)
+{
+	.maxstack  192
+	.locals init (unsigned int64)
+
+	IL_0000: ldc.r8 float64(0x1091e4a00cee077c)
+	IL_0009: ckfinite
+	IL_000a: conv.i4
+	IL_000b: ldarg.s 0x04
+	IL_000d: ldloc 0x0000
+	IL_0011: conv.i1
+	IL_0012: sub.ovf.un
+	IL_0013: add.ovf
+	IL_0014: ldarg.s 0x01
+	IL_0016: starg 0x0001
+	IL_001a: nop
+	IL_001b: brtrue 
+	IL_003c
+	IL_0020: ldarg.s 0x01
+	IL_0022: ldarg 0x0000
+	IL_0026: ldarg 0x0003
+	IL_002a: clt.un
+	IL_002c: ldarg 0x0004
+	IL_0030: xor
+	IL_0031: conv.r8
+	IL_0032: neg
+	IL_0033: starg 0x0001
+	IL_0037: conv.ovf.u4.un
+	IL_0038: starg 0x0005
+	IL_003c: ldc.i8 0x26f19f75aa0243b7
+	IL_0045: conv.i8
+	IL_0046: conv.r8
+	IL_0047: ldarg.s 0x01
+	IL_0049: conv.r.un
+	IL_004a: pop
+	IL_004b: ldarg.s 0x03
+	IL_004d: ldarg 0x0006
+	IL_0051: ceq
+	IL_0053: conv.r.un
+	IL_0054: cgt.un
+	IL_0056: ldloc 0x0000
+	IL_005a: conv.ovf.i8.un
+	IL_005b: brtrue 
+	IL_006b
+	IL_0060: ldarg 0x0001
+	IL_0064: pop
+	IL_0065: ldarg 0x0001
+	IL_0069: ckfinite
+	IL_006a: pop
+	IL_006b: ldarg.s 0x05
+	IL_006d: neg
+	IL_006e: conv.ovf.i8.un
+	IL_006f: ldloc.s 0x00
+	IL_0071: ceq
+	IL_0073: dup
+	IL_0074: div.un
+	IL_0075: ldarg 0x0001
+	IL_0079: neg
+	IL_007a: ckfinite
+	IL_007b: starg.s 0x01
+	IL_007d: bgt 
+	IL_0086
+	IL_0082: ldloc.s 0x00
+	IL_0084: conv.ovf.u2.un
+	IL_0085: pop
+	IL_0086: ldarg.s 0x04
+	IL_0088: conv.ovf.u4.un
+	IL_0089: conv.ovf.u8.un
+	IL_008a: ldarg.s 0x01
+	IL_008c: conv.ovf.u1
+	IL_008d: shr
+	IL_008e: conv.r4
+	IL_008f: ldarg 0x0006
+	IL_0093: conv.r.un
+	IL_0094: conv.r.un
+	IL_0095: ckfinite
+	IL_0096: ckfinite
+	IL_0097: clt
+	IL_0099: ldc.i8 0x643c1542f946b6ef
+	IL_00a2: conv.r8
+	IL_00a3: ldc.r8 float64(0x8bd4c4eb52d70435)
+	IL_00ac: conv.r.un
+	IL_00ad: conv.ovf.u8
+	IL_00ae: not
+	IL_00af: conv.r8
+	IL_00b0: conv.ovf.u1
+	IL_00b1: starg 0x0004
+	IL_00b5: ldc.i4 0x7771fb8b
+	IL_00ba: conv.r8
+	IL_00bb: cgt.un
+	IL_00bd: pop
+	IL_00be: neg
+	IL_00bf: ret   
+}
+
+.method private hidebysig static int32 
+  Main(string[] args) cil managed
+{
+	.entrypoint
+	// Code size       34 (0x22)
+	.maxstack  7
+	.locals init (int32 V_0)
+	IL_0000:  nop
+	.try
+	{
+	IL_0001:  nop
+	IL_0002:  ldc.i4.0
+	IL_0003:  ldc.r4     0.0
+	IL_0008:  ldc.i4.0
+	IL_0009:  ldc.i4.0
+	IL_000a:  ldc.i4.0
+	IL_000b:  ldc.i4.0
+	IL_000c:  ldc.i4.0
+	IL_000d:  call       int16 DevDiv_578214.Program::ILGEN_METHOD(uint16,
+																 float32,
+																 native unsigned int,
+																 uint16,
+																 uint8,
+																 int16,
+																 uint32)
+	IL_0012:  pop
+	IL_0013:  nop
+	IL_0014:  leave.s    IL_001b
+
+	}  // end .try
+	catch [System.Runtime]System.Object 
+	{
+	IL_0016:  pop
+	IL_0017:  nop
+	IL_0018:  nop
+	IL_0019:  leave.s    IL_001b
+
+	}  // end handler
+	IL_001b:  ldc.i4.s   100
+	IL_001d:  stloc.0
+	IL_001e:  br.s       IL_0020
+
+	IL_0020:  ldloc.0
+	IL_0021:  ret
+} // end of method Program::Main
+
+.method public hidebysig specialname rtspecialname 
+  instance void  .ctor() cil managed
+{
+	// Code size       8 (0x8)
+	.maxstack  8
+	IL_0000:  ldarg.0
+	IL_0001:  call       instance void [System.Runtime]System.Object::.ctor()
+	IL_0006:  nop
+	IL_0007:  ret
+} // end of method Program::.ctor
+
+} // end of class DevDiv_578214.Program
diff --git a/tests/src/JIT/Regression/JitBlue/DevDiv_578214/DevDiv_578214.ilproj b/tests/src/JIT/Regression/JitBlue/DevDiv_578214/DevDiv_578214.ilproj
new file mode 100644
index 0000000000..5934cf63ac
--- /dev/null
+++ b/tests/src/JIT/Regression/JitBlue/DevDiv_578214/DevDiv_578214.ilproj
@@ -0,0 +1,23 @@
+<?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>$(MSBuildProjectName)</AssemblyName>
+    <ProjectGuid>{95DFC527-4DC1-495E-97D7-E94EE1F7140D}</ProjectGuid>
+    <OutputType>Exe</OutputType>
+    <SolutionDir Condition="$(SolutionDir) == '' Or $(SolutionDir) == '*Undefined*'">..\..\</SolutionDir>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' "></PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' "></PropertyGroup>
+  <PropertyGroup>
+    <DebugType>None</DebugType>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).il" />
+  </ItemGroup>
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
+  <PropertyGroup Condition=" '$(MsBuildProjectDirOverride)' != '' "></PropertyGroup>
+</Project>