`JIT/opt/ValueNumbering/ExposedLocalsNumbering/ExposedLocalsNumbering` failing in CI

[jakobbotsch]

Example pipeline run (gcstress): https://dev.azure.com/dnceng-public/public/_build/results?buildId=748823&view=results
Example console log (win-x86): https://helixre107v0xdcypoyl9e7f.blob.core.windows.net/dotnet-runtime-refs-heads-main-5975cd368e984ab58d/JIT.opt.0.1/1/console.c75e012d.log?helixlogtype=result

14:51:36.875 Running test: JIT/opt/ValueNumbering/ExposedLocalsNumbering/ExposedLocalsNumbering.cmd

Return code:      1
Raw output file:      C:\h\w\AC2E0993\w\A3BC08F3\uploads\ValueNumbering\ExposedLocalsNumbering\output.txt
Raw output:
BEGIN EXECUTION
 "C:\h\w\AC2E0993\p\corerun.exe" -p "System.Reflection.Metadata.MetadataUpdater.IsSupported=false" -p "System.Runtime.Serialization.EnableUnsafeBinaryFormatterSerialization=true"  ExposedLocalsNumbering.dll 
Xunit.Sdk.EqualException: Assert.Equal() Failure: Values differ
Expected: 100
Actual:   101
   at Xunit.Assert.Equal[T](T expected, T actual, IEqualityComparer`1 comparer) in /_/src/Microsoft.DotNet.XUnitAssert/src/EqualityAsserts.cs:line 168
   at __GeneratedMainWrapper.Main()
Expected: 100
Actual: 101
END EXECUTION - FAILED
FAILED
Test failed. Trying to see if dump file was created in C:\cores since 7/20/2024 2:51:36 PM
Test Harness Exitcode is : 1
To run the test:
Set up CORE_ROOT and run.
> C:\h\w\AC2E0993\w\A3BC08F3\e\JIT\opt\JIT.opt\../ValueNumbering/ExposedLocalsNumbering/ExposedLocalsNumbering.cmd
Xunit.Sdk.TrueException: 
Return code:      1
Raw output file:      C:\h\w\AC2E0993\w\A3BC08F3\uploads\ValueNumbering\ExposedLocalsNumbering\output.txt
Raw output:
BEGIN EXECUTION
 "C:\h\w\AC2E0993\p\corerun.exe" -p "System.Reflection.Metadata.MetadataUpdater.IsSupported=false" -p "System.Runtime.Serialization.EnableUnsafeBinaryFormatterSerialization=true"  ExposedLocalsNumbering.dll 
Xunit.Sdk.EqualException: Assert.Equal() Failure: Values differ
Expected: 100
Actual:   101
   at Xunit.Assert.Equal[T](T expected, T actual, IEqualityComparer`1 comparer) in /_/src/Microsoft.DotNet.XUnitAssert/src/EqualityAsserts.cs:line 168
   at __GeneratedMainWrapper.Main()
Expected: 100
Actual: 101
END EXECUTION - FAILED
FAILED
Test failed. Trying to see if dump file was created in C:\cores since 7/20/2024 2:51:36 PM
Test Harness Exitcode is : 1
To run the test:
Set up CORE_ROOT and run.
> C:\h\w\AC2E0993\w\A3BC08F3\e\JIT\opt\JIT.opt\../ValueNumbering/ExposedLocalsNumbering/ExposedLocalsNumbering.cmd
   at Xunit.Assert.True(Nullable`1 condition, String userMessage) in /_/src/Microsoft.DotNet.XUnitAssert/src/BooleanAsserts.cs:line 146
   at TestLibrary.OutOfProcessTest.RunOutOfProcessTest(String assemblyPath, String testPathPrefix)
   at Program.<<Main>$>g__TestExecutor351|0_352(StreamWriter tempLogSw, StreamWriter statsCsvSw, <>c__DisplayClass0_0&)
14:51:42.813 Failed test: JIT/opt/ValueNumbering/ExposedLocalsNumbering/ExposedLocalsNumbering.cmd

cc @EgorBo @SingleAccretion

Build Information

Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=748928
Build error leg or test failing: JIT/opt/ValueNumbering/ExposedLocalsNumbering/ExposedLocalsNumbering.cmd
Pull request: #105185

Error Message

Fill the error message using step by step known issues guidance.

{
  "ErrorMessage": "",
  "ErrorPattern": "Failed test.*ExposedLocalsNumbering",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=748823
Error message validated: [Failed test.*ExposedLocalsNumbering]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 7/20/2024 7:12:53 PM UTC

Report

Build	Definition	Test	Pull Request
748928	dotnet/runtime	JIT/opt/ValueNumbering/ExposedLocalsNumbering/ExposedLocalsNumbering.cmd	#105185
748823	dotnet/runtime	JIT/opt/ValueNumbering/ExposedLocalsNumbering/ExposedLocalsNumbering.cmd

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
2	2	2

[dotnet-policy-service]

Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch
See info in area-owners.md if you want to be subscribed.

[SingleAccretion]

This is a real (silent bad codegen) bug. The problem is in importation, where we duplicate the index load (V02 is the exposed index):

impIntrinsic: Expanding Span<T>.get_Item, T=System.Int32, sizeof(T)=4
with ptr-to-span
               [000007] -----------                         *  LCL_ADDR  byref  V00 arg0         [+0]
and index
               [000008] -----------                         *  LCL_VAR   int    V02 loc1         

    [ 2]  21 (0x015) ldind.i4
    [ 2]  22 (0x016) add
    [ 1]  23 (0x017) stloc.0

STMT00003 ( 0x00C[E-] ... ??? )
               [000023] DA-XGO-----                         *  STORE_LCL_VAR int    V01 loc0         
               [000022] ---XGO-----                         \--*  ADD       int   
               [000006] -----------                            +--*  LCL_VAR   int    V01 loc0         
               [000021] ---XGO-----                            \--*  IND       int   
               [000020] ---XGO-----                               \--*  COMMA     byref 
               [000013] ---XGO-----                                  +--*  BOUNDS_CHECK_Rng void  
               [000008] -----------                                  |  +--*  LCL_VAR   int    V02 loc1         
               [000012] n---G------                                  |  \--*  IND       int   
               [000011] -----------                                  |     \--*  FIELD_ADDR byref  System.Span`1[int]:_length
               [000007] -----------                                  |        \--*  LCL_ADDR  byref  V00 arg0         [+0]
               [000019] ----GO-----                                  \--*  ADD       byref 
               [000018] n---G------                                     +--*  IND       byref 
               [000017] -----------                                     |  \--*  FIELD_ADDR byref  System.Span`1[int]:_reference
               [000010] -----------                                     |     \--*  LCL_ADDR  byref  V00 arg0         [+0]
               [000016] -----------                                     \--*  MUL       long  
               [000014] ---------U-                                        +--*  CAST      long <- uint
               [000009] -----------                                        |  \--*  LCL_VAR   int    V02 loc1         
               [000015] -----------                                        \--*  CNS_INT   long   4

As a result, in codegen we end up with:

IN000b: 000048 call     [RyuJitReproduction.Program:CaptureIndex(ulong)]
IN000c: 00004E cmp      dword ptr [V02 rbp-0x40], ebx
IN000d: 000051 jae      G_M16903_IG10
IN000e: 000057 mov      ecx, dword ptr [V02 rbp-0x40]
IN000f: 00005A mov      ebx, dword ptr [rdi+4*rcx]