Random jit stress failures in JIT\Directed\arglist\vararg #81049

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1. ghost added

   area-CodeGen-coreclrCLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMICLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI

   on Jan 23, 2023
2. ghost added

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   on Jan 23, 2023
4. AndyAyersMS

   added

   JitStressCLR JIT issues involving JIT internal stress modesCLR JIT issues involving JIT internal stress modes

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5. AndyAyersMS

   added this to the 8.0.0 milestone on Jan 23, 2023
6. AndyAyersMS commented on Jan 30, 2023

   

   AndyAyersMS

   on Jan 30, 2023

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   Also failed again this week, same two parts of the tests

   set DOTNET_TieredCompilation=0
   set DOTNET_JitStress=3b1
   
    ... 
         Failure: check_passing_four_three_double_struct(first, second, third, fourth)
         Failure: TestPassingTwentyFourByteStructsc
   
7. AndyAyersMS

   added

   blocking-clean-ci-optionalBlocking optional rolling runsBlocking optional rolling runs

   on Jan 30, 2023
8. JulieLeeMSFT commented on Jan 30, 2023

   

   JulieLeeMSFT

   on Jan 30, 2023

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   Assigning to @jakobbotsch for struct related failure.
9. JulieLeeMSFT

   assigned

   jakobbotsch

   on Jan 30, 2023
10. jakobbotsch commented on Jan 31, 2023

    

    jakobbotsch

    on Jan 31, 2023

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    I bisected this to 559aa0e, i.e. the new stress mode I added recently. Investigating in more detail now.
11. jakobbotsch commented on Jan 31, 2023

    

    jakobbotsch

    on Jan 31, 2023

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    After some forward subs, morph and some stress cloning we end up with:

    fgMorphTree BB01, STMT00021 (after)
                   [000237] -ACXG------                         ▌  ASG       int   
                   [000238] D------N---                         ├──▌  LCL_VAR   int    V00 loc0         
                   [000239] -ACXG------                         └──▌  CALL      int    NativeVarargTest.VarArg:ReportFailure(bool,System.String,int,int):int
                   [000240] -ACXG------ arg0 setup                 ├──▌  ASG       int   
                   [000241] D------N---                            │  ├──▌  LCL_VAR   int    V15 tmp9         
                   [000242] -ACXG------                            │  └──▌  EQ        int   
                   [000243] -----------                            │     ├──▌  ADD       double
                   [000244] -----------                            │     │  ├──▌  LCL_VAR   double V05 loc5          (last use)
                   [000245] -----------                            │     │  └──▌  ADD       double
                   [000246] -----------                            │     │     ├──▌  ADD       double
                   [000247] -----------                            │     │     │  ├──▌  LCL_FLD   double(AX) V04 loc4         [+0]
                   [000248] -----------                            │     │     │  └──▌  LCL_FLD   double(AX) V04 loc4         [+8]
                   [000249] -----------                            │     │     └──▌  LCL_FLD   double(AX) V04 loc4         [+16]
                   [000250] -ACXG------                            │     └──▌  CALL      double NativeVarargTest.VarArg:check_passing_four_three_double_struct(NativeVarargTest.ThreeDoubleStruct,NativeVarargTest.ThreeDoubleStruct,NativeVarargTest.ThreeDoubleStruct,NativeVarargTest.ThreeDoubleStruct):double
                   [000252] -A--------- arg1 setup                 │        ├──▌  COMMA     void  
                   [000253] -A---------                            │        │  ├──▌  COMMA     void  
                   [000254] -A---------                            │        │  │  ├──▌  ASG       double
                   [000255] U------N---                            │        │  │  │  ├──▌  LCL_FLD   double(AX) V13 tmp7         [+0]
                   [000256] -----------                            │        │  │  │  └──▌  LCL_VAR   double V07 tmp1         
                   [000257] -A---------                            │        │  │  └──▌  ASG       double
                   [000258] U------N---                            │        │  │     ├──▌  LCL_FLD   double(AX) V13 tmp7         [+8]
                   [000259] -----------                            │        │  │     └──▌  LCL_VAR   double V08 tmp2         
                   [000260] -A---------                            │        │  └──▌  ASG       double
                   [000261] U------N---                            │        │     ├──▌  LCL_FLD   double(AX) V13 tmp7         [+16]
                   [000262] -----------                            │        │     └──▌  LCL_VAR   double V09 tmp3         
                   [000265] -A--------- arg3 setup                 │        ├──▌  COMMA     void  
                   [000266] -A---------                            │        │  ├──▌  COMMA     void  
                   [000267] -A---------                            │        │  │  ├──▌  ASG       double
                   [000268] U------N---                            │        │  │  │  ├──▌  LCL_FLD   double(AX) V14 tmp8         [+0]
                   [000269] -----------                            │        │  │  │  └──▌  LCL_VAR   double V10 tmp4         
                   [000270] -A---------                            │        │  │  └──▌  ASG       double
                   [000271] U------N---                            │        │  │     ├──▌  LCL_FLD   double(AX) V14 tmp8         [+8]
                   [000272] -----------                            │        │  │     └──▌  LCL_VAR   double V11 tmp5         
                   [000273] -A---------                            │        │  └──▌  ASG       double
                   [000274] U------N---                            │        │     ├──▌  LCL_FLD   double(AX) V14 tmp8         [+16]
                   [000275] -----------                            │        │     └──▌  LCL_VAR   double V12 tmp6         
         (  3,  3) [000277] ----------- arg4 out+20                │        ├──▌  LCL_VAR_ADDR long   V04 loc4         
                   [000263] ----------- arg1 in rdx                │        ├──▌  LCL_VAR_ADDR long   V13 tmp7         
                   [000276] ----------- arg3 in r9                 │        ├──▌  LCL_VAR_ADDR long   V14 tmp8         
         (  3,  3) [000264] ----------- arg2 in r8                 │        ├──▌  LCL_VAR_ADDR long   V02 loc2         
                   [000251] H---------- va cookie in rcx           │        └──▌  CNS_INT(h) long   0x24af975fed0 vararg
                   [000278] ----------- arg0 in rcx                ├──▌  LCL_VAR   int    V15 tmp9         
                   [000279] H---------- arg1 in rdx                ├──▌  CNS_INT(h) ref     'check_passing_four_three_double_struct(first, second, third, fo'
    
                   [000280] ----------- arg2 in r8                 ├──▌  CNS_INT   int    100
                   [000281] ----------- arg3 in r9                 └──▌  CNS_INT   int    84

    This misses some GTF_GLOB_REF markings on the [000247]-[000249] uses. Later fgFindOperOrder comes along and reverses the operands of the EQ node, which causes the problem.

    There is a fundamental problem here which is that we don't set GTF_GLOB_REF on accesses of locals until during morph, yet the last-use copy elision is marking an existing local as address exposed during morph. So previous uses will not be marked GTF_GLOB_REF. Which is actually correct, those uses will not be global uses, but only as long as they not reordered with the future call argument.

    Need to ponder a bit how to fix it. The temporary simple workaround might be to revisit the current statement and recompute GTF_GLOB_REF flags when we do this optimization, but that doesn't really prevent something downstream from coming along and reordering previous statements/local uses with the call. We might need to mark these as address exposed before morph to handle this (this could maybe be done together with #76926).
12. jakobbotsch

    added a commit that references this issue on Jan 31, 2023

    JIT: Update GTF_GLOB_REF after last-use copy omission

    ...

    This issue will close once commit 89c1f5f is merged into the 'main' branch.

    89c1f5f
13. ghost added

    in-prThere is an active PR which will close this issue when it is mergedThere is an active PR which will close this issue when it is merged

    on Jan 31, 2023
14. jakobbotsch

    closed this as completedin #81430on Feb 1, 2023
15. jakobbotsch

    added a commit that references this issue on Feb 1, 2023

    JIT: Update GTF_GLOB_REF after last-use copy omission (#81430)

    ...

    This issue will close once commit 58176f5 is merged into the 'main' branch.

    58176f5
16. ghost removed

    in-prThere is an active PR which will close this issue when it is mergedThere is an active PR which will close this issue when it is merged

    on Feb 1, 2023
17. ghost locked as resolved and limited conversation to collaborators on Mar 4, 2023