JIT: Deep inlining of polymorphic recursion can cause hangs during JIT

[jakobbotsch]

While investigating #88451 I noticed that another test in that test group fails often in jit_stress_random when the inliner ends up inlining a polymorphic recursive function. The test is this one and already seems to be a problem about hangs during inlining:

https://github.com/dotnet/runtime/blob/main/src/tests/JIT/Methodical/inlining/bug505642/test.cs

https://dev.azure.com/dnceng-public/public/_build/results?buildId=364925&view=ms.vss-test-web.build-test-results-tab is an example test run where this fails on multiple platforms:

set DOTNET_TieredCompilation=0
set DOTNET_JitStress=272
...
19:52:51.828 Running test: JIT/Methodical/inlining/bug505642/test_bug505642/test_bug505642.dll
App Exit Code: 259
Expected: 100
Actual: 259
END EXECUTION - FAILED
FAILED
[XUnitLogChecker]: 21:51:46.54: Could not read the file JIT\Methodical\Methodical_others\Methodical_others.testStats.csv. Retrying...

When I break we are usually inside resolveToken called from fgFindJumpTargets during inlining, printing some name on the EE side.

cc @AndyAyersMS, fallout from #88749? Perhaps we need to disallow recursive inlining if it makes the instantiation more complex.

Tagging subscribers to this area: @JulieLeeMSFT, @jakobbotsch
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Issue Details

---

While investigating #88451 I noticed that another test in that test group fails often in jit_stress_random when the inliner ends up inlining a polymorphic recursive function. The test is this one and already seems to be a problem about hangs during inlining:

https://github.com/dotnet/runtime/blob/main/src/tests/JIT/Methodical/inlining/bug505642/test.cs

https://dev.azure.com/dnceng-public/public/_build/results?buildId=364925&view=ms.vss-test-web.build-test-results-tab is an example test run where this fails on multiple platforms:

set DOTNET_TieredCompilation=0
set DOTNET_JitStress=272
...
19:52:51.828 Running test: JIT/Methodical/inlining/bug505642/test_bug505642/test_bug505642.dll
App Exit Code: 259
Expected: 100
Actual: 259
END EXECUTION - FAILED
FAILED
[XUnitLogChecker]: 21:51:46.54: Could not read the file JIT\Methodical\Methodical_others\Methodical_others.testStats.csv. Retrying...

When I break we are usually inside resolveToken called from fgFindJumpTargets during inlining, printing some name on the EE side.

cc @AndyAyersMS, fallout from #88749? Perhaps we need to disallow recursive inlining it makes the instantiation more complex.

Author:	jakobbotsch
Assignees:	-
Labels:	area-CodeGen-coreclr
Milestone:	-

[jakobbotsch]

I have added some code in fgCheckInlineDepthAndRecursion to print the complexity (number of classes in the instantiation) of each inlinee and I see:

fgInlineAppendStatements: no gc ref inline locals.
Successfully inlined Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`--------------------------------------------------------------------------------------------
INLINER: during 'fgInline' result 'success' reason 'below ALWAYS_INLINE size' for 'M:meth[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]](int,Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]):Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]' calling 'Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]INLINER: during 'fgInline' result 'success' reason 'below ALWAYS_INLINE size'
Expanding INLINE_CANDIDATE in statement STMT00069 in BB27:
STMT00069 ( INL12 @ 0x010[--] ... ??? ) <- INL10 @ 0x010[--] <- INL08 @ 0x010[--] <- INL06 @ 0x010[--] <- INL04 @ 0x010[--] <- INL02 @ 0x010[--] <- INLRT @ 0x010[--]
 [000241] I-C-G------ ▌ CALL void M:meth[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]],Tuple`2[Tuple`2[Tuple`2[int,int],Tuple`2[int,int]],Tuple`2[Tuple`2[int,int],Tuple`2[int,int]]]],Tuple`2[Tuple`2[Tuple`2[Tuple`2[int,int],Tu (exactContextHnd=0x00007FF8148E3CF8)
 [000244] ----------- retbuf ├──▌ LCL_ADDR byref V35 tmp32 [+0]
 [000233] ----------- arg1 ├──▌ SUB int 
 [000231] ----------- │ ├──▌ LCL_VAR int V32 tmp29 
 [000232] ----------- │ └──▌ CNS_INT int 1
 [000240] ----------- arg2 └──▌ LCL_VAR struct<Tuple`2, 16384> V34 tmp31 

Recursive inline. Ancestor complexity: 4095. New complexity: 8191
Recursive inline. Ancestor complexity: 2047. New complexity: 8191
Recursive inline. Ancestor complexity: 1023. New complexity: 8191
Recursive inline. Ancestor complexity: 511. New complexity: 8191
Recursive inline. Ancestor complexity: 255. New complexity: 8191
Recursive inline. Ancestor complexity: 127. New complexity: 8191
Recursive inline. Ancestor complexity: 63. New complexity: 8191

which indicates that the inline candidate already has 7 parents in the inline tree, but it seems to continue trying to inline.

[jakobbotsch]

This example repros the issue without any jit stress:

using System;
using System.Runtime.CompilerServices;

public class Program
{
 [MethodImpl(MethodImplOptions.NoOptimization)]
 public static int Main()
 {
 return Foo(8, 100);
 }

 private static T Foo<T>(int v, T x)
 {
 return (v >= 0) ? Foo(v - 1, (x, x)).Item1 : x;
 }
}

It hangs under DOTNET_TieredCompilation=0 (with checked builds, at least).

[BruceForstall]

This is failing all over the jitstress pipeline:

https://dev.azure.com/dnceng-public/public/_build/results?buildId=367750&view=results