Assert failure: Assertion failed '!block->HasFlag(BBF_DONT_REMOVE)' in 'Program:TestEntryPoint():int'

[VincentBu]

Failed in: runtime-coreclr jitstress-random 20260315.1

Failed tests:

coreclr linux arm64 Checked jitstress_random_1 @ AzureLinux.3.Arm64.Open
- JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd

Error message:

Assert failure(PID 4665 [0x00001239], Thread: 4665 [0x1239]): Assertion failed '!block->HasFlag(BBF_DONT_REMOVE)' in 'Program:TestEntryPoint():int' during 'If conversion' (IL size 46; hash 0xeaa4cc8d; FullOpts)

    File: /__w/1/s/src/coreclr/jit/fgbasic.cpp:5154
    Image: /datadisks/disk1/work/A34F08F4/p/corerun

apply_reg_state: ip and cfa unchanged; stopping here (ip=0xf909c78fc548)
apply_reg_state: ip and cfa unchanged; stopping here (ip=0xf909c78fc548)
waitpid() returned successfully (wstatus 00000000) WEXITSTATUS 0 WTERMSIG 0
/datadisks/disk1/work/A34F08F4/w/A4DE08E1/e/JIT/JIT_others/../RyuJIT/DoWhileBndChk/DoWhileBndChk.sh: line 425:  4665 Aborted                 (core dumped) $LAUNCHER $ExePath "${CLRTestExecutionArguments[@]}"

Return code:      1
Raw output file:      /datadisks/disk1/work/A34F08F4/w/A4DE08E1/uploads/RyuJIT/DoWhileBndChk/output.txt
Raw output:
BEGIN EXECUTION
/datadisks/disk1/work/A34F08F4/p/corerun -p System.Reflection.Metadata.MetadataUpdater.IsSupported=false -p System.Runtime.Serialization.EnableUnsafeBinaryFormatterSerialization=true DoWhileBndChk.dll ''
[createdump] Gathering state for process 4665 corerun
[createdump] Crashing thread 1239 signal 6 (0006)
[createdump] Writing crash report to file /datadisks/disk1/dumps/coredump.4665.dmp.crashreport.json
[createdump] Crash report successfully written
[createdump] Writing minidump with heap to file /datadisks/disk1/dumps/coredump.4665.dmp
[createdump] Written 60702720 bytes (14820 pages) to core file
[createdump] Target process is alive
[createdump] Dump successfully written in 179ms
Expected: 100
Actual: 134
END EXECUTION - FAILED
Test Harness Exitcode is : 1
To run the test:
Set up CORE_ROOT and run.
> /datadisks/disk1/work/A34F08F4/w/A4DE08E1/e/JIT/JIT_others/../RyuJIT/DoWhileBndChk/DoWhileBndChk.sh

Stack trace:

   at Xunit.Assert.True(Nullable`1 condition, String userMessage) in /_/src/arcade/src/Microsoft.DotNet.XUnitAssert/src/BooleanAsserts.cs:line 141
   at TestLibrary.OutOfProcessTest.RunOutOfProcessTest(String assemblyPath, String testPathPrefix)
   at Program.<<Main>$>g__TestExecutor13|0_14(StreamWriter tempLogSw, StreamWriter statsCsvSw, <>c__DisplayClass0_0&)

Kusto query result:

Queued	Pipeline	Pipeline Configuration	OS	Arch	Test	Outcome	Properties	Build Reason
2025-11-24 16:48:35.327000+00:00	runtime-interpreter	Checked-interpmode1	azurelinux.3.amd64.open.rt	x64	JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd	Failed	{"System.StageName":"Build","operatingSystem":"AzureLinux.3.Amd64.Open","System.StageAttempt":"1","architecture":"x64","System.JobAttempt":"1","AzurePipelinesTestRunId":"33530638","DefinitionId":"316","BuildId":"1211193","System.JobName":"__default","DefinitionName":"runtime-interpreter","BuildNumber":"20251124.1","Project":"public","configuration":"Checked-interpmode1","CollectionUri":"https://dev.azure.com/dnceng-public/","System.PhaseName":"run_test_p1__linux_x64_checked","Reason":"Schedule","System.PhaseAttempt":"1","System.JobId":"6dfec640-5b96-5d95-2a5b-7c236ea2d5c5"}	Schedule
2025-11-24 16:48:30.935000+00:00	runtime-interpreter	Checked-interpmode1_no_tiered_compilation	azurelinux.3.amd64.open.rt	x64	JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd	Failed	{"System.StageName":"Build","operatingSystem":"AzureLinux.3.Amd64.Open","System.StageAttempt":"1","architecture":"x64","System.JobAttempt":"1","AzurePipelinesTestRunId":"33530636","DefinitionId":"316","BuildId":"1211193","System.JobName":"__default","DefinitionName":"runtime-interpreter","BuildNumber":"20251124.1","Project":"public","configuration":"Checked-interpmode1_no_tiered_compilation","CollectionUri":"https://dev.azure.com/dnceng-public/","System.PhaseName":"run_test_p1__linux_x64_checked","Reason":"Schedule","System.PhaseAttempt":"1","System.JobId":"6dfec640-5b96-5d95-2a5b-7c236ea2d5c5"}	Schedule
2025-11-21 16:46:09.753000+00:00	runtime-interpreter	Checked-interpmode1	azurelinux.3.amd64.open.rt	x64	JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd	Failed	{"operatingSystem":"AzureLinux.3.Amd64.Open","System.JobName":"__default","AzurePipelinesTestRunId":"33482320","System.JobAttempt":"1","System.PhaseName":"run_test_p1__linux_x64_checked","System.StageName":"Build","CollectionUri":"https://dev.azure.com/dnceng-public/","Project":"public","DefinitionName":"runtime-interpreter","BuildId":"1209667","Reason":"Schedule","configuration":"Checked-interpmode1","System.PhaseAttempt":"1","architecture":"x64","System.StageAttempt":"1","System.JobId":"6dfec640-5b96-5d95-2a5b-7c236ea2d5c5","DefinitionId":"316","BuildNumber":"20251121.1"}	Schedule
2025-11-21 16:44:10.064000+00:00	runtime-interpreter	Checked-interpmode1_no_tiered_compilation	azurelinux.3.amd64.open.rt	x64	JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd	Failed	{"System.StageAttempt":"1","System.StageName":"Build","Reason":"Schedule","System.JobName":"__default","DefinitionName":"runtime-interpreter","DefinitionId":"316","System.PhaseName":"run_test_p1__linux_x64_checked","architecture":"x64","Project":"public","BuildNumber":"20251121.1","System.PhaseAttempt":"1","AzurePipelinesTestRunId":"33482308","configuration":"Checked-interpmode1_no_tiered_compilation","BuildId":"1209667","operatingSystem":"AzureLinux.3.Amd64.Open","System.JobAttempt":"1","CollectionUri":"https://dev.azure.com/dnceng-public/","System.JobId":"6dfec640-5b96-5d95-2a5b-7c236ea2d5c5"}	Schedule
2025-11-19 16:47:05.658000+00:00	runtime-interpreter	Checked-interpmode1	azurelinux.3.amd64.open.rt	x64	JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd	Failed	{"BuildId":"1207530","Project":"public","System.StageName":"Build","operatingSystem":"AzureLinux.3.Amd64.Open","System.JobId":"6dfec640-5b96-5d95-2a5b-7c236ea2d5c5","Reason":"Schedule","System.JobName":"__default","architecture":"x64","CollectionUri":"https://dev.azure.com/dnceng-public/","AzurePipelinesTestRunId":"33424960","BuildNumber":"20251119.1","System.PhaseName":"run_test_p1__linux_x64_checked","configuration":"Checked-interpmode1","DefinitionId":"316","System.StageAttempt":"1","System.JobAttempt":"1","DefinitionName":"runtime-interpreter","System.PhaseAttempt":"1"}	Schedule
2025-11-19 16:46:57.922000+00:00	runtime-interpreter	Checked-interpmode1_no_tiered_compilation	azurelinux.3.amd64.open.rt	x64	JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd	Failed	{"System.StageAttempt":"1","System.JobAttempt":"1","Project":"public","System.PhaseAttempt":"1","AzurePipelinesTestRunId":"33424954","architecture":"x64","BuildId":"1207530","System.JobName":"__default","operatingSystem":"AzureLinux.3.Amd64.Open","DefinitionName":"runtime-interpreter","System.JobId":"6dfec640-5b96-5d95-2a5b-7c236ea2d5c5","System.StageName":"Build","CollectionUri":"https://dev.azure.com/dnceng-public/","DefinitionId":"316","BuildNumber":"20251119.1","System.PhaseName":"run_test_p1__linux_x64_checked","configuration":"Checked-interpmode1_no_tiered_compilation","Reason":"Schedule"}	Schedule
2025-11-19 15:16:46.683000+00:00	runtime-interpreter	Checked-interpmode1	osx.13.amd64.open	x64	JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd	Failed	{"BuildId":"1207530","System.PhaseAttempt":"1","System.StageName":"Build","DefinitionName":"runtime-interpreter","configuration":"Checked-interpmode1","System.JobAttempt":"1","Project":"public","System.StageAttempt":"1","architecture":"x64","BuildNumber":"20251119.1","Reason":"Schedule","System.JobId":"bf644a0b-2dbe-5a03-d8c6-a86fdd97c823","operatingSystem":"OSX.13.Amd64.Open","AzurePipelinesTestRunId":"33423504","DefinitionId":"316","System.JobName":"__default","CollectionUri":"https://dev.azure.com/dnceng-public/","System.PhaseName":"run_test_p1__osx_x64_checked"}	Schedule
2025-11-19 15:12:27.354000+00:00	runtime-interpreter	Checked-interpmode1_no_tiered_compilation	osx.13.amd64.open	x64	JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd	Failed	{"System.PhaseName":"run_test_p1__osx_x64_checked","System.PhaseAttempt":"1","operatingSystem":"OSX.13.Amd64.Open","CollectionUri":"https://dev.azure.com/dnceng-public/","BuildId":"1207530","System.StageAttempt":"1","AzurePipelinesTestRunId":"33423494","System.StageName":"Build","Reason":"Schedule","DefinitionName":"runtime-interpreter","System.JobId":"bf644a0b-2dbe-5a03-d8c6-a86fdd97c823","System.JobAttempt":"1","BuildNumber":"20251119.1","architecture":"x64","Project":"public","configuration":"Checked-interpmode1_no_tiered_compilation","System.JobName":"__default","DefinitionId":"316"}	Schedule
2025-11-17 17:16:18.402000+00:00	runtime-interpreter	Checked-interpmode1	azurelinux.3.amd64.open.rt	x64	JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd	Failed	{"Reason":"Schedule","BuildId":"1205459","System.JobName":"__default","operatingSystem":"AzureLinux.3.Amd64.Open","System.JobId":"6dfec640-5b96-5d95-2a5b-7c236ea2d5c5","configuration":"Checked-interpmode1","BuildNumber":"20251117.1","CollectionUri":"https://dev.azure.com/dnceng-public/","System.PhaseName":"run_test_p1__linux_x64_checked","DefinitionId":"316","architecture":"x64","AzurePipelinesTestRunId":"33367336","System.StageName":"Build","Project":"public","System.PhaseAttempt":"1","System.StageAttempt":"1","System.JobAttempt":"1","DefinitionName":"runtime-interpreter"}	Schedule
2025-11-17 16:59:25.142000+00:00	runtime-interpreter	Checked-interpmode1_no_tiered_compilation	azurelinux.3.amd64.open.rt	x64	JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd	Failed	{"BuildId":"1205459","BuildNumber":"20251117.1","architecture":"x64","CollectionUri":"https://dev.azure.com/dnceng-public/","configuration":"Checked-interpmode1_no_tiered_compilation","System.PhaseName":"run_test_p1__linux_x64_checked","System.StageName":"Build","System.StageAttempt":"1","System.JobId":"6dfec640-5b96-5d95-2a5b-7c236ea2d5c5","Project":"public","System.JobName":"__default","System.PhaseAttempt":"1","operatingSystem":"AzureLinux.3.Amd64.Open","Reason":"Schedule","DefinitionId":"316","System.JobAttempt":"1","DefinitionName":"runtime-interpreter","AzurePipelinesTestRunId":"33367086"}	Schedule
2025-11-17 15:05:24.325000+00:00	runtime-interpreter	Checked-interpmode1	osx.13.amd64.open	x64	JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd	Failed	{"configuration":"Checked-interpmode1","System.JobId":"bf644a0b-2dbe-5a03-d8c6-a86fdd97c823","architecture":"x64","Project":"public","BuildNumber":"20251117.1","BuildId":"1205459","System.JobAttempt":"1","DefinitionId":"316","System.PhaseName":"run_test_p1__osx_x64_checked","CollectionUri":"https://dev.azure.com/dnceng-public/","System.JobName":"__default","System.StageAttempt":"1","System.StageName":"Build","Reason":"Schedule","System.PhaseAttempt":"1","operatingSystem":"OSX.13.Amd64.Open","AzurePipelinesTestRunId":"33365674","DefinitionName":"runtime-interpreter"}	Schedule
2025-11-17 14:57:41.775000+00:00	runtime-interpreter	Checked-interpmode1_no_tiered_compilation	osx.13.amd64.open	x64	JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd	Failed	{"System.JobAttempt":"1","operatingSystem":"OSX.13.Amd64.Open","BuildNumber":"20251117.1","System.StageName":"Build","architecture":"x64","DefinitionId":"316","System.JobId":"bf644a0b-2dbe-5a03-d8c6-a86fdd97c823","System.StageAttempt":"1","System.PhaseName":"run_test_p1__osx_x64_checked","configuration":"Checked-interpmode1_no_tiered_compilation","CollectionUri":"https://dev.azure.com/dnceng-public/","System.JobName":"__default","DefinitionName":"runtime-interpreter","Project":"public","Reason":"Schedule","BuildId":"1205459","System.PhaseAttempt":"1","AzurePipelinesTestRunId":"33365538"}	Schedule

[dotnet-policy-service]

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

[BoyBaykiller]

Probably caused by #125072, I'll take a look.

[JulieLeeMSFT]

Failed in

• runtime-jit-experimental 20260315.1

Console Log: Console Log

[BoyBaykiller]

This particular case will be fixed by my upcoming #125347. I made the PR before this issue came up and it just so happens to fix it. That's because it no longer recognizes this as a valid if-conversion and bails out. I think it's fine that we'll no longer create a SELECT here because we're inside exception handling anyway and the new codegen also looks better to me https://www.diffchecker.com/2a3Y2xCQ/.

The IR of importance is:

*************** Starting PHASE If conversion

Conditionally executing BB09 inside BB11

------------ BB11 [0010] [???..???) -> BB12(0.5),BB15(0.5) (cond), preds={BB05} succs={BB15,BB12}

***** BB11 [0010]
STMT00015 ( ??? ... ??? )
N005 ( 12, 17) [000067] -----O-----                         *  JTRUE     void   $VN.Void
N004 ( 10, 15) [000036] J----O?N---                         \--*  NE        int    $405
N002 (  6,  4) [000035] #----O?----                            +--*  IND       long   $144
N001 (  3,  2) [000031] ------?----                            |  \--*  LCL_VAR   ref    V05 tmp2         u:2 (last use) $242
N003 (  3, 10) [000030] H-----?----                            \--*  CNS_INT(h) long   0x7ff95bb5e4e8 class System.IndexOutOfRangeException $42

------------ BB15 [0014] [???..???) -> BB09(1) (always), preds={BB11} succs={BB09}

------------ BB09 [0008] [027..02A) -> BB12(1) (always), preds={BB15} succs={BB12}

***** BB09 [0008]
STMT00011 ( 0x027[E--] ... 0x029 )
N002 (  5,  4) [000050] DA---+-----                         *  STORE_LCL_VAR int    V00 loc0         d:3 $VN.Void
N001 (  1,  1) [000049] -----+-----                         \--*  CNS_INT   int    100 $ca

These blocks are part of exception handling so can't be removed. With my upcoming PR if-conversion will bail out early in this case because it doesn't handle flow through multiple blocks (BB15 -> BB09).
In theory this assert could still fire with the new PR if we have a case where the single Then or Else block is marked as BBF_DONT_REMOVE. But I can't imagine how this would happen.

[VincentBu]

Failed in: runtime-coreclr jitstress-random 20260322.1

Failed tests:

coreclr osx x64 Checked jitstress_random_2 @ OSX.15.Amd64.Open
- JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.cmd

Error message:

Assert failure(PID 17551 [0x0000448f], Thread: 187984 [0x2de50]): Assertion failed '!block->HasFlag(BBF_DONT_REMOVE)' in 'Program:TestEntryPoint():int' during 'If conversion' (IL size 46; hash 0xeaa4cc8d; FullOpts)

    File: /Users/runner/work/1/s/src/coreclr/jit/fgbasic.cpp:5154
    Image: /private/tmp/helix/working/AA80098C/p/corerun

waitpid() returned successfully (wstatus 00000000) WEXITSTATUS 0 WTERMSIG 0
/private/tmp/helix/working/AA80098C/w/B8E409E5/e/JIT/JIT_others/../RyuJIT/DoWhileBndChk/DoWhileBndChk.sh: line 425: 17551 Abort trap: 6           (core dumped) $LAUNCHER $ExePath "${CLRTestExecutionArguments[@]}"

Return code:      1
Raw output file:      /tmp/helix/working/AA80098C/w/B8E409E5/uploads/RyuJIT/DoWhileBndChk/output.txt
Raw output:
BEGIN EXECUTION
/tmp/helix/working/AA80098C/p/corerun -p System.Reflection.Metadata.MetadataUpdater.IsSupported=false -p System.Runtime.Serialization.EnableUnsafeBinaryFormatterSerialization=true DoWhileBndChk.dll ''
[createdump] Gathering state for process 17551 
[createdump] Crashing thread 2de50 signal 6 (0006)
[createdump] Writing crash report to file /cores/coredump.17551.dmp.crashreport.json
[createdump] Crash report successfully written
[createdump] Writing minidump with heap to file /cores/coredump.17551.dmp
[createdump] Written 717947016 bytes (175280 pages) to core file
[createdump] Target process is alive
[createdump] Dump successfully written in 3309ms
Expected: 100
Actual: 134
END EXECUTION - FAILED
Test Harness Exitcode is : 1
To run the test:
Set up CORE_ROOT and run.
> /private/tmp/helix/working/AA80098C/w/B8E409E5/e/JIT/JIT_others/../RyuJIT/DoWhileBndChk/DoWhileBndChk.sh

Stack trace:

   at Xunit.Assert.True(Nullable`1 condition, String userMessage) in /_/src/arcade/src/Microsoft.DotNet.XUnitAssert/src/BooleanAsserts.cs:line 141
   at TestLibrary.OutOfProcessTest.RunOutOfProcessTest(String assemblyPath, String testPathPrefix)
   at Program.<<Main>$>g__TestExecutor13|0_14(StreamWriter tempLogSw, StreamWriter statsCsvSw, <>c__DisplayClass0_0&)

[kg]

Summary:

JIT if-conversion attempts to remove BBF_DONT_REMOVE block during DoWhileBndChk compilation under stress modes.

Failed in (2):

• runtime-coreclr jitstress-random 20260408.1

• runtime-jit-experimental 20260408.1

Console Log: Console Log

Source: runtime-coreclr jitstress-random / coreclr linux arm64 Checked jitstress_random_1 @ AzureLinux.3.Arm64.Open / JIT_others

Failed tests:

runtime-coreclr jitstress-random

- coreclr linux arm64 Checked jitstress_random_1 @ AzureLinux.3.Arm64.Open

- coreclr osx x64 Checked jitstress_random_1 @ OSX.15.Amd64.Open

runtime-jit-experimental

- coreclr linux arm64 Checked jitoptrepeat @ AzureLinux.3.Arm64.Open

- coreclr linux x64 Checked jitoptrepeat @ AzureLinux.3.Amd64.Open

- coreclr osx arm64 Checked jitoptrepeat @ OSX.26.Arm64.Open

- coreclr osx x64 Checked jitoptrepeat @ OSX.15.Amd64.Open

- coreclr windows arm64 Checked jitoptrepeat @ Windows.11.Arm64.Open

- coreclr windows x64 Checked jitoptrepeat @ Windows.10.Amd64.Open

  - JIT_others

Error Message:

Assert failure(PID 7995 [0x00001f3b], Thread: 7995 [0x1f3b]): Assertion failed '!block->HasFlag(BBF_DONT_REMOVE)' in 'Program:TestEntryPoint():int' during 'If conversion' (IL size 46; hash 0xeaa4cc8d; FullOpts)

Stack Trace:

    clrjit!assertAbort
    clrjit fgbasic.cpp:5154

Analysis:

JIT if-conversion optimization attempts to remove a block marked BBF_DONT_REMOVE (exception handling). Fires at fgbasic.cpp:5154 under jitstress_random and jitoptrepeat. @BoyBaykiller identified root cause: blocks inside EH regions cannot be removed. PR #125347 is the planned fix. Exit code 22 on Linux, -1073740286 on Windows.

• Generated by ci-pipeline-monitor/scripts/generate_report.py *

[JulieLeeMSFT]

Summary:

JIT assertion failure in fgbasic.cpp:5154 during If conversion phase when compiling DoWhileBndChk test under jitstress-random mode. The assertion checks that a basic block does not have the BBF_DONT_REMOVE flag. Occurs on both arm64 (azurelinux) and x64 (osx) platforms.

Failed in (1):

• runtime-coreclr jitstress-random 20260408.1

Console Log: Console Log

Source: runtime-coreclr jitstress-random / coreclr linux arm64 Checked jitstress_random_1 @ AzureLinux.3.Arm64.Open / JIT_others

Failed tests:

- coreclr linux arm64 Checked jitstress_random_1 @ AzureLinux.3.Arm64.Open

- coreclr osx x64 Checked jitstress_random_1 @ OSX.15.Amd64.Open

  - JIT_others

Error Message:

Assert failure(PID 7995 [0x00001f3b], Thread: 7995 [0x1f3b]): Assertion failed '!block->HasFlag(BBF_DONT_REMOVE)' in 'Program:TestEntryPoint():int' during 'If conversion' (IL size 46; hash 0xeaa4cc8d; FullOpts)
    File: /__w/1/s/src/coreclr/jit/fgbasic.cpp:5154

Stack Trace:

Assert failure in src/coreclr/jit/fgbasic.cpp:5154
Running test: JIT/RyuJIT/DoWhileBndChk/DoWhileBndChk.dll
App Exit Code: 22

Analysis:

The JIT If conversion optimization pass encounters a block flagged as BBF_DONT_REMOVE that it should not be trying to remove. This is triggered by random JIT stress settings (DOTNET_JitStress=303 on arm64, DOTNET_JitStress=45 on x64). Tracked in issue #125600, assigned to BoyBaykiller.

Generated by ci-pipeline-monitor/scripts/generate_report.py