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Avoid generating degenerate flow during redundant branch optimization #48609

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kunalspathak opened this issue Feb 22, 2021 · 2 comments · Fixed by #99509
Closed

Avoid generating degenerate flow during redundant branch optimization #48609

kunalspathak opened this issue Feb 22, 2021 · 2 comments · Fixed by #99509
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@kunalspathak
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area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI in-pr There is an active PR which will close this issue when it is merged
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@kunalspathak
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kunalspathak commented Feb 22, 2021 •
edited by BruceForstall
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Today, we might end up generating degenerate flow during redundant branch optimization. We need to make sure that we don't do that and add an assertion check to make sure that we never have flDupCount > 1 unless it is a switch statement.

We saw #47101 issue because of this and it was fixed in #48607 by making sure assertion prop handles it. But eventually "redundant branch optimization" should not create such flow.

category:cq
theme:flowgraph
@dotnet-issue-labeler dotnet-issue-labeler bot added area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI untriaged New issue has not been triaged by the area owner labels Feb 22, 2021
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@dotnet/jit-contrib , @AndyAyersMS

@kunalspathak kunalspathak mentioned this issue Feb 22, 2021
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@JulieLeeMSFT JulieLeeMSFT removed the untriaged New issue has not been triaged by the area owner label Feb 25, 2021
@JulieLeeMSFT JulieLeeMSFT added this to the 6.0.0 milestone Feb 25, 2021
@JulieLeeMSFT JulieLeeMSFT linked a pull request Feb 25, 2021 that will close this issue
fix assertion merge for degenerate flow #48607
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@JulieLeeMSFT JulieLeeMSFT removed a link to a pull request Feb 25, 2021
fix assertion merge for degenerate flow #48607
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Not urgent for .NET 6.

@kunalspathak kunalspathak modified the milestones: 6.0.0, Future Jul 7, 2021
@AndyAyersMS AndyAyersMS mentioned this issue Sep 25, 2022
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AndyAyersMS added a commit to AndyAyersMS/runtime that referenced this issue Mar 11, 2024
@AndyAyersMS
JIT: don't create degenerate flow in fgReplaceJumpTarget
313654e 
Detect if the update has created degenerate BBJ_COND flow, and simplify.
Also symmetrize the true/false cases.

Fixes dotnet#48609.

Also fixes some issues seen in enhanced likelhood checking.
@AndyAyersMS AndyAyersMS mentioned this issue Mar 11, 2024
Merged
@dotnet-policy-service dotnet-policy-service bot added the in-pr There is an active PR which will close this issue when it is merged label Mar 11, 2024
AndyAyersMS added a commit to AndyAyersMS/runtime that referenced this issue Mar 11, 2024
@AndyAyersMS
JIT: don't create degenerate flow in fgReplaceJumpTarget
78cdd2c 
Detect if the update has created degenerate BBJ_COND flow, and simplify.
Also symmetrize the true/false cases.

Fixes dotnet#48609.

Also fixes some issues seen in enhanced likelhood checking.
AndyAyersMS added a commit that referenced this issue Mar 11, 2024
@AndyAyersMS
JIT: don't create degenerate flow in fgReplaceJumpTarget (#99509)
9d56a4c 
Detect if the update has created degenerate BBJ_COND flow, and simplify.

Fixes #48609.

Also fixes some issues seen in enhanced likelihood checking.
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@kunalspathak kunalspathak

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area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI in-pr There is an active PR which will close this issue when it is merged
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.NET Core CodeGen
Status: Done
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Future
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JIT: don't create degenerate flow in fgReplaceJumpTarget AndyAyersMS/runtime
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@kunalspathak @JulieLeeMSFT