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8275583: [lworld] C2 fails to scalarize inline types in safepoint debug info in rare cases #568

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@TobiHartmann TobiHartmann commented Oct 20, 2021

In rare cases, it can happen that inline types are not scalarized in safepoint debug info and we hit an assert. The problem is that InlineTypeBaseNode::Ideal is only called by IGVN if the node (or one of its inputs) has been modified but not if folding of output nodes leads to a direct connection to a SafePointNode. Usually, the node is still scalarized when we visit all inline type nodes via Compile::process_inline_types but there are cases when that's too late and not scalarizing the node early (prevents other nodes from being removed (for example, during macro expansion).

The fix is to simply move the code to SafePointNode::Ideal which will be invoked whenever one of the (debug) inputs changed.

I also fixed an issue where FastLockNodes with an InlineTypePtrNode input are not folded and keep allocations alive.

Best regards,
Tobias


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  • JDK-8275583: [lworld] C2 fails to scalarize inline types in safepoint debug info in rare cases

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@bridgekeeper bridgekeeper bot commented Oct 20, 2021

👋 Welcome back thartmann! A progress list of the required criteria for merging this PR into lworld will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

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@openjdk openjdk bot commented Oct 20, 2021

@TobiHartmann This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8275583: [lworld] C2 fails to scalarize inline types in safepoint debug info in rare cases

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At the time when this comment was updated there had been 1 new commit pushed to the lworld branch:

  • c61edd5: 8272448: [lworld] C2 compilation fails with "Bad graph detected in build_loop_late"

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@mlbridge mlbridge bot commented Oct 20, 2021

Webrevs

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@TobiHartmann TobiHartmann commented Oct 20, 2021

/integrate

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@openjdk openjdk bot commented Oct 20, 2021

Going to push as commit 3354fc0.
Since your change was applied there has been 1 commit pushed to the lworld branch:

  • c61edd5: 8272448: [lworld] C2 compilation fails with "Bad graph detected in build_loop_late"

Your commit was automatically rebased without conflicts.

@openjdk openjdk bot closed this Oct 20, 2021
@openjdk openjdk bot added integrated and removed ready rfr labels Oct 20, 2021
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@openjdk openjdk bot commented Oct 20, 2021

@TobiHartmann Pushed as commit 3354fc0.

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