8295788: C2 compilation hits "assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root()) failed: missed a node" #11162

rwestrel · 2022-11-15T11:42:00Z

This failure is similar to previous failures with loop strip mining: a
node is encountered that has control set in the outer strip mined loop
but is not reachable from the safepoint. There's already logic in loop
cloning to find those and fix their control to be outside the
loop. Usually a node ends up in the outer loop because some of its
inputs is in the outer loop. The current logic to catch nodes that are
erroneously assigned control in the outer loop is to start from
safepoint's inputs and look for uses with incorrect control. That
doesn't work in this case because: 1) the node is created by
IdealLoopTree::reassociate in the outer loop because its inputs are
indeed there 2) but a pass of split if updates the control to be
inside the inner loop.

To fix this, I propose reusing the existing clone_outer_loop_helper()
but apply it to the loop body as well. I had to tweak that method
because I ran into cases of dead nodes still reachable from a node in
the loop body but removed from the _body list by
IdealLoopTree::DCE_loop_body() (and as a result not cloned).

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Issue

JDK-8295788: C2 compilation hits "assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root()) failed: missed a node"

Reviewers

Vladimir Kozlov (@vnkozlov - Reviewer) ⚠️ Review applies to 32271652
Tobias Hartmann (@TobiHartmann - Reviewer)

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bridgekeeper · 2022-11-15T11:42:07Z

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

openjdk · 2022-11-15T11:44:58Z

@rwestrel The following label will be automatically applied to this pull request:

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mlbridge · 2022-11-15T11:47:54Z

Webrevs

vnkozlov

Make sense.

openjdk · 2022-11-15T20:33:37Z

@rwestrel 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:

8295788: C2 compilation hits "assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root()) failed: missed a node"

Reviewed-by: kvn, thartmann

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 148 new commits pushed to the master branch:

2b6dbc7: 8293856: AArch64: Remove clear_inst_mark from aarch64_enc_java_dynamic_call
2f063b8: 8296846: Minor cleanup of some dead code in Flow.java
ab6b7ef: 8296901: Do not create unsigned certificate and CRL
7b3984c: 8296463: Memory leak in JVM_StartThread with the integration of Virtual threads
373e52c: 8296785: Use realloc for CHeap-allocated BitMaps
a53be20: 8282404: DrawStringWithInfiniteXform.java failed with "RuntimeException: drawString with InfiniteXform transform takes long time"
66228f7: 8297074: Use enhanced-for cycle instead of Enumeration in javax.crypto
819af69: 8249693: java/nio/channels/FileChannel/FileExtensionAndMap.java uses @ignore w/o bug id
9c432a0: 8297165: Update Pandoc to version 2.19.2 for Oracle builds
8b140e2: 8297152: Add a @sealedGraph tag to ZoneId
... and 138 more: https://git.openjdk.org/jdk/compare/d4376f8b55391485365797d1c4d0dbbc6ed2ad92...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

TobiHartmann

Looks good to me otherwise.

test/hotspot/jtreg/compiler/loopstripmining/TestUseFromInnerInOuterUnusedBySfpt.java

TobiHartmann · 2022-11-16T06:17:53Z

src/hotspot/share/opto/loopopts.cpp

@@ -2297,6 +2299,11 @@ void PhaseIdealLoop::clone_outer_loop(LoopNode* head, CloneLoopMode mode, IdealL
      clone_outer_loop_helper(old, loop, outer_loop, old_new, wq, this, true);
    }

+    for (uint i = 0; i < loop->_body.size(); i++) {
+      Node* old = loop->_body.at(i);
+      clone_outer_loop_helper(old, loop, outer_loop, old_new, wq, this, true);


While you're at it, could you rename the helper method to something more meaningful?

Thanks for reviewing this. I did in the new commit. Does it look good to you?

…OuterUnusedBySfpt.java Co-authored-by: Tobias Hartmann <tobias.hartmann@oracle.com>

TobiHartmann

Looks good, thanks for updating!

rwestrel · 2022-11-18T10:02:20Z

@vnkozlov @TobiHartmann thanks for the reviews.

rwestrel · 2022-11-18T13:44:15Z

/integrate

openjdk · 2022-11-18T13:46:19Z

Going to push as commit 761a4f4.
Since your change was applied there have been 150 commits pushed to the master branch:

2f2d404: 8297129: Inflater documentation refers to 'deflate' methods
dd18d76: 8297173: usageTicks and totalTicks should be volatile to ensure that different threads get the latest ticks
2b6dbc7: 8293856: AArch64: Remove clear_inst_mark from aarch64_enc_java_dynamic_call
2f063b8: 8296846: Minor cleanup of some dead code in Flow.java
ab6b7ef: 8296901: Do not create unsigned certificate and CRL
7b3984c: 8296463: Memory leak in JVM_StartThread with the integration of Virtual threads
373e52c: 8296785: Use realloc for CHeap-allocated BitMaps
a53be20: 8282404: DrawStringWithInfiniteXform.java failed with "RuntimeException: drawString with InfiniteXform transform takes long time"
66228f7: 8297074: Use enhanced-for cycle instead of Enumeration in javax.crypto
819af69: 8249693: java/nio/channels/FileChannel/FileExtensionAndMap.java uses @ignore w/o bug id
... and 140 more: https://git.openjdk.org/jdk/compare/d4376f8b55391485365797d1c4d0dbbc6ed2ad92...master

Your commit was automatically rebased without conflicts.

openjdk · 2022-11-18T13:46:38Z

@rwestrel Pushed as commit 761a4f4.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

rwestrel added 2 commits November 15, 2022 09:28

fix

0235a9b

test

3227165

openjdk bot added the rfr Pull request is ready for review label Nov 15, 2022

openjdk bot added the hotspot-compiler hotspot-compiler-dev@openjdk.org label Nov 15, 2022

vnkozlov approved these changes Nov 15, 2022

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openjdk bot added the ready Pull request is ready to be integrated label Nov 15, 2022

TobiHartmann approved these changes Nov 16, 2022

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rwestrel and others added 2 commits November 18, 2022 09:42

Update test/hotspot/jtreg/compiler/loopstripmining/TestUseFromInnerIn…

b824a62

…OuterUnusedBySfpt.java Co-authored-by: Tobias Hartmann <tobias.hartmann@oracle.com>

more

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TobiHartmann approved these changes Nov 18, 2022

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8295788: C2 compilation hits "assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root()) failed: missed a node" #11162

8295788: C2 compilation hits "assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root()) failed: missed a node" #11162

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8295788: C2 compilation hits "assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root()) failed: missed a node" #11162

8295788: C2 compilation hits "assert((mode == ControlAroundStripMined && use == sfpt) || !use->is_reachable_from_root()) failed: missed a node" #11162

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