8260650: test failed with "assert(false) failed: infinite loop in PhaseIterGVN::optimize" #3022
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…sform_no_reclaim().
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src/hotspot/share/opto/phaseX.cpp
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| } | ||
| NOT_PRODUCT( if( loop_count != 0 ) { set_progress(); } ) | ||
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| NOT_PRODUCT(if(loop_count != 0) { set_progress(); }) |
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Newline after if is missing.
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You mean space? I put the space in.
src/hotspot/share/opto/phaseX.cpp
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| assert(loop_count++ < K, "infinite loop in PhaseGVN::transform"); | ||
| NOT_PRODUCT(loop_count++;) | ||
| #ifdef ASSERT | ||
| if (loop_count >= K * C->live_nodes()) { |
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With old code, loop_count would be 0 in the first iteration (due to the postfix increment), with your changes it is 2. Is that intended? I see that you've changed < to >= but I still find it counter-intuitive that the loop_count is not the actual count. Also, it's inconsistent with PhaseIterGVN::transform where you increment after the check.
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Yeah, you're right it is a little sloppy. I will straighten this out. The intent is to count optimization steps. Since in transform_old and transform_no_reclaim, the loop is peeled to have the first apply_ideal() happen before it, I start the loop with 1. The original code had quite a few flaws, so, don't be concerned about counting the same way, the heuristic of the limit is obviously very approximate.
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@TobiHartmann, I've hopefully addressed your comments, please take another look when you have a chance. |
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@veresov This change now passes all automated pre-integration checks. After integration, the commit message for the final commit will be: 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 18 new commits pushed to the
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.
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@veresov Since your change was applied there have been 22 commits pushed to the
Your commit was automatically rebased without conflicts. Pushed as commit 996079b. |
The test constructs a large tree of
AddINodes that add constants to a variable. The tree is completely constant-foldable. Depending of the processing order the folding process may happen in the loop inPhaseIterGVN::transform_old()instead of going through the worklist. That blows through the loop limit, which triggers assert. The solution is to make the loop limit proportional to the number of live nodes. I chose it to beK*live_nodes(), which is already the limit inPhaseIterGVN::optimize(). I also noticed the same problem inPhaseGVN::transform_no_reclaim()and adjusted the code accordingly.Progress
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$ git fetch https://git.openjdk.java.net/jdk pull/3022/head:pull/3022$ git checkout pull/3022