JDK-8263577 : C2: reachable nodes shouldn't have dead uses at the end of optimizations
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 8,11,17
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2021-03-15
  • Updated: 2023-12-04
  • Resolved: 2021-03-16
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JDK 17
17 b14Fixed
Related Reports
Duplicate :  
JDK-8262289 - [lworld] LoopNode::verify_strip_mined fails
Duplicate :  
JDK-8312438 - assert(n->req() == 2 && n->in(1) != __null) failed: Only one data input expected
Duplicate :  
JDK-8307522 - C2: assert(n->req() == 2 && n->in(1) != __null) failed
Relates :  
JDK-8263672 - fatal error: no reachable node should have no use
Relates :  
JDK-8267212 - test/jdk/java/util/Collections/FindSubList.java intermittent crash with "no reachable node should have no use"
Relates :  
JDK-8264649 - runtime/InternalApi/ThreadCpuTimesDeadlock.java crash in fastdebug C2 with -XX:-UseTLAB
Relates :  
JDK-8321278 - C2: Partial peeling fails with assert "last_peel <- first_not_peeled"
Description
It's not uncommon for c2 to leave dead uses hanging from reachable nodes. It's usually harmless but can cause confusion (such as in 
valhalla JDK-8262289, not reproducible with non valhalla code AFAICT).
Comments
Start backport this bug to jdk11u-dev, detail discuss in JDK-8272131.
01-09-2021
ILW = MLH = P4
16-03-2021
Changeset: 20297a1b Author: Roland Westrelin <roland@openjdk.org> Date: 2021-03-16 08:20:52 +0000 URL: https://git.openjdk.java.net/jdk/commit/20297a1b
16-03-2021