JDK-8275328 : C2: assert(n->outcnt() != 0 || C->top() == n || n->is_Proj()) failed: No dead instructions after post-alloc
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 18
  • Priority: P4
  • Status: Closed
  • Resolution: Duplicate
  • Submitted: 2021-10-15
  • Updated: 2021-10-15
  • Resolved: 2021-10-15
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JDK 18
18Resolved
Related Reports
Duplicate :  
JDK-8268882 - C2: assert(n->outcnt() != 0 || C->top() == n || n->is_Proj()) failed: No dead instructions after post-alloc
Relates :  
JDK-8273612 - Fix for JDK-8272873 causes timeout in running some tests with -Xcomp
Description
(synopsis is provisional, feel free to change it or close as duplicate of known bug) 

Attached Fuzzer test fails like:

$ ../build/linux-x86_64-server-fastdebug/images/jdk/bin/java -Xmx512m -XX:+UnlockDiagnosticVMOptions -XX:+StressGCM -XX:+StressCCP -Xcomp -XX:CompileOnly=Test -XX:-TieredCompilation  -XX:StressSeed=84360828 Test

# A fatal error has been detected by the Java Runtime Environment:
#
#  Internal Error (/home/shade/trunks/jdk/src/hotspot/share/opto/chaitin.cpp:1670), pid=3439441, tid=3439454
#  assert(n->outcnt() != 0 || C->top() == n || n->is_Proj()) failed: No dead instructions after post-alloc

Bisection shows it started with JDK-8273612, but that might only be because the profiling info had changed a bit.
Comments
Might be related to JDK-8268882. I propose to close this as a dup and reopen it if the fix for JDK-8268882 is unrelated.
15-10-2021