JDK-8308149 : C2 VerifyIterativeGVN: verify CFG consistency (MultiBranchNode::required_outcnt() == outcnt())
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 21
  • Priority: P4
  • Status: Open
  • Resolution: Unresolved
  • Submitted: 2023-05-16
  • Updated: 2023-06-05
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tbdUnresolved
Related Reports
Relates :  
JDK-8298951 - Umbrella: improve CCP and IGVN verification
Description
This is a subtask of JDK-8298951.

Recently, we have had a series of malformed control flow bugs.
They only get triggered in Compile::final_graph_reshaping.
I want to find more of them, and find them already after IGVN.
Comments
This is the draft PR: https://github.com/openjdk/jdk/pull/13999
05-06-2023
Looks like there are a few broken control flow bugs around now. I'll first try to fix those before I continue work here.
26-05-2023
Fuzzer jasm failures with the flag: java -jar ~/Documents/asmtools-7.0-build/release/lib/asmtools.jar jasm X1.jasm /home/emanuel/Documents/fork5-jdk/build/linux-x64-debug/jdk/bin/java -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -Xcomp -XX:CompileCommand=compileonly,X1::test* -XX:-TieredCompilation -XX:RepeatCompilation=1000 -XX:+StressIGVN -XX:VerifyIterativeGVN=100 X1 MultiBranch has bad outcnt: 1 (expected: 2) 157 If === 149 156 [[ 158 ]] P=0.900000, C=-1.000000 !jvms: X1::test @ bci:33 158 IfTrue === 157 [[ 254 250 ]] #1 !jvms: X1::test @ bci:33
23-05-2023
PR: https://github.com/openjdk/jdk/pull/13999
16-05-2023