Bug ID: JDK-8279062 C2: assert(t->meet(t0) == t) failed: Not monotonic after JDK-8278413

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JDK 18
18Resolved

Reliably happens on x86_32:

$ CONF=linux-x86-server-fastdebug make run-test TEST=serviceability/jvmti/GetLocalVariable/GetLocalVars.java 

#  Internal Error (/home/shade/trunks/shipilev-jdk18/src/hotspot/share/opto/phaseX.cpp:1741), pid=2708428, tid=2708444
#  assert(t->meet(t0) == t) failed: Not monotonic

Current thread (0xa4666478):  JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=2721649, stack(0xa373f000,0xa3800000)]

Current CompileTask:
C2:   5783 1738    b  4       java.util.IdentityHashMap::<init> (44 bytes)

Stack: [0xa373f000,0xa3800000],  sp=0xa37fd2f0,  free space=760k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0x1393634]  PhaseCCP::analyze()+0x484
V  [libjvm.so+0x95edc1]  Compile::Optimize()+0x931
V  [libjvm.so+0x96109a]  Compile::Compile(ciEnv*, ciMethod*, int, Options, DirectiveSet*)+0x135a
V  [libjvm.so+0x786323]  C2Compiler::compile_method(ciEnv*, ciMethod*, int, bool, DirectiveSet*)+0x863
V  [libjvm.so+0x97355d]  CompileBroker::invoke_compiler_on_method(CompileTask*)+0x15bd
V  [libjvm.so+0x974479]  CompileBroker::compiler_thread_loop()+0x849
V  [libjvm.so+0x99d3fb]  CompilerThread::thread_entry(JavaThread*, JavaThread*)+0x2b
V  [libjvm.so+0x16d2628]  JavaThread::thread_main_inner()+0x5b8
V  [libjvm.so+0x16d4bd2]  JavaThread::run()+0x382
V  [libjvm.so+0x16db4ae]  Thread::call_run()+0xfe
V  [libjvm.so+0x130d873]  thread_native_entry(Thread*)+0x123
C  [libpthread.so.0+0x8635]  start_thread+0xf5

Bisection points to JDK-8278413.

I think it is easier to back out the change at this point: JDK-8279204. The failure is gone after the backout.

23-12-2021

Closing this as it is not an issue anymore after the backout of JDK-8278413 with JDK-8279204. This bug should be addressed with the redo fix in JDK-8279219.

23-12-2021

ILW = Assertion in CCP and recent regression, x86_32 and with single test only?, disable compilation of affected method = HLM = P3

21-12-2021

Relates :	JDK-8287851 - C2 crash: assert(t->meet(t0) == t) failed: Not monotonic
Relates :	JDK-8279219 - [REDO] C2 crash when allocating array of size too large
Relates :	JDK-8278413 - C2 crash when allocating array of size too large