FULL PRODUCT VERSION :
openjdk version "1.8.0_b14-8u92"
OpenJDK Runtime Environment (build 1.8.0_b14-8u92-root_2016_07_04_14_06-b00)
OpenJDK 64-Bit Server VM (build 25.b14-b00, mixed mode)

FULL OS VERSION :
Linux evgeni 3.2.0-4-amd64 #1 SMP Debian 3.2.81-1 x86_64 GNU/Linux

A DESCRIPTION OF THE PROBLEM :
Eclipse seemed to randomly crash at different points. The crash logs pointed to the top of the stack being in PhaseIdealLoop::build_loop_late_post(Node*) and the error at 0x11e. Because this is not your build, I will paste disassembly of the area:

The build was made after checking-out the tag jdk8u92-b14 in each subrepo to be certain we used the stable version, because there was no OpenJDK package for a Debian that old.

As far as I've managed to trace it, beyond the printed stack, it happens at src/share/vm/opto/loopnode.cpp:3567
legal = idom(legal);

More specifically in the inline function in src/share/vm/opto/loopnode.hpp PhaseIdealLoop::idom_no_update(Node*) line 732
http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/file/15928d255046/src/share/vm/opto/loopnode.hpp#l732

C++ is not my greatest strength, but I do love assembly and especially reverse-engineering, so I'm fairly certain the crash happens after line 730 (the assignment of n) and before the check for the "while".

It's up to you to figure-out if this just needs a null-pointer check or the data is corrupt.


THE PROBLEM WAS REPRODUCIBLE WITH -Xint FLAG: Did not try

THE PROBLEM WAS REPRODUCIBLE WITH -server FLAG: Did not try

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
We are uncertain what usage in Eclipse Neon causes it, but the project being worked on was a Maven project under Java and it is maintained under git. Those plugins would probably be or become active.

ERROR MESSAGES/STACK TRACES THAT OCCUR :

Current thread (0x00000000024df000): JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=18395, stack(0x00007fcda43fe000,0x00007fcda44ff000)]

siginfo: si_signo: 11 (SIGSEGV), si_code: 1 (SEGV_MAPERR), si_addr: 0x0000000000000008

Registers:
RAX=0x0000000003807d70, RBX=0x00007fcda44fa3c0, RCX=0x0000000000000000, RDX=0x0000000000000000
RSP=0x00007fcda44f9ec0, RBP=0x00007fcda44f9f00, RSI=0x00007fcda04da540, RDI=0x0000000000000000
R8 =0x0000000003df28a0, R9 =0x00000000000c0000, R10=0x00007fcda2c71318, R11=0x00000000042771d8
R12=0x00007fcda44fa3e0, R13=0x00007fcd90571af0, R14=0x0000000004276ea0, R15=0x00007fcda2c71318
RIP=0x00007fcdb9b29aae, EFLAGS=0x0000000000010206, CSGSFS=0x0000000000000033, ERR=0x0000000000000004
  TRAPNO=0x000000000000000e



Stack: [0x00007fcda43fe000,0x00007fcda44ff000], sp=0x00007fcda44f9ec0, free space=1007k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x754aae] PhaseIdealLoop::build_loop_late_post(Node*)+0x11e
V [libjvm.so+0x755003] PhaseIdealLoop::build_loop_late(VectorSet&, Node_List&, Node_Stack&)+0x113
V [libjvm.so+0x7560e1] PhaseIdealLoop::build_and_optimize(bool, bool)+0x691
V [libjvm.so+0x4673c9] Compile::Optimize()+0x9e9
V [libjvm.so+0x469597] Compile::Compile(ciEnv*, C2Compiler*, ciMethod*, int, bool, bool, bool)+0x1277
V [libjvm.so+0x3cec18] C2Compiler::compile_method(ciEnv*, ciMethod*, int)+0x1b8
V [libjvm.so+0x470416] CompileBroker::invoke_compiler_on_method(CompileTask*)+0xa56
V [libjvm.so+0x471245] CompileBroker::compiler_thread_loop()+0x5d5
V [libjvm.so+0x970387] JavaThread::thread_main_inner()+0x247
V [libjvm.so+0x970847] JavaThread::run()+0x467
V [libjvm.so+0x8372b2] java_start(Thread*)+0xf2
C [libpthread.so.0+0x6b50] start_thread+0xd0


Current CompileTask:
C2:2996557 22222 4 org.eclipse.jdt.internal.compiler.parser.TypeConverter::decodeType (1094 bytes)


Disassembly:

0000000000754a7d <PhaseIdealLoop::build_loop_late_post(Node*)+0xed> call 0000000000754620 <PhaseIdealLoop::get_late_ctrl(Node*, Node*)>
0000000000754a82 <PhaseIdealLoop::build_loop_late_post(Node*)+0xf2> test rax,rax
0000000000754a85 <PhaseIdealLoop::build_loop_late_post(Node*)+0xf5> je 0000000000754e8e <PhaseIdealLoop::build_loop_late_post(Node*)+0x4fe>
0000000000754a8b <PhaseIdealLoop::build_loop_late_post(Node*)+0xfb> cmp rax,r15
0000000000754a8e <PhaseIdealLoop::build_loop_late_post(Node*)+0xfe> je 0000000000754e1b <PhaseIdealLoop::build_loop_late_post(Node*)+0x48b>
0000000000754a94 <PhaseIdealLoop::build_loop_late_post(Node*)+0x104> mov edx,DWORD PTR [rax+0x28]
0000000000754a97 <PhaseIdealLoop::build_loop_late_post(Node*)+0x107> mov r13,rax
0000000000754a9a <PhaseIdealLoop::build_loop_late_post(Node*)+0x10a> nop WORD PTR [rax+rax*1+0x0]
0000000000754aa0 <PhaseIdealLoop::build_loop_late_post(Node*)+0x110> mov rax,QWORD PTR [rbx+0x9f8]
0000000000754aa7 <PhaseIdealLoop::build_loop_late_post(Node*)+0x117> lea rax,[rax+rdx*8]
0000000000754aab <PhaseIdealLoop::build_loop_late_post(Node*)+0x11b> mov rcx,QWORD PTR [rax]
0000000000754aae <PhaseIdealLoop::build_loop_late_post(Node*)+0x11e> mov rdx,QWORD PTR [rcx+0x8]
0000000000754ab2 <PhaseIdealLoop::build_loop_late_post(Node*)+0x122> cmp QWORD PTR [rdx],0x0
0000000000754ab6 <PhaseIdealLoop::build_loop_late_post(Node*)+0x126> jne 0000000000754ae1 <PhaseIdealLoop::build_loop_late_post(Node*)+0x151>
0000000000754ab8 <PhaseIdealLoop::build_loop_late_post(Node*)+0x128> mov r9d,DWORD PTR [rbx+0x28]
0000000000754abc <PhaseIdealLoop::build_loop_late_post(Node*)+0x12c> nop DWORD PTR [rax+0x0]



REPRODUCIBILITY :
This bug can be reproduced often.