C2 crash in PhaseIdealLoop::build_loop_late_post_work

[Christian Hagedorn]

Hi Martin

Yes, this is a known problem (see JDK-8251925). We also see it failing 
with only this benchmark, often in log-regression. I played around with 
different settings by just running log-regression, for example, which 
did not seem to trigger it, though. Do you have a fast reproducer?

It started to fail after JDK-8249749 which, however, just seem to have 
revealed the problem.

Best regards,
Christian

On 27.10.20 12:07, Doerr, Martin wrote:
> Hi,
> 
> we observe C2 crashes on all x86_64 platforms when running Renaissance Benchmark "log-regression" since 2020-08-10.
> (hg was at "8250848: [aarch64] nativeGotJump_at() missing call to verify()." when we've seen it first.)
> 
> 
> #  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x00007ffd594e9322, pid=1439804, tid=1516348
> 
> #
> 
> # JRE version: OpenJDK Runtime Environment (16.0.0.1) (build 16.0.0.1-internal+0-adhoc.openjdk.jdk-dev)
> 
> # Java VM: OpenJDK 64-Bit Server VM (16.0.0.1-internal+0-adhoc.openjdk.jdk-dev, mixed mode, sharing, tiered, compressed oops, g1 gc, windows-amd64)
> 
> # Problematic frame:
> 
> # V  [jvm.dll+0x559322]  PhaseIdealLoop::build_loop_late_post_work+0x212
> 
> 
> 
> Host: Intel(R) Xeon(R) CPU E7-8880 v4 @ 2.20GHz, 8 cores, 15G,  Windows Server 2016 , 64 bit Build 14393 (10.0.14393.3630)
> 
> Time: Sat Oct 24 19:40:57 2020 W. Europe Daylight Time elapsed time: 16.016253 seconds (0d 0h 0m 16s)
> 
> 
> V  [jvm.dll+0x559322]  PhaseIdealLoop::build_loop_late_post_work+0x212  (loopnode.cpp:5312)
> 
> V  [jvm.dll+0x5590b4]  PhaseIdealLoop::build_loop_late+0x214  (loopnode.cpp:5159)
> 
> V  [jvm.dll+0x558418]  PhaseIdealLoop::build_and_optimize+0x7b8  (loopnode.cpp:3874)
> 
> V  [jvm.dll+0x21410a]  Compile::optimize_loops+0x15a  (compile.cpp:1960)
> 
> V  [jvm.dll+0x20d900]  Compile::Optimize+0xf90  (compile.cpp:2184)
> 
> V  [jvm.dll+0x20b105]  Compile::Compile+0xba5  (compile.cpp:735)
> 
> V  [jvm.dll+0x19de6b]  C2Compiler::compile_method+0xab  (c2compiler.cpp:104)
> 
> Is this a known problem?
> 
> Best regards,
> Martin
>