[16] RFR (S) 8249749: modify a primitive array through a stream and a for cycle causes jre crash

[Vladimir Kozlov]

https://bugs.openjdk.java.net/browse/JDK-8251994

On 8/18/20 3:03 PM, Vladimir Kozlov wrote:
> I reproduced it with -XX:UseAVX=0.
> 
> I will file bug and take care of it.
> 
> Thanks,
> Vladimir K
> 
> On 8/18/20 2:57 PM, Vladimir Kozlov wrote:
>> Thank you for reporting, Martin
>>
>> Please, file bug and specify JDK version, VM flags and CPUID features on machine where it fail.
>>
>> We test on x86 and aarch64 and I did not see any issues so far.
>>
>> Regards,
>> Vladimir
>>
>> On 8/18/20 2:25 PM, Doerr, Martin wrote:
>>> Hi Vladimir,
>>>
>>> we are hitting the following assertion after this change was pushed:
>>> assert(my_pack(s) == __null) failed: only in one pack
>>>
>>> Stack:
>>> V  [jvm.dll+0xbbac55]  SuperWord::construct_my_pack_map+0x135  (superword.cpp:1723)
>>> V  [jvm.dll+0xbb57f7]  SuperWord::SLP_extract+0x427  (superword.cpp:520)
>>> V  [jvm.dll+0xbcba0b]  SuperWord::transform_loop+0x48b  (superword.cpp:170)
>>> V  [jvm.dll+0x895a09]  PhaseIdealLoop::build_and_optimize+0xef9  (loopnode.cpp:3270)
>>> V  [jvm.dll+0x3df4b6]  Compile::Optimize+0xf76  (compile.cpp:2187)
>>> ...
>>>
>>> Seems to be reproducible by JTREG test compiler/vectorization/TestComplexAddrExpr.java on some x64 and aarch64 machines.
>>> (May depend on CPU model.)
>>>
>>> Is this a known issue?
>>> Or should I open a bug?
>>>
>>> Best regards,
>>> Martin
>>>
>>>
>>>> -----Original Message-----
>>>> From: hotspot-compiler-dev <hotspot-compiler-dev-
>>>> retn at openjdk.java.net> On Behalf Of Vladimir Kozlov
>>>> Sent: Montag, 10. August 2020 19:03
>>>> To: hotspot compiler <hotspot-compiler-dev at openjdk.java.net>
>>>> Subject: Re: [16] RFR (S) 8249749: modify a primitive array through a stream
>>>> and a for cycle causes jre crash
>>>>
>>>> Thank you, Vladimir
>>>>
>>>> Vladimir K
>>>>
>>>> On 8/10/20 2:04 AM, Vladimir Ivanov wrote:
>>>>>
>>>>>> http://cr.openjdk.java.net/~kvn/8249749/webrev.00/
>>>>>
>>>>> Looks good.
>>>>>
>>>>> Best regards,
>>>>> Vladimir Ivanov
>>>>>
>>>>>> https://bugs.openjdk.java.net/browse/JDK-8249749
>>>>>>
>>>>>> SuperWord does not recognize array indexing pattern used in the test
>>>> due to additional AddI node:
>>>>>>
>>>>>> AddI(AddI(Invariant(j*n), Loop_phi(i)), Loop_inc(1))
>>>>>>
>>>>>> As result it can't find memory reference to align vectors. But code ignores
>>>> that and continue execution.
>>>>>> Later when align_to_ref is referenced we hit SEGV because it is NULL.
>>>>>>
>>>>>> The fix is to check align_to_ref for NULL early and bailout.
>>>>>>
>>>>>> I also adjusted code in SWPointer::scaled_iv_plus_offset() to recognize
>>>> this address pattern to vectorize test's code.
>>>>>> And added missing _invar setting.
>>>>>>
>>>>>> And I slightly modified tracking code to investigate this issue.
>>>>>>
>>>>>> Added new test to check some complex address expressions similar to
>>>> bug's test case. Not all cases in test are
>>>>>> vectorized - there are other conditions which prevent that.
>>>>>>
>>>>>> Tested tier1,tier2,hs-tier3,precheckin-comp
>>>>>>
>>>>>> Thanks,
>>>>>> Vladimir K