RFR(S): 8213538: VM crashes when MaxVectorSize is set to 0, 1 or 2

[Nils Eliasson]

Updated:

http://cr.openjdk.java.net/~neliasso/8213538/webrev.03/

Regards

// Nils

On 2018-11-13 17:55, Vladimir Kozlov wrote:
> You don't need max_max because the value reflect real max vector size 
> supported by hardware. And we use this size to initialize a flag - 
> only this initialization is related to flag. There for I asked 
> "max_vector_size and min_vector_size" names.
>
> Thanks,
> Vladimir
>
> On 11/13/18 1:31 AM, Nils Eliasson wrote:
>> Hi,
>>
>> The flag name is MaxVectorSize - so then it becomes 
>> max_max_vector_size and min_max_vector_size which is a bit hard to 
>> read. In this new rev I opted for max_MaxVectorSize and 
>> min_MaxVectorSize to emphasize the relationship with the flag.
>>
>> I am all open to other suggestions.
>>
>> http://cr.openjdk.java.net/~neliasso/8213538/webrev.02
>>
>> Regards,
>> Nils
>>
>>
>> On 2018-11-12 19:18, Vladimir Kozlov wrote:
>>> Hi Nils,
>>>
>>> Fix and refactoring looks good.
>>>
>>> The only complain I have is names of locals. Can you use full names: 
>>> max_vector_size and min_vector_size?
>>>
>>> Please, add testing results link to bug report.
>>>
>>> Thanks,
>>> Vladimir
>>>
>>> On 11/12/18 3:14 AM, Nils Eliasson wrote:
>>>> Hi,
>>>>
>>>> This patch add the requirement that MaxVectorSize must be at least 
>>>> 4 on x64.
>>>>
>>>> The background is that we crash in startup when testing when 
>>>> setting it to 0, 1 or 2. When MaxVectorSize is less than 4, the XMM 
>>>> reg types won't be initialized, and then we crash in intrinsics 
>>>> that unconditionally use XMM regs. Since SSE2 is the required 
>>>> minimum on x64, the assumption that you can use XMM regs is always 
>>>> valid. This adds the requirement that MaxVectorSize is at least 4.
>>>>
>>>> I had to do a little refactoring to make the code more readable, 
>>>> but the essence is the same.
>>>>
>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8213538
>>>>
>>>> Webrev: http://cr.openjdk.java.net/~neliasso/8213538/webrev/
>>>>
>>>> Testing is running.
>>>>
>>>> Please review,
>>>>
>>>> // Nils
>>>>
>>