[9] RFR(S): 8158214: Crash with "assert(VM_Version::supports_sse4_1()) failed" if UseSSE < 4 is set

[Tobias Hartmann]

Hi Vladimir,

thanks for the review!

On 31.05.2016 19:48, Vladimir Kozlov wrote:
> Is it only pinsrd instruction requires sse4.1? I looked on crc32 code and we can use pinsrw instruction with shift:
> 
> if (supports_sse4_1()) {
>   pinsrd(xmm1, crc, 0);
> } else {
>   pinsrw(xmm1, crc, 0);
>   shrl(crc, 16);
>   pinsrw(xmm1, crc, 1);
> }

Right, 'pinsrd' is the only SSE 4.1 instruction in the crc32 code, so this works.

Here's the new webrev:
http://cr.openjdk.java.net/~thartmann/8158214/webrev.01/

Thanks,
Tobias

> Unfortunately UseAESCTRIntrinsics use more sse4.1 instructions so we can't do that. And it is already guarded by supports_sse4_1().
> 
> Changes which remove UseSSE checks in vm_version_x86.cpp are good.
> 
> Thanks,
> Vladimir
> 
> 
> On 5/31/16 5:48 AM, Tobias Hartmann wrote:
>> Hi,
>>
>> please review the following patch:
>>
>> https://bugs.openjdk.java.net/browse/JDK-8158214
>> http://cr.openjdk.java.net/~thartmann/8158214/webrev.00/
>>
>> The VM crashes during stub generation if UseSSE = 3 is set. The problem is that even if SSE 4 is not available or disabled, MacroAssembler::kernel_crc32() emits the 'pinsrd' instruction which is a SSE 4.1 instruction.
>>
>> The solution is to only emit CRC32 intrinsics if SSE 4.1 is available (the UseSSE > 2 check is not strong enough). I also removed the unnecessary UseSSE >= 4 checks because they are included in the supports_sse4_2() check.
>>
>> Tested with JPRT and RBT (running).
>>
>> Thanks,
>> Tobias
>>