[Vector]fromArray/allTrue performance

[王卓(卓仁)]

Hello,
I am Zhuoren from Alibaba JVM team. Glad to take part in project panama.
We have integrated Vector API to Alibaba JDK, and another Alibaba team is now using Vector API to optimize their applications.
Here are some issues we found in our previous work and blocked future optimization, and I am searching for solutions.

1. The performance of Long128Species::fromArray(long[] a, int ax, Mask<Long, Shapes.S128Bit> m) is bad. The attached java file is a test for this API. 
I checked the performance issue is due to intrinsic failure.
x86.ad: 
        case Op_VectorLoadMask:
          if (UseSSE <= 3) { ret_value = false; }
          else if (vlen == 1 || vlen == 2) { ret_value = false; } // Implementation limitation
          else if (size_in_bits >= 256 && UseAVX < 2) { ret_value = false; } // Implementation limitation
          break;

I wonder if there will be a fix for this issue, because this API is very important to our optimizations. The fromArray.patch is the workaround we are using. How to improve this workaround is also welcome.

2. anyTrue/allTrue on 512 bit
This is another intrinsic failure:
        case Op_VectorTest:
          if (UseAVX <= 0) { ret_value = false; }
          else if (size_in_bits != 128 && size_in_bits != 256) { ret_value = false; } // Implementation limitation
          break;
This also blocked some of our 512 bit optimizations, but I have no workaround for this now.

Please share with me your advice, thanks!

Regards,
Zhuo