[vectorIntrinsics] RFR: 8282389: Add new vector operations to count leading and trailing zeros.

[Xiaohong Gong]

On Fri, 25 Feb 2022 18:59:34 GMT, Swati Sharma <duke at openjdk.java.net> wrote:

> Hi All,
> 
> Added support for new vector operations CLZ (count number of leading zeros) and CTZ (could number of trailing zeros) for all the integral vector types(Byte/Short/Integer/Long).
> Added validation and performance tests corresponding the these operations in existing VectorAPI JTREG/JMH suite.
> 
> Kindly review and share your feedback.
> 
> Thanks and Regards,
> Swati Sharma
> Intel

Could you please update the copyright year to "2022" for all the modified files? Thanks!

src/hotspot/share/prims/vectorSupport.hpp line 59:

> 57:     VECTOR_OP_BIT_COUNT = 3,
> 58:     VECTOR_OP_CTZ     = 29,
> 59:     VECTOR_OP_CLZ     = 30,

Seems weird, could you please either move these two to the end of this enum or set the number to "4, 5"?

src/jdk.incubator.vector/share/classes/jdk/incubator/vector/ByteVector.java line 1798:

> 1796: 
> 1797:     static int numberOfTrailingZeros(byte a) {
> 1798:         return a != 0 ? Integer.numberOfTrailingZeros(a) : 8;

Integer.numberOfTrailingZeros((int)a & 0xFF) ?

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PR: https://git.openjdk.java.net/panama-vector/pull/176