RFR: 8278584: compiler/vectorapi/VectorMaskLoadStoreTest.java failed with "Error: ShouldNotReachHere()" [v2]

[Jie Fu]

> Hi all,
> 
> I'd like to fix the vector_length_encoding error in `long_to_maskLE8_avx` and `long_to_maskGT8_avx`.
> Since the input parameter of `vector_length_encoding` [1] is the number of vector bytes (not number of vector bits), I believe we shouldn't `mask_len*8` [2][3].
> 
> The patch also removes an useless statement [4].
> 
> Testing:
>    - vector api tests on Linux/x64-{AVX512, AVX2}
> 
> Thanks.
> Best regards,
> Jie
> 
> [1] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/x86/x86.ad#L1219
> [2] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/x86/x86.ad#L9552
> [3] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/x86/x86.ad#L9568
> [4] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/x86/x86.ad#L9580

Jie Fu has updated the pull request incrementally with one additional commit since the last revision:

  Add a jtreg test

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6808/files
  - new: https://git.openjdk.java.net/jdk/pull/6808/files/ecb8e76a..e3cabbac

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6808&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6808&range=00-01

  Stats: 216 lines in 1 file changed: 216 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6808.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6808/head:pull/6808

PR: https://git.openjdk.java.net/jdk/pull/6808