RFR: 8277843: [Vector API] scalar2vector generates incorrect type info for mask operations if Op_MaskAll is unavailable [v2]

[Jie Fu]

> Hi all,
> 
> This bug was first observed on x86_32/AVX512.
> It caused 62 vector api test failures.
> 
> ==============================
> Test summary
> ==============================
>    TEST                                              TOTAL  PASS  FAIL ERROR
>>> jtreg:test/jdk/jdk/incubator/vector                  74    12    62     0 <<
> ==============================
> 
> 
> You can easily reproduce this bug on an AVX512 machine with x86_32.
> Or you can also reproduce it on an AVX512 machine with x86_64 if you disable `Op_MaskAll` like this.
> 
> diff --git a/src/hotspot/cpu/x86/x86.ad b/src/hotspot/cpu/x86/x86.ad
> index 3f6d5a44b0d..d5a751b310d 100644
> --- a/src/hotspot/cpu/x86/x86.ad
> +++ b/src/hotspot/cpu/x86/x86.ad
> @@ -1819,6 +1819,7 @@ const bool Matcher::match_rule_supported_vector(int opcode, int vlen, BasicType
>        }
>        break;
>      case Op_MaskAll:
> +      return false;
>        if (!is_LP64 || !VM_Version::supports_evex()) {
>          return false;
>        }
> 
> 
> The failure reason is that `VectorNode::scalar2vector` generate incorrect IR for mask operations if `Op_MaskAll` is unavailable.
> So it shouldn't be used for mask operations if `Op_MaskAll` is unavailable.
> 
> Testing (with two more bug fixes https://github.com/openjdk/jdk/pull/6535 and https://github.com/openjdk/jdk/pull/6533):
>  - vector api tests on {x86_64, x86_32}/{AVX512, AVX256}, all passed
>  - vector api tests on aarch64, all passed
> 
> Thanks.
> Best regards,
> Jie

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

  Address review comments

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6562/files
  - new: https://git.openjdk.java.net/jdk/pull/6562/files/35c908b8..3772300b

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6562&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6562&range=00-01

  Stats: 17 lines in 2 files changed: 2 ins; 13 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6562.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6562/head:pull/6562

PR: https://git.openjdk.java.net/jdk/pull/6562