[vector] RFR: Unify VectorMaskCmp shape between x86 and aarch64

[Paul Sandoz]

Looks ok to me, I don’t quite feel qualified to review the aarch64 changes, but I checked for similar matching patterns in x86.ad.

Paul.

> On Apr 7, 2020, at 6:38 AM, Vladimir Ivanov <vladimir.x.ivanov at oracle.com> wrote:
> 
> http://cr.openjdk.java.net/~vlivanov/panama/vector/vcmp/webrev.00/
> 
> Get rid of platform-specific differences in VectorMaskCmp.
> 
> Testing: jdk/incubator/vector tests
> 
> The patch is against vectorIntrinsics branch.
> 
> Best regards,
> Vladimir Ivanov