RFR: 8283232: x86: Improve vector broadcast operations [v2]

[Jatin Bhateja]

On Wed, 16 Mar 2022 15:56:44 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

> > Hi, forwarding results within the same bypass domain does not result in delay, data bypass delay happens when the data crosses different domains, according to "Intel® 64 and IA-32 Architectures Optimization Reference Manual"
> > > When a source of a micro-op executed in one stack comes from a micro-op executed in another stack, a delay can occur. The delay occurs also for transitions between Intel SSE integer and Intel SSE floating-point operations. In some of the cases, the data transition is done using a micro-op that is added to the instruction flow.
> > 
> > 
> > The manual mentions the guideline at section 3.5.2.2
> > ![image](https://user-images.githubusercontent.com/49088128/158618209-c0674ba7-1c93-4014-a7e1-330f4e5846da.png)
> > Thanks.
> 
> Thanks meant to refer to above text. I have removed incorrect reference.

It will still be good if we can come up with a micro benchmark, that shows the gain with the patch.

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PR: https://git.openjdk.java.net/jdk/pull/7832