[15] RFR (L) 8235825: C2: Merge AD instructions for Replicate nodes

[John Rose]

Reviewed again.  It reads well.  I agree about future steps.  — John

On Dec 16, 2019, at 2:29 PM, Vladimir Ivanov <vladimir.x.ivanov at oracle.com> wrote:
> 
> Updated version:
>  http://cr.openjdk.java.net/~vlivanov/jbhateja/8235825/webrev.02/ <http://cr.openjdk.java.net/~vlivanov/jbhateja/8235825/webrev.02/>
> 
> What's changed:
>  * Added more comments
>  * Fixed missing cases (Repl4B_imm() and Repl8B_imm)
>    * Double-checked that there are no other missing cases left:
> http://cr.openjdk.java.net/~vlivanov/jbhateja/8235825/webrev.02/repl.txt <http://cr.openjdk.java.net/~vlivanov/jbhateja/8235825/webrev.02/repl.txt>