RFR(S): 8154943: AArch64: redundant address computation instructions with vectorization

[Roland Westrelin]

> node.cpp change is good.
> 
> compile.cpp I understand when you replace "similar" (same in(1)) node
> with it but it is not clear that you also processing users (whole
> following chain) to remove similar nodes. Add comment.
> I think the check "!(k->Opcode() == Op_ConvI2L || ... " (and use
> 'continue' instead of 'break') should be done when you push a node on
> the list wq.push(u).

Thanks for the review, Vladimir. What about this?

http://cr.openjdk.java.net/~roland/8154943/webrev.01/

Roland.