RFR(S): 8223138: Small clean-up in loop-tree support.

[Vladimir Ivanov]

Looks good.

Small nit: I find original version of IdealLoopTree::tail() easier to 
read. What do you think about the folloing?

inline Node* IdealLoopTree::tail() {
   // Handle lazy update of _tail field
   if (_tail->in(0) == NULL) {
     _tail = _phase->get_ctrl(n);
   }
   return _tail;
}

Best regards,
Vladimir Ivanov

On 30/04/2019 07:09, Patric Hedlin wrote:
> Dear all,
> 
> I would like to ask for help to review the following change/update:
> 
> Issue:  https://bugs.openjdk.java.net/browse/JDK-8223138
> Webrev: http://cr.openjdk.java.net/~phedlin/tr8223138/
> 
> 8223138: Small clean-up in loop-tree support.
> 
>      Rename predicate 'is_inner()' to 'is_innermost()' to be accurate.
>      Add 'is_root()' predicate for root parent test in loop-tree.
>      Change definition of 'is_loop()' to always lazy-read the tail,
>      since it should never be NULL. Clean-up of 'tail()' definition.
> 
> 
> Testing: Part of 8216137 (hs-tier1..4, hs-precheckin-comp, Kitchensink24h)
> 
> 
> Best regards,
> Patric
>