RFR: 8184914: Use MacroAssembler::cmpoop() consistently when comparing heap objects

[coleen.phillimore at oracle.com]

This looks reasonable to me.  Maybe the compiler group should review the 
c1 part.  I changed the mailing list to hotspot-dev.
I can sponsor this for you.
Thanks,
Coleen

On 10/17/17 4:22 PM, Roman Kennke wrote:
> (Not sure if this is the correct list to ask.. if not, please let me 
> know and/or redirect me)
>
> Currently, cmpoop() is only declared for 32-bit x86, and only used in 
> 2 places in C1 to compare oops. In other places, oops are compared 
> using cmpptr(). It would be useful to distinguish normal pointer 
> comparisons from heap object comparisons, and use cmpoop() 
> consistently for heap object comparisons. This would remove clutter in 
> several places where we have #ifdef _LP64 around comparisons, and 
> would also allow to insert necessary barriers for GCs that need them 
> (e.g. Shenandoah) later.
>
> http://cr.openjdk.java.net/~rkennke/8184914/webrev.00/ 
> <http://cr.openjdk.java.net/%7Erkennke/8184914/webrev.00/>
>
> Tested by running hotspot_gc jtreg tests.
>
> Can I get a review please?
>
> Thanks, Roman
>
>