RFR (S) 8150669: C1 intrinsic for Class.isPrimitive

[Aleksey Shipilev]

Hi Vladimir,

Fixed all your findings in a new webrev:
  http://cr.openjdk.java.net/~shade/8150669/webrev.03/

Passes JPRT -testset hotspot; microbenchmarks; new test.

On 03/01/2016 01:07 PM, Vladimir Ivanov wrote:
> I have a general question: why did you decide to intrinsify the method
> into a native call? Class::is_primitive looks pretty trivial to
> translate it right into machine code:
>   bool java_lang_Class::is_primitive(oop java_class) {
>     bool is_primitive = (java_class->metadata_field(_klass_offset) ==
> NULL);
> ...
>     return is_primitive;
>   }

Yeah, previous version was just a stripped-down isInstance intrinsic
code. But you are right, we can just read class data without messing
with runtime calls, which improves performance even without canonicalizing:
  http://cr.openjdk.java.net/~shade/8150669/notes.txt

Cheers,
-Aleksey


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