RFR (S) 8135033: C1 should fast-path Object.class.isInstance(obj) to true

[Igor Veresov]

Looks good to me.

igor

> On Sep 3, 2015, at 2:07 PM, Aleksey Shipilev <aleksey.shipilev at oracle.com> wrote:
> 
> Hi,
> 
> Continuing on VarHandles saga, more C1 quirks show up. Let's fix a
> simple one: Object.class.isInstance(obj) should fold to "true". C2
> handles this well, but not C1 (this is further exacerbated when tiered
> policy decides Class.cast-holding method is trivial):
>  https://bugs.openjdk.java.net/browse/JDK-8135033
> 
> Patch:
>  http://cr.openjdk.java.net/~shade/8135033/webrev.00/
> 
> Testing:
>  * JPRT
>  * Targeted microbenchmarks, eyeballing assembly
> 
> Thanks,
> -Aleksey
>