RFR(XS): 8228367: [lworld] Constant, null-free inline type fields should be treated as flattenable

[Remi Forax]

Hi Tobias,
this seems wrong to me, it's the tail wagging the dog.

The scalarization has nothing to do with the fact of being flattenable or not,
the flattenability is a storage property so for value in fields or array elements, not for value on the stack.

Being a null-free inline type is enough, you do not have to check if the fields are flattenable or not.

Rémi

----- Mail original -----
> De: "Tobias Hartmann" <tobias.hartmann at oracle.com>
> À: "valhalla-dev" <valhalla-dev at openjdk.java.net>
> Envoyé: Jeudi 18 Juillet 2019 14:26:11
> Objet: RFR(XS): 8228367: [lworld] Constant, null-free inline type fields should be treated as flattenable

> Hi,
> 
> please review the following patch:
> https://bugs.openjdk.java.net/browse/JDK-8228367
> http://cr.openjdk.java.net/~thartmann/8228367/webrev.00/
> 
> When loading a constant, null-free inline type field from an inline type, we
> should treat that field
> as flattenable (even if it is not declared as flattenable) to trigger
> scalarization.
> 
> I also had to remove the assert in ValueTypeNode::pass_fields because it is too
> strong.
> 
> Thanks,
> Tobias