RFR 8220701 [lworld] Remove ValueArrayFlatten command line flag

[David Simms]

globals.hpp: "<0 no limit", maybe add "==0 disabled".

Looks good !

/D

On 18/03/2019 10:34 PM, Ioi Lam wrote:
> https://bugs.openjdk.java.net/browse/JDK-8220701
> http://cr.openjdk.java.net/~iklam/valhalla/8220701-remove-ValueArrayFlatten-flag.v01/ 
>
>
> In the test cases, I've replaced all occurrence of
>
>    -XX:+ValueArrayFlatten -> -XX:ValueArrayElemMaxFlatSize=-1
>    -XX:-ValueArrayFlatten -> -XX:ValueArrayElemMaxFlatSize=0
>
> In the VM code, I just replaced ValueArrayFlatten with an #ifdef for now,
>
>     #define ValueArrayFlatten (EnableValhalla && 
> (ValueArrayElemMaxFlatSize != 0))
>
> ... because the affected VM code is likely to be changed soon by [1], or
> the follow-up fixes in C1/C2 to support [1].
>
> Also, some of the compiler tests probably need to be updated after [1],
> as C1 (and I think C2 as well) can't really distinguish between 3 
> types of
> arrays (pojo, non-nullable/non-flattened, non-nullable/flattened).
>
> Testing: Passed all tests under
>
>     test/hotspot/jtreg/compiler/valhalla
>     test/hotspot/jtreg/runtime/valhalla
>     test/jdk/valhalla
>
>
> Thanks
> - Ioi
>
> ---------
>
> [1] https://bugs.openjdk.java.net/browse/JDK-8220790
>     [lworld][lw2] improve support for value arrays
>