[15] RFR (M): 8237581: Improve allocation expansion

[Nils Eliasson]

Hi,

I split the patch into two parts for easier review:

Refactoring:

http://cr.openjdk.java.net/~neliasso/8237581/webrev.refactor/

The actual change (on top of the refactoring)

http://cr.openjdk.java.net/~neliasso/8237581/webrev.change/


Best regards,
Nils Eliasson

On 2020-01-24 09:36, Nils Eliasson wrote:
> Hi,
>
> This patch improves expand_allocate_common when there is no use of the 
> allocation.
>
> Three cases are improved:
>
> - With unknown allocation length - don't expand the fast path. No 
> allocation is needed when it isn't used. NegativeArraySizeException 
> will still be caught by the slowpath.
> - With known length inside the legal range - No fast path or slow path 
> is needed. The allocation node is removed.
> - With known length outside the legal range - only a slow path is needed.
>
> I also refactored the code a bit, keeping the general structure for 
> easy diff, but extracting some routines too make it more readable.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8237581
> Webrev: http://cr.openjdk.java.net/~neliasso/8237581/webrev.03/
>
> Please review!
>
> Best regards,
> Nils Eliasson
>
>