RFR 8078563 - add profitability tests for reductions

[Christian Thalinger]

I think this looks good but as I said I’m not an expert in this area.  It would be good to have an additional reviewer.

> On Apr 29, 2015, at 10:23 AM, Berg, Michael C <michael.c.berg at intel.com> wrote:
> 
> Christian, do you have any additional comments or does the code look ok?
>  
> Thanks,
> Michael
>  
> From: Christian Thalinger [mailto:christian.thalinger at oracle.com] 
> Sent: Monday, April 27, 2015 9:49 AM
> To: Berg, Michael C
> Cc: hotspot-compiler-dev at openjdk.java.net
> Subject: Re: RFR 8078563 - add profitability tests for reductions
>  
> +       // Length 2 reductions of INT/LONG do not offer performance benefits
> +       if (((arith_type->basic_type() == T_INT) || (arith_type->basic_type() == T_LONG)) && (size == 2)) {
>  
> I don’t know that code very well but can there be reductions with size == 1?
>  
> On Apr 23, 2015, at 5:53 PM, Berg, Michael C <michael.c.berg at intel.com <mailto:michael.c.berg at intel.com>> wrote:
>  
> Hi Folks,
> 
> We (Intel) would like to add profitability tests to superword to gate scenarios where reduction optimization overhead is roughly equal to the benefit gained by vectorization.
> We would like to do this for all x86 enabled microarchitectures that support reductions and superword.  This new constraint was tested on SSE and AVX (1,2) enabled platforms.
> The contribution as referenced by RFR 8078563 is defined by the information at the links below.
> 
> Please review this bug entry and its code and comment as needed:
> 
> https://bugs.openjdk.java.net/browse/JDK-8078563 <https://bugs.openjdk.java.net/browse/JDK-8078563>
>  
> And its code and test addition (this is a small patch):
>  
> http://cr.openjdk.java.net/~kvn/8078563/webrev/ <http://cr.openjdk.java.net/~kvn/8078563/webrev/>
> 
> 
> Vladimir Koslov has offered to sponsor this patch.
>  
> Thanks,
> Michael
>  

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/attachments/20150429/1a4f6440/attachment.html>