8230015: [instruction selector] generic vector operands support.

[Bhateja, Jatin]

Hi Vivek,

Please find below the CR link for submit-repo testing.

http://cr.openjdk.java.net/~jbhateja/genericVectorOperands/webrev.01/

Thanks,
Jatin

> -----Original Message-----
> From: Deshpande, Vivek R
> Sent: Saturday, August 31, 2019 3:55 AM
> To: Bhateja, Jatin <jatin.bhateja at intel.com>; Yang Zhang (Arm Technology
> China) <Yang.Zhang at arm.com>; hotspot-compiler-dev at openjdk.java.net
> Cc: Vladimir Kozlov <vladimir.kozlov at oracle.com>
> Subject: RE: 8230015: [instruction selector] generic vector operands support.
> 
> Hi Jatin,
> 
> Could you please give me the updated patch with #ifdefs and I can submit it
> to submit-repo for testing.
> 
> Regards,
> Vivek
> 
> -----Original Message-----
> From: hotspot-compiler-dev [mailto:hotspot-compiler-dev-
> bounces at openjdk.java.net] On Behalf Of Bhateja, Jatin
> Sent: Wednesday, August 28, 2019 2:45 AM
> To: Yang Zhang (Arm Technology China) <Yang.Zhang at arm.com>; hotspot-
> compiler-dev at openjdk.java.net
> Cc: Vladimir Kozlov <vladimir.kozlov at oracle.com>
> Subject: RE: 8230015: [instruction selector] generic vector operands support.
> 
> 
> Hi Yang,
> 
> Thanks for your response.
> 
> We are also working over the idea of moving out the operator (uOp and
> bOp) into a separate ideal node, but that will need changes in shape of ideal
> graph.
> 
> Generic operands is another level of optimization which will complement
> "aggressive optimization".
> In addition, it will also reduce the number of checks for different vector
> operand type (vecS, vecD, vecX, vecY, vecZ and their legacy variants) within
> ADLC generate DFA used while matching,  since there will only be two vector
> operands (vecG and legVecG) now.
> 
> Current patch enables this support only for x86 target, to get a feedback
> from community.
> 
> Best Regards,
> Jatin
> 
> 
> > -----Original Message-----
> > From: Yang Zhang (Arm Technology China) <Yang.Zhang at arm.com>
> > Sent: Wednesday, August 28, 2019 2:49 PM
> > To: Bhateja, Jatin <jatin.bhateja at intel.com>; hotspot-compiler-
> > dev at openjdk.java.net
> > Cc: Vladimir Kozlov <vladimir.kozlov at oracle.com>
> > Subject: RE: 8230015: [instruction selector] generic vector operands
> support.
> >
> > Hi Jatin
> >
> > The question how to reduce code size is discussed previously. I also
> > create a JBS to track it under panama project.
> > https://bugs.openjdk.java.net/browse/JDK-8229866
> > There is a more aggressive idea.
> > http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2019-
> > April/033362.html
> >
> > Using the idea of generic vector operands, I implement an example
> > (vaddB/S/I) in AArch64 platform. The code size reduction in libjvm.so
> > is ~30kb. If all the vector instructions are merged, the estimated
> > size reduction will be ~300kb.
> >
> > How about using a more aggressive way to reduce code size?
> >
> > PS. When I test this patch in AArch64 platform, build fails with the
> > log undefined reference to
> > `Matcher::do_post_selection_processing(Compile*,
> > Node*)'.
> > I fix this failure by adding #ifdef X86 to these code.
> >
> > Regards
> > Yang
> >
> > -----Original Message-----
> > From: hotspot-compiler-dev <hotspot-compiler-dev-
> > bounces at openjdk.java.net> On Behalf Of Bhateja, Jatin
> > Sent: Thursday, August 22, 2019 2:50 PM
> > To: hotspot-compiler-dev at openjdk.java.net
> > Cc: Vladimir Kozlov <vladimir.kozlov at oracle.com>
> > Subject: 8230015: [instruction selector] generic vector operands support.
> >
> > Hi All,
> >
> > Please find below a patch for generic vector operands[1] support
> > during instruction selection.
> >
> > Motivation behind the patch is to reduce the number of vector
> > selection patterns whose operands meagerly differ in vector lengths.
> > This will not only result in lesser code being generated by ADLC which
> > effectively translates to size reduction in libjvm.so but also help in
> > better maintenance of AD files.
> >
> > Using generic operands we were able to collapse multiple vector
> > patterns over mainline
> >              Initial number of vector instruction patterns (vec[XYZSD] +
> > legVec[ZXYSD]   :  510
> >              Reduced vector instruction patterns  (vecG + legVecG)
> > :  222
> >
> > With this we could see around 1MB size reduction in libjvm.so.
> >
> > In order to have minimal impact over downstream compiler passes, a
> > post- selection pass has been introduced (currently enabled only for
> > X86 target) which replaces these generic operands with their
> > corresponding concreter vector length variants.
> >
> > JBS      : https://bugs.openjdk.java.net/browse/JDK-8230015
> > Patch  :
> > http://cr.openjdk.java.net/~jbhateja/genericVectorOperands/webrev.00/
> >
> > Kindly review and share your feedback.
> >
> > Best Regards,
> > Jatin Bhateja
> >
> > [1]
> > http://cr.openjdk.java.net/~jbhateja/genericVectorOperands/generic_ope
> > ra
> > nds_support_v1.0.pdf
> >
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