[LLVMdev] [RFC][PATCH] Adding absd/hadd/sad intrinsics

[Shahid, Asghar-ahmad]

Hi Devs,

Pinging..., as didn't get any response yet. Or shall I assume it is acceptable to all?

Regards,
Shahid

> -----Original Message-----
> From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu]
> On Behalf Of Shahid, Asghar-ahmad
> Sent: Friday, May 01, 2015 10:29 PM
> To: llvmdev at cs.uiuc.edu
> Subject: [LLVMdev] [RFC][PATCH] Adding absd/hadd/sad intrinsics
> 
> Hi All,
> 
> I would like to introduce intrinsics to generate efficient codes for 'absolute
> differences', 'horizontal add'
> and 'sum of absolute differences' Idioms used by user programs.
> 
> Identifying these idioms at lower level (Codegen) is complex. These idioms
> can be identified in LV/SLP and vectorized using above intrinsics to generate
> better code.
> 
> Proposal:
> 1. Add intrinsics for 'absolute differences', 'horizontal add' and 'sum of
> absolute differences' having variants of Fixed / floating point data types and
> signed/unsigned operations.
> 2. Recognize these idioms at loop vectorizer or SLP and replace with
> corresponding intrinsics based on the target's Backend support.
> 
> Having these intrinsic will also help in cost modeling for these idioms which is
> complex down the lane.
> 
> Pls find attached a patch regarding this which is incomplete & dirty at this
> moment, however, it may help in this discussion.
> 
> Regards,
> Shahid
>