RE: [Patch,tree-optimization]: Add new path Splitting pass on tree ssa representation

[Ajit Kumar Agarwal <ajit.kumar.agarwal@xilinx.com>]

-----Original Message-----
From: Jeff Law [mailto:law@redhat.com] 
Sent: Wednesday, January 27, 2016 12:48 PM
To: Ajit Kumar Agarwal; Richard Biener
Cc: GCC Patches; Vinod Kathail; Shail Aditya Gupta; Vidhumouli Hunsigida; Nagaraju Mekala
Subject: Re: [Patch,tree-optimization]: Add new path Splitting pass on tree ssa representation

On 01/18/2016 11:27 AM, Ajit Kumar Agarwal wrote:

>>
>> Ajit, can you confirm which of adpcm_code or adpcm_decode where path 
>> splitting is showing a gain?  I suspect it's the former but would 
>> like to make sure so that I can adjust the heuristics properly.
>>> I'd still like to have this answered when you can Ajit, just to be 
>>> 100% that it's the path splitting in adpcm_code that's responsible 
>>> for the improvements you're seeing in adpcm.
>
> The adpcm_coder get optimized with path splitting whereas the 
> adpcm_decoder is not optimized further with path splitting. In 
> adpcm_decoder the join node is duplicated into its predecessors and 
> with the duplication of join node the code is not optimized further.
>>Right.  Just wanted to make sure my analysis corresponded with what you were seeing in your benchmarking -- and it does.

>>I suspect that if we looked at this problem from the angle of isolating paths based on how constant PHI arguments feed into and allow simplifications in later blocks that we might get >>better long term results -- including improving adpcm_decoder which has the same idiom as adpcm_coder -- it's just in the wrong spot in the CFG.
>>But that's obviously gcc-7 material.

Can I look into it.

Thanks & Regards
Ajit

Jeff