[LLVMdev] RE : Is there any llvm neon intrinsic that maps to vmla.f32 instruction ?

[Sebastien DELDON-GNB]

Hi Renato,

No I've used LNT before and it might not be as simple as you think to get it working here. I'll see what I can do, but It's unlikely I'll have much time to spend on this topic in the coming weeks.

I'm more interested coming back to my original question, and would like to know how to proceed if I want to define my own LLVM intrinsic to generate VMLA instruction. My goal is not to get my work committed to LLVM trunk and thus pollute community work with intrinsics that are only useful  to me.

Thanks for your answer
Best Regards
Seb

From: Renato Golin [mailto:renato.golin at linaro.org]
Sent: Friday, February 15, 2013 5:17 PM
To: Sebastien DELDON-GNB
Cc: Lang Hames; llvmdev at cs.uiuc.edu
Subject: Re: [LLVMdev] RE : Is there any llvm neon intrinsic that maps to vmla.f32 instruction ?

On 15 February 2013 16:00, Sebastien DELDON-GNB <sebastien.deldon at st.com<mailto:sebastien.deldon at st.com>> wrote:
to which I added -mattr=-vmlx-forwarding to disable vmlx forwarding for cortex-a9.
When I DISABLE vmlx forwarding I'm observing a 7% speed-up on ref dataset for MILC. So I'm observing something similar to what I've observed on STE platform available on SNOWBALL board.

Hi Seb,

Thanks for doing this, as we expected, it's a general A9 issue. Ok, now we need to get the LNT going. Have you ever done that? It's quite simple.

Just follow this guide:
http://llvm.org/docs/lnt/quickstart.html

Optionally, compile LLVM+Clang and use the attached run.sh file to run the LNT (changing the paths accordingly).

That should take a few hours and, if you have the Perf server running, will allow you to run it twice (with and without vmlx) and compare the results.

cheers,
--renato
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